[V2,0/1] tools/dtrace: initial implementation of DTrace

Message ID	201907101542.x6AFgOO9012232@userv0121.oracle.com
State	Rejected
Delegated to:	BPF Maintainers
Headers	show Return-Path: <bpf-owner@vger.kernel.org> Message-Id: <201907101542.x6AFgOO9012232@userv0121.oracle.com> MIME-Version: 1.0 Date: Wed, 10 Jul 2019 08:42:24 -0700 (PDT) From: Kris Van Hees <kris.van.hees@oracle.com> To: netdev@vger.kernel.org, bpf@vger.kernel.org, dtrace-devel@oss.oracle.com, linux-kernel@vger.kernel.org Cc: rostedt@goodmis.org, mhiramat@kernel.org, acme@kernel.org, ast@kernel.org, daniel@iogearbox.net, Peter Zijlstra <peterz@infradead.org>, Chris Mason <clm@fb.com> Subject: [PATCH V2 0/1] tools/dtrace: initial implementation of DTrace In-Reply-To: <201907101537.x6AFboMR015946@aserv0122.oracle.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Sender: bpf-owner@vger.kernel.org Precedence: bulk

This patch's subject should of course be [PATCH V2 1/1] rather than 0/1. Sorry about that. On Wed, Jul 10, 2019 at 08:42:24AM -0700, Kris Van Hees wrote: > This initial implementation of a tiny subset of DTrace functionality > provides the following options: > > dtrace [-lvV] [-b bufsz] -s script > -b set trace buffer size > -l list probes (only works with '-s script' for now) > -s enable or list probes for the specified BPF program > -V report DTrace API version > > The patch comprises quite a bit of code due to DTrace requiring a few > crucial components, even in its most basic form. > > The code is structured around the command line interface implemented in > dtrace.c. It provides option parsing and drives the three modes of > operation that are currently implemented: > > 1. Report DTrace API version information. > Report the version information and terminate. > > 2. List probes in BPF programs. > Initialize the list of probes that DTrace recognizes, load BPF > programs, parse all BPF ELF section names, resolve them into > known probes, and emit the probe names. Then terminate. > > 3. Load BPF programs and collect tracing data. > Initialize the list of probes that DTrace recognizes, load BPF > programs and attach them to their corresponding probes, set up > perf event output buffers, and start processing tracing data. > > This implementation makes extensive use of BPF (handled by dt_bpf.c) and > the perf event output ring buffer (handled by dt_buffer.c). DTrace-style > probe handling (dt_probe.c) offers an interface to probes that hides the > implementation details of the individual probe types by provider (dt_fbt.c > and dt_syscall.c). Probe lookup by name uses a hashtable implementation > (dt_hash.c). The dt_utils.c code populates a list of online CPU ids, so > we know what CPUs we can obtain tracing data from. > > Building the tool is trivial because its only dependency (libbpf) is in > the kernel tree under tools/lib/bpf. A simple 'make' in the tools/dtrace > directory suffices. > > The 'dtrace' executable needs to run as root because BPF programs cannot > be loaded by non-root users. > > Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com> > Reviewed-by: David Mc Lean <david.mclean@oracle.com> > Reviewed-by: Eugene Loh <eugene.loh@oracle.com> > --- > Changes in v2: > - Use ring_buffer_read_head() and ring_buffer_write_tail() to > avoid use of volatile. > - Handle perf events that wrap around the ring buffer boundary. > - Remove unnecessary PERF_EVENT_IOC_ENABLE. > - Remove -I$(srctree)/tools/perf from KBUILD_HOSTCFLAGS since it > is not actually used. > - Use PT_REGS_PARM1(x), etc instead of my own macros. Adding > PT_REGS_PARM6(x) in bpf_sample.c because we need to be able to > support up to 6 arguments passed by registers. > --- > MAINTAINERS | 6 + > tools/dtrace/Makefile | 87 ++++++++++ > tools/dtrace/bpf_sample.c | 146 ++++++++++++++++ > tools/dtrace/dt_bpf.c | 185 ++++++++++++++++++++ > tools/dtrace/dt_buffer.c | 338 +++++++++++++++++++++++++++++++++++++ > tools/dtrace/dt_fbt.c | 201 ++++++++++++++++++++++ > tools/dtrace/dt_hash.c | 211 +++++++++++++++++++++++ > tools/dtrace/dt_probe.c | 230 +++++++++++++++++++++++++ > tools/dtrace/dt_syscall.c | 179 ++++++++++++++++++++ > tools/dtrace/dt_utils.c | 132 +++++++++++++++ > tools/dtrace/dtrace.c | 249 +++++++++++++++++++++++++++ > tools/dtrace/dtrace.h | 13 ++ > tools/dtrace/dtrace_impl.h | 101 +++++++++++ > 13 files changed, 2078 insertions(+) > create mode 100644 tools/dtrace/Makefile > create mode 100644 tools/dtrace/bpf_sample.c > create mode 100644 tools/dtrace/dt_bpf.c > create mode 100644 tools/dtrace/dt_buffer.c > create mode 100644 tools/dtrace/dt_fbt.c > create mode 100644 tools/dtrace/dt_hash.c > create mode 100644 tools/dtrace/dt_probe.c > create mode 100644 tools/dtrace/dt_syscall.c > create mode 100644 tools/dtrace/dt_utils.c > create mode 100644 tools/dtrace/dtrace.c > create mode 100644 tools/dtrace/dtrace.h > create mode 100644 tools/dtrace/dtrace_impl.h > > diff --git a/MAINTAINERS b/MAINTAINERS > index cfa9ed89c031..410240732d55 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -5485,6 +5485,12 @@ W: https://linuxtv.org > S: Odd Fixes > F: drivers/media/pci/dt3155/ > > +DTRACE > +M: Kris Van Hees <kris.van.hees@oracle.com> > +L: dtrace-devel@oss.oracle.com > +S: Maintained > +F: tools/dtrace/ > + > DVB_USB_AF9015 MEDIA DRIVER > M: Antti Palosaari <crope@iki.fi> > L: linux-media@vger.kernel.org > diff --git a/tools/dtrace/Makefile b/tools/dtrace/Makefile > new file mode 100644 > index 000000000000..03ae498d1429 > --- /dev/null > +++ b/tools/dtrace/Makefile > @@ -0,0 +1,87 @@ > +# SPDX-License-Identifier: GPL-2.0 > +# > +# This Makefile is based on samples/bpf. > +# > +# Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. > + > +DT_VERSION := 2.0.0 > +DT_GIT_VERSION := $(shell git rev-parse HEAD 2>/dev/null || \ > + echo Unknown) > + > +DTRACE_PATH ?= $(abspath $(srctree)/$(src)) > +TOOLS_PATH := $(DTRACE_PATH)/.. > +SAMPLES_PATH := $(DTRACE_PATH)/../../samples > + > +hostprogs-y := dtrace > + > +LIBBPF := $(TOOLS_PATH)/lib/bpf/libbpf.a > +OBJS := dt_bpf.o dt_buffer.o dt_utils.o dt_probe.o \ > + dt_hash.o \ > + dt_fbt.o dt_syscall.o > + > +dtrace-objs := $(OBJS) dtrace.o > + > +always := $(hostprogs-y) > +always += bpf_sample.o > + > +KBUILD_HOSTCFLAGS += -DDT_VERSION=\"$(DT_VERSION)\" > +KBUILD_HOSTCFLAGS += -DDT_GIT_VERSION=\"$(DT_GIT_VERSION)\" > +KBUILD_HOSTCFLAGS += -I$(srctree)/tools/lib > +KBUILD_HOSTCFLAGS += -I$(srctree)/tools/include/uapi > +KBUILD_HOSTCFLAGS += -I$(srctree)/tools/include/ > +KBUILD_HOSTCFLAGS += -I$(srctree)/usr/include > + > +KBUILD_HOSTLDLIBS := $(LIBBPF) -lelf > + > +LLC ?= llc > +CLANG ?= clang > +LLVM_OBJCOPY ?= llvm-objcopy > + > +ifdef CROSS_COMPILE > +HOSTCC = $(CROSS_COMPILE)gcc > +CLANG_ARCH_ARGS = -target $(ARCH) > +endif > + > +all: > + $(MAKE) -C ../../ $(CURDIR)/ DTRACE_PATH=$(CURDIR) > + > +clean: > + $(MAKE) -C ../../ M=$(CURDIR) clean > + @rm -f *~ > + > +$(LIBBPF): FORCE > + $(MAKE) -C $(dir $@) RM='rm -rf' LDFLAGS= srctree=$(DTRACE_PATH)/../../ O= > + > +FORCE: > + > +.PHONY: verify_cmds verify_target_bpf $(CLANG) $(LLC) > + > +verify_cmds: $(CLANG) $(LLC) > + @for TOOL in $^ ; do \ > + if ! (which -- "$${TOOL}" > /dev/null 2>&1); then \ > + echo "*** ERROR: Cannot find LLVM tool $${TOOL}" ;\ > + exit 1; \ > + else true; fi; \ > + done > + > +verify_target_bpf: verify_cmds > + @if ! (${LLC} -march=bpf -mattr=help > /dev/null 2>&1); then \ > + echo "*** ERROR: LLVM (${LLC}) does not support 'bpf' target" ;\ > + echo " NOTICE: LLVM version >= 3.7.1 required" ;\ > + exit 2; \ > + else true; fi > + > +$(DTRACE_PATH)/*.c: verify_target_bpf $(LIBBPF) > +$(src)/*.c: verify_target_bpf $(LIBBPF) > + > +$(obj)/%.o: $(src)/%.c > + @echo " CLANG-bpf " $@ > + $(Q)$(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) -I$(obj) \ > + -I$(srctree)/tools/testing/selftests/bpf/ \ > + -D__KERNEL__ -D__BPF_TRACING__ -Wno-unused-value -Wno-pointer-sign \ > + -D__TARGET_ARCH_$(ARCH) -Wno-compare-distinct-pointer-types \ > + -Wno-gnu-variable-sized-type-not-at-end \ > + -Wno-address-of-packed-member -Wno-tautological-compare \ > + -Wno-unknown-warning-option $(CLANG_ARCH_ARGS) \ > + -I$(srctree)/samples/bpf/ -include asm_goto_workaround.h \ > + -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf $(LLC_FLAGS) -filetype=obj -o $@ > diff --git a/tools/dtrace/bpf_sample.c b/tools/dtrace/bpf_sample.c > new file mode 100644 > index 000000000000..9862f75f92d3 > --- /dev/null > +++ b/tools/dtrace/bpf_sample.c > @@ -0,0 +1,146 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * This sample DTrace BPF tracing program demonstrates how actions can be > + * associated with different probe types. > + * > + * The kprobe/ksys_write probe is a Function Boundary Tracing (FBT) entry probe > + * on the ksys_write(fd, buf, count) function in the kernel. Arguments to the > + * function can be retrieved from the CPU registers (struct pt_regs). > + * > + * The tracepoint/syscalls/sys_enter_write probe is a System Call entry probe > + * for the write(d, buf, count) system call. Arguments to the system call can > + * be retrieved from the tracepoint data passed to the BPF program as context > + * struct syscall_data) when the probe fires. > + * > + * The BPF program associated with each probe prepares a DTrace BPF context > + * (struct dt_bpf_context) that stores the probe ID and up to 10 arguments. > + * Only 3 arguments are used in this sample. Then the prorgams call a shared > + * BPF function (bpf_action) that implements the actual action to be taken when > + * a probe fires. It prepares a data record to be stored in the tracing buffer > + * and submits it to the buffer. The data in the data record is obtained from > + * the DTrace BPF context. > + * > + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. > + */ > +#include <uapi/linux/bpf.h> > +#include <linux/ptrace.h> > +#include <linux/version.h> > +#include <uapi/linux/unistd.h> > +#include "bpf_helpers.h" > + > +#include "dtrace.h" > + > +struct syscall_data { > + struct pt_regs *regs; > + long syscall_nr; > + long arg[6]; > +}; > + > +struct bpf_map_def SEC("maps") buffers = { > + .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, > + .key_size = sizeof(u32), > + .value_size = sizeof(u32), > + .max_entries = NR_CPUS, > +}; > + > +#if defined(bpf_target_x86) > +# define PT_REGS_PARM6(x) ((x)->r9) > +#elif defined(bpf_target_s390x) > +# define PT_REGS_PARM6(x) ((x)->gprs[7]) > +#elif defined(bpf_target_arm) > +# define PT_REGS_PARM6(x) ((x)->uregs[5]) > +#elif defined(bpf_target_arm64) > +# define PT_REGS_PARM6(x) ((x)->regs[5]) > +#elif defined(bpf_target_mips) > +# define PT_REGS_PARM6(x) ((x)->regs[9]) > +#elif defined(bpf_target_powerpc) > +# define PT_REGS_PARM6(x) ((x)->gpr[8]) > +#elif defined(bpf_target_sparc) > +# define PT_REGS_PARM6(x) ((x)->u_regs[UREG_I5]) > +#else > +# error Argument retrieval from pt_regs is not supported yet on this arch. > +#endif > + > +/* > + * We must pass a valid BPF context pointer because the bpf_perf_event_output() > + * helper requires a BPF context pointer as first argument (and the verifier is > + * validating that we pass a value that is known to be a context pointer). > + * > + * This BPF function implements the following D action: > + * { > + * trace(curthread); > + * trace(arg0); > + * trace(arg1); > + * trace(arg2); > + * } > + * > + * Expected output will look like: > + * CPU ID > + * 15 70423 0xffff8c0968bf8ec0 0x00000000000001 0x0055e019eb3f60 0x0000000000002c > + * 15 18876 0xffff8c0968bf8ec0 0x00000000000001 0x0055e019eb3f60 0x0000000000002c > + * | | +-- curthread +--> arg0 (fd) +--> arg1 (buf) +-- arg2 (count) > + * | | > + * | +--> probe ID > + * | > + * +--> CPU the probe fired on > + */ > +static noinline int bpf_action(void *bpf_ctx, struct dt_bpf_context *ctx) > +{ > + int cpu = bpf_get_smp_processor_id(); > + struct data { > + u32 probe_id; /* mandatory */ > + > + u64 task; /* first data item (current task) */ > + u64 arg0; /* 2nd data item (arg0, fd) */ > + u64 arg1; /* 3rd data item (arg1, buf) */ > + u64 arg2; /* 4th data item (arg2, count) */ > + } rec; > + > + memset(&rec, 0, sizeof(rec)); > + > + rec.probe_id = ctx->probe_id; > + rec.task = bpf_get_current_task(); > + rec.arg0 = ctx->argv[0]; > + rec.arg1 = ctx->argv[1]; > + rec.arg2 = ctx->argv[2]; > + > + bpf_perf_event_output(bpf_ctx, &buffers, cpu, &rec, sizeof(rec)); > + > + return 0; > +} > + > +SEC("kprobe/ksys_write") > +int bpf_kprobe(struct pt_regs *regs) > +{ > + struct dt_bpf_context ctx; > + > + memset(&ctx, 0, sizeof(ctx)); > + > + ctx.probe_id = 18876; > + ctx.argv[0] = PT_REGS_PARM1(regs); > + ctx.argv[1] = PT_REGS_PARM2(regs); > + ctx.argv[2] = PT_REGS_PARM3(regs); > + ctx.argv[3] = PT_REGS_PARM4(regs); > + ctx.argv[4] = PT_REGS_PARM5(regs); > + ctx.argv[5] = PT_REGS_PARM6(regs); > + > + return bpf_action(regs, &ctx); > +} > + > +SEC("tracepoint/syscalls/sys_enter_write") > +int bpf_tp(struct syscall_data *scd) > +{ > + struct dt_bpf_context ctx; > + > + memset(&ctx, 0, sizeof(ctx)); > + > + ctx.probe_id = 70423; > + ctx.argv[0] = scd->arg[0]; > + ctx.argv[1] = scd->arg[1]; > + ctx.argv[2] = scd->arg[2]; > + > + return bpf_action(scd, &ctx); > +} > + > +char _license[] SEC("license") = "GPL"; > +u32 _version SEC("version") = LINUX_VERSION_CODE; > diff --git a/tools/dtrace/dt_bpf.c b/tools/dtrace/dt_bpf.c > new file mode 100644 > index 000000000000..78c90de016c6 > --- /dev/null > +++ b/tools/dtrace/dt_bpf.c > @@ -0,0 +1,185 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * This file provides the interface for handling BPF. It uses the bpf library > + * to interact with BPF ELF object files. > + * > + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. > + */ > +#include <errno.h> > +#include <stdarg.h> > +#include <stdio.h> > +#include <string.h> > +#include <unistd.h> > +#include <bpf/libbpf.h> > +#include <linux/kernel.h> > +#include <linux/perf_event.h> > +#include <sys/ioctl.h> > + > +#include "dtrace_impl.h" > + > +/* > + * Validate the output buffer map that is specified in the BPF ELF object. It > + * must match the following definition to be valid: > + * > + * struct bpf_map_def SEC("maps") buffers = { > + * .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, > + * .key_size = sizeof(u32), > + * .value_size = sizeof(u32), > + * .max_entries = num, > + * }; > + * where num is greater than dt_maxcpuid. > + */ > +static int is_valid_buffers(const struct bpf_map_def *mdef) > +{ > + return mdef->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && > + mdef->key_size == sizeof(u32) && > + mdef->value_size == sizeof(u32) && > + mdef->max_entries > dt_maxcpuid; > +} > + > +/* > + * List the probes specified in the given BPF ELF object file. > + */ > +int dt_bpf_list_probes(const char *fn) > +{ > + struct bpf_object *obj; > + struct bpf_program *prog; > + int rc, fd; > + > + libbpf_set_print(NULL); > + > + /* > + * Listing probes is done before the DTrace command line utility loads > + * the supplied programs. We load them here without attaching them to > + * probes so that we can retrieve the ELF section names for each BPF > + * program. The section name indicates the probe that the program is > + * associated with. > + */ > + rc = bpf_prog_load(fn, BPF_PROG_TYPE_UNSPEC, &obj, &fd); > + if (rc) > + return rc; > + > + /* > + * Loop through the programs in the BPF ELF object, and try to resolve > + * the section names into probes. Use the supplied callback function > + * to emit the probe description. > + */ > + for (prog = bpf_program__next(NULL, obj); prog != NULL; > + prog = bpf_program__next(prog, obj)) { > + struct dt_probe *probe; > + > + probe = dt_probe_resolve_event(bpf_program__title(prog, false)); > + > + printf("%5d %10s %17s %33s %s\n", probe->id, > + probe->prv_name ? probe->prv_name : "", > + probe->mod_name ? probe->mod_name : "", > + probe->fun_name ? probe->fun_name : "", > + probe->prb_name ? probe->prb_name : ""); > + } > + > + > + /* Done with the BPF ELF object. */ > + bpf_object__close(obj); > + > + return 0; > +} > + > +/* > + * Load the given BPF ELF object file. > + */ > +int dt_bpf_load_file(const char *fn) > +{ > + struct bpf_object *obj; > + struct bpf_map *map; > + struct bpf_program *prog; > + int rc, fd; > + > + libbpf_set_print(NULL); > + > + /* Load the BPF ELF object file. */ > + rc = bpf_prog_load(fn, BPF_PROG_TYPE_UNSPEC, &obj, &fd); > + if (rc) > + return rc; > + > + /* Validate buffers map. */ > + map = bpf_object__find_map_by_name(obj, "buffers"); > + if (map && is_valid_buffers(bpf_map__def(map))) > + dt_bufmap_fd = bpf_map__fd(map); > + else > + goto fail; > + > + /* > + * Loop through the programs and resolve each into the matching probe. > + * Attach the program to the probe. > + */ > + for (prog = bpf_program__next(NULL, obj); prog != NULL; > + prog = bpf_program__next(prog, obj)) { > + struct dt_probe *probe; > + > + probe = dt_probe_resolve_event(bpf_program__title(prog, false)); > + if (!probe) > + return -ENOENT; > + if (probe->prov && probe->prov->attach) > + probe->prov->attach(bpf_program__title(prog, false), > + bpf_program__fd(prog)); > + } > + > + return 0; > + > +fail: > + bpf_object__close(obj); > + return -EINVAL; > +} > + > +/* > + * Store the (key, value) pair in the map referenced by the given fd. > + */ > +int dt_bpf_map_update(int fd, const void *key, const void *val) > +{ > + union bpf_attr attr; > + > + memset(&attr, 0, sizeof(attr)); > + > + attr.map_fd = fd; > + attr.key = (u64)(unsigned long)key; > + attr.value = (u64)(unsigned long)val; > + attr.flags = 0; > + > + return bpf(BPF_MAP_UPDATE_ELEM, &attr); > +} > + > +/* > + * Attach a trace event and associate a BPF program with it. > + */ > +int dt_bpf_attach(int event_id, int bpf_fd) > +{ > + int event_fd; > + int rc; > + struct perf_event_attr attr = {}; > + > + attr.type = PERF_TYPE_TRACEPOINT; > + attr.sample_type = PERF_SAMPLE_RAW; > + attr.sample_period = 1; > + attr.wakeup_events = 1; > + attr.config = event_id; > + > + /* > + * Register the event (based on its id), and obtain a fd. It gets > + * created as an enabled probe, so we don't have to explicitly enable > + * it. > + */ > + event_fd = perf_event_open(&attr, -1, 0, -1, 0); > + if (event_fd < 0) { > + perror("sys_perf_event_open"); > + return -1; > + } > + > + /* Associate the BPF program with the event. */ > + rc = ioctl(event_fd, PERF_EVENT_IOC_SET_BPF, bpf_fd); > + if (rc < 0) { > + perror("PERF_EVENT_IOC_SET_BPF"); > + return -1; > + } > + > + return 0; > +} > diff --git a/tools/dtrace/dt_buffer.c b/tools/dtrace/dt_buffer.c > new file mode 100644 > index 000000000000..19bb7e4cfc92 > --- /dev/null > +++ b/tools/dtrace/dt_buffer.c > @@ -0,0 +1,338 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * This file provides the tracing buffer handling for DTrace. It makes use of > + * the perf event output ring buffers that can be written to from BPF programs. > + * > + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. > + */ > +#include <errno.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > +#include <syscall.h> > +#include <unistd.h> > +#include <sys/epoll.h> > +#include <sys/ioctl.h> > +#include <sys/mman.h> > +#include <linux/bpf.h> > +#include <linux/perf_event.h> > +#include <linux/ring_buffer.h> > + > +#include "dtrace_impl.h" > + > +/* > + * Probe data is recorded in per-CPU perf ring buffers. > + */ > +struct dtrace_buffer { > + int cpu; /* ID of CPU that uses this buffer */ > + int fd; /* fd of perf output buffer */ > + size_t page_size; /* size of each page in buffer */ > + size_t data_size; /* total buffer size */ > + u8 *base; /* address of buffer */ > + u8 *endp; /* address of end of buffer */ > + u8 *tmp; /* temporary event buffer */ > + u32 tmp_len; /* length of temporary event buffer */ > +}; > + > +static struct dtrace_buffer *dt_buffers; > + > +/* > + * File descriptor for the BPF map that holds the buffers for the online CPUs. > + * The map is a bpf_array indexed by CPU id, and it stores a file descriptor as > + * value (the fd for the perf_event that represents the CPU buffer). > + */ > +int dt_bufmap_fd = -1; > + > +/* > + * Create a perf_event buffer for the given DTrace buffer. This will create > + * a perf_event ring_buffer, mmap it, and enable the perf_event that owns the > + * buffer. > + */ > +static int perf_buffer_open(struct dtrace_buffer *buf) > +{ > + int pefd; > + struct perf_event_attr attr = {}; > + > + /* > + * Event configuration for BPF-generated output in perf_event ring > + * buffers. The event is created in enabled state. > + */ > + attr.config = PERF_COUNT_SW_BPF_OUTPUT; > + attr.type = PERF_TYPE_SOFTWARE; > + attr.sample_type = PERF_SAMPLE_RAW; > + attr.sample_period = 1; > + attr.wakeup_events = 1; > + pefd = perf_event_open(&attr, -1, buf->cpu, -1, PERF_FLAG_FD_CLOEXEC); > + if (pefd < 0) { > + fprintf(stderr, "perf_event_open(cpu %d): %s\n", buf->cpu, > + strerror(errno)); > + goto fail; > + } > + > + /* > + * We add buf->page_size to the buf->data_size, because perf maintains > + * a meta-data page at the beginning of the memory region. That page > + * is used for reader/writer symchronization. > + */ > + buf->fd = pefd; > + buf->base = mmap(NULL, buf->page_size + buf->data_size, > + PROT_READ | PROT_WRITE, MAP_SHARED, buf->fd, 0); > + buf->endp = buf->base + buf->page_size + buf->data_size - 1; > + if (!buf->base) > + goto fail; > + > + return 0; > + > +fail: > + if (buf->base) { > + munmap(buf->base, buf->page_size + buf->data_size); > + buf->base = NULL; > + buf->endp = NULL; > + } > + if (buf->fd) { > + close(buf->fd); > + buf->fd = -1; > + } > + > + return -1; > +} > + > +/* > + * Close the given DTrace buffer. This function disables the perf_event that > + * owns the buffer, munmaps the memory space, and closes the perf buffer fd. > + */ > +static void perf_buffer_close(struct dtrace_buffer *buf) > +{ > + /* > + * If the perf buffer failed to open, there is no need to close it. > + */ > + if (buf->fd < 0) > + return; > + > + if (ioctl(buf->fd, PERF_EVENT_IOC_DISABLE, 0) < 0) > + fprintf(stderr, "PERF_EVENT_IOC_DISABLE(cpu %d): %s\n", > + buf->cpu, strerror(errno)); > + > + munmap(buf->base, buf->page_size + buf->data_size); > + > + if (close(buf->fd)) > + fprintf(stderr, "perf buffer close(cpu %d): %s\n", > + buf->cpu, strerror(errno)); > + > + buf->base = NULL; > + buf->fd = -1; > +} > + > +/* > + * Initialize the probe data buffers (one per online CPU). Each buffer will > + * contain the given number of pages (i.e. total size of each buffer will be > + * num_pages * getpagesize()). This function also sets up an event polling > + * descriptor that monitors all CPU buffers at once. > + */ > +int dt_buffer_init(int num_pages) > +{ > + int i; > + int epoll_fd; > + > + if (dt_bufmap_fd < 0) > + return -EINVAL; > + > + /* Allocate the per-CPU buffer structs. */ > + dt_buffers = calloc(dt_numcpus, sizeof(struct dtrace_buffer)); > + if (dt_buffers == NULL) > + return -ENOMEM; > + > + /* Set up the event polling file descriptor. */ > + epoll_fd = epoll_create1(EPOLL_CLOEXEC); > + if (epoll_fd < 0) { > + free(dt_buffers); > + return -errno; > + } > + > + for (i = 0; i < dt_numcpus; i++) { > + int cpu = dt_cpuids[i]; > + struct epoll_event ev; > + struct dtrace_buffer *buf = &dt_buffers[i]; > + > + buf->cpu = cpu; > + buf->page_size = getpagesize(); > + buf->data_size = num_pages * buf->page_size; > + buf->tmp = NULL; > + buf->tmp_len = 0; > + > + /* Try to create the perf buffer for this DTrace buffer. */ > + if (perf_buffer_open(buf) == -1) > + continue; > + > + /* Store the perf buffer fd in the buffer map. */ > + dt_bpf_map_update(dt_bufmap_fd, &cpu, &buf->fd); > + > + /* Add the buffer to the event polling descriptor. */ > + ev.events = EPOLLIN; > + ev.data.ptr = buf; > + if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, buf->fd, &ev) == -1) { > + fprintf(stderr, "EPOLL_CTL_ADD(cpu %d): %s\n", > + buf->cpu, strerror(errno)); > + continue; > + } > + } > + > + return epoll_fd; > +} > + > +/* > + * Clean up the buffers. > + */ > +void dt_buffer_exit(int epoll_fd) > +{ > + int i; > + > + for (i = 0; i < dt_numcpus; i++) > + perf_buffer_close(&dt_buffers[i]); > + > + free(dt_buffers); > + close(epoll_fd); > +} > + > +/* > + * Process and output the probe data at the supplied address. > + */ > +static void output_event(int cpu, u64 *buf) > +{ > + u8 *data = (u8 *)buf; > + struct perf_event_header *hdr; > + > + hdr = (struct perf_event_header *)data; > + data += sizeof(struct perf_event_header); > + > + if (hdr->type == PERF_RECORD_SAMPLE) { > + u8 *ptr = data; > + u32 i, size, probe_id; > + > + /* > + * struct { > + * struct perf_event_header header; > + * u32 size; > + * u32 probe_id; > + * u32 gap; > + * u64 data[n]; > + * } > + * and data points to the 'size' member at this point. > + */ > + if (ptr > (u8 *)buf + hdr->size) { > + fprintf(stderr, "BAD: corrupted sample header\n"); > + return; > + } > + > + size = *(u32 *)data; > + data += sizeof(size); > + ptr += sizeof(size) + size; > + if (ptr != (u8 *)buf + hdr->size) { > + fprintf(stderr, "BAD: invalid sample size\n"); > + return; > + } > + > + probe_id = *(u32 *)data; > + data += sizeof(probe_id); > + size -= sizeof(probe_id); > + data += sizeof(u32); /* skip 32-bit gap */ > + size -= sizeof(u32); > + buf = (u64 *)data; > + > + printf("%3d %6d ", cpu, probe_id); > + for (i = 0, size /= sizeof(u64); i < size; i++) > + printf("%#016lx ", buf[i]); > + printf("\n"); > + } else if (hdr->type == PERF_RECORD_LOST) { > + u64 lost; > + > + /* > + * struct { > + * struct perf_event_header header; > + * u64 id; > + * u64 lost; > + * } > + * and data points to the 'id' member at this point. > + */ > + lost = *(u64 *)(data + sizeof(u64)); > + > + printf("[%ld probes dropped]\n", lost); > + } else > + fprintf(stderr, "UNKNOWN: record type %d\n", hdr->type); > +} > + > +/* > + * Process the available probe data in the given buffer. > + */ > +static void process_data(struct dtrace_buffer *buf) > +{ > + struct perf_event_mmap_page *rb_page = (void *)buf->base; > + struct perf_event_header *hdr; > + u8 *base; > + u64 head, tail; > + > + /* Set base to be the start of the buffer data. */ > + base = buf->base + buf->page_size; > + > + for (;;) { > + head = ring_buffer_read_head(rb_page); > + tail = rb_page->data_tail; > + > + if (tail == head) > + break; > + > + do { > + u8 *event = base + tail % buf->data_size; > + u32 len; > + > + hdr = (struct perf_event_header *)event; > + len = hdr->size; > + > + /* > + * If the perf event data wraps around the boundary of > + * the buffer, we make a copy in contiguous memory. > + */ > + if (event + len > buf->endp) { > + u8 *dst; > + u32 num; > + > + /* Increase buffer as needed. */ > + if (buf->tmp_len < len) { > + buf->tmp = realloc(buf->tmp, len); > + buf->tmp_len = len; > + } > + > + dst = buf->tmp; > + num = buf->endp - event + 1; > + memcpy(dst, event, num); > + memcpy(dst + num, base, len - num); > + > + event = dst; > + } > + > + output_event(buf->cpu, (u64 *)event); > + > + tail += hdr->size; > + } while (tail != head); > + > + ring_buffer_write_tail(rb_page, tail); > + } > +} > + > +/* > + * Wait for data to become available in any of the buffers. > + */ > +int dt_buffer_poll(int epoll_fd, int timeout) > +{ > + struct epoll_event events[dt_numcpus]; > + int i, cnt; > + > + cnt = epoll_wait(epoll_fd, events, dt_numcpus, timeout); > + if (cnt < 0) > + return -errno; > + > + for (i = 0; i < cnt; i++) > + process_data((struct dtrace_buffer *)events[i].data.ptr); > + > + return cnt; > +} > diff --git a/tools/dtrace/dt_fbt.c b/tools/dtrace/dt_fbt.c > new file mode 100644 > index 000000000000..fcf95243bf97 > --- /dev/null > +++ b/tools/dtrace/dt_fbt.c > @@ -0,0 +1,201 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * The Function Boundary Tracing (FBT) provider for DTrace. > + * > + * FBT probes are exposed by the kernel as kprobes. They are listed in the > + * TRACEFS/available_filter_functions file. Some kprobes are associated with > + * a specific kernel module, while most are in the core kernel. > + * > + * Mapping from event name to DTrace probe name: > + * > + * <name> fbt:vmlinux:<name>:entry > + * fbt:vmlinux:<name>:return > + * or > + * <name> [<modname>] fbt:<modname>:<name>:entry > + * fbt:<modname>:<name>:return > + * > + * Mapping from BPF section name to DTrace probe name: > + * > + * kprobe/<name> fbt:vmlinux:<name>:entry > + * kretprobe/<name> fbt:vmlinux:<name>:return > + * > + * (Note that the BPF section does not carry information about the module that > + * the function is found in. This means that BPF section name cannot be used > + * to distinguish between functions with the same name occurring in different > + * modules.) > + * > + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. > + */ > +#include <fcntl.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > +#include <unistd.h> > +#include <linux/bpf.h> > +#include <sys/stat.h> > +#include <sys/types.h> > + > +#include "dtrace_impl.h" > + > +#define KPROBE_EVENTS TRACEFS "kprobe_events" > +#define PROBE_LIST TRACEFS "available_filter_functions" > + > +static const char provname[] = "fbt"; > +static const char modname[] = "vmlinux"; > + > +/* > + * Scan the PROBE_LIST file and add entry and return probes for every function > + * that is listed. > + */ > +static int fbt_populate(void) > +{ > + FILE *f; > + char buf[256]; > + char *p; > + > + f = fopen(PROBE_LIST, "r"); > + if (f == NULL) > + return -1; > + > + while (fgets(buf, sizeof(buf), f)) { > + /* > + * Here buf is either "funcname\n" or "funcname [modname]\n". > + */ > + p = strchr(buf, '\n'); > + if (p) { > + *p = '\0'; > + if (p > buf && *(--p) == ']') > + *p = '\0'; > + } else { > + /* If we didn't see a newline, the line was too long. > + * Report it, and continue until the end of the line. > + */ > + fprintf(stderr, "%s: Line too long: %s\n", > + PROBE_LIST, buf); > + do > + fgets(buf, sizeof(buf), f); > + while (strchr(buf, '\n') == NULL); > + continue; > + } > + > + /* > + * Now buf is either "funcname" or "funcname [modname". If > + * there is no module name provided, we will use the default. > + */ > + p = strchr(buf, ' '); > + if (p) { > + *p++ = '\0'; > + if (*p == '[') > + p++; > + } > + > + dt_probe_new(&dt_fbt, provname, p ? p : modname, buf, "entry"); > + dt_probe_new(&dt_fbt, provname, p ? p : modname, buf, "return"); > + } > + > + fclose(f); > + > + return 0; > +} > + > +#define ENTRY_PREFIX "kprobe/" > +#define EXIT_PREFIX "kretprobe/" > + > +/* > + * Perform a probe lookup based on an event name (BPF ELF section name). > + */ > +static struct dt_probe *fbt_resolve_event(const char *name) > +{ > + const char *prbname; > + struct dt_probe tmpl; > + struct dt_probe *probe; > + > + if (!name) > + return NULL; > + > + if (strncmp(name, ENTRY_PREFIX, sizeof(ENTRY_PREFIX) - 1) == 0) { > + name += sizeof(ENTRY_PREFIX) - 1; > + prbname = "entry"; > + } else if (strncmp(name, EXIT_PREFIX, sizeof(EXIT_PREFIX) - 1) == 0) { > + name += sizeof(EXIT_PREFIX) - 1; > + prbname = "return"; > + } else > + return NULL; > + > + memset(&tmpl, 0, sizeof(tmpl)); > + tmpl.prv_name = provname; > + tmpl.mod_name = modname; > + tmpl.fun_name = name; > + tmpl.prb_name = prbname; > + > + probe = dt_probe_by_name(&tmpl); > + > + return probe; > +} > + > +/* > + * Attach the given BPF program (identified by its file descriptor) to the > + * kprobe identified by the given section name. > + */ > +static int fbt_attach(const char *name, int bpf_fd) > +{ > + char efn[256]; > + char buf[256]; > + int event_id, fd, rc; > + > + name += 7; /* skip "kprobe/" */ > + snprintf(buf, sizeof(buf), "p:%s %s\n", name, name); > + > + /* > + * Register the kprobe with the tracing subsystem. This will create > + * a tracepoint event. > + */ > + fd = open(KPROBE_EVENTS, O_WRONLY | O_APPEND); > + if (fd < 0) { > + perror(KPROBE_EVENTS); > + return -1; > + } > + rc = write(fd, buf, strlen(buf)); > + if (rc < 0) { > + perror(KPROBE_EVENTS); > + close(fd); > + return -1; > + } > + close(fd); > + > + /* > + * Read the tracepoint event id for the kprobe we just registered. > + */ > + strcpy(efn, EVENTSFS); > + strcat(efn, "kprobes/"); > + strcat(efn, name); > + strcat(efn, "/id"); > + > + fd = open(efn, O_RDONLY); > + if (fd < 0) { > + perror(efn); > + return -1; > + } > + rc = read(fd, buf, sizeof(buf)); > + if (rc < 0 || rc >= sizeof(buf)) { > + perror(efn); > + close(fd); > + return -1; > + } > + close(fd); > + buf[rc] = '\0'; > + event_id = atoi(buf); > + > + /* > + * Attaching a BPF program (by file descriptor) to an event (by ID) is > + * a generic operation provided by the BPF interface code. > + */ > + return dt_bpf_attach(event_id, bpf_fd); > +} > + > +struct dt_provider dt_fbt = { > + .name = "fbt", > + .populate = &fbt_populate, > + .resolve_event = &fbt_resolve_event, > + .attach = &fbt_attach, > +}; > diff --git a/tools/dtrace/dt_hash.c b/tools/dtrace/dt_hash.c > new file mode 100644 > index 000000000000..b1f563bc0773 > --- /dev/null > +++ b/tools/dtrace/dt_hash.c > @@ -0,0 +1,211 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * This file provides a generic hashtable implementation for probes. > + * > + * The hashtable is created with 4 user-provided functions: > + * hval(probe) - calculate a hash value for the given probe > + * cmp(probe1, probe2) - compare two probes > + * add(head, probe) - add a probe to a list of probes > + * del(head, probe) - delete a probe from a list of probes > + * > + * Probes are hashed into a hashtable slot based on the return value of > + * hval(probe). Each hashtable slot holds a list of buckets, with each > + * bucket storing probes that are equal under the cmp(probe1, probe2) > + * function. Probes are added to the list of probes in a bucket using the > + * add(head, probe) function, and they are deleted using a call to the > + * del(head, probe) function. > + * > + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. > + */ > +#include <errno.h> > +#include <stdint.h> > +#include <stdlib.h> > + > +#include "dtrace_impl.h" > + > +/* > + * Hashtable implementation for probes. > + */ > +struct dt_hbucket { > + u32 hval; > + struct dt_hbucket *next; > + struct dt_probe *head; > + int nprobes; > +}; > + > +struct dt_htab { > + struct dt_hbucket **tab; > + int size; > + int mask; > + int nbuckets; > + dt_hval_fn hval; /* calculate hash value */ > + dt_cmp_fn cmp; /* compare 2 probes */ > + dt_add_fn add; /* add probe to list */ > + dt_del_fn del; /* delete probe from list */ > +}; > + > +/* > + * Create a new (empty) hashtable. > + */ > +struct dt_htab *dt_htab_new(dt_hval_fn hval, dt_cmp_fn cmp, dt_add_fn add, > + dt_del_fn del) > +{ > + struct dt_htab *htab = malloc(sizeof(struct dt_htab)); > + > + if (!htab) > + return NULL; > + > + htab->size = 1; > + htab->mask = htab->size - 1; > + htab->nbuckets = 0; > + htab->hval = hval; > + htab->cmp = cmp; > + htab->add = add; > + htab->del = del; > + > + htab->tab = calloc(htab->size, sizeof(struct dt_hbucket *)); > + if (!htab->tab) { > + free(htab); > + return NULL; > + } > + > + return htab; > +} > + > +/* > + * Resize the hashtable by doubling the number of slots. > + */ > +static int resize(struct dt_htab *htab) > +{ > + int i; > + int osize = htab->size; > + int nsize = osize << 1; > + int nmask = nsize - 1; > + struct dt_hbucket **ntab; > + > + ntab = calloc(nsize, sizeof(struct dt_hbucket *)); > + if (!ntab) > + return -ENOMEM; > + > + for (i = 0; i < osize; i++) { > + struct dt_hbucket *bucket, *next; > + > + for (bucket = htab->tab[i]; bucket; bucket = next) { > + int idx = bucket->hval & nmask; > + > + next = bucket->next; > + bucket->next = ntab[idx]; > + ntab[idx] = bucket; > + } > + } > + > + free(htab->tab); > + htab->tab = ntab; > + htab->size = nsize; > + htab->mask = nmask; > + > + return 0; > +} > + > +/* > + * Add a probe to the hashtable. Resize if necessary, and allocate a new > + * bucket if necessary. > + */ > +int dt_htab_add(struct dt_htab *htab, struct dt_probe *probe) > +{ > + u32 hval = htab->hval(probe); > + int idx; > + struct dt_hbucket *bucket; > + > +retry: > + idx = hval & htab->mask; > + for (bucket = htab->tab[idx]; bucket; bucket = bucket->next) { > + if (htab->cmp(bucket->head, probe) == 0) > + goto add; > + } > + > + if ((htab->nbuckets >> 1) > htab->size) { > + int err; > + > + err = resize(htab); > + if (err) > + return err; > + > + goto retry; > + } > + > + bucket = malloc(sizeof(struct dt_hbucket)); > + if (!bucket) > + return -ENOMEM; > + > + bucket->hval = hval; > + bucket->next = htab->tab[idx]; > + bucket->head = NULL; > + bucket->nprobes = 0; > + htab->tab[idx] = bucket; > + htab->nbuckets++; > + > +add: > + bucket->head = htab->add(bucket->head, probe); > + bucket->nprobes++; > + > + return 0; > +} > + > +/* > + * Find a probe in the hashtable. > + */ > +struct dt_probe *dt_htab_lookup(const struct dt_htab *htab, > + const struct dt_probe *probe) > +{ > + u32 hval = htab->hval(probe); > + int idx = hval & htab->mask; > + struct dt_hbucket *bucket; > + > + for (bucket = htab->tab[idx]; bucket; bucket = bucket->next) { > + if (htab->cmp(bucket->head, probe) == 0) > + return bucket->head; > + } > + > + return NULL; > +} > + > +/* > + * Remove a probe from the hashtable. If we are deleting the last probe in a > + * bucket, get rid of the bucket. > + */ > +int dt_htab_del(struct dt_htab *htab, struct dt_probe *probe) > +{ > + u32 hval = htab->hval(probe); > + int idx = hval & htab->mask; > + struct dt_hbucket *bucket; > + struct dt_probe *head; > + > + for (bucket = htab->tab[idx]; bucket; bucket = bucket->next) { > + if (htab->cmp(bucket->head, probe) == 0) > + break; > + } > + > + if (bucket == NULL) > + return -ENOENT; > + > + head = htab->del(bucket->head, probe); > + if (!head) { > + struct dt_hbucket *b = htab->tab[idx]; > + > + if (bucket == b) > + htab->tab[idx] = bucket->next; > + else { > + while (b->next != bucket) > + b = b->next; > + > + b->next = bucket->next; > + } > + > + htab->nbuckets--; > + free(bucket); > + } else > + bucket->head = head; > + > + return 0; > +} > diff --git a/tools/dtrace/dt_probe.c b/tools/dtrace/dt_probe.c > new file mode 100644 > index 000000000000..0b6228eaff29 > --- /dev/null > +++ b/tools/dtrace/dt_probe.c > @@ -0,0 +1,230 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * This file implements the interface to probes grouped by provider. > + * > + * Probes are named by a set of 4 identifiers: > + * - provider name > + * - module name > + * - function name > + * - probe name > + * > + * The Fully Qualified Name (FQN) is "provider:module:function:name". > + * > + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. > + */ > +#include <errno.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > +#include <linux/bpf.h> > +#include <linux/kernel.h> > + > +#include "dtrace_impl.h" > + > +static struct dt_provider *dt_providers[] = { > + &dt_fbt, > + &dt_syscall, > + }; > + > +static struct dt_htab *ht_byfqn; > + > +static u32 next_probe_id; > + > +/* > + * Calculate a hash value based on a given string and an initial value. The > + * initial value is used to calculate compound hash values, e.g. > + * > + * u32 hval; > + * > + * hval = str2hval(str1, 0); > + * hval = str2hval(str2, hval); > + */ > +static u32 str2hval(const char *p, u32 hval) > +{ > + u32 g; > + > + if (!p) > + return hval; > + > + while (*p) { > + hval = (hval << 4) + *p++; > + g = hval & 0xf0000000; > + if (g != 0) > + hval ^= g >> 24; > + > + hval &= ~g; > + } > + > + return hval; > +} > + > +/* > + * String compare function that can handle either or both strings being NULL. > + */ > +static int safe_strcmp(const char *p, const char *q) > +{ > + return (!p) ? (!q) ? 0 > + : -1 > + : (!q) ? 1 > + : strcmp(p, q); > +} > + > +/* > + * Calculate the hash value of a probe as the cummulative hash value of the > + * FQN. > + */ > +static u32 fqn_hval(const struct dt_probe *probe) > +{ > + u32 hval = 0; > + > + hval = str2hval(probe->prv_name, hval); > + hval = str2hval(":", hval); > + hval = str2hval(probe->mod_name, hval); > + hval = str2hval(":", hval); > + hval = str2hval(probe->fun_name, hval); > + hval = str2hval(":", hval); > + hval = str2hval(probe->prb_name, hval); > + > + return hval; > +} > + > +/* > + * Compare two probes based on the FQN. > + */ > +static int fqn_cmp(const struct dt_probe *p, const struct dt_probe *q) > +{ > + int rc; > + > + rc = safe_strcmp(p->prv_name, q->prv_name); > + if (rc) > + return rc; > + rc = safe_strcmp(p->mod_name, q->mod_name); > + if (rc) > + return rc; > + rc = safe_strcmp(p->fun_name, q->fun_name); > + if (rc) > + return rc; > + rc = safe_strcmp(p->prb_name, q->prb_name); > + if (rc) > + return rc; > + > + return 0; > +} > + > +/* > + * Add the given probe 'new' to the double-linked probe list 'head'. Probe > + * 'new' becomes the new list head. > + */ > +static struct dt_probe *fqn_add(struct dt_probe *head, struct dt_probe *new) > +{ > + if (!head) > + return new; > + > + new->he_fqn.next = head; > + head->he_fqn.prev = new; > + > + return new; > +} > + > +/* > + * Remove the given probe 'probe' from the double-linked probe list 'head'. > + * If we are deleting the current head, the next probe in the list is returned > + * as the new head. If that value is NULL, the list is now empty. > + */ > +static struct dt_probe *fqn_del(struct dt_probe *head, struct dt_probe *probe) > +{ > + if (head == probe) { > + if (!probe->he_fqn.next) > + return NULL; > + > + head = probe->he_fqn.next; > + head->he_fqn.prev = NULL; > + probe->he_fqn.next = NULL; > + > + return head; > + } > + > + if (!probe->he_fqn.next) { > + probe->he_fqn.prev->he_fqn.next = NULL; > + probe->he_fqn.prev = NULL; > + > + return head; > + } > + > + probe->he_fqn.prev->he_fqn.next = probe->he_fqn.next; > + probe->he_fqn.next->he_fqn.prev = probe->he_fqn.prev; > + probe->he_fqn.prev = probe->he_fqn.next = NULL; > + > + return head; > +} > + > +/* > + * Initialize the probe handling by populating the FQN hashtable with probes > + * from all providers. > + */ > +int dt_probe_init(void) > +{ > + int i; > + > + ht_byfqn = dt_htab_new(fqn_hval, fqn_cmp, fqn_add, fqn_del); > + > + for (i = 0; i < ARRAY_SIZE(dt_providers); i++) { > + if (dt_providers[i]->populate() < 0) > + return -1; > + } > + > + return 0; > +} > + > +/* > + * Allocate a new probe and add it to the FQN hashtable. > + */ > +int dt_probe_new(const struct dt_provider *prov, const char *pname, > + const char *mname, const char *fname, const char *name) > +{ > + struct dt_probe *probe; > + > + probe = malloc(sizeof(struct dt_probe)); > + if (!probe) > + return -ENOMEM; > + > + memset(probe, 0, sizeof(struct dt_probe)); > + probe->id = next_probe_id++; > + probe->prov = prov; > + probe->prv_name = pname ? strdup(pname) : NULL; > + probe->mod_name = mname ? strdup(mname) : NULL; > + probe->fun_name = fname ? strdup(fname) : NULL; > + probe->prb_name = name ? strdup(name) : NULL; > + > + dt_htab_add(ht_byfqn, probe); > + > + return 0; > +} > + > +/* > + * Perform a probe lookup based on FQN. > + */ > +struct dt_probe *dt_probe_by_name(const struct dt_probe *tmpl) > +{ > + return dt_htab_lookup(ht_byfqn, tmpl); > +} > + > +/* > + * Resolve an event name (BPF ELF section name) into a probe. We query each > + * provider, and as soon as we get a hit, we return the result. > + */ > +struct dt_probe *dt_probe_resolve_event(const char *name) > +{ > + int i; > + struct dt_probe *probe; > + > + for (i = 0; i < ARRAY_SIZE(dt_providers); i++) { > + if (!dt_providers[i]->resolve_event) > + continue; > + probe = dt_providers[i]->resolve_event(name); > + if (probe) > + return probe; > + } > + > + return NULL; > +} > diff --git a/tools/dtrace/dt_syscall.c b/tools/dtrace/dt_syscall.c > new file mode 100644 > index 000000000000..6695a4a1c701 > --- /dev/null > +++ b/tools/dtrace/dt_syscall.c > @@ -0,0 +1,179 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * The syscall provider for DTrace. > + * > + * System call probes are exposed by the kernel as tracepoint events in the > + * "syscalls" group. Entry probe names start with "sys_enter_" and exit probes > + * start with "sys_exit_". > + * > + * Mapping from event name to DTrace probe name: > + * > + * syscalls:sys_enter_<name> syscall:vmlinux:<name>:entry > + * syscalls:sys_exit_<name> syscall:vmlinux:<name>:return > + * > + * Mapping from BPF section name to DTrace probe name: > + * > + * tracepoint/syscalls/sys_enter_<name> syscall:vmlinux:<name>:entry > + * tracepoint/syscalls/sys_exit_<name> syscall:vmlinux:<name>:return > + * > + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. > + */ > +#include <ctype.h> > +#include <fcntl.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > +#include <unistd.h> > +#include <linux/bpf.h> > +#include <sys/stat.h> > +#include <sys/types.h> > + > +#include "dtrace_impl.h" > + > +static const char provname[] = "syscall"; > +static const char modname[] = "vmlinux"; > + > +#define PROBE_LIST TRACEFS "available_events" > + > +#define PROV_PREFIX "syscalls:" > +#define ENTRY_PREFIX "sys_enter_" > +#define EXIT_PREFIX "sys_exit_" > + > +/* > + * Scan the PROBE_LIST file and add probes for any syscalls events. > + */ > +static int syscall_populate(void) > +{ > + FILE *f; > + char buf[256]; > + > + f = fopen(PROBE_LIST, "r"); > + if (f == NULL) > + return -1; > + > + while (fgets(buf, sizeof(buf), f)) { > + char *p; > + > + /* * Here buf is "group:event". */ > + p = strchr(buf, '\n'); > + if (p) > + *p = '\0'; > + else { > + /* > + * If we didn't see a newline, the line was too long. > + * Report it, and continue until the end of the line. > + */ > + fprintf(stderr, "%s: Line too long: %s\n", > + PROBE_LIST, buf); > + do > + fgets(buf, sizeof(buf), f); > + while (strchr(buf, '\n') == NULL); > + continue; > + } > + > + /* We need "group:" to match "syscalls:". */ > + p = buf; > + if (memcmp(p, PROV_PREFIX, sizeof(PROV_PREFIX) - 1) != 0) > + continue; > + > + p += sizeof(PROV_PREFIX) - 1; > + /* > + * Now p will be just "event", and we are only interested in > + * events that match "sys_enter_*" or "sys_exit_*". > + */ > + if (!memcmp(p, ENTRY_PREFIX, sizeof(ENTRY_PREFIX) - 1)) { > + p += sizeof(ENTRY_PREFIX) - 1; > + dt_probe_new(&dt_syscall, provname, modname, p, > + "entry"); > + } else if (!memcmp(p, EXIT_PREFIX, sizeof(EXIT_PREFIX) - 1)) { > + p += sizeof(EXIT_PREFIX) - 1; > + dt_probe_new(&dt_syscall, provname, modname, p, > + "return"); > + } > + } > + > + fclose(f); > + > + return 0; > +} > + > +#define EVENT_PREFIX "tracepoint/syscalls/" > + > +/* > + * Perform a probe lookup based on an event name (BPF ELF section name). > + */ > +static struct dt_probe *systrace_resolve_event(const char *name) > +{ > + const char *prbname; > + struct dt_probe tmpl; > + struct dt_probe *probe; > + > + if (!name) > + return NULL; > + > + /* Exclude anything that is not a syscalls tracepoint */ > + if (strncmp(name, EVENT_PREFIX, sizeof(EVENT_PREFIX) - 1) != 0) > + return NULL; > + name += sizeof(EVENT_PREFIX) - 1; > + > + if (strncmp(name, ENTRY_PREFIX, sizeof(ENTRY_PREFIX) - 1) == 0) { > + name += sizeof(ENTRY_PREFIX) - 1; > + prbname = "entry"; > + } else if (strncmp(name, EXIT_PREFIX, sizeof(EXIT_PREFIX) - 1) == 0) { > + name += sizeof(EXIT_PREFIX) - 1; > + prbname = "return"; > + } else > + return NULL; > + > + memset(&tmpl, 0, sizeof(tmpl)); > + tmpl.prv_name = provname; > + tmpl.mod_name = modname; > + tmpl.fun_name = name; > + tmpl.prb_name = prbname; > + > + probe = dt_probe_by_name(&tmpl); > + > + return probe; > +} > + > +#define SYSCALLSFS EVENTSFS "syscalls/" > + > +/* > + * Attach the given BPF program (identified by its file descriptor) to the > + * event identified by the given section name. > + */ > +static int syscall_attach(const char *name, int bpf_fd) > +{ > + char efn[256]; > + char buf[256]; > + int event_id, fd, rc; > + > + name += sizeof(EVENT_PREFIX) - 1; > + strcpy(efn, SYSCALLSFS); > + strcat(efn, name); > + strcat(efn, "/id"); > + > + fd = open(efn, O_RDONLY); > + if (fd < 0) { > + perror(efn); > + return -1; > + } > + rc = read(fd, buf, sizeof(buf)); > + if (rc < 0 || rc >= sizeof(buf)) { > + perror(efn); > + close(fd); > + return -1; > + } > + close(fd); > + buf[rc] = '\0'; > + event_id = atoi(buf); > + > + return dt_bpf_attach(event_id, bpf_fd); > +} > + > +struct dt_provider dt_syscall = { > + .name = "syscall", > + .populate = &syscall_populate, > + .resolve_event = &systrace_resolve_event, > + .attach = &syscall_attach, > +}; > diff --git a/tools/dtrace/dt_utils.c b/tools/dtrace/dt_utils.c > new file mode 100644 > index 000000000000..55d51bae1d97 > --- /dev/null > +++ b/tools/dtrace/dt_utils.c > @@ -0,0 +1,132 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. > + */ > +#include <sys/types.h> > +#include <sys/stat.h> > +#include <fcntl.h> > +#include <stdlib.h> > +#include <string.h> > +#include <unistd.h> > + > +#include "dtrace_impl.h" > + > +#define BUF_SIZE 1024 /* max size for online cpu data */ > + > +int dt_numcpus; /* number of online CPUs */ > +int dt_maxcpuid; /* highest CPU id */ > +int *dt_cpuids; /* list of CPU ids */ > + > +/* > + * Populate the online CPU id information from sysfs data. We only do this > + * once because we do not care about CPUs coming online after we started > + * tracing. If a CPU goes offline during tracing, we do not care either > + * because that simply means that it won't be writing any new probe data into > + * its buffer. > + */ > +void cpu_list_populate(void) > +{ > + char buf[BUF_SIZE]; > + int fd, cnt, start, end, i; > + int *cpu; > + char *p, *q; > + > + fd = open("/sys/devices/system/cpu/online", O_RDONLY); > + if (fd < 0) > + goto fail; > + cnt = read(fd, buf, sizeof(buf)); > + close(fd); > + if (cnt <= 0) > + goto fail; > + > + /* > + * The string should always end with a newline, but let's make sure. > + */ > + if (buf[cnt - 1] == '\n') > + buf[--cnt] = 0; > + > + /* > + * Count how many CPUs we have. > + */ > + dt_numcpus = 0; > + p = buf; > + do { > + start = (int)strtol(p, &q, 10); > + switch (*q) { > + case '-': /* range */ > + p = q + 1; > + end = (int)strtol(p, &q, 10); > + dt_numcpus += end - start + 1; > + if (*q == 0) { /* end of string */ > + p = q; > + break; > + } > + if (*q != ',') > + goto fail; > + p = q + 1; > + break; > + case 0: /* end of string */ > + dt_numcpus++; > + p = q; > + break; > + case ',': /* gap */ > + dt_numcpus++; > + p = q + 1; > + break; > + } > + } while (*p != 0); > + > + dt_cpuids = calloc(dt_numcpus, sizeof(int)); > + cpu = dt_cpuids; > + > + /* > + * Fill in the CPU ids. > + */ > + p = buf; > + do { > + start = (int)strtol(p, &q, 10); > + switch (*q) { > + case '-': /* range */ > + p = q + 1; > + end = (int)strtol(p, &q, 10); > + for (i = start; i <= end; i++) > + *cpu++ = i; > + if (*q == 0) { /* end of string */ > + p = q; > + break; > + } > + if (*q != ',') > + goto fail; > + p = q + 1; > + break; > + case 0: /* end of string */ > + *cpu = start; > + p = q; > + break; > + case ',': /* gap */ > + *cpu++ = start; > + p = q + 1; > + break; > + } > + } while (*p != 0); > + > + /* Record the highest CPU id of the set of online CPUs. */ > + dt_maxcpuid = *(cpu - 1); > + > + return; > +fail: > + if (dt_cpuids) > + free(dt_cpuids); > + > + dt_numcpus = 0; > + dt_maxcpuid = 0; > + dt_cpuids = NULL; > +} > + > +void cpu_list_free(void) > +{ > + free(dt_cpuids); > + dt_numcpus = 0; > + dt_maxcpuid = 0; > + dt_cpuids = NULL; > +} > diff --git a/tools/dtrace/dtrace.c b/tools/dtrace/dtrace.c > new file mode 100644 > index 000000000000..36ad526c1cd4 > --- /dev/null > +++ b/tools/dtrace/dtrace.c > @@ -0,0 +1,249 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. > + */ > +#include <errno.h> > +#include <libgen.h> > +#include <stdarg.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > +#include <unistd.h> > +#include <linux/log2.h> > + > +#include "dtrace_impl.h" > + > +#define DTRACE_BUFSIZE 32 /* default buffer size (in pages) */ > + > +#define DMODE_VERS 0 /* display version information (-V) */ > +#define DMODE_LIST 1 /* list probes (-l) */ > +#define DMODE_EXEC 2 /* compile program and start tracing */ > + > +#define E_SUCCESS 0 > +#define E_ERROR 1 > +#define E_USAGE 2 > + > +#define NUM_PAGES(sz) (((sz) + getpagesize() - 1) / getpagesize()) > + > +static const char *dtrace_options = "+b:ls:V"; > + > +static char *g_pname; > +static int g_mode = DMODE_EXEC; > + > +static int usage(void) > +{ > + fprintf(stderr, "Usage: %s [-lV] [-b bufsz] -s script\n", g_pname); > + fprintf(stderr, > + "\t-b set trace buffer size\n" > + "\t-l list probes matching specified criteria\n" > + "\t-s enable or list probes for the specified BPF program\n" > + "\t-V report DTrace API version\n"); > + > + return E_USAGE; > +} > + > +static u64 parse_size(const char *arg) > +{ > + long long mul = 1; > + long long neg, val; > + size_t len; > + char *end; > + > + if (!arg) > + return -1; > + > + len = strlen(arg); > + if (!len) > + return -1; > + > + switch (arg[len - 1]) { > + case 't': > + case 'T': > + mul *= 1024; > + /* fall-through */ > + case 'g': > + case 'G': > + mul *= 1024; > + /* fall-through */ > + case 'm': > + case 'M': > + mul *= 1024; > + /* fall-through */ > + case 'k': > + case 'K': > + mul *= 1024; > + /* fall-through */ > + default: > + break; > + } > + > + neg = strtoll(arg, NULL, 0); > + errno = 0; > + val = strtoull(arg, &end, 0) * mul; > + > + if ((mul > 1 && end != &arg[len - 1]) || (mul == 1 && *end != '\0') || > + val < 0 || neg < 0 || errno != 0) > + return -1; > + > + return val; > +} > + > +int main(int argc, char *argv[]) > +{ > + int i; > + int modec = 0; > + int bufsize = DTRACE_BUFSIZE; > + int epoll_fd; > + int cnt; > + char **prgv; > + int prgc; > + > + g_pname = basename(argv[0]); > + > + if (argc == 1) > + return usage(); > + > + prgc = 0; > + prgv = calloc(argc, sizeof(char *)); > + if (!prgv) { > + fprintf(stderr, "failed to allocate memory for arguments: %s\n", > + strerror(errno)); > + return E_ERROR; > + } > + > + argv[0] = g_pname; /* argv[0] for getopt errors */ > + > + for (optind = 1; optind < argc; optind++) { > + int opt; > + > + while ((opt = getopt(argc, argv, dtrace_options)) != EOF) { > + u64 val; > + > + switch (opt) { > + case 'b': > + val = parse_size(optarg); > + if (val < 0) { > + fprintf(stderr, "invalid: -b %s\n", > + optarg); > + return E_ERROR; > + } > + > + /* > + * Bufsize needs to be a number of pages, and > + * must be a power of 2. This is required by > + * the perf event buffer code. > + */ > + bufsize = roundup_pow_of_two(NUM_PAGES(val)); > + if ((u64)bufsize * getpagesize() > val) > + fprintf(stderr, > + "bufsize increased to %ld\n", > + (u64)bufsize * getpagesize()); > + > + break; > + case 'l': > + g_mode = DMODE_LIST; > + modec++; > + break; > + case 's': > + prgv[prgc++] = optarg; > + break; > + case 'V': > + g_mode = DMODE_VERS; > + modec++; > + break; > + default: > + if (strchr(dtrace_options, opt) == NULL) > + return usage(); > + } > + } > + > + if (optind < argc) { > + fprintf(stderr, "unknown option '%s'\n", argv[optind]); > + return E_ERROR; > + } > + } > + > + if (modec > 1) { > + fprintf(stderr, > + "only one of [-lV] can be specified at a time\n"); > + return E_USAGE; > + } > + > + /* > + * We handle requests for version information first because we do not > + * need probe information for it. > + */ > + if (g_mode == DMODE_VERS) { > + printf("%s\n" > + "This is DTrace %s\n" > + "dtrace(1) version-control ID: %s\n", > + DT_VERS_STRING, DT_VERSION, DT_GIT_VERSION); > + > + return E_SUCCESS; > + } > + > + /* Initialize probes. */ > + if (dt_probe_init() < 0) { > + fprintf(stderr, "failed to initialize probes: %s\n", > + strerror(errno)); > + return E_ERROR; > + } > + > + /* > + * We handle requests to list probes next. > + */ > + if (g_mode == DMODE_LIST) { > + int rc = 0; > + > + printf("%5s %10s %17s %33s %s\n", > + "ID", "PROVIDER", "MODULE", "FUNCTION", "NAME"); > + for (i = 0; i < prgc; i++) { > + rc = dt_bpf_list_probes(prgv[i]); > + if (rc < 0) > + fprintf(stderr, "failed to load %s: %s\n", > + prgv[i], strerror(errno)); > + } > + > + return rc ? E_ERROR : E_SUCCESS; > + } > + > + if (!prgc) { > + fprintf(stderr, "missing BPF program(s)\n"); > + return E_ERROR; > + } > + > + /* Process the BPF program. */ > + for (i = 0; i < prgc; i++) { > + int err; > + > + err = dt_bpf_load_file(prgv[i]); > + if (err) { > + errno = -err; > + fprintf(stderr, "failed to load %s: %s\n", > + prgv[i], strerror(errno)); > + return E_ERROR; > + } > + } > + > + /* Get the list of online CPUs. */ > + cpu_list_populate(); > + > + /* Initialize buffers. */ > + epoll_fd = dt_buffer_init(bufsize); > + if (epoll_fd < 0) { > + errno = -epoll_fd; > + fprintf(stderr, "failed to allocate buffers: %s\n", > + strerror(errno)); > + return E_ERROR; > + } > + > + /* Process probe data. */ > + printf("%3s %6s\n", "CPU", "ID"); > + do { > + cnt = dt_buffer_poll(epoll_fd, 100); > + } while (cnt >= 0); > + > + dt_buffer_exit(epoll_fd); > + > + return E_SUCCESS; > +} > diff --git a/tools/dtrace/dtrace.h b/tools/dtrace/dtrace.h > new file mode 100644 > index 000000000000..c79398432d17 > --- /dev/null > +++ b/tools/dtrace/dtrace.h > @@ -0,0 +1,13 @@ > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ > +/* > + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. > + */ > +#ifndef _UAPI_LINUX_DTRACE_H > +#define _UAPI_LINUX_DTRACE_H > + > +struct dt_bpf_context { > + u32 probe_id; > + u64 argv[10]; > +}; > + > +#endif /* _UAPI_LINUX_DTRACE_H */ > diff --git a/tools/dtrace/dtrace_impl.h b/tools/dtrace/dtrace_impl.h > new file mode 100644 > index 000000000000..9aa51b4c4aee > --- /dev/null > +++ b/tools/dtrace/dtrace_impl.h > @@ -0,0 +1,101 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. > + */ > +#ifndef _DTRACE_H > +#define _DTRACE_H > + > +#include <unistd.h> > +#include <bpf/libbpf.h> > +#include <linux/types.h> > +#include <linux/ptrace.h> > +#include <linux/perf_event.h> > +#include <sys/syscall.h> > + > +#include "dtrace.h" > + > +#define DT_DEBUG > + > +#define DT_VERS_STRING "Oracle D 2.0.0" > + > +#define TRACEFS "/sys/kernel/debug/tracing/" > +#define EVENTSFS TRACEFS "events/" > + > +extern int dt_numcpus; > +extern int dt_maxcpuid; > +extern int *dt_cpuids; > + > +extern void cpu_list_populate(void); > +extern void cpu_list_free(void); > + > +struct dt_provider { > + char *name; > + int (*populate)(void); > + struct dt_probe *(*resolve_event)(const char *name); > + int (*attach)(const char *name, int bpf_fd); > +}; > + > +extern struct dt_provider dt_fbt; > +extern struct dt_provider dt_syscall; > + > +struct dt_hentry { > + struct dt_probe *next; > + struct dt_probe *prev; > +}; > + > +struct dt_htab; > + > +typedef u32 (*dt_hval_fn)(const struct dt_probe *); > +typedef int (*dt_cmp_fn)(const struct dt_probe *, const struct dt_probe *); > +typedef struct dt_probe *(*dt_add_fn)(struct dt_probe *, struct dt_probe *); > +typedef struct dt_probe *(*dt_del_fn)(struct dt_probe *, struct dt_probe *); > + > +extern struct dt_htab *dt_htab_new(dt_hval_fn hval, dt_cmp_fn cmp, > + dt_add_fn add, dt_del_fn del); > +extern int dt_htab_add(struct dt_htab *htab, struct dt_probe *probe); > +extern struct dt_probe *dt_htab_lookup(const struct dt_htab *htab, > + const struct dt_probe *probe); > +extern int dt_htab_del(struct dt_htab *htab, struct dt_probe *probe); > + > +struct dt_probe { > + u32 id; > + int event_fd; > + const struct dt_provider *prov; > + const char *prv_name; /* provider name */ > + const char *mod_name; /* module name */ > + const char *fun_name; /* function name */ > + const char *prb_name; /* probe name */ > + struct dt_hentry he_fqn; > +}; > + > +typedef void (*dt_probe_fn)(const struct dt_probe *probe); > + > +extern int dt_probe_init(void); > +extern int dt_probe_new(const struct dt_provider *prov, const char *pname, > + const char *mname, const char *fname, const char *name); > +extern struct dt_probe *dt_probe_by_name(const struct dt_probe *tmpl); > +extern struct dt_probe *dt_probe_resolve_event(const char *name); > + > +extern int dt_bpf_list_probes(const char *fn); > +extern int dt_bpf_load_file(const char *fn); > +extern int dt_bpf_map_update(int fd, const void *key, const void *val); > +extern int dt_bpf_attach(int event_id, int bpf_fd); > + > +extern int dt_bufmap_fd; > + > +extern int dt_buffer_init(int num_pages); > +extern int dt_buffer_poll(int epoll_fd, int timeout); > +extern void dt_buffer_exit(int epoll_fd); > + > +static inline int perf_event_open(struct perf_event_attr *attr, pid_t pid, > + int cpu, int group_fd, unsigned long flags) > +{ > + return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags); > +} > + > +extern inline int bpf(enum bpf_cmd cmd, union bpf_attr *attr) > +{ > + return syscall(__NR_bpf, cmd, attr, sizeof(union bpf_attr)); > +} > + > +#endif /* _DTRACE_H */ > -- > 2.20.1

diff --git a/MAINTAINERS b/MAINTAINERS index cfa9ed89c031..410240732d55 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5485,6 +5485,12 @@ W: https://linuxtv.org S: Odd Fixes F: drivers/media/pci/dt3155/ +DTRACE +M: Kris Van Hees <kris.van.hees@oracle.com> +L: dtrace-devel@oss.oracle.com +S: Maintained +F: tools/dtrace/ + DVB_USB_AF9015 MEDIA DRIVER M: Antti Palosaari <crope@iki.fi> L: linux-media@vger.kernel.org diff --git a/tools/dtrace/Makefile b/tools/dtrace/Makefile new file mode 100644 index 000000000000..03ae498d1429 --- /dev/null +++ b/tools/dtrace/Makefile @@ -0,0 +1,87 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# This Makefile is based on samples/bpf. +# +# Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + +DT_VERSION := 2.0.0 +DT_GIT_VERSION := $(shell git rev-parse HEAD 2>/dev/null || \ + echo Unknown) + +DTRACE_PATH ?= $(abspath $(srctree)/$(src)) +TOOLS_PATH := $(DTRACE_PATH)/.. +SAMPLES_PATH := $(DTRACE_PATH)/../../samples + +hostprogs-y := dtrace + +LIBBPF := $(TOOLS_PATH)/lib/bpf/libbpf.a +OBJS := dt_bpf.o dt_buffer.o dt_utils.o dt_probe.o \ + dt_hash.o \ + dt_fbt.o dt_syscall.o + +dtrace-objs := $(OBJS) dtrace.o + +always := $(hostprogs-y) +always += bpf_sample.o + +KBUILD_HOSTCFLAGS += -DDT_VERSION=\"$(DT_VERSION)\" +KBUILD_HOSTCFLAGS += -DDT_GIT_VERSION=\"$(DT_GIT_VERSION)\" +KBUILD_HOSTCFLAGS += -I$(srctree)/tools/lib +KBUILD_HOSTCFLAGS += -I$(srctree)/tools/include/uapi +KBUILD_HOSTCFLAGS += -I$(srctree)/tools/include/ +KBUILD_HOSTCFLAGS += -I$(srctree)/usr/include + +KBUILD_HOSTLDLIBS := $(LIBBPF) -lelf + +LLC ?= llc +CLANG ?= clang +LLVM_OBJCOPY ?= llvm-objcopy + +ifdef CROSS_COMPILE +HOSTCC = $(CROSS_COMPILE)gcc +CLANG_ARCH_ARGS = -target $(ARCH) +endif + +all: + $(MAKE) -C ../../ $(CURDIR)/ DTRACE_PATH=$(CURDIR) + +clean: + $(MAKE) -C ../../ M=$(CURDIR) clean + @rm -f *~ + +$(LIBBPF): FORCE + $(MAKE) -C $(dir $@) RM='rm -rf' LDFLAGS= srctree=$(DTRACE_PATH)/../../ O= + +FORCE: + +.PHONY: verify_cmds verify_target_bpf $(CLANG) $(LLC) + +verify_cmds: $(CLANG) $(LLC) + @for TOOL in $^ ; do \ + if ! (which -- "$${TOOL}" > /dev/null 2>&1); then \ + echo "*** ERROR: Cannot find LLVM tool $${TOOL}" ;\ + exit 1; \ + else true; fi; \ + done + +verify_target_bpf: verify_cmds + @if ! (${LLC} -march=bpf -mattr=help > /dev/null 2>&1); then \ + echo "*** ERROR: LLVM (${LLC}) does not support 'bpf' target" ;\ + echo " NOTICE: LLVM version >= 3.7.1 required" ;\ + exit 2; \ + else true; fi + +$(DTRACE_PATH)/*.c: verify_target_bpf $(LIBBPF) +$(src)/*.c: verify_target_bpf $(LIBBPF) + +$(obj)/%.o: $(src)/%.c + @echo " CLANG-bpf " $@ + $(Q)$(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) -I$(obj) \ + -I$(srctree)/tools/testing/selftests/bpf/ \ + -D__KERNEL__ -D__BPF_TRACING__ -Wno-unused-value -Wno-pointer-sign \ + -D__TARGET_ARCH_$(ARCH) -Wno-compare-distinct-pointer-types \ + -Wno-gnu-variable-sized-type-not-at-end \ + -Wno-address-of-packed-member -Wno-tautological-compare \ + -Wno-unknown-warning-option $(CLANG_ARCH_ARGS) \ + -I$(srctree)/samples/bpf/ -include asm_goto_workaround.h \ + -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf $(LLC_FLAGS) -filetype=obj -o $@ diff --git a/tools/dtrace/bpf_sample.c b/tools/dtrace/bpf_sample.c new file mode 100644 index 000000000000..9862f75f92d3 --- /dev/null +++ b/tools/dtrace/bpf_sample.c @@ -0,0 +1,146 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This sample DTrace BPF tracing program demonstrates how actions can be + * associated with different probe types. + * + * The kprobe/ksys_write probe is a Function Boundary Tracing (FBT) entry probe + * on the ksys_write(fd, buf, count) function in the kernel. Arguments to the + * function can be retrieved from the CPU registers (struct pt_regs). + * + * The tracepoint/syscalls/sys_enter_write probe is a System Call entry probe + * for the write(d, buf, count) system call. Arguments to the system call can + * be retrieved from the tracepoint data passed to the BPF program as context + * struct syscall_data) when the probe fires. + * + * The BPF program associated with each probe prepares a DTrace BPF context + * (struct dt_bpf_context) that stores the probe ID and up to 10 arguments. + * Only 3 arguments are used in this sample. Then the prorgams call a shared + * BPF function (bpf_action) that implements the actual action to be taken when + * a probe fires. It prepares a data record to be stored in the tracing buffer + * and submits it to the buffer. The data in the data record is obtained from + * the DTrace BPF context. + * + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + */ +#include <uapi/linux/bpf.h> +#include <linux/ptrace.h> +#include <linux/version.h> +#include <uapi/linux/unistd.h> +#include "bpf_helpers.h" + +#include "dtrace.h" + +struct syscall_data { + struct pt_regs *regs; + long syscall_nr; + long arg[6]; +}; + +struct bpf_map_def SEC("maps") buffers = { + .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, + .key_size = sizeof(u32), + .value_size = sizeof(u32), + .max_entries = NR_CPUS, +}; + +#if defined(bpf_target_x86) +# define PT_REGS_PARM6(x) ((x)->r9) +#elif defined(bpf_target_s390x) +# define PT_REGS_PARM6(x) ((x)->gprs[7]) +#elif defined(bpf_target_arm) +# define PT_REGS_PARM6(x) ((x)->uregs[5]) +#elif defined(bpf_target_arm64) +# define PT_REGS_PARM6(x) ((x)->regs[5]) +#elif defined(bpf_target_mips) +# define PT_REGS_PARM6(x) ((x)->regs[9]) +#elif defined(bpf_target_powerpc) +# define PT_REGS_PARM6(x) ((x)->gpr[8]) +#elif defined(bpf_target_sparc) +# define PT_REGS_PARM6(x) ((x)->u_regs[UREG_I5]) +#else +# error Argument retrieval from pt_regs is not supported yet on this arch. +#endif + +/* + * We must pass a valid BPF context pointer because the bpf_perf_event_output() + * helper requires a BPF context pointer as first argument (and the verifier is + * validating that we pass a value that is known to be a context pointer). + * + * This BPF function implements the following D action: + * { + * trace(curthread); + * trace(arg0); + * trace(arg1); + * trace(arg2); + * } + * + * Expected output will look like: + * CPU ID + * 15 70423 0xffff8c0968bf8ec0 0x00000000000001 0x0055e019eb3f60 0x0000000000002c + * 15 18876 0xffff8c0968bf8ec0 0x00000000000001 0x0055e019eb3f60 0x0000000000002c + * | | +-- curthread +--> arg0 (fd) +--> arg1 (buf) +-- arg2 (count) + * | | + * | +--> probe ID + * | + * +--> CPU the probe fired on + */ +static noinline int bpf_action(void *bpf_ctx, struct dt_bpf_context *ctx) +{ + int cpu = bpf_get_smp_processor_id(); + struct data { + u32 probe_id; /* mandatory */ + + u64 task; /* first data item (current task) */ + u64 arg0; /* 2nd data item (arg0, fd) */ + u64 arg1; /* 3rd data item (arg1, buf) */ + u64 arg2; /* 4th data item (arg2, count) */ + } rec; + + memset(&rec, 0, sizeof(rec)); + + rec.probe_id = ctx->probe_id; + rec.task = bpf_get_current_task(); + rec.arg0 = ctx->argv[0]; + rec.arg1 = ctx->argv[1]; + rec.arg2 = ctx->argv[2]; + + bpf_perf_event_output(bpf_ctx, &buffers, cpu, &rec, sizeof(rec)); + + return 0; +} + +SEC("kprobe/ksys_write") +int bpf_kprobe(struct pt_regs *regs) +{ + struct dt_bpf_context ctx; + + memset(&ctx, 0, sizeof(ctx)); + + ctx.probe_id = 18876; + ctx.argv[0] = PT_REGS_PARM1(regs); + ctx.argv[1] = PT_REGS_PARM2(regs); + ctx.argv[2] = PT_REGS_PARM3(regs); + ctx.argv[3] = PT_REGS_PARM4(regs); + ctx.argv[4] = PT_REGS_PARM5(regs); + ctx.argv[5] = PT_REGS_PARM6(regs); + + return bpf_action(regs, &ctx); +} + +SEC("tracepoint/syscalls/sys_enter_write") +int bpf_tp(struct syscall_data *scd) +{ + struct dt_bpf_context ctx; + + memset(&ctx, 0, sizeof(ctx)); + + ctx.probe_id = 70423; + ctx.argv[0] = scd->arg[0]; + ctx.argv[1] = scd->arg[1]; + ctx.argv[2] = scd->arg[2]; + + return bpf_action(scd, &ctx); +} + +char _license[] SEC("license") = "GPL"; +u32 _version SEC("version") = LINUX_VERSION_CODE; diff --git a/tools/dtrace/dt_bpf.c b/tools/dtrace/dt_bpf.c new file mode 100644 index 000000000000..78c90de016c6 --- /dev/null +++ b/tools/dtrace/dt_bpf.c @@ -0,0 +1,185 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file provides the interface for handling BPF. It uses the bpf library + * to interact with BPF ELF object files. + * + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + */ +#include <errno.h> +#include <stdarg.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> +#include <bpf/libbpf.h> +#include <linux/kernel.h> +#include <linux/perf_event.h> +#include <sys/ioctl.h> + +#include "dtrace_impl.h" + +/* + * Validate the output buffer map that is specified in the BPF ELF object. It + * must match the following definition to be valid: + * + * struct bpf_map_def SEC("maps") buffers = { + * .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, + * .key_size = sizeof(u32), + * .value_size = sizeof(u32), + * .max_entries = num, + * }; + * where num is greater than dt_maxcpuid. + */ +static int is_valid_buffers(const struct bpf_map_def *mdef) +{ + return mdef->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && + mdef->key_size == sizeof(u32) && + mdef->value_size == sizeof(u32) && + mdef->max_entries > dt_maxcpuid; +} + +/* + * List the probes specified in the given BPF ELF object file. + */ +int dt_bpf_list_probes(const char *fn) +{ + struct bpf_object *obj; + struct bpf_program *prog; + int rc, fd; + + libbpf_set_print(NULL); + + /* + * Listing probes is done before the DTrace command line utility loads + * the supplied programs. We load them here without attaching them to + * probes so that we can retrieve the ELF section names for each BPF + * program. The section name indicates the probe that the program is + * associated with. + */ + rc = bpf_prog_load(fn, BPF_PROG_TYPE_UNSPEC, &obj, &fd); + if (rc) + return rc; + + /* + * Loop through the programs in the BPF ELF object, and try to resolve + * the section names into probes. Use the supplied callback function + * to emit the probe description. + */ + for (prog = bpf_program__next(NULL, obj); prog != NULL; + prog = bpf_program__next(prog, obj)) { + struct dt_probe *probe; + + probe = dt_probe_resolve_event(bpf_program__title(prog, false)); + + printf("%5d %10s %17s %33s %s\n", probe->id, + probe->prv_name ? probe->prv_name : "", + probe->mod_name ? probe->mod_name : "", + probe->fun_name ? probe->fun_name : "", + probe->prb_name ? probe->prb_name : ""); + } + + + /* Done with the BPF ELF object. */ + bpf_object__close(obj); + + return 0; +} + +/* + * Load the given BPF ELF object file. + */ +int dt_bpf_load_file(const char *fn) +{ + struct bpf_object *obj; + struct bpf_map *map; + struct bpf_program *prog; + int rc, fd; + + libbpf_set_print(NULL); + + /* Load the BPF ELF object file. */ + rc = bpf_prog_load(fn, BPF_PROG_TYPE_UNSPEC, &obj, &fd); + if (rc) + return rc; + + /* Validate buffers map. */ + map = bpf_object__find_map_by_name(obj, "buffers"); + if (map && is_valid_buffers(bpf_map__def(map))) + dt_bufmap_fd = bpf_map__fd(map); + else + goto fail; + + /* + * Loop through the programs and resolve each into the matching probe. + * Attach the program to the probe. + */ + for (prog = bpf_program__next(NULL, obj); prog != NULL; + prog = bpf_program__next(prog, obj)) { + struct dt_probe *probe; + + probe = dt_probe_resolve_event(bpf_program__title(prog, false)); + if (!probe) + return -ENOENT; + if (probe->prov && probe->prov->attach) + probe->prov->attach(bpf_program__title(prog, false), + bpf_program__fd(prog)); + } + + return 0; + +fail: + bpf_object__close(obj); + return -EINVAL; +} + +/* + * Store the (key, value) pair in the map referenced by the given fd. + */ +int dt_bpf_map_update(int fd, const void *key, const void *val) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + + attr.map_fd = fd; + attr.key = (u64)(unsigned long)key; + attr.value = (u64)(unsigned long)val; + attr.flags = 0; + + return bpf(BPF_MAP_UPDATE_ELEM, &attr); +} + +/* + * Attach a trace event and associate a BPF program with it. + */ +int dt_bpf_attach(int event_id, int bpf_fd) +{ + int event_fd; + int rc; + struct perf_event_attr attr = {}; + + attr.type = PERF_TYPE_TRACEPOINT; + attr.sample_type = PERF_SAMPLE_RAW; + attr.sample_period = 1; + attr.wakeup_events = 1; + attr.config = event_id; + + /* + * Register the event (based on its id), and obtain a fd. It gets + * created as an enabled probe, so we don't have to explicitly enable + * it. + */ + event_fd = perf_event_open(&attr, -1, 0, -1, 0); + if (event_fd < 0) { + perror("sys_perf_event_open"); + return -1; + } + + /* Associate the BPF program with the event. */ + rc = ioctl(event_fd, PERF_EVENT_IOC_SET_BPF, bpf_fd); + if (rc < 0) { + perror("PERF_EVENT_IOC_SET_BPF"); + return -1; + } + + return 0; +} diff --git a/tools/dtrace/dt_buffer.c b/tools/dtrace/dt_buffer.c new file mode 100644 index 000000000000..19bb7e4cfc92 --- /dev/null +++ b/tools/dtrace/dt_buffer.c @@ -0,0 +1,338 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file provides the tracing buffer handling for DTrace. It makes use of + * the perf event output ring buffers that can be written to from BPF programs. + * + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + */ +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <syscall.h> +#include <unistd.h> +#include <sys/epoll.h> +#include <sys/ioctl.h> +#include <sys/mman.h> +#include <linux/bpf.h> +#include <linux/perf_event.h> +#include <linux/ring_buffer.h> + +#include "dtrace_impl.h" + +/* + * Probe data is recorded in per-CPU perf ring buffers. + */ +struct dtrace_buffer { + int cpu; /* ID of CPU that uses this buffer */ + int fd; /* fd of perf output buffer */ + size_t page_size; /* size of each page in buffer */ + size_t data_size; /* total buffer size */ + u8 *base; /* address of buffer */ + u8 *endp; /* address of end of buffer */ + u8 *tmp; /* temporary event buffer */ + u32 tmp_len; /* length of temporary event buffer */ +}; + +static struct dtrace_buffer *dt_buffers; + +/* + * File descriptor for the BPF map that holds the buffers for the online CPUs. + * The map is a bpf_array indexed by CPU id, and it stores a file descriptor as + * value (the fd for the perf_event that represents the CPU buffer). + */ +int dt_bufmap_fd = -1; + +/* + * Create a perf_event buffer for the given DTrace buffer. This will create + * a perf_event ring_buffer, mmap it, and enable the perf_event that owns the + * buffer. + */ +static int perf_buffer_open(struct dtrace_buffer *buf) +{ + int pefd; + struct perf_event_attr attr = {}; + + /* + * Event configuration for BPF-generated output in perf_event ring + * buffers. The event is created in enabled state. + */ + attr.config = PERF_COUNT_SW_BPF_OUTPUT; + attr.type = PERF_TYPE_SOFTWARE; + attr.sample_type = PERF_SAMPLE_RAW; + attr.sample_period = 1; + attr.wakeup_events = 1; + pefd = perf_event_open(&attr, -1, buf->cpu, -1, PERF_FLAG_FD_CLOEXEC); + if (pefd < 0) { + fprintf(stderr, "perf_event_open(cpu %d): %s\n", buf->cpu, + strerror(errno)); + goto fail; + } + + /* + * We add buf->page_size to the buf->data_size, because perf maintains + * a meta-data page at the beginning of the memory region. That page + * is used for reader/writer symchronization. + */ + buf->fd = pefd; + buf->base = mmap(NULL, buf->page_size + buf->data_size, + PROT_READ | PROT_WRITE, MAP_SHARED, buf->fd, 0); + buf->endp = buf->base + buf->page_size + buf->data_size - 1; + if (!buf->base) + goto fail; + + return 0; + +fail: + if (buf->base) { + munmap(buf->base, buf->page_size + buf->data_size); + buf->base = NULL; + buf->endp = NULL; + } + if (buf->fd) { + close(buf->fd); + buf->fd = -1; + } + + return -1; +} + +/* + * Close the given DTrace buffer. This function disables the perf_event that + * owns the buffer, munmaps the memory space, and closes the perf buffer fd. + */ +static void perf_buffer_close(struct dtrace_buffer *buf) +{ + /* + * If the perf buffer failed to open, there is no need to close it. + */ + if (buf->fd < 0) + return; + + if (ioctl(buf->fd, PERF_EVENT_IOC_DISABLE, 0) < 0) + fprintf(stderr, "PERF_EVENT_IOC_DISABLE(cpu %d): %s\n", + buf->cpu, strerror(errno)); + + munmap(buf->base, buf->page_size + buf->data_size); + + if (close(buf->fd)) + fprintf(stderr, "perf buffer close(cpu %d): %s\n", + buf->cpu, strerror(errno)); + + buf->base = NULL; + buf->fd = -1; +} + +/* + * Initialize the probe data buffers (one per online CPU). Each buffer will + * contain the given number of pages (i.e. total size of each buffer will be + * num_pages * getpagesize()). This function also sets up an event polling + * descriptor that monitors all CPU buffers at once. + */ +int dt_buffer_init(int num_pages) +{ + int i; + int epoll_fd; + + if (dt_bufmap_fd < 0) + return -EINVAL; + + /* Allocate the per-CPU buffer structs. */ + dt_buffers = calloc(dt_numcpus, sizeof(struct dtrace_buffer)); + if (dt_buffers == NULL) + return -ENOMEM; + + /* Set up the event polling file descriptor. */ + epoll_fd = epoll_create1(EPOLL_CLOEXEC); + if (epoll_fd < 0) { + free(dt_buffers); + return -errno; + } + + for (i = 0; i < dt_numcpus; i++) { + int cpu = dt_cpuids[i]; + struct epoll_event ev; + struct dtrace_buffer *buf = &dt_buffers[i]; + + buf->cpu = cpu; + buf->page_size = getpagesize(); + buf->data_size = num_pages * buf->page_size; + buf->tmp = NULL; + buf->tmp_len = 0; + + /* Try to create the perf buffer for this DTrace buffer. */ + if (perf_buffer_open(buf) == -1) + continue; + + /* Store the perf buffer fd in the buffer map. */ + dt_bpf_map_update(dt_bufmap_fd, &cpu, &buf->fd); + + /* Add the buffer to the event polling descriptor. */ + ev.events = EPOLLIN; + ev.data.ptr = buf; + if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, buf->fd, &ev) == -1) { + fprintf(stderr, "EPOLL_CTL_ADD(cpu %d): %s\n", + buf->cpu, strerror(errno)); + continue; + } + } + + return epoll_fd; +} + +/* + * Clean up the buffers. + */ +void dt_buffer_exit(int epoll_fd) +{ + int i; + + for (i = 0; i < dt_numcpus; i++) + perf_buffer_close(&dt_buffers[i]); + + free(dt_buffers); + close(epoll_fd); +} + +/* + * Process and output the probe data at the supplied address. + */ +static void output_event(int cpu, u64 *buf) +{ + u8 *data = (u8 *)buf; + struct perf_event_header *hdr; + + hdr = (struct perf_event_header *)data; + data += sizeof(struct perf_event_header); + + if (hdr->type == PERF_RECORD_SAMPLE) { + u8 *ptr = data; + u32 i, size, probe_id; + + /* + * struct { + * struct perf_event_header header; + * u32 size; + * u32 probe_id; + * u32 gap; + * u64 data[n]; + * } + * and data points to the 'size' member at this point. + */ + if (ptr > (u8 *)buf + hdr->size) { + fprintf(stderr, "BAD: corrupted sample header\n"); + return; + } + + size = *(u32 *)data; + data += sizeof(size); + ptr += sizeof(size) + size; + if (ptr != (u8 *)buf + hdr->size) { + fprintf(stderr, "BAD: invalid sample size\n"); + return; + } + + probe_id = *(u32 *)data; + data += sizeof(probe_id); + size -= sizeof(probe_id); + data += sizeof(u32); /* skip 32-bit gap */ + size -= sizeof(u32); + buf = (u64 *)data; + + printf("%3d %6d ", cpu, probe_id); + for (i = 0, size /= sizeof(u64); i < size; i++) + printf("%#016lx ", buf[i]); + printf("\n"); + } else if (hdr->type == PERF_RECORD_LOST) { + u64 lost; + + /* + * struct { + * struct perf_event_header header; + * u64 id; + * u64 lost; + * } + * and data points to the 'id' member at this point. + */ + lost = *(u64 *)(data + sizeof(u64)); + + printf("[%ld probes dropped]\n", lost); + } else + fprintf(stderr, "UNKNOWN: record type %d\n", hdr->type); +} + +/* + * Process the available probe data in the given buffer. + */ +static void process_data(struct dtrace_buffer *buf) +{ + struct perf_event_mmap_page *rb_page = (void *)buf->base; + struct perf_event_header *hdr; + u8 *base; + u64 head, tail; + + /* Set base to be the start of the buffer data. */ + base = buf->base + buf->page_size; + + for (;;) { + head = ring_buffer_read_head(rb_page); + tail = rb_page->data_tail; + + if (tail == head) + break; + + do { + u8 *event = base + tail % buf->data_size; + u32 len; + + hdr = (struct perf_event_header *)event; + len = hdr->size; + + /* + * If the perf event data wraps around the boundary of + * the buffer, we make a copy in contiguous memory. + */ + if (event + len > buf->endp) { + u8 *dst; + u32 num; + + /* Increase buffer as needed. */ + if (buf->tmp_len < len) { + buf->tmp = realloc(buf->tmp, len); + buf->tmp_len = len; + } + + dst = buf->tmp; + num = buf->endp - event + 1; + memcpy(dst, event, num); + memcpy(dst + num, base, len - num); + + event = dst; + } + + output_event(buf->cpu, (u64 *)event); + + tail += hdr->size; + } while (tail != head); + + ring_buffer_write_tail(rb_page, tail); + } +} + +/* + * Wait for data to become available in any of the buffers. + */ +int dt_buffer_poll(int epoll_fd, int timeout) +{ + struct epoll_event events[dt_numcpus]; + int i, cnt; + + cnt = epoll_wait(epoll_fd, events, dt_numcpus, timeout); + if (cnt < 0) + return -errno; + + for (i = 0; i < cnt; i++) + process_data((struct dtrace_buffer *)events[i].data.ptr); + + return cnt; +} diff --git a/tools/dtrace/dt_fbt.c b/tools/dtrace/dt_fbt.c new file mode 100644 index 000000000000..fcf95243bf97 --- /dev/null +++ b/tools/dtrace/dt_fbt.c @@ -0,0 +1,201 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * The Function Boundary Tracing (FBT) provider for DTrace. + * + * FBT probes are exposed by the kernel as kprobes. They are listed in the + * TRACEFS/available_filter_functions file. Some kprobes are associated with + * a specific kernel module, while most are in the core kernel. + * + * Mapping from event name to DTrace probe name: + * + * <name> fbt:vmlinux:<name>:entry + * fbt:vmlinux:<name>:return + * or + * <name> [<modname>] fbt:<modname>:<name>:entry + * fbt:<modname>:<name>:return + * + * Mapping from BPF section name to DTrace probe name: + * + * kprobe/<name> fbt:vmlinux:<name>:entry + * kretprobe/<name> fbt:vmlinux:<name>:return + * + * (Note that the BPF section does not carry information about the module that + * the function is found in. This means that BPF section name cannot be used + * to distinguish between functions with the same name occurring in different + * modules.) + * + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + */ +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <linux/bpf.h> +#include <sys/stat.h> +#include <sys/types.h> + +#include "dtrace_impl.h" + +#define KPROBE_EVENTS TRACEFS "kprobe_events" +#define PROBE_LIST TRACEFS "available_filter_functions" + +static const char provname[] = "fbt"; +static const char modname[] = "vmlinux"; + +/* + * Scan the PROBE_LIST file and add entry and return probes for every function + * that is listed. + */ +static int fbt_populate(void) +{ + FILE *f; + char buf[256]; + char *p; + + f = fopen(PROBE_LIST, "r"); + if (f == NULL) + return -1; + + while (fgets(buf, sizeof(buf), f)) { + /* + * Here buf is either "funcname\n" or "funcname [modname]\n". + */ + p = strchr(buf, '\n'); + if (p) { + *p = '\0'; + if (p > buf && *(--p) == ']') + *p = '\0'; + } else { + /* If we didn't see a newline, the line was too long. + * Report it, and continue until the end of the line. + */ + fprintf(stderr, "%s: Line too long: %s\n", + PROBE_LIST, buf); + do + fgets(buf, sizeof(buf), f); + while (strchr(buf, '\n') == NULL); + continue; + } + + /* + * Now buf is either "funcname" or "funcname [modname". If + * there is no module name provided, we will use the default. + */ + p = strchr(buf, ' '); + if (p) { + *p++ = '\0'; + if (*p == '[') + p++; + } + + dt_probe_new(&dt_fbt, provname, p ? p : modname, buf, "entry"); + dt_probe_new(&dt_fbt, provname, p ? p : modname, buf, "return"); + } + + fclose(f); + + return 0; +} + +#define ENTRY_PREFIX "kprobe/" +#define EXIT_PREFIX "kretprobe/" + +/* + * Perform a probe lookup based on an event name (BPF ELF section name). + */ +static struct dt_probe *fbt_resolve_event(const char *name) +{ + const char *prbname; + struct dt_probe tmpl; + struct dt_probe *probe; + + if (!name) + return NULL; + + if (strncmp(name, ENTRY_PREFIX, sizeof(ENTRY_PREFIX) - 1) == 0) { + name += sizeof(ENTRY_PREFIX) - 1; + prbname = "entry"; + } else if (strncmp(name, EXIT_PREFIX, sizeof(EXIT_PREFIX) - 1) == 0) { + name += sizeof(EXIT_PREFIX) - 1; + prbname = "return"; + } else + return NULL; + + memset(&tmpl, 0, sizeof(tmpl)); + tmpl.prv_name = provname; + tmpl.mod_name = modname; + tmpl.fun_name = name; + tmpl.prb_name = prbname; + + probe = dt_probe_by_name(&tmpl); + + return probe; +} + +/* + * Attach the given BPF program (identified by its file descriptor) to the + * kprobe identified by the given section name. + */ +static int fbt_attach(const char *name, int bpf_fd) +{ + char efn[256]; + char buf[256]; + int event_id, fd, rc; + + name += 7; /* skip "kprobe/" */ + snprintf(buf, sizeof(buf), "p:%s %s\n", name, name); + + /* + * Register the kprobe with the tracing subsystem. This will create + * a tracepoint event. + */ + fd = open(KPROBE_EVENTS, O_WRONLY | O_APPEND); + if (fd < 0) { + perror(KPROBE_EVENTS); + return -1; + } + rc = write(fd, buf, strlen(buf)); + if (rc < 0) { + perror(KPROBE_EVENTS); + close(fd); + return -1; + } + close(fd); + + /* + * Read the tracepoint event id for the kprobe we just registered. + */ + strcpy(efn, EVENTSFS); + strcat(efn, "kprobes/"); + strcat(efn, name); + strcat(efn, "/id"); + + fd = open(efn, O_RDONLY); + if (fd < 0) { + perror(efn); + return -1; + } + rc = read(fd, buf, sizeof(buf)); + if (rc < 0 || rc >= sizeof(buf)) { + perror(efn); + close(fd); + return -1; + } + close(fd); + buf[rc] = '\0'; + event_id = atoi(buf); + + /* + * Attaching a BPF program (by file descriptor) to an event (by ID) is + * a generic operation provided by the BPF interface code. + */ + return dt_bpf_attach(event_id, bpf_fd); +} + +struct dt_provider dt_fbt = { + .name = "fbt", + .populate = &fbt_populate, + .resolve_event = &fbt_resolve_event, + .attach = &fbt_attach, +}; diff --git a/tools/dtrace/dt_hash.c b/tools/dtrace/dt_hash.c new file mode 100644 index 000000000000..b1f563bc0773 --- /dev/null +++ b/tools/dtrace/dt_hash.c @@ -0,0 +1,211 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file provides a generic hashtable implementation for probes. + * + * The hashtable is created with 4 user-provided functions: + * hval(probe) - calculate a hash value for the given probe + * cmp(probe1, probe2) - compare two probes + * add(head, probe) - add a probe to a list of probes + * del(head, probe) - delete a probe from a list of probes + * + * Probes are hashed into a hashtable slot based on the return value of + * hval(probe). Each hashtable slot holds a list of buckets, with each + * bucket storing probes that are equal under the cmp(probe1, probe2) + * function. Probes are added to the list of probes in a bucket using the + * add(head, probe) function, and they are deleted using a call to the + * del(head, probe) function. + * + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + */ +#include <errno.h> +#include <stdint.h> +#include <stdlib.h> + +#include "dtrace_impl.h" + +/* + * Hashtable implementation for probes. + */ +struct dt_hbucket { + u32 hval; + struct dt_hbucket *next; + struct dt_probe *head; + int nprobes; +}; + +struct dt_htab { + struct dt_hbucket **tab; + int size; + int mask; + int nbuckets; + dt_hval_fn hval; /* calculate hash value */ + dt_cmp_fn cmp; /* compare 2 probes */ + dt_add_fn add; /* add probe to list */ + dt_del_fn del; /* delete probe from list */ +}; + +/* + * Create a new (empty) hashtable. + */ +struct dt_htab *dt_htab_new(dt_hval_fn hval, dt_cmp_fn cmp, dt_add_fn add, + dt_del_fn del) +{ + struct dt_htab *htab = malloc(sizeof(struct dt_htab)); + + if (!htab) + return NULL; + + htab->size = 1; + htab->mask = htab->size - 1; + htab->nbuckets = 0; + htab->hval = hval; + htab->cmp = cmp; + htab->add = add; + htab->del = del; + + htab->tab = calloc(htab->size, sizeof(struct dt_hbucket *)); + if (!htab->tab) { + free(htab); + return NULL; + } + + return htab; +} + +/* + * Resize the hashtable by doubling the number of slots. + */ +static int resize(struct dt_htab *htab) +{ + int i; + int osize = htab->size; + int nsize = osize << 1; + int nmask = nsize - 1; + struct dt_hbucket **ntab; + + ntab = calloc(nsize, sizeof(struct dt_hbucket *)); + if (!ntab) + return -ENOMEM; + + for (i = 0; i < osize; i++) { + struct dt_hbucket *bucket, *next; + + for (bucket = htab->tab[i]; bucket; bucket = next) { + int idx = bucket->hval & nmask; + + next = bucket->next; + bucket->next = ntab[idx]; + ntab[idx] = bucket; + } + } + + free(htab->tab); + htab->tab = ntab; + htab->size = nsize; + htab->mask = nmask; + + return 0; +} + +/* + * Add a probe to the hashtable. Resize if necessary, and allocate a new + * bucket if necessary. + */ +int dt_htab_add(struct dt_htab *htab, struct dt_probe *probe) +{ + u32 hval = htab->hval(probe); + int idx; + struct dt_hbucket *bucket; + +retry: + idx = hval & htab->mask; + for (bucket = htab->tab[idx]; bucket; bucket = bucket->next) { + if (htab->cmp(bucket->head, probe) == 0) + goto add; + } + + if ((htab->nbuckets >> 1) > htab->size) { + int err; + + err = resize(htab); + if (err) + return err; + + goto retry; + } + + bucket = malloc(sizeof(struct dt_hbucket)); + if (!bucket) + return -ENOMEM; + + bucket->hval = hval; + bucket->next = htab->tab[idx]; + bucket->head = NULL; + bucket->nprobes = 0; + htab->tab[idx] = bucket; + htab->nbuckets++; + +add: + bucket->head = htab->add(bucket->head, probe); + bucket->nprobes++; + + return 0; +} + +/* + * Find a probe in the hashtable. + */ +struct dt_probe *dt_htab_lookup(const struct dt_htab *htab, + const struct dt_probe *probe) +{ + u32 hval = htab->hval(probe); + int idx = hval & htab->mask; + struct dt_hbucket *bucket; + + for (bucket = htab->tab[idx]; bucket; bucket = bucket->next) { + if (htab->cmp(bucket->head, probe) == 0) + return bucket->head; + } + + return NULL; +} + +/* + * Remove a probe from the hashtable. If we are deleting the last probe in a + * bucket, get rid of the bucket. + */ +int dt_htab_del(struct dt_htab *htab, struct dt_probe *probe) +{ + u32 hval = htab->hval(probe); + int idx = hval & htab->mask; + struct dt_hbucket *bucket; + struct dt_probe *head; + + for (bucket = htab->tab[idx]; bucket; bucket = bucket->next) { + if (htab->cmp(bucket->head, probe) == 0) + break; + } + + if (bucket == NULL) + return -ENOENT; + + head = htab->del(bucket->head, probe); + if (!head) { + struct dt_hbucket *b = htab->tab[idx]; + + if (bucket == b) + htab->tab[idx] = bucket->next; + else { + while (b->next != bucket) + b = b->next; + + b->next = bucket->next; + } + + htab->nbuckets--; + free(bucket); + } else + bucket->head = head; + + return 0; +} diff --git a/tools/dtrace/dt_probe.c b/tools/dtrace/dt_probe.c new file mode 100644 index 000000000000..0b6228eaff29 --- /dev/null +++ b/tools/dtrace/dt_probe.c @@ -0,0 +1,230 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file implements the interface to probes grouped by provider. + * + * Probes are named by a set of 4 identifiers: + * - provider name + * - module name + * - function name + * - probe name + * + * The Fully Qualified Name (FQN) is "provider:module:function:name". + * + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + */ +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <linux/bpf.h> +#include <linux/kernel.h> + +#include "dtrace_impl.h" + +static struct dt_provider *dt_providers[] = { + &dt_fbt, + &dt_syscall, + }; + +static struct dt_htab *ht_byfqn; + +static u32 next_probe_id; + +/* + * Calculate a hash value based on a given string and an initial value. The + * initial value is used to calculate compound hash values, e.g. + * + * u32 hval; + * + * hval = str2hval(str1, 0); + * hval = str2hval(str2, hval); + */ +static u32 str2hval(const char *p, u32 hval) +{ + u32 g; + + if (!p) + return hval; + + while (*p) { + hval = (hval << 4) + *p++; + g = hval & 0xf0000000; + if (g != 0) + hval ^= g >> 24; + + hval &= ~g; + } + + return hval; +} + +/* + * String compare function that can handle either or both strings being NULL. + */ +static int safe_strcmp(const char *p, const char *q) +{ + return (!p) ? (!q) ? 0 + : -1 + : (!q) ? 1 + : strcmp(p, q); +} + +/* + * Calculate the hash value of a probe as the cummulative hash value of the + * FQN. + */ +static u32 fqn_hval(const struct dt_probe *probe) +{ + u32 hval = 0; + + hval = str2hval(probe->prv_name, hval); + hval = str2hval(":", hval); + hval = str2hval(probe->mod_name, hval); + hval = str2hval(":", hval); + hval = str2hval(probe->fun_name, hval); + hval = str2hval(":", hval); + hval = str2hval(probe->prb_name, hval); + + return hval; +} + +/* + * Compare two probes based on the FQN. + */ +static int fqn_cmp(const struct dt_probe *p, const struct dt_probe *q) +{ + int rc; + + rc = safe_strcmp(p->prv_name, q->prv_name); + if (rc) + return rc; + rc = safe_strcmp(p->mod_name, q->mod_name); + if (rc) + return rc; + rc = safe_strcmp(p->fun_name, q->fun_name); + if (rc) + return rc; + rc = safe_strcmp(p->prb_name, q->prb_name); + if (rc) + return rc; + + return 0; +} + +/* + * Add the given probe 'new' to the double-linked probe list 'head'. Probe + * 'new' becomes the new list head. + */ +static struct dt_probe *fqn_add(struct dt_probe *head, struct dt_probe *new) +{ + if (!head) + return new; + + new->he_fqn.next = head; + head->he_fqn.prev = new; + + return new; +} + +/* + * Remove the given probe 'probe' from the double-linked probe list 'head'. + * If we are deleting the current head, the next probe in the list is returned + * as the new head. If that value is NULL, the list is now empty. + */ +static struct dt_probe *fqn_del(struct dt_probe *head, struct dt_probe *probe) +{ + if (head == probe) { + if (!probe->he_fqn.next) + return NULL; + + head = probe->he_fqn.next; + head->he_fqn.prev = NULL; + probe->he_fqn.next = NULL; + + return head; + } + + if (!probe->he_fqn.next) { + probe->he_fqn.prev->he_fqn.next = NULL; + probe->he_fqn.prev = NULL; + + return head; + } + + probe->he_fqn.prev->he_fqn.next = probe->he_fqn.next; + probe->he_fqn.next->he_fqn.prev = probe->he_fqn.prev; + probe->he_fqn.prev = probe->he_fqn.next = NULL; + + return head; +} + +/* + * Initialize the probe handling by populating the FQN hashtable with probes + * from all providers. + */ +int dt_probe_init(void) +{ + int i; + + ht_byfqn = dt_htab_new(fqn_hval, fqn_cmp, fqn_add, fqn_del); + + for (i = 0; i < ARRAY_SIZE(dt_providers); i++) { + if (dt_providers[i]->populate() < 0) + return -1; + } + + return 0; +} + +/* + * Allocate a new probe and add it to the FQN hashtable. + */ +int dt_probe_new(const struct dt_provider *prov, const char *pname, + const char *mname, const char *fname, const char *name) +{ + struct dt_probe *probe; + + probe = malloc(sizeof(struct dt_probe)); + if (!probe) + return -ENOMEM; + + memset(probe, 0, sizeof(struct dt_probe)); + probe->id = next_probe_id++; + probe->prov = prov; + probe->prv_name = pname ? strdup(pname) : NULL; + probe->mod_name = mname ? strdup(mname) : NULL; + probe->fun_name = fname ? strdup(fname) : NULL; + probe->prb_name = name ? strdup(name) : NULL; + + dt_htab_add(ht_byfqn, probe); + + return 0; +} + +/* + * Perform a probe lookup based on FQN. + */ +struct dt_probe *dt_probe_by_name(const struct dt_probe *tmpl) +{ + return dt_htab_lookup(ht_byfqn, tmpl); +} + +/* + * Resolve an event name (BPF ELF section name) into a probe. We query each + * provider, and as soon as we get a hit, we return the result. + */ +struct dt_probe *dt_probe_resolve_event(const char *name) +{ + int i; + struct dt_probe *probe; + + for (i = 0; i < ARRAY_SIZE(dt_providers); i++) { + if (!dt_providers[i]->resolve_event) + continue; + probe = dt_providers[i]->resolve_event(name); + if (probe) + return probe; + } + + return NULL; +} diff --git a/tools/dtrace/dt_syscall.c b/tools/dtrace/dt_syscall.c new file mode 100644 index 000000000000..6695a4a1c701 --- /dev/null +++ b/tools/dtrace/dt_syscall.c @@ -0,0 +1,179 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * The syscall provider for DTrace. + * + * System call probes are exposed by the kernel as tracepoint events in the + * "syscalls" group. Entry probe names start with "sys_enter_" and exit probes + * start with "sys_exit_". + * + * Mapping from event name to DTrace probe name: + * + * syscalls:sys_enter_<name> syscall:vmlinux:<name>:entry + * syscalls:sys_exit_<name> syscall:vmlinux:<name>:return + * + * Mapping from BPF section name to DTrace probe name: + * + * tracepoint/syscalls/sys_enter_<name> syscall:vmlinux:<name>:entry + * tracepoint/syscalls/sys_exit_<name> syscall:vmlinux:<name>:return + * + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + */ +#include <ctype.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <linux/bpf.h> +#include <sys/stat.h> +#include <sys/types.h> + +#include "dtrace_impl.h" + +static const char provname[] = "syscall"; +static const char modname[] = "vmlinux"; + +#define PROBE_LIST TRACEFS "available_events" + +#define PROV_PREFIX "syscalls:" +#define ENTRY_PREFIX "sys_enter_" +#define EXIT_PREFIX "sys_exit_" + +/* + * Scan the PROBE_LIST file and add probes for any syscalls events. + */ +static int syscall_populate(void) +{ + FILE *f; + char buf[256]; + + f = fopen(PROBE_LIST, "r"); + if (f == NULL) + return -1; + + while (fgets(buf, sizeof(buf), f)) { + char *p; + + /* * Here buf is "group:event". */ + p = strchr(buf, '\n'); + if (p) + *p = '\0'; + else { + /* + * If we didn't see a newline, the line was too long. + * Report it, and continue until the end of the line. + */ + fprintf(stderr, "%s: Line too long: %s\n", + PROBE_LIST, buf); + do + fgets(buf, sizeof(buf), f); + while (strchr(buf, '\n') == NULL); + continue; + } + + /* We need "group:" to match "syscalls:". */ + p = buf; + if (memcmp(p, PROV_PREFIX, sizeof(PROV_PREFIX) - 1) != 0) + continue; + + p += sizeof(PROV_PREFIX) - 1; + /* + * Now p will be just "event", and we are only interested in + * events that match "sys_enter_*" or "sys_exit_*". + */ + if (!memcmp(p, ENTRY_PREFIX, sizeof(ENTRY_PREFIX) - 1)) { + p += sizeof(ENTRY_PREFIX) - 1; + dt_probe_new(&dt_syscall, provname, modname, p, + "entry"); + } else if (!memcmp(p, EXIT_PREFIX, sizeof(EXIT_PREFIX) - 1)) { + p += sizeof(EXIT_PREFIX) - 1; + dt_probe_new(&dt_syscall, provname, modname, p, + "return"); + } + } + + fclose(f); + + return 0; +} + +#define EVENT_PREFIX "tracepoint/syscalls/" + +/* + * Perform a probe lookup based on an event name (BPF ELF section name). + */ +static struct dt_probe *systrace_resolve_event(const char *name) +{ + const char *prbname; + struct dt_probe tmpl; + struct dt_probe *probe; + + if (!name) + return NULL; + + /* Exclude anything that is not a syscalls tracepoint */ + if (strncmp(name, EVENT_PREFIX, sizeof(EVENT_PREFIX) - 1) != 0) + return NULL; + name += sizeof(EVENT_PREFIX) - 1; + + if (strncmp(name, ENTRY_PREFIX, sizeof(ENTRY_PREFIX) - 1) == 0) { + name += sizeof(ENTRY_PREFIX) - 1; + prbname = "entry"; + } else if (strncmp(name, EXIT_PREFIX, sizeof(EXIT_PREFIX) - 1) == 0) { + name += sizeof(EXIT_PREFIX) - 1; + prbname = "return"; + } else + return NULL; + + memset(&tmpl, 0, sizeof(tmpl)); + tmpl.prv_name = provname; + tmpl.mod_name = modname; + tmpl.fun_name = name; + tmpl.prb_name = prbname; + + probe = dt_probe_by_name(&tmpl); + + return probe; +} + +#define SYSCALLSFS EVENTSFS "syscalls/" + +/* + * Attach the given BPF program (identified by its file descriptor) to the + * event identified by the given section name. + */ +static int syscall_attach(const char *name, int bpf_fd) +{ + char efn[256]; + char buf[256]; + int event_id, fd, rc; + + name += sizeof(EVENT_PREFIX) - 1; + strcpy(efn, SYSCALLSFS); + strcat(efn, name); + strcat(efn, "/id"); + + fd = open(efn, O_RDONLY); + if (fd < 0) { + perror(efn); + return -1; + } + rc = read(fd, buf, sizeof(buf)); + if (rc < 0 || rc >= sizeof(buf)) { + perror(efn); + close(fd); + return -1; + } + close(fd); + buf[rc] = '\0'; + event_id = atoi(buf); + + return dt_bpf_attach(event_id, bpf_fd); +} + +struct dt_provider dt_syscall = { + .name = "syscall", + .populate = &syscall_populate, + .resolve_event = &systrace_resolve_event, + .attach = &syscall_attach, +}; diff --git a/tools/dtrace/dt_utils.c b/tools/dtrace/dt_utils.c new file mode 100644 index 000000000000..55d51bae1d97 --- /dev/null +++ b/tools/dtrace/dt_utils.c @@ -0,0 +1,132 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + */ +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include "dtrace_impl.h" + +#define BUF_SIZE 1024 /* max size for online cpu data */ + +int dt_numcpus; /* number of online CPUs */ +int dt_maxcpuid; /* highest CPU id */ +int *dt_cpuids; /* list of CPU ids */ + +/* + * Populate the online CPU id information from sysfs data. We only do this + * once because we do not care about CPUs coming online after we started + * tracing. If a CPU goes offline during tracing, we do not care either + * because that simply means that it won't be writing any new probe data into + * its buffer. + */ +void cpu_list_populate(void) +{ + char buf[BUF_SIZE]; + int fd, cnt, start, end, i; + int *cpu; + char *p, *q; + + fd = open("/sys/devices/system/cpu/online", O_RDONLY); + if (fd < 0) + goto fail; + cnt = read(fd, buf, sizeof(buf)); + close(fd); + if (cnt <= 0) + goto fail; + + /* + * The string should always end with a newline, but let's make sure. + */ + if (buf[cnt - 1] == '\n') + buf[--cnt] = 0; + + /* + * Count how many CPUs we have. + */ + dt_numcpus = 0; + p = buf; + do { + start = (int)strtol(p, &q, 10); + switch (*q) { + case '-': /* range */ + p = q + 1; + end = (int)strtol(p, &q, 10); + dt_numcpus += end - start + 1; + if (*q == 0) { /* end of string */ + p = q; + break; + } + if (*q != ',') + goto fail; + p = q + 1; + break; + case 0: /* end of string */ + dt_numcpus++; + p = q; + break; + case ',': /* gap */ + dt_numcpus++; + p = q + 1; + break; + } + } while (*p != 0); + + dt_cpuids = calloc(dt_numcpus, sizeof(int)); + cpu = dt_cpuids; + + /* + * Fill in the CPU ids. + */ + p = buf; + do { + start = (int)strtol(p, &q, 10); + switch (*q) { + case '-': /* range */ + p = q + 1; + end = (int)strtol(p, &q, 10); + for (i = start; i <= end; i++) + *cpu++ = i; + if (*q == 0) { /* end of string */ + p = q; + break; + } + if (*q != ',') + goto fail; + p = q + 1; + break; + case 0: /* end of string */ + *cpu = start; + p = q; + break; + case ',': /* gap */ + *cpu++ = start; + p = q + 1; + break; + } + } while (*p != 0); + + /* Record the highest CPU id of the set of online CPUs. */ + dt_maxcpuid = *(cpu - 1); + + return; +fail: + if (dt_cpuids) + free(dt_cpuids); + + dt_numcpus = 0; + dt_maxcpuid = 0; + dt_cpuids = NULL; +} + +void cpu_list_free(void) +{ + free(dt_cpuids); + dt_numcpus = 0; + dt_maxcpuid = 0; + dt_cpuids = NULL; +} diff --git a/tools/dtrace/dtrace.c b/tools/dtrace/dtrace.c new file mode 100644 index 000000000000..36ad526c1cd4 --- /dev/null +++ b/tools/dtrace/dtrace.c @@ -0,0 +1,249 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + */ +#include <errno.h> +#include <libgen.h> +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <linux/log2.h> + +#include "dtrace_impl.h" + +#define DTRACE_BUFSIZE 32 /* default buffer size (in pages) */ + +#define DMODE_VERS 0 /* display version information (-V) */ +#define DMODE_LIST 1 /* list probes (-l) */ +#define DMODE_EXEC 2 /* compile program and start tracing */ + +#define E_SUCCESS 0 +#define E_ERROR 1 +#define E_USAGE 2 + +#define NUM_PAGES(sz) (((sz) + getpagesize() - 1) / getpagesize()) + +static const char *dtrace_options = "+b:ls:V"; + +static char *g_pname; +static int g_mode = DMODE_EXEC; + +static int usage(void) +{ + fprintf(stderr, "Usage: %s [-lV] [-b bufsz] -s script\n", g_pname); + fprintf(stderr, + "\t-b set trace buffer size\n" + "\t-l list probes matching specified criteria\n" + "\t-s enable or list probes for the specified BPF program\n" + "\t-V report DTrace API version\n"); + + return E_USAGE; +} + +static u64 parse_size(const char *arg) +{ + long long mul = 1; + long long neg, val; + size_t len; + char *end; + + if (!arg) + return -1; + + len = strlen(arg); + if (!len) + return -1; + + switch (arg[len - 1]) { + case 't': + case 'T': + mul *= 1024; + /* fall-through */ + case 'g': + case 'G': + mul *= 1024; + /* fall-through */ + case 'm': + case 'M': + mul *= 1024; + /* fall-through */ + case 'k': + case 'K': + mul *= 1024; + /* fall-through */ + default: + break; + } + + neg = strtoll(arg, NULL, 0); + errno = 0; + val = strtoull(arg, &end, 0) * mul; + + if ((mul > 1 && end != &arg[len - 1]) || (mul == 1 && *end != '\0') || + val < 0 || neg < 0 || errno != 0) + return -1; + + return val; +} + +int main(int argc, char *argv[]) +{ + int i; + int modec = 0; + int bufsize = DTRACE_BUFSIZE; + int epoll_fd; + int cnt; + char **prgv; + int prgc; + + g_pname = basename(argv[0]); + + if (argc == 1) + return usage(); + + prgc = 0; + prgv = calloc(argc, sizeof(char *)); + if (!prgv) { + fprintf(stderr, "failed to allocate memory for arguments: %s\n", + strerror(errno)); + return E_ERROR; + } + + argv[0] = g_pname; /* argv[0] for getopt errors */ + + for (optind = 1; optind < argc; optind++) { + int opt; + + while ((opt = getopt(argc, argv, dtrace_options)) != EOF) { + u64 val; + + switch (opt) { + case 'b': + val = parse_size(optarg); + if (val < 0) { + fprintf(stderr, "invalid: -b %s\n", + optarg); + return E_ERROR; + } + + /* + * Bufsize needs to be a number of pages, and + * must be a power of 2. This is required by + * the perf event buffer code. + */ + bufsize = roundup_pow_of_two(NUM_PAGES(val)); + if ((u64)bufsize * getpagesize() > val) + fprintf(stderr, + "bufsize increased to %ld\n", + (u64)bufsize * getpagesize()); + + break; + case 'l': + g_mode = DMODE_LIST; + modec++; + break; + case 's': + prgv[prgc++] = optarg; + break; + case 'V': + g_mode = DMODE_VERS; + modec++; + break; + default: + if (strchr(dtrace_options, opt) == NULL) + return usage(); + } + } + + if (optind < argc) { + fprintf(stderr, "unknown option '%s'\n", argv[optind]); + return E_ERROR; + } + } + + if (modec > 1) { + fprintf(stderr, + "only one of [-lV] can be specified at a time\n"); + return E_USAGE; + } + + /* + * We handle requests for version information first because we do not + * need probe information for it. + */ + if (g_mode == DMODE_VERS) { + printf("%s\n" + "This is DTrace %s\n" + "dtrace(1) version-control ID: %s\n", + DT_VERS_STRING, DT_VERSION, DT_GIT_VERSION); + + return E_SUCCESS; + } + + /* Initialize probes. */ + if (dt_probe_init() < 0) { + fprintf(stderr, "failed to initialize probes: %s\n", + strerror(errno)); + return E_ERROR; + } + + /* + * We handle requests to list probes next. + */ + if (g_mode == DMODE_LIST) { + int rc = 0; + + printf("%5s %10s %17s %33s %s\n", + "ID", "PROVIDER", "MODULE", "FUNCTION", "NAME"); + for (i = 0; i < prgc; i++) { + rc = dt_bpf_list_probes(prgv[i]); + if (rc < 0) + fprintf(stderr, "failed to load %s: %s\n", + prgv[i], strerror(errno)); + } + + return rc ? E_ERROR : E_SUCCESS; + } + + if (!prgc) { + fprintf(stderr, "missing BPF program(s)\n"); + return E_ERROR; + } + + /* Process the BPF program. */ + for (i = 0; i < prgc; i++) { + int err; + + err = dt_bpf_load_file(prgv[i]); + if (err) { + errno = -err; + fprintf(stderr, "failed to load %s: %s\n", + prgv[i], strerror(errno)); + return E_ERROR; + } + } + + /* Get the list of online CPUs. */ + cpu_list_populate(); + + /* Initialize buffers. */ + epoll_fd = dt_buffer_init(bufsize); + if (epoll_fd < 0) { + errno = -epoll_fd; + fprintf(stderr, "failed to allocate buffers: %s\n", + strerror(errno)); + return E_ERROR; + } + + /* Process probe data. */ + printf("%3s %6s\n", "CPU", "ID"); + do { + cnt = dt_buffer_poll(epoll_fd, 100); + } while (cnt >= 0); + + dt_buffer_exit(epoll_fd); + + return E_SUCCESS; +} diff --git a/tools/dtrace/dtrace.h b/tools/dtrace/dtrace.h new file mode 100644 index 000000000000..c79398432d17 --- /dev/null +++ b/tools/dtrace/dtrace.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + */ +#ifndef _UAPI_LINUX_DTRACE_H +#define _UAPI_LINUX_DTRACE_H + +struct dt_bpf_context { + u32 probe_id; + u64 argv[10]; +}; + +#endif /* _UAPI_LINUX_DTRACE_H */ diff --git a/tools/dtrace/dtrace_impl.h b/tools/dtrace/dtrace_impl.h new file mode 100644 index 000000000000..9aa51b4c4aee --- /dev/null +++ b/tools/dtrace/dtrace_impl.h @@ -0,0 +1,101 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + */ +#ifndef _DTRACE_H +#define _DTRACE_H + +#include <unistd.h> +#include <bpf/libbpf.h> +#include <linux/types.h> +#include <linux/ptrace.h> +#include <linux/perf_event.h> +#include <sys/syscall.h> + +#include "dtrace.h" + +#define DT_DEBUG + +#define DT_VERS_STRING "Oracle D 2.0.0" + +#define TRACEFS "/sys/kernel/debug/tracing/" +#define EVENTSFS TRACEFS "events/" + +extern int dt_numcpus; +extern int dt_maxcpuid; +extern int *dt_cpuids; + +extern void cpu_list_populate(void); +extern void cpu_list_free(void); + +struct dt_provider { + char *name; + int (*populate)(void); + struct dt_probe *(*resolve_event)(const char *name); + int (*attach)(const char *name, int bpf_fd); +}; + +extern struct dt_provider dt_fbt; +extern struct dt_provider dt_syscall; + +struct dt_hentry { + struct dt_probe *next; + struct dt_probe *prev; +}; + +struct dt_htab; + +typedef u32 (*dt_hval_fn)(const struct dt_probe *); +typedef int (*dt_cmp_fn)(const struct dt_probe *, const struct dt_probe *); +typedef struct dt_probe *(*dt_add_fn)(struct dt_probe *, struct dt_probe *); +typedef struct dt_probe *(*dt_del_fn)(struct dt_probe *, struct dt_probe *); + +extern struct dt_htab *dt_htab_new(dt_hval_fn hval, dt_cmp_fn cmp, + dt_add_fn add, dt_del_fn del); +extern int dt_htab_add(struct dt_htab *htab, struct dt_probe *probe); +extern struct dt_probe *dt_htab_lookup(const struct dt_htab *htab, + const struct dt_probe *probe); +extern int dt_htab_del(struct dt_htab *htab, struct dt_probe *probe); + +struct dt_probe { + u32 id; + int event_fd; + const struct dt_provider *prov; + const char *prv_name; /* provider name */ + const char *mod_name; /* module name */ + const char *fun_name; /* function name */ + const char *prb_name; /* probe name */ + struct dt_hentry he_fqn; +}; + +typedef void (*dt_probe_fn)(const struct dt_probe *probe); + +extern int dt_probe_init(void); +extern int dt_probe_new(const struct dt_provider *prov, const char *pname, + const char *mname, const char *fname, const char *name); +extern struct dt_probe *dt_probe_by_name(const struct dt_probe *tmpl); +extern struct dt_probe *dt_probe_resolve_event(const char *name); + +extern int dt_bpf_list_probes(const char *fn); +extern int dt_bpf_load_file(const char *fn); +extern int dt_bpf_map_update(int fd, const void *key, const void *val); +extern int dt_bpf_attach(int event_id, int bpf_fd); + +extern int dt_bufmap_fd; + +extern int dt_buffer_init(int num_pages); +extern int dt_buffer_poll(int epoll_fd, int timeout); +extern void dt_buffer_exit(int epoll_fd); + +static inline int perf_event_open(struct perf_event_attr *attr, pid_t pid, + int cpu, int group_fd, unsigned long flags) +{ + return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags); +} + +extern inline int bpf(enum bpf_cmd cmd, union bpf_attr *attr) +{ + return syscall(__NR_bpf, cmd, attr, sizeof(union bpf_attr)); +} + +#endif /* _DTRACE_H */

[V2,0/1] tools/dtrace: initial implementation of DTrace

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