diff mbox series

[bpf-next,3/3] tools: bpftool: improve architecture detection by using ifindex

Message ID 20180117000521.29826-4-jakub.kicinski@netronome.com
State Accepted, archived
Delegated to: BPF Maintainers
Headers show
Series bpf: add dumping and disassembler for non-host JITs | expand

Commit Message

Jakub Kicinski Jan. 17, 2018, 12:05 a.m. UTC 
From: Jiong Wang <jiong.wang@netronome.com>

The current architecture detection method in bpftool is designed for host
case.

For offload case, we can't use the architecture of "bpftool" itself.
Instead, we could call the existing "ifindex_to_name_ns" to get DEVNAME,
then read pci id from /sys/class/dev/DEVNAME/device/vendor, finally we map
vendor id to bfd arch name which will finally be used to select bfd backend
for the disassembler.

Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
---
 tools/bpf/bpftool/common.c     | 72 ++++++++++++++++++++++++++++++++++++++++++
 tools/bpf/bpftool/jit_disasm.c | 16 +++++++++-
 tools/bpf/bpftool/main.h       |  5 ++-
 tools/bpf/bpftool/prog.c       | 12 ++++++-
 4 files changed, 102 insertions(+), 3 deletions(-)

Comments

Alexei Starovoitov Jan. 17, 2018, 3:42 a.m. UTC | #1 
On Tue, Jan 16, 2018 at 04:05:21PM -0800, Jakub Kicinski wrote:
> From: Jiong Wang <jiong.wang@netronome.com>
> 
> The current architecture detection method in bpftool is designed for host
> case.
> 
> For offload case, we can't use the architecture of "bpftool" itself.
> Instead, we could call the existing "ifindex_to_name_ns" to get DEVNAME,
> then read pci id from /sys/class/dev/DEVNAME/device/vendor, finally we map
> vendor id to bfd arch name which will finally be used to select bfd backend
> for the disassembler.
> 
> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
> Signed-off-by: Jiong Wang <jiong.wang@netronome.com>

awesome addition!
Acked-by: Alexei Starovoitov <ast@kernel.org>

> +	switch (vendor_id) {
> +	case 0x19ee:
> +		device_id = read_sysfs_netdev_hex_int(devname, "device");
> +		if (device_id != 0x4000 &&
> +		    device_id != 0x6000 &&
> +		    device_id != 0x6003)
> +			p_info("Unknown NFP device ID, assuming it is NFP-6xxx arch");
> +		return "NFP-6xxx";

is this a canonical name that bfd will understand?
a link to bfd patches?
Jakub Kicinski Jan. 17, 2018, 4:02 a.m. UTC | #2 
CC: Francois

On Tue, 16 Jan 2018 19:42:15 -0800, Alexei Starovoitov wrote:
> > +	switch (vendor_id) {
> > +	case 0x19ee:
> > +		device_id = read_sysfs_netdev_hex_int(devname, "device");
> > +		if (device_id != 0x4000 &&
> > +		    device_id != 0x6000 &&
> > +		    device_id != 0x6003)
> > +			p_info("Unknown NFP device ID, assuming it is NFP-6xxx arch");
> > +		return "NFP-6xxx";  
> 
> is this a canonical name that bfd will understand?

Yes, we started with just "nfp", but tossed "6k" for good measure.

> a link to bfd patches?

Unfortunately not posted, yet.
diff mbox series

Patch

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index 6601c95a9258..0b482c0070e0 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -34,6 +34,7 @@ 
 /* Author: Jakub Kicinski <kubakici@wp.pl> */
 
 #include <errno.h>
+#include <fcntl.h>
 #include <fts.h>
 #include <libgen.h>
 #include <mntent.h>
@@ -433,6 +434,77 @@  ifindex_to_name_ns(__u32 ifindex, __u32 ns_dev, __u32 ns_ino, char *buf)
 	return if_indextoname(ifindex, buf);
 }
 
+static int read_sysfs_hex_int(char *path)
+{
+	char vendor_id_buf[8];
+	int len;
+	int fd;
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0) {
+		p_err("Can't open %s: %s", path, strerror(errno));
+		return -1;
+	}
+
+	len = read(fd, vendor_id_buf, sizeof(vendor_id_buf));
+	close(fd);
+	if (len < 0) {
+		p_err("Can't read %s: %s", path, strerror(errno));
+		return -1;
+	}
+	if (len >= (int)sizeof(vendor_id_buf)) {
+		p_err("Value in %s too long", path);
+		return -1;
+	}
+
+	vendor_id_buf[len] = 0;
+
+	return strtol(vendor_id_buf, NULL, 0);
+}
+
+static int read_sysfs_netdev_hex_int(char *devname, const char *entry_name)
+{
+	char full_path[64];
+
+	snprintf(full_path, sizeof(full_path), "/sys/class/net/%s/device/%s",
+		 devname, entry_name);
+
+	return read_sysfs_hex_int(full_path);
+}
+
+const char *ifindex_to_bfd_name_ns(__u32 ifindex, __u64 ns_dev, __u64 ns_ino)
+{
+	char devname[IF_NAMESIZE];
+	int vendor_id;
+	int device_id;
+
+	if (!ifindex_to_name_ns(ifindex, ns_dev, ns_ino, devname)) {
+		p_err("Can't get net device name for ifindex %d: %s", ifindex,
+		      strerror(errno));
+		return NULL;
+	}
+
+	vendor_id = read_sysfs_netdev_hex_int(devname, "vendor");
+	if (vendor_id < 0) {
+		p_err("Can't get device vendor id for %s", devname);
+		return NULL;
+	}
+
+	switch (vendor_id) {
+	case 0x19ee:
+		device_id = read_sysfs_netdev_hex_int(devname, "device");
+		if (device_id != 0x4000 &&
+		    device_id != 0x6000 &&
+		    device_id != 0x6003)
+			p_info("Unknown NFP device ID, assuming it is NFP-6xxx arch");
+		return "NFP-6xxx";
+	default:
+		p_err("Can't get bfd arch name for device vendor id 0x%04x",
+		      vendor_id);
+		return NULL;
+	}
+}
+
 void print_dev_plain(__u32 ifindex, __u64 ns_dev, __u64 ns_inode)
 {
 	char name[IF_NAMESIZE];
diff --git a/tools/bpf/bpftool/jit_disasm.c b/tools/bpf/bpftool/jit_disasm.c
index 57d32e8a1391..87439320ef70 100644
--- a/tools/bpf/bpftool/jit_disasm.c
+++ b/tools/bpf/bpftool/jit_disasm.c
@@ -76,7 +76,8 @@  static int fprintf_json(void *out, const char *fmt, ...)
 	return 0;
 }
 
-void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes)
+void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
+		       const char *arch)
 {
 	disassembler_ftype disassemble;
 	struct disassemble_info info;
@@ -100,6 +101,19 @@  void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes)
 	else
 		init_disassemble_info(&info, stdout,
 				      (fprintf_ftype) fprintf);
+
+	/* Update architecture info for offload. */
+	if (arch) {
+		const bfd_arch_info_type *inf = bfd_scan_arch(arch);
+
+		if (inf) {
+			bfdf->arch_info = inf;
+		} else {
+			p_err("No libfd support for %s", arch);
+			return;
+		}
+	}
+
 	info.arch = bfd_get_arch(bfdf);
 	info.mach = bfd_get_mach(bfdf);
 	info.buffer = image;
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 65b526fe6e7e..b8e9584d6246 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -121,7 +121,10 @@  int do_cgroup(int argc, char **arg);
 
 int prog_parse_fd(int *argc, char ***argv);
 
-void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes);
+void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
+		       const char *arch);
 void print_hex_data_json(uint8_t *data, size_t len);
 
+const char *ifindex_to_bfd_name_ns(__u32 ifindex, __u64 ns_dev, __u64 ns_ino);
+
 #endif
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 099e21cf1b5c..e8e2baaf93c2 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -776,7 +776,17 @@  static int do_dump(int argc, char **argv)
 		}
 	} else {
 		if (member_len == &info.jited_prog_len) {
-			disasm_print_insn(buf, *member_len, opcodes);
+			const char *name = NULL;
+
+			if (info.ifindex) {
+				name = ifindex_to_bfd_name_ns(info.ifindex,
+							      info.netns_dev,
+							      info.netns_ino);
+				if (!name)
+					goto err_free;
+			}
+
+			disasm_print_insn(buf, *member_len, opcodes, name);
 		} else {
 			kernel_syms_load(&dd);
 			if (json_output)