From patchwork Mon Jan 11 13:02:10 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mahesh J Salgaonkar X-Patchwork-Id: 42616 X-Patchwork-Delegate: benh@kernel.crashing.org Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from bilbo.ozlabs.org (localhost [127.0.0.1]) by ozlabs.org (Postfix) with ESMTP id B8879B7EAD for ; Tue, 12 Jan 2010 00:02:57 +1100 (EST) Received: by ozlabs.org (Postfix) id 7CC41B7C31; Tue, 12 Jan 2010 00:02:50 +1100 (EST) Delivered-To: linuxppc-dev@ozlabs.org Received: from e23smtp05.au.ibm.com (e23smtp05.au.ibm.com [202.81.31.147]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp05.au.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 2CB92B7C14 for ; Tue, 12 Jan 2010 00:02:49 +1100 (EST) Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [202.81.31.246]) by e23smtp05.au.ibm.com (8.14.3/8.13.1) with ESMTP id o0BCxXMO027552 for ; Mon, 11 Jan 2010 23:59:33 +1100 Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o0BCwKUx1634362 for ; Mon, 11 Jan 2010 23:58:20 +1100 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o0BD2l3R028842 for ; Tue, 12 Jan 2010 00:02:48 +1100 Received: from in.ibm.com (mars-009124035038.in.ibm.com [9.124.35.38]) by d23av02.au.ibm.com (8.14.3/8.13.1/NCO v10.0 AVin) with SMTP id o0BD2jqq028703; Tue, 12 Jan 2010 00:02:45 +1100 Date: Mon, 11 Jan 2010 18:32:10 +0530 From: Mahesh Salgaonkar To: linux-kernel@vger.kernel.org Subject: [PATCH -tip tracing/kprobes v2] Powerpc port of the kprobe-based event tracer Message-ID: <20100111130210.GA31980@in.ibm.com> References: <20100111125952.604518521@mars.in.ibm.com> MIME-Version: 1.0 Content-Disposition: inline; filename="kprobes.ppc.patch" User-Agent: Mutt/1.5.20 (2009-06-14) Cc: Michael Neuling , Mahesh Salgaonkar , linuxppc-dev@ozlabs.org, systemtap@sources.redhat.com, Ingo Molnar , Masami Hiramatsu X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org This patch ports the kprobe-based event tracer to powerpc. This patch is based in x86 port. This brings powerpc on par with x86. ChangeLog - v2: - Removed regs_get_argument_nth() API as function argument access syntax is dropped from kprobe-tracer. Please refer to patches below on Linux PPC mailing list: http://lists.ozlabs.org/pipermail/linuxppc-dev/2010-January/079331.html http://lists.ozlabs.org/pipermail/linuxppc-dev/2010-January/079332.html - Rebased to commit f61d6b1dcb06d62bc20d40e51c7a1e80275a80ab of -tip This patch is dependent on following patch: http://lists.ozlabs.org/pipermail/linuxppc-dev/2010-January/079331.html Port the following API's to ppc for accessing registers and stack entries from pt_regs. - regs_query_register_offset(const char *name) Query the offset of "name" register. - regs_query_register_name(unsigned int offset) Query the name of register by its offset. - regs_get_register(struct pt_regs *regs, unsigned int offset) Get the value of a register by its offset. - regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr) Check the address is in the kernel stack. - regs_get_kernel_stack_nth(struct pt_regs *reg, unsigned int nth) Get Nth entry of the kernel stack. (N >= 0) Signed-off-by: Mahesh Salgaonkar Acked-by: Masami Hiramatsu --- arch/powerpc/include/asm/ptrace.h | 61 ++++++++++++++++++++++ arch/powerpc/kernel/ptrace.c | 102 +++++++++++++++++++++++++++++++++++++ kernel/trace/Kconfig | 2 - 3 files changed, 164 insertions(+), 1 deletions(-) diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h index cbd759e..cb2eeda 100644 --- a/arch/powerpc/include/asm/ptrace.h +++ b/arch/powerpc/include/asm/ptrace.h @@ -83,6 +83,7 @@ struct pt_regs { #define instruction_pointer(regs) ((regs)->nip) #define user_stack_pointer(regs) ((regs)->gpr[1]) +#define kernel_stack_pointer(regs) ((regs)->gpr[1]) #define regs_return_value(regs) ((regs)->gpr[3]) #ifdef CONFIG_SMP @@ -131,6 +132,66 @@ do { \ } while (0) #endif /* __powerpc64__ */ +/* Query offset/name of register from its name/offset */ +#include +#include +extern int regs_query_register_offset(const char *name); +extern const char *regs_query_register_name(unsigned int offset); +#define MAX_REG_OFFSET (offsetof(struct pt_regs, result)) + +/** + * regs_get_register() - get register value from its offset + * @regs: pt_regs from which register value is gotten + * @offset: offset number of the register. + * + * regs_get_register returns the value of a register whose offset from @regs. + * The @offset is the offset of the register in struct pt_regs. + * If @offset is bigger than MAX_REG_OFFSET, this returns 0. + */ +static inline unsigned long regs_get_register(struct pt_regs *regs, + unsigned int offset) +{ + if (unlikely(offset > MAX_REG_OFFSET)) + return 0; + return *(unsigned long *)((unsigned long)regs + offset); +} + +/** + * regs_within_kernel_stack() - check the address in the stack + * @regs: pt_regs which contains kernel stack pointer. + * @addr: address which is checked. + * + * regs_within_kernel_stack() checks @addr is within the kernel stack page(s). + * If @addr is within the kernel stack, it returns true. If not, returns false. + */ + +static inline bool regs_within_kernel_stack(struct pt_regs *regs, + unsigned long addr) +{ + return ((addr & ~(THREAD_SIZE - 1)) == + (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))); +} + +/** + * regs_get_kernel_stack_nth() - get Nth entry of the stack + * @regs: pt_regs which contains kernel stack pointer. + * @n: stack entry number. + * + * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which + * is specified by @regs. If the @n th entry is NOT in the kernel stack, + * this returns 0. + */ +static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, + unsigned int n) +{ + unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs); + addr += n; + if (regs_within_kernel_stack(regs, (unsigned long)addr)) + return *addr; + else + return 0; +} + /* * These are defined as per linux/ptrace.h, which see. */ diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c index ef14988..e816aba 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c @@ -39,6 +39,108 @@ #include /* + * The parameter save area on the stack is used to store arguments being passed + * to callee function and is located at fixed offset from stack pointer. + */ +#ifdef CONFIG_PPC32 +#define PARAMETER_SAVE_AREA_OFFSET 24 /* bytes */ +#else /* CONFIG_PPC32 */ +#define PARAMETER_SAVE_AREA_OFFSET 48 /* bytes */ +#endif + +struct pt_regs_offset { + const char *name; + int offset; +}; + +#define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)} +#define REG_OFFSET_END {.name = NULL, .offset = 0} + +static const struct pt_regs_offset regoffset_table[] = { + REG_OFFSET_NAME(gpr[0]), + REG_OFFSET_NAME(gpr[1]), + REG_OFFSET_NAME(gpr[2]), + REG_OFFSET_NAME(gpr[3]), + REG_OFFSET_NAME(gpr[4]), + REG_OFFSET_NAME(gpr[5]), + REG_OFFSET_NAME(gpr[6]), + REG_OFFSET_NAME(gpr[7]), + REG_OFFSET_NAME(gpr[8]), + REG_OFFSET_NAME(gpr[9]), + REG_OFFSET_NAME(gpr[10]), + REG_OFFSET_NAME(gpr[11]), + REG_OFFSET_NAME(gpr[12]), + REG_OFFSET_NAME(gpr[13]), + REG_OFFSET_NAME(gpr[14]), + REG_OFFSET_NAME(gpr[15]), + REG_OFFSET_NAME(gpr[16]), + REG_OFFSET_NAME(gpr[17]), + REG_OFFSET_NAME(gpr[18]), + REG_OFFSET_NAME(gpr[19]), + REG_OFFSET_NAME(gpr[20]), + REG_OFFSET_NAME(gpr[21]), + REG_OFFSET_NAME(gpr[22]), + REG_OFFSET_NAME(gpr[23]), + REG_OFFSET_NAME(gpr[24]), + REG_OFFSET_NAME(gpr[25]), + REG_OFFSET_NAME(gpr[26]), + REG_OFFSET_NAME(gpr[27]), + REG_OFFSET_NAME(gpr[28]), + REG_OFFSET_NAME(gpr[29]), + REG_OFFSET_NAME(gpr[30]), + REG_OFFSET_NAME(gpr[31]), + REG_OFFSET_NAME(nip), + REG_OFFSET_NAME(msr), + REG_OFFSET_NAME(orig_gpr3), + REG_OFFSET_NAME(ctr), + REG_OFFSET_NAME(link), + REG_OFFSET_NAME(xer), + REG_OFFSET_NAME(ccr), +#ifdef CONFIG_PPC64 + REG_OFFSET_NAME(softe), +#else + REG_OFFSET_NAME(mq), +#endif + REG_OFFSET_NAME(trap), + REG_OFFSET_NAME(dar), + REG_OFFSET_NAME(dsisr), + REG_OFFSET_NAME(result), + REG_OFFSET_END, +}; + +/** + * regs_query_register_offset() - query register offset from its name + * @name: the name of a register + * + * regs_query_register_offset() returns the offset of a register in struct + * pt_regs from its name. If the name is invalid, this returns -EINVAL; + */ +int regs_query_register_offset(const char *name) +{ + const struct pt_regs_offset *roff; + for (roff = regoffset_table; roff->name != NULL; roff++) + if (!strcmp(roff->name, name)) + return roff->offset; + return -EINVAL; +} + +/** + * regs_query_register_name() - query register name from its offset + * @offset: the offset of a register in struct pt_regs. + * + * regs_query_register_name() returns the name of a register from its + * offset in struct pt_regs. If the @offset is invalid, this returns NULL; + */ +const char *regs_query_register_name(unsigned int offset) +{ + const struct pt_regs_offset *roff; + for (roff = regoffset_table; roff->name != NULL; roff++) + if (roff->offset == offset) + return roff->name; + return NULL; +} + +/* * does not yet catch signals sent when the child dies. * in exit.c or in signal.c. */ diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 6c22d8a..4d95966 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -451,7 +451,7 @@ config BLK_DEV_IO_TRACE config KPROBE_EVENT depends on KPROBES - depends on X86 + depends on X86 || PPC bool "Enable kprobes-based dynamic events" select TRACING default y