From mboxrd@z Thu Jan 1 00:00:00 1970 From: takahiro.akashi@linaro.org (AKASHI Takahiro) Date: Thu, 16 Jul 2015 10:08:03 +0900 Subject: [RFC 2/3] arm64: refactor save_stack_trace() In-Reply-To: <55A6FA82.9000901@linaro.org> References: <1436765375-7119-1-git-send-email-takahiro.akashi@linaro.org> <1436765375-7119-3-git-send-email-takahiro.akashi@linaro.org> <20150714093154.4d73e551@gandalf.local.home> <55A5A75A.1060401@linaro.org> <20150714225105.6c1e4f15@gandalf.local.home> <55A646EE.6030402@linaro.org> <20150715105536.42949ea9@gandalf.local.home> <20150715121337.3b31aa84@gandalf.local.home> <55A6FA82.9000901@linaro.org> Message-ID: <55A703F3.8050203@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 07/16/2015 09:27 AM, AKASHI Takahiro wrote: > On 07/16/2015 01:13 AM, Steven Rostedt wrote: >> On Wed, 15 Jul 2015 10:55:36 -0400 >> Steven Rostedt wrote: >> >> >>> I'll take a look at it and try to clean up the code. >> >> Does the following patch make sense for you? > > Looks nice. The patch greatly simplifies changes on arm64 side. As follows: - Takahiro AKASHI diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index c5534fa..868d6f1 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -15,6 +15,7 @@ #define MCOUNT_ADDR ((unsigned long)_mcount) #define MCOUNT_INSN_SIZE AARCH64_INSN_SIZE +#define FTRACE_STACK_FRAME_OFFSET 4 /* sync it up with stacktrace.c */ #ifndef __ASSEMBLY__ #include diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 1da6029..2c1bf7d 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -260,6 +260,13 @@ static inline void ftrace_kill(void) { } #endif /* CONFIG_FUNCTION_TRACER */ #ifdef CONFIG_STACK_TRACER +/* + * the offset value to add to return address from save_stack_trace() + */ +#ifndef FTRACE_STACK_FRAME_OFFSET +#define FTRACE_STACK_FRAME_OFFSET 0 +#endif + extern int stack_tracer_enabled; int stack_trace_sysctl(struct ctl_table *table, int write, diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 9384647..c5b9748 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -105,7 +105,7 @@ check_stack(unsigned long ip, unsigned long *stack) /* Skip over the overhead of the stack tracer itself */ for (i = 0; i < max_stack_trace.nr_entries; i++) { - if (stack_dump_trace[i] == ip) + if ((stack_dump_trace[i] + FTRACE_STACK_FRAME_OFFSET) == ip) break; } @@ -131,7 +131,8 @@ check_stack(unsigned long ip, unsigned long *stack) p = start; for (; p < top && i < max_stack_trace.nr_entries; p++) { - if (*p == stack_dump_trace[i]) { + if (*p == (stack_dump_trace[i] + + FTRACE_STACK_FRAME_OFFSET)) { stack_dump_trace[x] = stack_dump_trace[i++]; this_size = stack_dump_index[x++] = (top - p) * sizeof(unsigned long); -- 1.7.9.5