| Message ID | 1447828989-4980-7-git-send-email-takahiro.akashi@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 11/24/2015 10:50 PM, Jungseok Lee wrote: > On Nov 18, 2015, at 3:43 PM, AKASHI Takahiro wrote: >> The patch ("arm64: ftrace: add arch-specific stack tracer") introduced >> a function prologue analyzer. >> >> Given that there is no fixed template for a function prologue, at least >> on gcc for aarch64, a function prologue analyzer may be rather heuristic. >> So this patch adds a kernel command line option, >> function_prologue_analyzer_test, in order to run a basic test at startup >> by executing an analyzer against all the *traceable* functions. >> >> For function_prologue_analyzer_test=2, the output looks like: >> >> po sp fp symbol >> == == == ====== >> 0: 0 0x040 0x000 gic_handle_irq+0x20/0xa4 >> 1: 0 0x040 0x000 gic_handle_irq+0x34/0x114 >> 2: 0 0x030 0x000 run_init_process+0x14/0x48 >> 3: 0 0x020 0x000 try_to_run_init_process+0x14/0x58 >> 4: 0 0x080 0x000 do_one_initcall+0x1c/0x194 >> ... >> 22959: 0 0x020 0x000 tty_lock_slave+0x14/0x3c >> 22960: 0 0x020 0x000 tty_unlock_slave+0x14/0x3c >> function prologue analyzer test: 0 errors >> >> "po" indicates a position of callsite of mcount(), and should be zero >> if an analyzer has parsed a function prologue successfully and reached >> a location where fp is properly updated. >> "sp" is a final offset to a parent's fp at the exit of function prologue. >> "fp" is also an ofset against sp at the exit of function prologue. >> So normally, >> <new sp> = <old fp> + <"sp"> >> <new fp> = <new sp> - <"fp"> >> >> And the last line shows the number of possible errors in the result. >> >> For function_prologue_analyzer_test=1, only the last line will be shown. >> >> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> >> --- >> arch/arm64/include/asm/insn.h | 2 +- >> arch/arm64/kernel/stacktrace.c | 52 ++++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 53 insertions(+), 1 deletion(-) >> >> diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h >> index 8d5c538..1dfae16 100644 >> --- a/arch/arm64/include/asm/insn.h >> +++ b/arch/arm64/include/asm/insn.h >> @@ -281,7 +281,7 @@ __AARCH64_INSN_FUNCS(hint, 0xFFFFF01F, 0xD503201F) >> __AARCH64_INSN_FUNCS(br, 0xFFFFFC1F, 0xD61F0000) >> __AARCH64_INSN_FUNCS(blr, 0xFFFFFC1F, 0xD63F0000) >> __AARCH64_INSN_FUNCS(ret, 0xFFFFFC1F, 0xD65F0000) >> -__AARCH64_INSN_FUNCS(eret, 0xFFFFFFFF, 0xD69F00E0) >> +__AARCH64_INSN_FUNCS(eret, 0xFFFFFFFF, 0xD69F03E0) > > How about folding(squashing) this hunk into [PATCH 4/6]? > >> #undef __AARCH64_INSN_FUNCS >> >> diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c >> index 1d18bc4..19dad62 100644 >> --- a/arch/arm64/kernel/stacktrace.c >> +++ b/arch/arm64/kernel/stacktrace.c >> @@ -18,6 +18,7 @@ >> #include <linux/kernel.h> >> #include <linux/export.h> >> #include <linux/ftrace.h> >> +#include <linux/kallsyms.h> >> #include <linux/sched.h> >> #include <linux/stacktrace.h> >> >> @@ -348,5 +349,56 @@ void save_stack_trace_sp(struct stack_trace *trace, >> { >> __save_stack_trace_tsk(current, trace, stack_dump_sp); >> } >> + >> +static int start_analyzer_test __initdata; >> + >> +static int __init enable_analyzer_test(char *str) >> +{ >> + get_option(&str, &start_analyzer_test); >> + return 0; >> +} >> +early_param("function_prologue_analyzer_test", enable_analyzer_test); >> + >> +static void __init do_test_function_prologue_analyzer(void) >> +{ >> + extern unsigned long __start_mcount_loc[]; >> + extern unsigned long __stop_mcount_loc[]; >> + unsigned long count, i, errors; >> + int print_once; >> + >> + count = __stop_mcount_loc - __start_mcount_loc; >> + errors = print_once = 0; >> + for (i = 0; i < count; i++) { >> + unsigned long addr, sp_off, fp_off; >> + int pos; >> + bool check; >> + char buf[60]; >> + >> + addr = __start_mcount_loc[i]; >> + pos = analyze_function_prologue(addr, &sp_off, &fp_off); >> + check = ((pos != 0) || !sp_off || (sp_off <= fp_off)); >> + if (check) >> + errors++; >> + if (check || (start_analyzer_test > 1)) { >> + if (!print_once) { >> + pr_debug(" po sp fp symbol\n"); >> + pr_debug(" == == == ======\n"); >> + print_once++; >> + } >> + sprint_symbol(buf, addr); >> + pr_debug("%5ld: %d 0x%03lx 0x%03lx %s\n", >> + i, pos, sp_off, fp_off, buf); >> + } > > It would be hard to find out which entry has an error if start_analyer_test is > set to 2. How about adding one more column to mark 'OK' or 'NG'? Thank you for the comment. > BTW, as I mentioned in previous thread, I'm also waiting for feedbacks on the > analyzer itself :) Me, too. -Takahiro AKASHI > Best Regards > Jungseok Lee > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h index 8d5c538..1dfae16 100644 --- a/arch/arm64/include/asm/insn.h +++ b/arch/arm64/include/asm/insn.h @@ -281,7 +281,7 @@ __AARCH64_INSN_FUNCS(hint, 0xFFFFF01F, 0xD503201F) __AARCH64_INSN_FUNCS(br, 0xFFFFFC1F, 0xD61F0000) __AARCH64_INSN_FUNCS(blr, 0xFFFFFC1F, 0xD63F0000) __AARCH64_INSN_FUNCS(ret, 0xFFFFFC1F, 0xD65F0000) -__AARCH64_INSN_FUNCS(eret, 0xFFFFFFFF, 0xD69F00E0) +__AARCH64_INSN_FUNCS(eret, 0xFFFFFFFF, 0xD69F03E0) #undef __AARCH64_INSN_FUNCS diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 1d18bc4..19dad62 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -18,6 +18,7 @@ #include <linux/kernel.h> #include <linux/export.h> #include <linux/ftrace.h> +#include <linux/kallsyms.h> #include <linux/sched.h> #include <linux/stacktrace.h> @@ -348,5 +349,56 @@ void save_stack_trace_sp(struct stack_trace *trace, { __save_stack_trace_tsk(current, trace, stack_dump_sp); } + +static int start_analyzer_test __initdata; + +static int __init enable_analyzer_test(char *str) +{ + get_option(&str, &start_analyzer_test); + return 0; +} +early_param("function_prologue_analyzer_test", enable_analyzer_test); + +static void __init do_test_function_prologue_analyzer(void) +{ + extern unsigned long __start_mcount_loc[]; + extern unsigned long __stop_mcount_loc[]; + unsigned long count, i, errors; + int print_once; + + count = __stop_mcount_loc - __start_mcount_loc; + errors = print_once = 0; + for (i = 0; i < count; i++) { + unsigned long addr, sp_off, fp_off; + int pos; + bool check; + char buf[60]; + + addr = __start_mcount_loc[i]; + pos = analyze_function_prologue(addr, &sp_off, &fp_off); + check = ((pos != 0) || !sp_off || (sp_off <= fp_off)); + if (check) + errors++; + if (check || (start_analyzer_test > 1)) { + if (!print_once) { + pr_debug(" po sp fp symbol\n"); + pr_debug(" == == == ======\n"); + print_once++; + } + sprint_symbol(buf, addr); + pr_debug("%5ld: %d 0x%03lx 0x%03lx %s\n", + i, pos, sp_off, fp_off, buf); + } + } + pr_debug("function prologue analyzer test: %ld errors\n", errors); +} + +static int __init test_function_prologue_analyzer(void) +{ + if (start_analyzer_test) + do_test_function_prologue_analyzer(); + return 0; +} +late_initcall(test_function_prologue_analyzer); #endif /* CONFIG_STACK_TRACER */ #endif
The patch ("arm64: ftrace: add arch-specific stack tracer") introduced a function prologue analyzer. Given that there is no fixed template for a function prologue, at least on gcc for aarch64, a function prologue analyzer may be rather heuristic. So this patch adds a kernel command line option, function_prologue_analyzer_test, in order to run a basic test at startup by executing an analyzer against all the *traceable* functions. For function_prologue_analyzer_test=2, the output looks like: po sp fp symbol == == == ====== 0: 0 0x040 0x000 gic_handle_irq+0x20/0xa4 1: 0 0x040 0x000 gic_handle_irq+0x34/0x114 2: 0 0x030 0x000 run_init_process+0x14/0x48 3: 0 0x020 0x000 try_to_run_init_process+0x14/0x58 4: 0 0x080 0x000 do_one_initcall+0x1c/0x194 ... 22959: 0 0x020 0x000 tty_lock_slave+0x14/0x3c 22960: 0 0x020 0x000 tty_unlock_slave+0x14/0x3c function prologue analyzer test: 0 errors "po" indicates a position of callsite of mcount(), and should be zero if an analyzer has parsed a function prologue successfully and reached a location where fp is properly updated. "sp" is a final offset to a parent's fp at the exit of function prologue. "fp" is also an ofset against sp at the exit of function prologue. So normally, <new sp> = <old fp> + <"sp"> <new fp> = <new sp> - <"fp"> And the last line shows the number of possible errors in the result. For function_prologue_analyzer_test=1, only the last line will be shown. Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> --- arch/arm64/include/asm/insn.h | 2 +- arch/arm64/kernel/stacktrace.c | 52 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 53 insertions(+), 1 deletion(-) -- 1.7.9.5 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel