From nobody Tue Feb 10 10:53:27 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2C69C76196 for ; Fri, 31 Mar 2023 12:50:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231889AbjCaMuM (ORCPT ); Fri, 31 Mar 2023 08:50:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50330 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232645AbjCaMt3 (ORCPT ); Fri, 31 Mar 2023 08:49:29 -0400 Received: from mail-m118111.qiye.163.com (mail-m118111.qiye.163.com [115.236.118.111]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E67B42030E; Fri, 31 Mar 2023 05:49:08 -0700 (PDT) Received: from ubuntu.localdomain (unknown [117.133.56.22]) by mail-m118111.qiye.163.com (Hmail) with ESMTPA id 898ED5801A4; Fri, 31 Mar 2023 20:48:02 +0800 (CST) From: Donglin Peng To: mhiramat@kernel.org, rostedt@goodmis.org, linux@armlinux.org.uk, mark.rutland@arm.com, will@kernel.org, catalin.marinas@arm.com, rmk+kernel@armlinux.org.uk, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, tglx@linutronix.de, dave.hansen@linux.intel.com, x86@kernel.org, bp@alien8.de, hpa@zytor.com, chenhuacai@kernel.org, zhangqing@loongson.cn, kernel@xen0n.name, mingo@redhat.com, peterz@infradead.org, xiehuan09@gmail.com, dinghui@sangfor.com.cn, huangcun@sangfor.com.cn, dolinux.peng@gmail.com Cc: linux-trace-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Donglin Peng , Florian Kauer Subject: [PATCH v10 1/8] function_graph: Support recording and printing the return value of function Date: Fri, 31 Mar 2023 05:47:37 -0700 Message-Id: <37831bc91d01ce2b80c7eb1e38e38238980dad15.1680265828.git.pengdonglin@sangfor.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVkZGUoZVkMdT05NTk5OTRkfGlUTARMWGhIXJBQOD1 lXWRgSC1lBWUpKTFVKSEhVTk1VSUlZV1kWGg8SFR0UWUFZT0tIVUpKS0hKTFVKS0tVS1kG X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6NU06GQw6Dz0SPU0ZDTkYIT80 PU5PCilVSlVKTUNLSU1NQ0NPT0JPVTMWGhIXVQseFRwfFBUcFxIVOwgaFRwdFAlVGBQWVRgVRVlX WRILWUFZSkpMVUpISFVOTVVJSVlXWQgBWUFKTU5CTDcG X-HM-Tid: 0a8737b5f2842eb7kusn898ed5801a4 X-HM-MType: 1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Analyzing system call failures with the function_graph tracer can be a time-consuming process, particularly when locating the kernel function that first returns an error in the trace logs. This change aims to simplify the process by recording the function return value to the 'retval' member of 'ftrace_graph_ent' and printing it when outputting the trace log. We have introduced new trace options: funcgraph-retval and funcgraph-retval-hex. The former controls whether to display the return value, while the latter controls the display format. Please note that even if a function's return type is void, a return value will still be printed. You can simply ignore it. This patch only establishes the fundamental infrastructure. Subsequent patches will make this feature available on some commonly used processor architectures. Here is an example: I attempted to attach the demo process to a cpu cgroup, but it failed: echo `pidof demo` > /sys/fs/cgroup/cpu/test/tasks -bash: echo: write error: Invalid argument The strace logs indicate that the write system call returned -EINVAL(-22): ... write(1, "273\n", 4) =3D -1 EINVAL (Invalid argument) ... To capture trace logs during a write system call, use the following commands: cd /sys/kernel/debug/tracing/ echo 0 > tracing_on echo > trace echo *sys_write > set_graph_function echo *spin* > set_graph_notrace echo *rcu* >> set_graph_notrace echo *alloc* >> set_graph_notrace echo preempt* >> set_graph_notrace echo kfree* >> set_graph_notrace echo $$ > set_ftrace_pid echo function_graph > current_tracer echo 1 > options/funcgraph-retval echo 0 > options/funcgraph-retval-hex echo 1 > tracing_on echo `pidof demo` > /sys/fs/cgroup/cpu/test/tasks echo 0 > tracing_on cat trace > ~/trace.log To locate the root cause, search for error code -22 directly in the file trace.log and identify the first function that returned -22. Once you have identified this function, examine its code to determine the root cause. For example, in the trace log below, cpu_cgroup_can_attach returned -22 first, so we can focus our analysis on this function to identify the root cause. ... 1) | cgroup_migrate() { 1) 0.651 us | cgroup_migrate_add_task(); /* =3D 0xffff93fcfd346c00 */ 1) | cgroup_migrate_execute() { 1) | cpu_cgroup_can_attach() { 1) | cgroup_taskset_first() { 1) 0.732 us | cgroup_taskset_next(); /* =3D 0xffff93fc8fb20000 */ 1) 1.232 us | } /* cgroup_taskset_first =3D 0xffff93fc8fb20000 */ 1) 0.380 us | sched_rt_can_attach(); /* =3D 0x0 */ 1) 2.335 us | } /* cpu_cgroup_can_attach =3D -22 */ 1) 4.369 us | } /* cgroup_migrate_execute =3D -22 */ 1) 7.143 us | } /* cgroup_migrate =3D -22 */ ... Tested-by: Florian Kauer Acked-by: Masami Hiramatsu (Google) Signed-off-by: Donglin Peng --- v9: - Update comments for ftrace_return_to_handler v8: - Add some comments on CONFIG_HAVE_FUNCTION_GRAPH_RETVAL - Make CONFIG_FUNCTION_GRAPH_RETVAL switable v7: - Rename trace option 'graph_retval_hex' to 'funcgraph-retval-hex' - Separate each architecture modification info individual patches - Introduce a new structure fgraph_ret_regs for each architecture to hold return registers v6: - Remove the conversion code for short and char types, because these two types are rarely used to store an error code. v5: - Pass both the return values to ftrace_return_to_handler - Modify the parameter sequence of ftrace_return_to_handler to decrease the modification of assembly code, thanks to Russell King - Wrap __ftrace_return_to_handler with ftrace_return_to_handler for compatible v4: - Modify commit message - Introduce new option graph_retval_hex to control display format - Introduce macro CONFIG_FUNCTION_GRAPH_RETVAL and CONFIG_HAVE_FUNCTION_GRAPH_RETVAL - Add related arch maintainers to review v3: - Modify the commit message: add trace logs processed with the btf tool v2: - Modify the commit message: use BTF to get the return type of function --- include/linux/ftrace.h | 3 + kernel/trace/Kconfig | 15 +++++ kernel/trace/fgraph.c | 23 ++++++- kernel/trace/trace.h | 2 + kernel/trace/trace_entries.h | 26 ++++++++ kernel/trace/trace_functions_graph.c | 93 +++++++++++++++++++++++++--- 6 files changed, 151 insertions(+), 11 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 366c730beaa3..be662a11cd13 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -1032,6 +1032,9 @@ struct ftrace_graph_ent { */ struct ftrace_graph_ret { unsigned long func; /* Current function */ +#ifdef CONFIG_FUNCTION_GRAPH_RETVAL + unsigned long retval; +#endif int depth; /* Number of functions that overran the depth limit for current task */ unsigned int overrun; diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index a856d4a34c67..87de5964c81d 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -31,6 +31,9 @@ config HAVE_FUNCTION_GRAPH_TRACER help See Documentation/trace/ftrace-design.rst =20 +config HAVE_FUNCTION_GRAPH_RETVAL + bool + config HAVE_DYNAMIC_FTRACE bool help @@ -227,6 +230,18 @@ config FUNCTION_GRAPH_TRACER the return value. This is done by setting the current return address on the current task structure into a stack of calls. =20 +config FUNCTION_GRAPH_RETVAL + bool "Function Graph Return Value" + depends on HAVE_FUNCTION_GRAPH_RETVAL + depends on FUNCTION_GRAPH_TRACER + default n + help + Support recording and printing the function return value when + using function graph tracer. It can be helpful to locate functions + that return errors. This feature is off by default, and you can + enable it via the trace option funcgraph-retval. + See Documentation/trace/ftrace.rst + config DYNAMIC_FTRACE bool "enable/disable function tracing dynamically" depends on FUNCTION_TRACER diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 218cd95bf8e4..170ec9429efb 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -240,12 +240,16 @@ static struct notifier_block ftrace_suspend_notifier = =3D { * Send the trace to the ring-buffer. * @return the original return address. */ -unsigned long ftrace_return_to_handler(unsigned long frame_pointer) +static unsigned long __ftrace_return_to_handler(struct fgraph_ret_regs *re= t_regs, + unsigned long frame_pointer) { struct ftrace_graph_ret trace; unsigned long ret; =20 ftrace_pop_return_trace(&trace, &ret, frame_pointer); +#ifdef CONFIG_FUNCTION_GRAPH_RETVAL + trace.retval =3D fgraph_ret_regs_return_value(ret_regs); +#endif trace.rettime =3D trace_clock_local(); ftrace_graph_return(&trace); /* @@ -266,6 +270,23 @@ unsigned long ftrace_return_to_handler(unsigned long f= rame_pointer) return ret; } =20 +/* + * After all architecures have selected HAVE_FUNCTION_GRAPH_RETVAL, we can + * leave only ftrace_return_to_handler(ret_regs). + */ +#ifdef CONFIG_HAVE_FUNCTION_GRAPH_RETVAL +unsigned long ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs) +{ + return __ftrace_return_to_handler(ret_regs, + fgraph_ret_regs_frame_pointer(ret_regs)); +} +#else +unsigned long ftrace_return_to_handler(unsigned long frame_pointer) +{ + return __ftrace_return_to_handler(NULL, frame_pointer); +} +#endif + /** * ftrace_graph_get_ret_stack - return the entry of the shadow stack * @task: The task to read the shadow stack from diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 616e1aa1c4da..0a3c4582df10 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -831,6 +831,8 @@ static __always_inline bool ftrace_hash_empty(struct ft= race_hash *hash) #define TRACE_GRAPH_PRINT_TAIL 0x100 #define TRACE_GRAPH_SLEEP_TIME 0x200 #define TRACE_GRAPH_GRAPH_TIME 0x400 +#define TRACE_GRAPH_PRINT_RETVAL 0x800 +#define TRACE_GRAPH_PRINT_RETVAL_HEX 0x1000 #define TRACE_GRAPH_PRINT_FILL_SHIFT 28 #define TRACE_GRAPH_PRINT_FILL_MASK (0x3 << TRACE_GRAPH_PRINT_FILL_SHIFT) =20 diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h index cd41e863b51c..340b2fa98218 100644 --- a/kernel/trace/trace_entries.h +++ b/kernel/trace/trace_entries.h @@ -86,6 +86,30 @@ FTRACE_ENTRY_PACKED(funcgraph_entry, ftrace_graph_ent_en= try, ); =20 /* Function return entry */ +#ifdef CONFIG_FUNCTION_GRAPH_RETVAL + +FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry, + + TRACE_GRAPH_RET, + + F_STRUCT( + __field_struct( struct ftrace_graph_ret, ret ) + __field_packed( unsigned long, ret, func ) + __field_packed( unsigned long, ret, retval ) + __field_packed( int, ret, depth ) + __field_packed( unsigned int, ret, overrun ) + __field_packed( unsigned long long, ret, calltime) + __field_packed( unsigned long long, ret, rettime ) + ), + + F_printk("<-- %ps (%d) (start: %llx end: %llx) over: %d retval: %lx", + (void *)__entry->func, __entry->depth, + __entry->calltime, __entry->rettime, + __entry->depth, __entry->retval) +); + +#else + FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry, =20 TRACE_GRAPH_RET, @@ -105,6 +129,8 @@ FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_en= try, __entry->depth) ); =20 +#endif + /* * Context switch trace entry - which task (and prio) we switched from/to: * diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_func= tions_graph.c index 203204cadf92..c35fbaab2a47 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -58,6 +58,12 @@ static struct tracer_opt trace_opts[] =3D { { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) }, /* Display function name after trailing } */ { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) }, +#ifdef CONFIG_FUNCTION_GRAPH_RETVAL + /* Display function return value ? */ + { TRACER_OPT(funcgraph-retval, TRACE_GRAPH_PRINT_RETVAL) }, + /* Display function return value in hexadecimal format ? */ + { TRACER_OPT(funcgraph-retval-hex, TRACE_GRAPH_PRINT_RETVAL_HEX) }, +#endif /* Include sleep time (scheduled out) between entry and return */ { TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) }, =20 @@ -619,6 +625,56 @@ print_graph_duration(struct trace_array *tr, unsigned = long long duration, trace_seq_puts(s, "| "); } =20 +#ifdef CONFIG_FUNCTION_GRAPH_RETVAL + +#define __TRACE_GRAPH_PRINT_RETVAL TRACE_GRAPH_PRINT_RETVAL + +static void print_graph_retval(struct trace_seq *s, unsigned long retval, + bool leaf, void *func, bool hex_format) +{ + unsigned long err_code =3D 0; + + if (retval =3D=3D 0 || hex_format) + goto done; + + /* Check if the return value matches the negative format */ + if (IS_ENABLED(CONFIG_64BIT) && (retval & BIT(31)) && + (((u64)retval) >> 32) =3D=3D 0) { + /* sign extension */ + err_code =3D (unsigned long)(s32)retval; + } else { + err_code =3D retval; + } + + if (!IS_ERR_VALUE(err_code)) + err_code =3D 0; + +done: + if (leaf) { + if (hex_format || (err_code =3D=3D 0)) + trace_seq_printf(s, "%ps(); /* =3D 0x%lx */\n", + func, retval); + else + trace_seq_printf(s, "%ps(); /* =3D %ld */\n", + func, err_code); + } else { + if (hex_format || (err_code =3D=3D 0)) + trace_seq_printf(s, "} /* %ps =3D 0x%lx */\n", + func, retval); + else + trace_seq_printf(s, "} /* %ps =3D %ld */\n", + func, err_code); + } +} + +#else + +#define __TRACE_GRAPH_PRINT_RETVAL 0 + +#define print_graph_retval(_seq, _retval, _leaf, _func, _format) do {} whi= le (0) + +#endif + /* Case of a leaf function on its call entry */ static enum print_line_t print_graph_entry_leaf(struct trace_iterator *iter, @@ -663,7 +719,15 @@ print_graph_entry_leaf(struct trace_iterator *iter, for (i =3D 0; i < call->depth * TRACE_GRAPH_INDENT; i++) trace_seq_putc(s, ' '); =20 - trace_seq_printf(s, "%ps();\n", (void *)call->func); + /* + * Write out the function return value if the option function-retval is + * enabled. + */ + if (flags & __TRACE_GRAPH_PRINT_RETVAL) + print_graph_retval(s, graph_ret->retval, true, (void *)call->func, + !!(flags & TRACE_GRAPH_PRINT_RETVAL_HEX)); + else + trace_seq_printf(s, "%ps();\n", (void *)call->func); =20 print_graph_irq(iter, graph_ret->func, TRACE_GRAPH_RET, cpu, iter->ent->pid, flags); @@ -942,16 +1006,25 @@ print_graph_return(struct ftrace_graph_ret *trace, s= truct trace_seq *s, trace_seq_putc(s, ' '); =20 /* - * If the return function does not have a matching entry, - * then the entry was lost. Instead of just printing - * the '}' and letting the user guess what function this - * belongs to, write out the function name. Always do - * that if the funcgraph-tail option is enabled. + * Always write out the function name and its return value if the + * function-retval option is enabled. */ - if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL)) - trace_seq_puts(s, "}\n"); - else - trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func); + if (flags & __TRACE_GRAPH_PRINT_RETVAL) { + print_graph_retval(s, trace->retval, false, (void *)trace->func, + !!(flags & TRACE_GRAPH_PRINT_RETVAL_HEX)); + } else { + /* + * If the return function does not have a matching entry, + * then the entry was lost. Instead of just printing + * the '}' and letting the user guess what function this + * belongs to, write out the function name. Always do + * that if the funcgraph-tail option is enabled. + */ + if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL)) + trace_seq_puts(s, "}\n"); + else + trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func); + } =20 /* Overrun */ if (flags & TRACE_GRAPH_PRINT_OVERRUN) --=20 2.25.1 From nobody Tue Feb 10 10:53:27 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0DEBBC6FD18 for ; Fri, 31 Mar 2023 12:49:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232620AbjCaMtZ (ORCPT ); Fri, 31 Mar 2023 08:49:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48660 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231654AbjCaMtG (ORCPT ); Fri, 31 Mar 2023 08:49:06 -0400 Received: from mail-m118111.qiye.163.com (mail-m118111.qiye.163.com [115.236.118.111]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 76B0420C1F; Fri, 31 Mar 2023 05:48:44 -0700 (PDT) Received: from ubuntu.localdomain (unknown [117.133.56.22]) by mail-m118111.qiye.163.com (Hmail) with ESMTPA id 8D4DD580250; Fri, 31 Mar 2023 20:48:04 +0800 (CST) From: Donglin Peng To: mhiramat@kernel.org, rostedt@goodmis.org, linux@armlinux.org.uk, mark.rutland@arm.com, will@kernel.org, catalin.marinas@arm.com, rmk+kernel@armlinux.org.uk, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, tglx@linutronix.de, dave.hansen@linux.intel.com, x86@kernel.org, bp@alien8.de, hpa@zytor.com, chenhuacai@kernel.org, zhangqing@loongson.cn, kernel@xen0n.name, mingo@redhat.com, peterz@infradead.org, xiehuan09@gmail.com, dinghui@sangfor.com.cn, huangcun@sangfor.com.cn, dolinux.peng@gmail.com Cc: linux-trace-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Donglin Peng Subject: [PATCH v10 2/8] tracing: Add documentation for funcgraph-retval and funcgraph-retval-hex Date: Fri, 31 Mar 2023 05:47:38 -0700 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVkZQkpDVh5LGEoZQh9ISEIZGlUTARMWGhIXJBQOD1 lXWRgSC1lBWUpKTFVKSEhVTk1VSUlZV1kWGg8SFR0UWUFZT0tIVUpISkJIT1VKS0tVS1kG X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6ORQ6FCo6CD0UE003HTg#ITIK KghPCU9VSlVKTUNLSU1NQ0NNSU9OVTMWGhIXVQseFRwfFBUcFxIVOwgaFRwdFAlVGBQWVRgVRVlX WRILWUFZSkpMVUpISFVOTVVJSVlXWQgBWUFMTk9LNwY+ X-HM-Tid: 0a8737b5fa4c2eb7kusn8d4dd580250 X-HM-MType: 1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add documentation for the two newly introduced options for the function_graph tracer. The funcgraph-retval option is used to control whether or not to display the return value, while the funcgraph-retval-hex option is used to control the display format of the return value. Signed-off-by: Donglin Peng Acked-by: Masami Hiramatsu (Google) --- v9: - Update limitation description v7: - Rename trace option 'graph_retval_hex' to 'funcgraph-retval-hex' - Update documentation description v6: - Modify the limitations for funcgraph-retval - Optimize the English expression v5: - Describe the limitations of funcgraph-retval --- Documentation/trace/ftrace.rst | 74 ++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst index b927fb2b94dc..f572ae419219 100644 --- a/Documentation/trace/ftrace.rst +++ b/Documentation/trace/ftrace.rst @@ -1328,6 +1328,19 @@ Options for function_graph tracer: only a closing curly bracket "}" is displayed for the return of a function. =20 + funcgraph-retval + When set, the return value of each traced function + will be printed after an equal sign "=3D". By default + this is off. + + funcgraph-retval-hex + When set, the return value will always be printed + in hexadecimal format. If the option is not set and + the return value is an error code, it will be printed + in signed decimal format; otherwise it will also be + printed in hexadecimal format. By default, this option + is off. + sleep-time When running function graph tracer, to include the time a task schedules out in its function. @@ -2673,6 +2686,67 @@ It is default disabled. 0) 1.757 us | } /* kmem_cache_free() */ 0) 2.861 us | } /* putname() */ =20 +The return value of each traced function can be displayed after +an equal sign "=3D". When encountering system call failures, it +can be verfy helpful to quickly locate the function that first +returns an error code. + + - hide: echo nofuncgraph-retval > trace_options + - show: echo funcgraph-retval > trace_options + + Example with funcgraph-retval:: + + 1) | cgroup_migrate() { + 1) 0.651 us | cgroup_migrate_add_task(); /* =3D 0xffff93fcfd= 346c00 */ + 1) | cgroup_migrate_execute() { + 1) | cpu_cgroup_can_attach() { + 1) | cgroup_taskset_first() { + 1) 0.732 us | cgroup_taskset_next(); /* =3D 0xffff93fc= 8fb20000 */ + 1) 1.232 us | } /* cgroup_taskset_first =3D 0xffff93fc8f= b20000 */ + 1) 0.380 us | sched_rt_can_attach(); /* =3D 0x0 */ + 1) 2.335 us | } /* cpu_cgroup_can_attach =3D -22 */ + 1) 4.369 us | } /* cgroup_migrate_execute =3D -22 */ + 1) 7.143 us | } /* cgroup_migrate =3D -22 */ + +The above example shows that the function cpu_cgroup_can_attach +returned the error code -22 firstly, then we can read the code +of this function to get the root cause. + +When the option funcgraph-retval-hex is not set, the return value can +be displayed in a smart way. Specifically, if it is an error code, +it will be printed in signed decimal format, otherwise it will +printed in hexadecimal format. + + - smart: echo nofuncgraph-retval-hex > trace_options + - hexadecimal always: echo funcgraph-retval-hex > trace_options + + Example with funcgraph-retval-hex:: + + 1) | cgroup_migrate() { + 1) 0.651 us | cgroup_migrate_add_task(); /* =3D 0xffff93fc= fd346c00 */ + 1) | cgroup_migrate_execute() { + 1) | cpu_cgroup_can_attach() { + 1) | cgroup_taskset_first() { + 1) 0.732 us | cgroup_taskset_next(); /* =3D 0xffff93= fc8fb20000 */ + 1) 1.232 us | } /* cgroup_taskset_first =3D 0xffff93fc= 8fb20000 */ + 1) 0.380 us | sched_rt_can_attach(); /* =3D 0x0 */ + 1) 2.335 us | } /* cpu_cgroup_can_attach =3D 0xffffffea = */ + 1) 4.369 us | } /* cgroup_migrate_execute =3D 0xffffffea */ + 1) 7.143 us | } /* cgroup_migrate =3D 0xffffffea */ + +At present, there are some limitations when using the funcgraph-retval +option, and these limitations will be eliminated in the future: + +- Even if the function return type is void, a return value will still + be printed, and you can just ignore it. + +- Even if return values are stored in multiple registers, only the + value contained in the first register will be recorded and printed. + To illustrate, in the x86 architecture, eax and edx are used to store + a 64-bit return value, with the lower 32 bits saved in eax and the + upper 32 bits saved in edx. However, only the value stored in eax + will be recorded and printed. + You can put some comments on specific functions by using trace_printk() For example, if you want to put a comment inside the __might_sleep() function, you just have to include --=20 2.25.1 From nobody Tue Feb 10 10:53:27 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A023CC76196 for ; Fri, 31 Mar 2023 12:49:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230101AbjCaMtl (ORCPT ); Fri, 31 Mar 2023 08:49:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232306AbjCaMtR (ORCPT ); Fri, 31 Mar 2023 08:49:17 -0400 Received: from mail-m118111.qiye.163.com (mail-m118111.qiye.163.com [115.236.118.111]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D321721A8F; Fri, 31 Mar 2023 05:48:53 -0700 (PDT) Received: from ubuntu.localdomain (unknown [117.133.56.22]) by mail-m118111.qiye.163.com (Hmail) with ESMTPA id 5001158015C; Fri, 31 Mar 2023 20:48:06 +0800 (CST) From: Donglin Peng To: mhiramat@kernel.org, rostedt@goodmis.org, linux@armlinux.org.uk, mark.rutland@arm.com, will@kernel.org, catalin.marinas@arm.com, rmk+kernel@armlinux.org.uk, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, tglx@linutronix.de, dave.hansen@linux.intel.com, x86@kernel.org, bp@alien8.de, hpa@zytor.com, chenhuacai@kernel.org, zhangqing@loongson.cn, kernel@xen0n.name, mingo@redhat.com, peterz@infradead.org, xiehuan09@gmail.com, dinghui@sangfor.com.cn, huangcun@sangfor.com.cn, dolinux.peng@gmail.com Cc: linux-trace-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Donglin Peng Subject: [PATCH v10 3/8] ARM: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL Date: Fri, 31 Mar 2023 05:47:39 -0700 Message-Id: <4737b3d08e1a4a7218e16c99f8ac308881d695c9.1680265828.git.pengdonglin@sangfor.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVkaGRlIVh8dHR9NSklPQk9PTVUTARMWGhIXJBQOD1 lXWRgSC1lBWUpKTFVKSEhVTk1VSUlZV1kWGg8SFR0UWUFZT0tIVUpKS0hKTFVKS0tVS1kG X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6OD46NTo5PD0OLU09QjkeITgW HUgKCj9VSlVKTUNLSU1NQ0NMQklIVTMWGhIXVQseFRwfFBUcFxIVOwgaFRwdFAlVGBQWVRgVRVlX WRILWUFZSkpMVUpISFVOTVVJSVlXWQgBWUFNSE5MNwY+ X-HM-Tid: 0a8737b601162eb7kusn5001158015c X-HM-MType: 1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The previous patch ("function_graph: Support recording and printing the return value of function") has laid the groundwork for the for the funcgraph-retval, and this modification makes it available on the ARM platform. We introduce a new structure called fgraph_ret_regs for the ARM platform to hold return registers and the frame pointer. We then fill its content in the return_to_handler and pass its address to the function ftrace_return_to_handler to record the return value. Signed-off-by: Donglin Peng --- v10: - Use CONFIG_FUNCTION_GRAPH_TRACER to control fgraph_ret_regs definition v9: - Fix stack pointer align issues - Update the commit message v8: - Modify the control range of CONFIG_HAVE_FUNCTION_GRAPH_RETVAL --- arch/arm/Kconfig | 1 + arch/arm/include/asm/ftrace.h | 22 ++++++++++++++++++++++ arch/arm/kernel/asm-offsets.c | 8 +++++++- arch/arm/kernel/entry-ftrace.S | 10 ++++++---- 4 files changed, 36 insertions(+), 5 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index e24a9820e12f..73061379855a 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -98,6 +98,7 @@ config ARM select HAVE_FAST_GUP if ARM_LPAE select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL select HAVE_FUNCTION_ERROR_INJECTION + select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER if !XIP_KERNEL select HAVE_GCC_PLUGINS diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h index 7e9251ca29fe..3c457902b355 100644 --- a/arch/arm/include/asm/ftrace.h +++ b/arch/arm/include/asm/ftrace.h @@ -77,4 +77,26 @@ static inline bool arch_syscall_match_sym_name(const cha= r *sym, =20 #endif /* ifndef __ASSEMBLY__ */ =20 +#ifndef __ASSEMBLY__ +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +struct fgraph_ret_regs { + /* r0 - r3 */ + unsigned long regs[4]; + + unsigned long fp; + unsigned long __unused; +}; + +static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret= _regs *ret_regs) +{ + return ret_regs->regs[0]; +} + +static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_re= t_regs *ret_regs) +{ + return ret_regs->fp; +} +#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */ +#endif + #endif /* _ASM_ARM_FTRACE */ diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c index 38121c59cbc2..18bb85115b21 100644 --- a/arch/arm/kernel/asm-offsets.c +++ b/arch/arm/kernel/asm-offsets.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include "signal.h" @@ -170,5 +171,10 @@ int main(void) DEFINE(KEXEC_INDIR_PAGE, offsetof(struct kexec_relocate_data, kexec_indi= rection_page)); DEFINE(KEXEC_MACH_TYPE, offsetof(struct kexec_relocate_data, kexec_mach_= type)); DEFINE(KEXEC_R2, offsetof(struct kexec_relocate_data, kexec_r2)); - return 0;=20 +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + BLANK(); + DEFINE(FGRET_REGS_SIZE, sizeof(struct fgraph_ret_regs)); + BLANK(); +#endif + return 0; } diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S index 3e7bcaca5e07..d41a1676608c 100644 --- a/arch/arm/kernel/entry-ftrace.S +++ b/arch/arm/kernel/entry-ftrace.S @@ -257,11 +257,13 @@ ENDPROC(ftrace_graph_regs_caller) =20 #ifdef CONFIG_FUNCTION_GRAPH_TRACER ENTRY(return_to_handler) - stmdb sp!, {r0-r3} - add r0, sp, #16 @ sp at exit of instrumented routine + mov ip, sp @ sp at exit of instrumented routine + stmdb sp!, {r0-r3, ip, lr} @ fill fgraph_ret_regs + mov r0, sp bl ftrace_return_to_handler - mov lr, r0 @ r0 has real ret addr - ldmia sp!, {r0-r3} + mov lr, r0 @ r0 has real ret addr + ldmia sp, {r0-r3} + add sp, sp, #FGRET_REGS_SIZE @ restore stack pointer ret lr ENDPROC(return_to_handler) #endif --=20 2.25.1 From nobody Tue Feb 10 10:53:27 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D31FFC77B6C for ; Fri, 31 Mar 2023 12:49:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232588AbjCaMtp (ORCPT ); Fri, 31 Mar 2023 08:49:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232350AbjCaMtR (ORCPT ); Fri, 31 Mar 2023 08:49:17 -0400 Received: from mail-m118111.qiye.163.com (mail-m118111.qiye.163.com [115.236.118.111]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 30A8621A90; Fri, 31 Mar 2023 05:48:54 -0700 (PDT) Received: from ubuntu.localdomain (unknown [117.133.56.22]) by mail-m118111.qiye.163.com (Hmail) with ESMTPA id 026F3580192; Fri, 31 Mar 2023 20:48:07 +0800 (CST) From: Donglin Peng To: mhiramat@kernel.org, rostedt@goodmis.org, linux@armlinux.org.uk, mark.rutland@arm.com, will@kernel.org, catalin.marinas@arm.com, rmk+kernel@armlinux.org.uk, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, tglx@linutronix.de, dave.hansen@linux.intel.com, x86@kernel.org, bp@alien8.de, hpa@zytor.com, chenhuacai@kernel.org, zhangqing@loongson.cn, kernel@xen0n.name, mingo@redhat.com, peterz@infradead.org, xiehuan09@gmail.com, dinghui@sangfor.com.cn, huangcun@sangfor.com.cn, dolinux.peng@gmail.com Cc: linux-trace-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Donglin Peng Subject: [PATCH v10 4/8] arm64: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL Date: Fri, 31 Mar 2023 05:47:40 -0700 Message-Id: <8f75bbf69eb49afb8e14b10dad6e091c43cff4e2.1680265828.git.pengdonglin@sangfor.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVlCS04aVksdTRhOHkNDSx9NGlUTARMWGhIXJBQOD1 lXWRgSC1lBWUpKTFVKSEhVTk1VSUlZV1kWGg8SFR0UWUFZT0tIVUpKS0hKTFVKS0tVS1kG X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6PU06Egw4Nj0IC00WQj8SITEK EA5PCQtVSlVKTUNLSU1NQ0NCTUNOVTMWGhIXVQseFRwfFBUcFxIVOwgaFRwdFAlVGBQWVRgVRVlX WRILWUFZSkpMVUpISFVOTVVJSVlXWQgBWUFMSUhNNwY+ X-HM-Tid: 0a8737b607a72eb7kusn026f3580192 X-HM-MType: 1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The previous patch ("function_graph: Support recording and printing the return value of function") has laid the groundwork for the for the funcgraph-retval, and this modification makes it available on the ARM64 platform. We introduce a new structure called fgraph_ret_regs for the ARM64 platform to hold return registers and the frame pointer. We then fill its content in the return_to_handler and pass its address to the function ftrace_return_to_handler to record the return value. Signed-off-by: Donglin Peng Reviewed-by: Mark Rutland Tested-by: Mark Rutland --- v10: - Use CONFIG_FUNCTION_GRAPH_TRACER to control fgraph_ret_regs definition v9: - Update the commit message v8: - Fix issues in ARM64 asm code - Modify the control range of CONFIG_HAVE_FUNCTION_GRAPH_RETVAL --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/ftrace.h | 22 ++++++++++++++++++++++ arch/arm64/kernel/asm-offsets.c | 13 +++++++++++++ arch/arm64/kernel/entry-ftrace.S | 27 ++++++++++++++------------- 4 files changed, 50 insertions(+), 13 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 1023e896d46b..48856d230800 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -195,6 +195,7 @@ config ARM64 select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_ERROR_INJECTION + select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_GRAPH_TRACER select HAVE_GCC_PLUGINS select HAVE_HW_BREAKPOINT if PERF_EVENTS diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrac= e.h index 1c2672bbbf37..657adcbd80a4 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -170,4 +170,26 @@ static inline bool arch_syscall_match_sym_name(const c= har *sym, } #endif /* ifndef __ASSEMBLY__ */ =20 +#ifndef __ASSEMBLY__ +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +struct fgraph_ret_regs { + /* x0 - x7 */ + unsigned long regs[8]; + + unsigned long fp; + unsigned long __unused; +}; + +static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret= _regs *ret_regs) +{ + return ret_regs->regs[0]; +} + +static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_re= t_regs *ret_regs) +{ + return ret_regs->fp; +} +#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */ +#endif + #endif /* __ASM_FTRACE_H */ diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offset= s.c index ae345b06e9f7..75082e0409bf 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -197,6 +197,19 @@ int main(void) #endif #ifdef CONFIG_FUNCTION_TRACER DEFINE(FTRACE_OPS_FUNC, offsetof(struct ftrace_ops, func)); +#endif + BLANK(); +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + DEFINE(FGRET_REGS_X0, offsetof(struct fgraph_ret_regs, regs[0])); + DEFINE(FGRET_REGS_X1, offsetof(struct fgraph_ret_regs, regs[1])); + DEFINE(FGRET_REGS_X2, offsetof(struct fgraph_ret_regs, regs[2])); + DEFINE(FGRET_REGS_X3, offsetof(struct fgraph_ret_regs, regs[3])); + DEFINE(FGRET_REGS_X4, offsetof(struct fgraph_ret_regs, regs[4])); + DEFINE(FGRET_REGS_X5, offsetof(struct fgraph_ret_regs, regs[5])); + DEFINE(FGRET_REGS_X6, offsetof(struct fgraph_ret_regs, regs[6])); + DEFINE(FGRET_REGS_X7, offsetof(struct fgraph_ret_regs, regs[7])); + DEFINE(FGRET_REGS_FP, offsetof(struct fgraph_ret_regs, fp)); + DEFINE(FGRET_REGS_SIZE, sizeof(struct fgraph_ret_regs)); #endif return 0; } diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftr= ace.S index 350ed81324ac..da1443bcf776 100644 --- a/arch/arm64/kernel/entry-ftrace.S +++ b/arch/arm64/kernel/entry-ftrace.S @@ -270,22 +270,23 @@ SYM_FUNC_END(ftrace_stub_graph) */ SYM_CODE_START(return_to_handler) /* save return value regs */ - sub sp, sp, #64 - stp x0, x1, [sp] - stp x2, x3, [sp, #16] - stp x4, x5, [sp, #32] - stp x6, x7, [sp, #48] + sub sp, sp, #FGRET_REGS_SIZE + stp x0, x1, [sp, #FGRET_REGS_X0] + stp x2, x3, [sp, #FGRET_REGS_X2] + stp x4, x5, [sp, #FGRET_REGS_X4] + stp x6, x7, [sp, #FGRET_REGS_X6] + str x29, [sp, #FGRET_REGS_FP] // parent's fp =20 - mov x0, x29 // parent's fp - bl ftrace_return_to_handler// addr =3D ftrace_return_to_hander(fp); - mov x30, x0 // restore the original return address + mov x0, sp + bl ftrace_return_to_handler // addr =3D ftrace_return_to_hander(regs); + mov x30, x0 // restore the original return address =20 /* restore return value regs */ - ldp x0, x1, [sp] - ldp x2, x3, [sp, #16] - ldp x4, x5, [sp, #32] - ldp x6, x7, [sp, #48] - add sp, sp, #64 + ldp x0, x1, [sp, #FGRET_REGS_X0] + ldp x2, x3, [sp, #FGRET_REGS_X2] + ldp x4, x5, [sp, #FGRET_REGS_X4] + ldp x6, x7, [sp, #FGRET_REGS_X6] + add sp, sp, #FGRET_REGS_SIZE =20 ret SYM_CODE_END(return_to_handler) --=20 2.25.1 From nobody Tue Feb 10 10:53:27 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 96823C6FD18 for ; Fri, 31 Mar 2023 12:49:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232321AbjCaMtj (ORCPT ); Fri, 31 Mar 2023 08:49:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47982 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232267AbjCaMtR (ORCPT ); Fri, 31 Mar 2023 08:49:17 -0400 Received: from mail-m118111.qiye.163.com (mail-m118111.qiye.163.com [115.236.118.111]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C9B0C21A8E; Fri, 31 Mar 2023 05:48:53 -0700 (PDT) Received: from ubuntu.localdomain (unknown [117.133.56.22]) by mail-m118111.qiye.163.com (Hmail) with ESMTPA id BB8AF580243; Fri, 31 Mar 2023 20:48:09 +0800 (CST) From: Donglin Peng To: mhiramat@kernel.org, rostedt@goodmis.org, linux@armlinux.org.uk, mark.rutland@arm.com, will@kernel.org, catalin.marinas@arm.com, rmk+kernel@armlinux.org.uk, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, tglx@linutronix.de, dave.hansen@linux.intel.com, x86@kernel.org, bp@alien8.de, hpa@zytor.com, chenhuacai@kernel.org, zhangqing@loongson.cn, kernel@xen0n.name, mingo@redhat.com, peterz@infradead.org, xiehuan09@gmail.com, dinghui@sangfor.com.cn, huangcun@sangfor.com.cn, dolinux.peng@gmail.com Cc: linux-trace-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Donglin Peng Subject: [PATCH v10 5/8] riscv: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL Date: Fri, 31 Mar 2023 05:47:41 -0700 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVlDGkkZVksYHkwfGhlNSx9JQlUTARMWGhIXJBQOD1 lXWRgSC1lBWUpKTFVKSEhVTk1VSUlZV1kWGg8SFR0UWUFZT0tIVUpKS0hKTFVKS0tVS1kG X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6Ojo6TRw6Mj0KIU0vKz8#ITAW DhUaCTxVSlVKTUNLSU1NQ0JKTkxLVTMWGhIXVQseFRwfFBUcFxIVOwgaFRwdFAlVGBQWVRgVRVlX WRILWUFZSkpMVUpISFVOTVVJSVlXWQgBWUFOSElKNwY+ X-HM-Tid: 0a8737b60e762eb7kusnbb8af580243 X-HM-MType: 1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The previous patch ("function_graph: Support recording and printing the return value of function") has laid the groundwork for the for the funcgraph-retval, and this modification makes it available on the RISC-V platform. We introduce a new structure called fgraph_ret_regs for the RISC-V platform to hold return registers and the frame pointer. We then fill its content in the return_to_handler and pass its address to the function ftrace_return_to_handler to record the return value. Signed-off-by: Donglin Peng --- v10: - Use CONFIG_FUNCTION_GRAPH_TRACER to control fgraph_ret_regs definition v9: - Update the commit message v8: - Modify the control range of CONFIG_HAVE_FUNCTION_GRAPH_RETVAL --- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/ftrace.h | 21 +++++++++++++++++++++ arch/riscv/kernel/mcount.S | 7 +------ 3 files changed, 23 insertions(+), 6 deletions(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 5b182d1c196c..0573eae28823 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -138,6 +138,7 @@ config RISCV select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && $(cc-option,-fpatchab= le-function-entry=3D8) select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL + select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION =20 diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrac= e.h index d47d87c2d7e3..740a979171e5 100644 --- a/arch/riscv/include/asm/ftrace.h +++ b/arch/riscv/include/asm/ftrace.h @@ -111,4 +111,25 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftr= ace *rec); =20 #endif /* CONFIG_DYNAMIC_FTRACE */ =20 +#ifndef __ASSEMBLY__ +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +struct fgraph_ret_regs { + unsigned long a1; + unsigned long a0; + unsigned long s0; + unsigned long ra; +}; + +static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret= _regs *ret_regs) +{ + return ret_regs->a0; +} + +static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_re= t_regs *ret_regs) +{ + return ret_regs->s0; +} +#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */ +#endif + #endif /* _ASM_RISCV_FTRACE_H */ diff --git a/arch/riscv/kernel/mcount.S b/arch/riscv/kernel/mcount.S index 30102aadc4d7..8a6e5a9e842a 100644 --- a/arch/riscv/kernel/mcount.S +++ b/arch/riscv/kernel/mcount.S @@ -65,13 +65,8 @@ ENTRY(return_to_handler) * So alternatively we check the *old* frame pointer position, that is, the * value stored in -16(s0) on entry, and the s0 on return. */ -#ifdef HAVE_FUNCTION_GRAPH_FP_TEST - mv t6, s0 -#endif SAVE_RET_ABI_STATE -#ifdef HAVE_FUNCTION_GRAPH_FP_TEST - mv a0, t6 -#endif + mv a0, sp call ftrace_return_to_handler mv a2, a0 RESTORE_RET_ABI_STATE --=20 2.25.1 From nobody Tue Feb 10 10:53:27 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 93C2EC76196 for ; Fri, 31 Mar 2023 12:49:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232566AbjCaMtV (ORCPT ); Fri, 31 Mar 2023 08:49:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231718AbjCaMtG (ORCPT ); Fri, 31 Mar 2023 08:49:06 -0400 Received: from mail-m118111.qiye.163.com (mail-m118111.qiye.163.com [115.236.118.111]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 64EE0210D; Fri, 31 Mar 2023 05:48:44 -0700 (PDT) Received: from ubuntu.localdomain (unknown [117.133.56.22]) by mail-m118111.qiye.163.com (Hmail) with ESMTPA id 9F28A580172; Fri, 31 Mar 2023 20:48:11 +0800 (CST) From: Donglin Peng To: mhiramat@kernel.org, rostedt@goodmis.org, linux@armlinux.org.uk, mark.rutland@arm.com, will@kernel.org, catalin.marinas@arm.com, rmk+kernel@armlinux.org.uk, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, tglx@linutronix.de, dave.hansen@linux.intel.com, x86@kernel.org, bp@alien8.de, hpa@zytor.com, chenhuacai@kernel.org, zhangqing@loongson.cn, kernel@xen0n.name, mingo@redhat.com, peterz@infradead.org, xiehuan09@gmail.com, dinghui@sangfor.com.cn, huangcun@sangfor.com.cn, dolinux.peng@gmail.com Cc: linux-trace-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Donglin Peng Subject: [PATCH v10 6/8] x86/ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL Date: Fri, 31 Mar 2023 05:47:42 -0700 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVkaSR5KVkJISx1PTxgaTR4fQlUTARMWGhIXJBQOD1 lXWRgSC1lBWUpKTFVKSEhVTk1VSUlZV1kWGg8SFR0UWUFZT0tIVUpKS0hKTFVKS0tVS1kG X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6Phw6LRw*Nz0KTE0aHT84ITka USJPCgxVSlVKTUNLSU1NQ0JIT0lOVTMWGhIXVQseFRwfFBUcFxIVOwgaFRwdFAlVGBQWVRgVRVlX WRILWUFZSkpMVUpISFVOTVVJSVlXWQgBWUFNS0hPNwY+ X-HM-Tid: 0a8737b616012eb7kusn9f28a580172 X-HM-MType: 1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The previous patch ("function_graph: Support recording and printing the return value of function") has laid the groundwork for the for the funcgraph-retval, and this modification makes it available on the x86 platform. We introduce a new structure called fgraph_ret_regs for the x86 platform to hold return registers and the frame pointer. We then fill its content in the return_to_handler and pass its address to the function ftrace_return_to_handler to record the return value. Signed-off-by: Donglin Peng --- v10: - Use CONFIG_FUNCTION_GRAPH_TRACER to control fgraph_ret_regs definition v9: - Update the commit message v8: - Modify the control range of CONFIG_HAVE_FUNCTION_GRAPH_RETVAL --- arch/x86/Kconfig | 1 + arch/x86/include/asm/ftrace.h | 20 ++++++++++++++++++++ arch/x86/kernel/ftrace_32.S | 8 +++++--- arch/x86/kernel/ftrace_64.S | 7 ++++--- 4 files changed, 30 insertions(+), 6 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index a825bf031f49..956cc988bdf9 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -214,6 +214,7 @@ config X86 select HAVE_FAST_GUP select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE select HAVE_FTRACE_MCOUNT_RECORD + select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) select HAVE_FUNCTION_TRACER select HAVE_GCC_PLUGINS diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h index 5061ac98ffa1..38d1df9aed37 100644 --- a/arch/x86/include/asm/ftrace.h +++ b/arch/x86/include/asm/ftrace.h @@ -147,4 +147,24 @@ static inline bool arch_trace_is_compat_syscall(struct= pt_regs *regs) #endif /* !COMPILE_OFFSETS */ #endif /* !__ASSEMBLY__ */ =20 +#ifndef __ASSEMBLY__ +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +struct fgraph_ret_regs { + unsigned long ax; + unsigned long dx; + unsigned long bp; +}; + +static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret= _regs *ret_regs) +{ + return ret_regs->ax; +} + +static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_re= t_regs *ret_regs) +{ + return ret_regs->bp; +} +#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */ +#endif + #endif /* _ASM_X86_FTRACE_H */ diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S index a0ed0e4a2c0c..5a9cc723f81f 100644 --- a/arch/x86/kernel/ftrace_32.S +++ b/arch/x86/kernel/ftrace_32.S @@ -182,12 +182,14 @@ SYM_CODE_END(ftrace_graph_caller) =20 .globl return_to_handler return_to_handler: - pushl %eax + pushl $0 pushl %edx - movl $0, %eax + pushl %eax + movl %esp, %eax call ftrace_return_to_handler movl %eax, %ecx - popl %edx popl %eax + popl %edx + addl $4, %esp # skip ebp JMP_NOSPEC ecx #endif diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S index fb4f1e01b64a..ef78c0bbae62 100644 --- a/arch/x86/kernel/ftrace_64.S +++ b/arch/x86/kernel/ftrace_64.S @@ -344,12 +344,13 @@ STACK_FRAME_NON_STANDARD_FP(__fentry__) SYM_CODE_START(return_to_handler) UNWIND_HINT_EMPTY ANNOTATE_NOENDBR - subq $16, %rsp + subq $24, %rsp =20 /* Save the return values */ movq %rax, (%rsp) movq %rdx, 8(%rsp) - movq %rbp, %rdi + movq %rbp, 16(%rsp) + movq %rsp, %rdi =20 call ftrace_return_to_handler =20 @@ -357,7 +358,7 @@ SYM_CODE_START(return_to_handler) movq 8(%rsp), %rdx movq (%rsp), %rax =20 - addq $16, %rsp + addq $24, %rsp /* * Jump back to the old return address. This cannot be JMP_NOSPEC rdi * since IBT would demand that contain ENDBR, which simply isn't so for --=20 2.25.1 From nobody Tue Feb 10 10:53:27 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 64F7FC76196 for ; Fri, 31 Mar 2023 12:50:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232554AbjCaMuJ (ORCPT ); Fri, 31 Mar 2023 08:50:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232641AbjCaMt2 (ORCPT ); Fri, 31 Mar 2023 08:49:28 -0400 Received: from mail-m118111.qiye.163.com (mail-m118111.qiye.163.com [115.236.118.111]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 13B302031B; Fri, 31 Mar 2023 05:49:09 -0700 (PDT) Received: from ubuntu.localdomain (unknown [117.133.56.22]) by mail-m118111.qiye.163.com (Hmail) with ESMTPA id 7D0D958022B; Fri, 31 Mar 2023 20:48:13 +0800 (CST) From: Donglin Peng To: mhiramat@kernel.org, rostedt@goodmis.org, linux@armlinux.org.uk, mark.rutland@arm.com, will@kernel.org, catalin.marinas@arm.com, rmk+kernel@armlinux.org.uk, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, tglx@linutronix.de, dave.hansen@linux.intel.com, x86@kernel.org, bp@alien8.de, hpa@zytor.com, chenhuacai@kernel.org, zhangqing@loongson.cn, kernel@xen0n.name, mingo@redhat.com, peterz@infradead.org, xiehuan09@gmail.com, dinghui@sangfor.com.cn, huangcun@sangfor.com.cn, dolinux.peng@gmail.com Cc: linux-trace-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Donglin Peng Subject: [PATCH v10 7/8] LoongArch: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL Date: Fri, 31 Mar 2023 05:47:43 -0700 Message-Id: <2f5d47ce9f7cf35ee2d292def7106169b9e41dc5.1680265828.git.pengdonglin@sangfor.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVlDQ0hOVk1KTxodGUtISRlLSFUTARMWGhIXJBQOD1 lXWRgSC1lBWUpKTFVKSEhVTk1VSUlZV1kWGg8SFR0UWUFZT0tIVUpKS0hKTFVKS0tVS1kG X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6Pyo6GSo*DD0UTE1MQjpMITQ0 TigwFCNVSlVKTUNLSU1NQ0JOSUlNVTMWGhIXVQseFRwfFBUcFxIVOwgaFRwdFAlVGBQWVRgVRVlX WRILWUFZSkpMVUpISFVOTVVJSVlXWQgBWUFMQ01MNwY+ X-HM-Tid: 0a8737b61d302eb7kusn7d0d958022b X-HM-MType: 1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The previous patch ("function_graph: Support recording and printing the return value of function") has laid the groundwork for the for the funcgraph-retval, and this modification makes it available on the LoongArch platform. We introduce a new structure called fgraph_ret_regs for the LoongArch platform to hold return registers and the frame pointer. We then fill its content in the return_to_handler and pass its address to the function ftrace_return_to_handler to record the return value. Signed-off-by: Donglin Peng Reviewed-by: Huacai Chen --- v10: - Fix code style issues for LoongArch - Use CONFIG_FUNCTION_GRAPH_TRACER to control fgraph_ret_regs definition v9: - Fix stack pointer align issues - Update the commit message v8: - Modify the control range of CONFIG_HAVE_FUNCTION_GRAPH_RETVAL --- arch/loongarch/Kconfig | 1 + arch/loongarch/include/asm/ftrace.h | 22 ++++++++++++++++++++++ arch/loongarch/kernel/asm-offsets.c | 15 ++++++++++++++- arch/loongarch/kernel/mcount.S | 14 ++++++++------ arch/loongarch/kernel/mcount_dyn.S | 15 ++++++++------- 5 files changed, 53 insertions(+), 14 deletions(-) diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index 7fd51257e0ed..4bf60132869b 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -99,6 +99,7 @@ config LOONGARCH select HAVE_FAST_GUP select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_ARG_ACCESS_API + select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER select HAVE_GENERIC_VDSO diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/a= sm/ftrace.h index 3418d32d4fc7..22797b7504b5 100644 --- a/arch/loongarch/include/asm/ftrace.h +++ b/arch/loongarch/include/asm/ftrace.h @@ -63,4 +63,26 @@ void ftrace_graph_func(unsigned long ip, unsigned long p= arent_ip, =20 #endif /* CONFIG_FUNCTION_TRACER */ =20 +#ifndef __ASSEMBLY__ +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +struct fgraph_ret_regs { + /* a0 - a1 */ + unsigned long regs[2]; + + unsigned long fp; + unsigned long __unused; +}; + +static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret= _regs *ret_regs) +{ + return ret_regs->regs[0]; +} + +static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_re= t_regs *ret_regs) +{ + return ret_regs->fp; +} +#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */ +#endif + #endif /* _ASM_LOONGARCH_FTRACE_H */ diff --git a/arch/loongarch/kernel/asm-offsets.c b/arch/loongarch/kernel/as= m-offsets.c index 4bdb203fc66e..505e4bf59603 100644 --- a/arch/loongarch/kernel/asm-offsets.c +++ b/arch/loongarch/kernel/asm-offsets.c @@ -12,6 +12,7 @@ #include #include #include +#include =20 void output_ptreg_defines(void) { @@ -264,7 +265,7 @@ void output_smpboot_defines(void) #ifdef CONFIG_HIBERNATION void output_pbe_defines(void) { - COMMENT(" Linux struct pbe offsets. "); + COMMENT("Linux struct pbe offsets."); OFFSET(PBE_ADDRESS, pbe, address); OFFSET(PBE_ORIG_ADDRESS, pbe, orig_address); OFFSET(PBE_NEXT, pbe, next); @@ -272,3 +273,15 @@ void output_pbe_defines(void) BLANK(); } #endif + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +void output_fgraph_ret_regs_defines(void) +{ + COMMENT("LoongArch fgraph_ret_regs offsets."); + OFFSET(FGRET_REGS_A0, fgraph_ret_regs, regs[0]); + OFFSET(FGRET_REGS_A1, fgraph_ret_regs, regs[1]); + OFFSET(FGRET_REGS_FP, fgraph_ret_regs, fp); + DEFINE(FGRET_REGS_SIZE, sizeof(struct fgraph_ret_regs)); + BLANK(); +} +#endif diff --git a/arch/loongarch/kernel/mcount.S b/arch/loongarch/kernel/mcount.S index 8cdc1563cd33..cb8e5803de4b 100644 --- a/arch/loongarch/kernel/mcount.S +++ b/arch/loongarch/kernel/mcount.S @@ -79,18 +79,20 @@ SYM_FUNC_START(ftrace_graph_caller) SYM_FUNC_END(ftrace_graph_caller) =20 SYM_FUNC_START(return_to_handler) - PTR_ADDI sp, sp, -2 * SZREG - PTR_S a0, sp, 0 - PTR_S a1, sp, SZREG + PTR_ADDI sp, sp, -FGRET_REGS_SIZE + PTR_S a0, sp, FGRET_REGS_A0 + PTR_S a1, sp, FGRET_REGS_A1 + PTR_S zero, sp, FGRET_REGS_FP =20 + move a0, sp bl ftrace_return_to_handler =20 /* Restore the real parent address: a0 -> ra */ move ra, a0 =20 - PTR_L a0, sp, 0 - PTR_L a1, sp, SZREG - PTR_ADDI sp, sp, 2 * SZREG + PTR_L a0, sp, FGRET_REGS_A0 + PTR_L a1, sp, FGRET_REGS_A1 + PTR_ADDI sp, sp, FGRET_REGS_SIZE jr ra SYM_FUNC_END(return_to_handler) #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ diff --git a/arch/loongarch/kernel/mcount_dyn.S b/arch/loongarch/kernel/mco= unt_dyn.S index bbabf06244c2..ec24ae1de741 100644 --- a/arch/loongarch/kernel/mcount_dyn.S +++ b/arch/loongarch/kernel/mcount_dyn.S @@ -131,18 +131,19 @@ SYM_CODE_END(ftrace_graph_caller) =20 SYM_CODE_START(return_to_handler) /* Save return value regs */ - PTR_ADDI sp, sp, -2 * SZREG - PTR_S a0, sp, 0 - PTR_S a1, sp, SZREG + PTR_ADDI sp, sp, -FGRET_REGS_SIZE + PTR_S a0, sp, FGRET_REGS_A0 + PTR_S a1, sp, FGRET_REGS_A1 + PTR_S zero, sp, FGRET_REGS_FP =20 - move a0, zero + move a0, sp bl ftrace_return_to_handler move ra, a0 =20 /* Restore return value regs */ - PTR_L a0, sp, 0 - PTR_L a1, sp, SZREG - PTR_ADDI sp, sp, 2 * SZREG + PTR_L a0, sp, FGRET_REGS_A0 + PTR_L a1, sp, FGRET_REGS_A1 + PTR_ADDI sp, sp, FGRET_REGS_SIZE =20 jr ra SYM_CODE_END(return_to_handler) --=20 2.25.1 From nobody Tue Feb 10 10:53:27 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52014C76196 for ; Fri, 31 Mar 2023 12:50:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231741AbjCaMuG (ORCPT ); Fri, 31 Mar 2023 08:50:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50172 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232628AbjCaMt1 (ORCPT ); Fri, 31 Mar 2023 08:49:27 -0400 Received: from mail-m118111.qiye.163.com (mail-m118111.qiye.163.com [115.236.118.111]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D08291FD0A; Fri, 31 Mar 2023 05:49:07 -0700 (PDT) Received: from ubuntu.localdomain (unknown [117.133.56.22]) by mail-m118111.qiye.163.com (Hmail) with ESMTPA id 4BB2A580485; Fri, 31 Mar 2023 20:48:15 +0800 (CST) From: Donglin Peng To: mhiramat@kernel.org, rostedt@goodmis.org, linux@armlinux.org.uk, mark.rutland@arm.com, will@kernel.org, catalin.marinas@arm.com, rmk+kernel@armlinux.org.uk, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, tglx@linutronix.de, dave.hansen@linux.intel.com, x86@kernel.org, bp@alien8.de, hpa@zytor.com, chenhuacai@kernel.org, zhangqing@loongson.cn, kernel@xen0n.name, mingo@redhat.com, peterz@infradead.org, xiehuan09@gmail.com, dinghui@sangfor.com.cn, huangcun@sangfor.com.cn, dolinux.peng@gmail.com Cc: linux-trace-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Donglin Peng Subject: [PATCH v10 8/8] selftests/ftrace: Add funcgraph-retval test case Date: Fri, 31 Mar 2023 05:47:44 -0700 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVlCQ0NOVh5DS0gfQxodQh9KTlUTARMWGhIXJBQOD1 lXWRgSC1lBWUpKTFVKSEhVTk1VSUlZV1kWGg8SFR0UWUFZT0tIVUpKS0hKTFVKS0tVS1kG X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6NxQ6MDo6MT0WIU0SHTo6IT0N IilPClZVSlVKTUNLSU1NQ0JNQkhNVTMWGhIXVQseFRwfFBUcFxIVOwgaFRwdFAlVGBQWVRgVRVlX WRILWUFZSkpMVUpISFVOTVVJSVlXWQgBWUFPSE5DNwY+ X-HM-Tid: 0a8737b624292eb7kusn4bb2a580485 X-HM-MType: 1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add a test case for the funcgraph-retval and funcgraph-retval-hex trace options. Signed-off-by: Donglin Peng --- v10: - Fix issues in selftest v8: - Fix issues in selftest --- .../ftrace/test.d/ftrace/fgraph-retval.tc | 43 +++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/ftrace/fgraph-ret= val.tc diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-retval.tc = b/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-retval.tc new file mode 100644 index 000000000000..5819aa2dd6ad --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-retval.tc @@ -0,0 +1,43 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: ftrace - function graph print function return value +# requires: options/funcgraph-retval options/funcgraph-retval-hex function= _graph:tracer + +# Make sure that funcgraph-retval works + +fail() { # msg + echo $1 + exit_fail +} + +disable_tracing +clear_trace + +read PID _ < /proc/self/stat +[ -f set_ftrace_pid ] && echo ${PID} > set_ftrace_pid +[ -f set_ftrace_filter ] && echo proc_reg_write > set_ftrace_filter +[ -f set_graph_function ] && echo proc_reg_write > set_graph_function +echo function_graph > current_tracer +echo funcgraph-retval > trace_options + +set +e +enable_tracing +echo > /proc/interrupts +disable_tracing +set -e + +: "Test printing the error code in signed decimal format" +echo nofuncgraph-retval-hex > trace_options +count=3D`cat trace | grep 'proc_reg_write' | grep '=3D -5' | wc -l` +if [ $count -eq 0 ]; then + fail "Return value can not be printed in signed decimal format" +fi + +: "Test printing the error code in hexadecimal format" +echo funcgraph-retval-hex > trace_options +count=3D`cat trace | grep 'proc_reg_write' | grep 'fffffffb' | wc -l` +if [ $count -eq 0 ]; then + fail "Return value can not be printed in hexadecimal format" +fi + +exit 0 --=20 2.25.1