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From: Peter Zijlstra <peterz@infradead.org>
To: Donglin Peng <pengdonglin@sangfor.com.cn>
Cc: mhiramat@kernel.org, rostedt@goodmis.org, linux@armlinux.org.uk,
	mark.rutland@arm.com, will@kernel.org, catalin.marinas@arm.com,
	palmer@dabbelt.com, paul.walmsley@sifive.com, tglx@linutronix.de,
	dave.hansen@linux.intel.com, x86@kernel.org, mingo@redhat.com,
	xiehuan09@gmail.com, dinghui@sangfor.com.cn,
	huangcun@sangfor.com.cn, dolinux.peng@gmail.com,
	linux-trace-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 1/2] function_graph: Support recording and printing the return value of function
Date: Wed, 15 Mar 2023 14:49:11 +0100	[thread overview]
Message-ID: <20230315134911.GD2006103@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20230315133911.958741-2-pengdonglin@sangfor.com.cn>

On Wed, Mar 15, 2023 at 06:39:10AM -0700, Donglin Peng wrote:
> diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S
> index a0ed0e4a2c0c..44a773d9de82 100644
> --- a/arch/x86/kernel/ftrace_32.S
> +++ b/arch/x86/kernel/ftrace_32.S
> @@ -184,6 +184,10 @@ SYM_CODE_END(ftrace_graph_caller)
>  return_to_handler:
>  	pushl	%eax
>  	pushl	%edx
> +#ifdef CONFIG_FUNCTION_GRAPH_RETVAL
> +	/* Pass the function return value to ftrace_return_to_handler*/
> +	movl	%eax, %edx
> +#endif
>  	movl	$0, %eax
>  	call	ftrace_return_to_handler
>  	movl	%eax, %ecx
> diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S
> index 1265ad519249..35ac9c58dc77 100644
> --- a/arch/x86/kernel/ftrace_64.S
> +++ b/arch/x86/kernel/ftrace_64.S
> @@ -348,6 +348,10 @@ SYM_CODE_START(return_to_handler)
>  	movq %rax, (%rsp)
>  	movq %rdx, 8(%rsp)
>  	movq %rbp, %rdi
> +#ifdef CONFIG_FUNCTION_GRAPH_RETVAL
> +	/* Pass the function return value to ftrace_return_to_handler */
> +	movq %rax, %rsi
> +#endif
>  
>  	call ftrace_return_to_handler

What about the case of double register return values (when the value
is returned in the A,D pair) ?

  reply	other threads:[~2023-03-15 13:50 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-15 13:39 [PATCH v4 0/2] function_graph: Support recording and printing the return value of function Donglin Peng
2023-03-15 13:39 ` [PATCH v4 1/2] " Donglin Peng
2023-03-15 13:49   ` Peter Zijlstra [this message]
2023-03-15 14:13     ` Steven Rostedt
2023-03-15 14:57       ` Peter Zijlstra
2023-03-16  3:18         ` Donglin Peng
2023-03-16 12:39           ` Masami Hiramatsu
2023-03-16 13:13             ` Donglin Peng
2023-03-16 23:21   ` Russell King (Oracle)
2023-03-17  2:49     ` Donglin Peng
2023-03-18 16:40       ` Steven Rostedt
2023-03-19  4:14         ` Donglin Peng
2023-03-15 13:39 ` [PATCH v4 2/2] tracing: Add documentation for funcgraph-retval and graph_retval_hex Donglin Peng

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