From: Chengming Zhou <zhouchengming@bytedance.com>
To: rostedt@goodmis.org, mark.rutland@arm.com, mingo@redhat.com,
tglx@linutronix.de, catalin.marinas@arm.com, will@kernel.org,
dave.hansen@linux.intel.com, broonie@kernel.org
Cc: x86@kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, songmuchun@bytedance.com,
qirui.001@bytedance.com
Subject: Re: [PATCH v3 3/3] arm64/ftrace: Make function graph use ftrace directly
Date: Tue, 22 Mar 2022 20:48:00 +0800 [thread overview]
Message-ID: <c8b7508b-ce2a-c7dc-92c4-ca5f17992844@bytedance.com> (raw)
In-Reply-To: <20220224093251.49971-3-zhouchengming@bytedance.com>
Hello,
ping... have any comments?
Thanks.
On 2022/2/24 5:32 下午, Chengming Zhou wrote:
> As we do in commit 0c0593b45c9b ("x86/ftrace: Make function graph
> use ftrace directly"), we don't need special hook for graph tracer,
> but instead we use graph_ops:func function to install return_hooker.
>
> Since commit 3b23e4991fb6 ("arm64: implement ftrace with regs") add
> implementation for FTRACE_WITH_REGS on arm64, we can easily adopt
> the same cleanup on arm64. And this cleanup only changes the
> FTRACE_WITH_REGS implementation, so the mcount-based implementation
> is unaffected.
>
> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
> ---
> Changes in v3:
> - Add comments in ftrace_graph_func() as suggested by Steve.
>
> Changes in v2:
> - Remove FTRACE_WITH_REGS ftrace_graph_caller asm as suggested by Mark.
> ---
> arch/arm64/include/asm/ftrace.h | 7 +++++++
> arch/arm64/kernel/entry-ftrace.S | 17 -----------------
> arch/arm64/kernel/ftrace.c | 17 +++++++++++++++++
> 3 files changed, 24 insertions(+), 17 deletions(-)
>
> diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
> index 1494cfa8639b..dbc45a4157fa 100644
> --- a/arch/arm64/include/asm/ftrace.h
> +++ b/arch/arm64/include/asm/ftrace.h
> @@ -80,8 +80,15 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
>
> #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
> struct dyn_ftrace;
> +struct ftrace_ops;
> +struct ftrace_regs;
> +
> int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
> #define ftrace_init_nop ftrace_init_nop
> +
> +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
> + struct ftrace_ops *op, struct ftrace_regs *fregs);
> +#define ftrace_graph_func ftrace_graph_func
> #endif
>
> #define ftrace_return_address(n) return_address(n)
> diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
> index e535480a4069..d42a205ef625 100644
> --- a/arch/arm64/kernel/entry-ftrace.S
> +++ b/arch/arm64/kernel/entry-ftrace.S
> @@ -97,12 +97,6 @@ SYM_CODE_START(ftrace_common)
> SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL)
> bl ftrace_stub
>
> -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> -SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL) // ftrace_graph_caller();
> - nop // If enabled, this will be replaced
> - // "b ftrace_graph_caller"
> -#endif
> -
> /*
> * At the callsite x0-x8 and x19-x30 were live. Any C code will have preserved
> * x19-x29 per the AAPCS, and we created frame records upon entry, so we need
> @@ -127,17 +121,6 @@ ftrace_common_return:
> ret x9
> SYM_CODE_END(ftrace_common)
>
> -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> -SYM_CODE_START(ftrace_graph_caller)
> - ldr x0, [sp, #S_PC]
> - sub x0, x0, #AARCH64_INSN_SIZE // ip (callsite's BL insn)
> - add x1, sp, #S_LR // parent_ip (callsite's LR)
> - ldr x2, [sp, #PT_REGS_SIZE] // parent fp (callsite's FP)
> - bl prepare_ftrace_return
> - b ftrace_common_return
> -SYM_CODE_END(ftrace_graph_caller)
> -#endif
> -
> #else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
>
> /*
> diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
> index 4506c4a90ac1..35eb7c9b5e53 100644
> --- a/arch/arm64/kernel/ftrace.c
> +++ b/arch/arm64/kernel/ftrace.c
> @@ -268,6 +268,22 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
> }
>
> #ifdef CONFIG_DYNAMIC_FTRACE
> +
> +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
> +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
> + struct ftrace_ops *op, struct ftrace_regs *fregs)
> +{
> + /*
> + * Athough graph_ops doesn't have FTRACE_OPS_FL_SAVE_REGS set in flags,
> + * regs can't be NULL in DYNAMIC_FTRACE_WITH_REGS. By design, it should
> + * be fixed when DYNAMIC_FTRACE_WITH_ARGS is implemented.
> + */
> + struct pt_regs *regs = arch_ftrace_get_regs(fregs);
> + unsigned long *parent = (unsigned long *)&procedure_link_pointer(regs);
> +
> + prepare_ftrace_return(ip, parent, frame_pointer(regs));
> +}
> +#else
> /*
> * Turn on/off the call to ftrace_graph_caller() in ftrace_caller()
> * depending on @enable.
> @@ -297,5 +313,6 @@ int ftrace_disable_ftrace_graph_caller(void)
> {
> return ftrace_modify_graph_caller(false);
> }
> +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
> #endif /* CONFIG_DYNAMIC_FTRACE */
> #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
next prev parent reply other threads:[~2022-03-22 12:48 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-24 9:32 [PATCH v3 1/3] ftrace: cleanup ftrace_graph_caller enable and disable Chengming Zhou
2022-02-24 9:32 ` [PATCH v3 2/3] x86/ftrace: cleanup graph tracer Chengming Zhou
2022-02-24 9:32 ` [PATCH v3 3/3] arm64/ftrace: Make function graph use ftrace directly Chengming Zhou
2022-03-22 12:48 ` Chengming Zhou [this message]
2022-03-22 13:41 ` Steven Rostedt
2022-03-22 14:14 ` [External] " Chengming Zhou
2022-03-22 14:49 ` Steven Rostedt
2022-04-07 2:26 ` Chengming Zhou
2022-04-07 8:58 ` Mark Brown
2022-04-07 12:39 ` Chengming Zhou
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