From: Steven Rostedt <rostedt@goodmis.org>
To: Puranjay Mohan <puranjay@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Samuel Holland <samuel.holland@sifive.com>,
Matthew Bystrin <dev.mbstr@gmail.com>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
puranjay12@gmail.com
Subject: Re: [PATCH] riscv: stacktrace: fix usage of ftrace_graph_ret_addr()
Date: Tue, 18 Jun 2024 12:13:56 -0400 [thread overview]
Message-ID: <20240618121356.08f961eb@rorschach.local.home> (raw)
In-Reply-To: <20240618145820.62112-1-puranjay@kernel.org>
On Tue, 18 Jun 2024 14:58:20 +0000
Puranjay Mohan <puranjay@kernel.org> wrote:
> ftrace_graph_ret_addr() takes an `idx` integer pointer that is used to
> optimize the stack unwinding. Pass it a valid pointer to utilize the
> optimizations that might be available in the future.
>
> The commit is making riscv's usage of ftrace_graph_ret_addr() match
> x86_64.
>
> Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Not only that, the updated code for ftrace_graph_ret_addr() will just
return the passed in return address if it is NULL. Basically, it will
not work without this.
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
-- Steve
> ---
> arch/riscv/kernel/stacktrace.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
> index 528ec7cc9a62..6cb7f9ca9d82 100644
> --- a/arch/riscv/kernel/stacktrace.c
> +++ b/arch/riscv/kernel/stacktrace.c
> @@ -32,6 +32,7 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
> bool (*fn)(void *, unsigned long), void *arg)
> {
> unsigned long fp, sp, pc;
> + int graph_idx = 0;
> int level = 0;
>
> if (regs) {
> @@ -68,7 +69,7 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
> pc = regs->ra;
> } else {
> fp = frame->fp;
> - pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
> + pc = ftrace_graph_ret_addr(current, &graph_idx, frame->ra,
> &frame->ra);
> if (pc == (unsigned long)ret_from_exception) {
> if (unlikely(!__kernel_text_address(pc) || !fn(arg, pc)))
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next prev parent reply other threads:[~2024-06-18 16:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-18 14:58 [PATCH] riscv: stacktrace: fix usage of ftrace_graph_ret_addr() Puranjay Mohan
2024-06-18 16:13 ` Steven Rostedt [this message]
2024-07-04 13:10 ` patchwork-bot+linux-riscv
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