From: Mark Rutland <mark.rutland@arm.com>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, will@kernel.org,
rostedt@goodmis.org, samitolvanen@google.com,
keescook@chromium.org, mhiramat@kernel.org
Subject: Re: [PATCH] ftrace: Allow WITH_ARGS flavour of graph tracer with shadow call stack
Date: Fri, 9 Dec 2022 14:40:25 +0000 [thread overview]
Message-ID: <Y5NI2TKtGbDKyt53@FVFF77S0Q05N> (raw)
In-Reply-To: <20221209143402.3332369-1-ardb@kernel.org>
On Fri, Dec 09, 2022 at 03:34:02PM +0100, Ard Biesheuvel wrote:
> The recent switch on arm64 from DYNAMIC_FTRACE_WITH_REGS to
> DYNAMIC_FTRACE_WITH_ARGS failed to take into account that we currently
> require the former in order to allow the function graph tracer to be
> enabled in combination with shadow call stacks. This means that this is
> no longer permitted at all, in spite of the fact that either flavour of
> ftrace works perfectly fine in this combination.
>
> Given that arm64 is the only arch that implements shadow call stacks in
> the first place, let's update the condition to just reflect the arm64
> change. When other architectures adopt shadow call stack support, this
> can be revisited if needed.
>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
My bad; sorry about this, and thanks for the fix!
Acked-by: Mark Rutland <mark.rutland@arm.com>
We should probably also add:
Fixes: 26299b3f6ba26bfc ("ftrace: arm64: move from REGS to ARGS")
Mark.
> ---
> arch/Kconfig | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 072a1b39e3afd0d1..683f365b5e31c856 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -635,7 +635,7 @@ config ARCH_SUPPORTS_SHADOW_CALL_STACK
> config SHADOW_CALL_STACK
> bool "Shadow Call Stack"
> depends on ARCH_SUPPORTS_SHADOW_CALL_STACK
> - depends on DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER
> + depends on DYNAMIC_FTRACE_WITH_ARGS || !FUNCTION_GRAPH_TRACER
> help
> This option enables the compiler's Shadow Call Stack, which
> uses a shadow stack to protect function return addresses from
> --
> 2.35.1
>
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next prev parent reply other threads:[~2022-12-09 14:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-09 14:34 [PATCH] ftrace: Allow WITH_ARGS flavour of graph tracer with shadow call stack Ard Biesheuvel
2022-12-09 14:40 ` Mark Rutland [this message]
2022-12-09 21:51 ` Steven Rostedt
2022-12-12 10:36 ` Mark Rutland
2022-12-13 11:36 ` Will Deacon
2022-12-11 3:27 ` Masami Hiramatsu
2022-12-12 10:46 ` Mark Rutland
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