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Message-ID: <e78a7de3-147b-4c9c-87c1-8937dcabfa5c@gmail.com>
Date:   Mon, 11 Dec 2023 12:46:56 -0300
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Subject: Re: [PATCH] x86/Kconfig: rust: Patchable function Rust compat
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To:     Matthew Maurer <mmaurer@google.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@gmail.com>
Cc:     "H. Peter Anvin" <hpa@zytor.com>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>,
        Benno Lossin <benno.lossin@proton.me>,
        Andreas Hindborg <a.hindborg@samsung.com>,
        Alice Ryhl <aliceryhl@google.com>,
        linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org
References: <20231211150753.293883-1-mmaurer@google.com>
From:   Martin Rodriguez Reboredo <yakoyoku@gmail.com>
In-Reply-To: <20231211150753.293883-1-mmaurer@google.com>
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Precedence: bulk

On 12/11/23 12:07, Matthew Maurer wrote:
> Rust doesn't yet support patchable entry, but likely will soon. Disable
> function padding when Rust is used but doesn't support it, and propagate
> the flag when it does.
> 
> Signed-off-by: Matthew Maurer <mmaurer@google.com>
> ---
> [...]
> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> index 1a068de12a56..0228af62742e 100644
> --- a/arch/x86/Makefile
> +++ b/arch/x86/Makefile
> @@ -211,7 +211,9 @@ endif
>   
>   ifdef CONFIG_CALL_PADDING
>   PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
> +PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)

It seems that at a glance there's no discussion around this, neither an
issue, branch, PR or commit. Do you happen to have a link to it?

>   KBUILD_CFLAGS += $(PADDING_CFLAGS)
> +KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS)
>   export PADDING_CFLAGS
>   endif
>