From: Kees Cook <keescook@chromium.org>
To: Heiko Carstens <hca@linux.ibm.com>
Cc: Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>
Subject: Re: [PATCH 1/2] Compiler Attributes: Add __uninitialized macro
Date: Mon, 5 Feb 2024 08:21:47 -0800 [thread overview]
Message-ID: <202402050818.B11CFAD2B@keescook> (raw)
In-Reply-To: <20240205154844.3757121-2-hca@linux.ibm.com>
On Mon, Feb 05, 2024 at 04:48:43PM +0100, Heiko Carstens wrote:
> With INIT_STACK_ALL_PATTERN or INIT_STACK_ALL_ZERO enabled the kernel will
> be compiled with -ftrivial-auto-var-init=<...> which causes initialization
> of stack variables at function entry time.
>
> In order to avoid the performance impact that comes with this users can use
> the "uninitialized" attribute to prevent such initialization.
>
> Therefore provide the __uninitialized macro which can be used for cases
> where INIT_STACK_ALL_PATTERN or INIT_STACK_ALL_ZERO is enabled, but only
> selected variables should not be initialized.
>
> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Thanks! We had something similar a while back with syscall entry:
efa90c11f62e ("stack: Constrain and fix stack offset randomization with Clang builds")
Acked-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
next prev parent reply other threads:[~2024-02-05 16:21 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-05 15:48 [PATCH 0/2] Compiler Attributes, s390: Provide and use __uninitialized macro Heiko Carstens
2024-02-05 15:48 ` [PATCH 1/2] Compiler Attributes: Add " Heiko Carstens
2024-02-05 16:21 ` Kees Cook [this message]
2024-02-06 1:28 ` Nathan Chancellor
2024-02-05 15:48 ` [PATCH 2/2] s390/fpu: make use of " Heiko Carstens
2024-02-05 16:26 ` Kees Cook
2024-02-05 16:35 ` Heiko Carstens
2024-02-05 17:00 ` Kees Cook
2024-02-06 1:31 ` Nathan Chancellor
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