From: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
To: Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@kernel.org>, Theodore Ts'o <tytso@mit.edu>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Nathan Chancellor <nathan@kernel.org>
Cc: Christophe Leroy <chleroy@kernel.org>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Huacai Chen <chenhuacai@kernel.org>,
WANG Xuerui <kernel@xen0n.name>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Paul Walmsley <pjw@kernel.org>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Alexandre Ghiti <alex@ghiti.fr>,
Heiko Carstens <hca@linux.ibm.com>,
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Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, loongarch@lists.linux.dev,
linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org,
linux-s390@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH v2] random: vDSO: Avoid call to memset() when zeroing reserved in __cvdso_getrandom_data()
Date: Fri, 2 Oct 2026 12:57:06 +0200 [thread overview]
Message-ID: <179093852073.149722.832232613857480812.b4-ty@kernel.org> (raw)
In-Reply-To: <20260925-vdso-getrandom-avoid-memset-llvm-24-v2-1-ce640f872393@kernel.org>
On Fri, 25 Sep 2026 22:46:32 +0100, Nathan Chancellor wrote:
> After a recent change in LLVM [1], builds with the random vDSO
> implementation, such as PowerPC and RISC-V, fail when checking the vDSO:
>
> arch/powerpc/kernel/vdso/vdso32.so.dbg: dynamic relocations are not supported
> arch/riscv/kernel/vdso/vdso.so.dbg: dynamic relocations are not supported
>
> memset() is now generated when zeroing params->reserved for some builds
> because LLVM has an optimization (now run in more instances) that can
> recognize at compile time when it is assigning a static value to a
> contiguous area of memory and turn that into a call to memset(). Both
> clang and GCC assume memset() is always available [2].
>
> [...]
Applied, thanks!
[1/1] random: vDSO: Avoid call to memset() when zeroing reserved in __cvdso_getrandom_data()
(no commit info)
Best regards,
--
Christophe Leroy (CS GROUP) <chleroy@kernel.org>
next prev parent reply other threads:[~2026-10-02 10:57 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-25 21:46 Nathan Chancellor
2026-09-25 21:53 ` Nick Desaulniers
2026-09-25 21:56 ` Nick Desaulniers
2026-09-25 22:00 ` Nick Desaulniers
2026-09-25 22:19 ` Nathan Chancellor
2026-09-26 6:34 ` Christophe Leroy (CS GROUP)
2026-09-26 10:02 ` Jason A. Donenfeld
2026-09-26 10:55 ` Christophe Leroy (CS GROUP)
2026-09-26 12:29 ` Jason A. Donenfeld
2026-09-29 18:24 ` Nick Desaulniers
2026-09-30 13:38 ` Nathan Chancellor
2026-09-30 14:21 ` Jason A. Donenfeld
2026-09-30 14:44 ` Jason A. Donenfeld
2026-09-30 15:13 ` Nathan Chancellor
2026-09-30 15:16 ` Jason A. Donenfeld
2026-10-01 4:41 ` Christophe Leroy (CS GROUP)
2026-10-01 9:25 ` Jason A. Donenfeld
2026-10-01 10:20 ` Nathan Chancellor
2026-10-01 10:48 ` Jason A. Donenfeld
2026-10-01 11:03 ` Nathan Chancellor
2026-10-02 9:49 ` Nathan Chancellor
2026-10-02 10:13 ` Jason A. Donenfeld
2026-10-02 18:21 ` Christophe Leroy (CS GROUP)
2026-10-02 9:18 ` Christophe Leroy (CS GROUP)
2026-10-02 9:27 ` Jason A. Donenfeld
2026-09-26 12:39 ` Nathan Chancellor
2026-09-26 9:39 ` Andreas Schwab
2026-09-26 12:19 ` Nathan Chancellor
2026-09-26 12:32 ` Jason A. Donenfeld
2026-09-26 12:49 ` Nathan Chancellor
2026-09-27 7:02 ` David Laight
2026-09-29 16:59 ` Nathan Chancellor
2026-09-29 17:44 ` David Laight
2026-10-02 10:57 ` Christophe Leroy (CS GROUP) [this message]
2026-10-02 10:58 ` Jason A. Donenfeld
2026-10-02 11:01 ` LEROY Christophe
2026-10-02 11:02 ` Christophe Leroy (CS GROUP)
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