Thread (37 messages) 37 messages, 7 authors, 8d ago

Re: [PATCH v2] random: vDSO: Avoid call to memset() when zeroing reserved in __cvdso_getrandom_data()

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From: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Date: 2026-10-02 10:57:52
Also in: linux-arm-kernel, linux-riscv, linux-s390, lkml, llvm, loongarch

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) [off-list ref]
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