Hi, Ruoyao, Why no subject? On Fri, Aug 16, 2024 at 7:07 PM Xi Ruoyao <xry111@xxxxxxxxxxx> wrote: > > Subject: [PATCH v3 0/2] LoongArch: Implement getrandom() in vDSO > > For the rationale to implement getrandom() in vDSO see [1]. > > The vDSO getrandom() needs a stack-less ChaCha20 implementation, so we > need to add architecture-specific code and wire it up with the generic > code. Both generic LoongArch implementation and Loongson SIMD eXtension > based implementation are added. To dispatch them at runtime without > invoking cpucfg on each call, the alternative runtime patching mechanism > is extended to cover the vDSO. > > The implementation is tested with the kernel selftests added by the last > patch in [1]. I had to make some adjustments to make it work on > LoongArch (see [2], I've not submitted the changes as at now because I'm > unsure about the KHDR_INCLUDES addition). The vdso_test_getrandom > bench-single result: > > vdso: 25000000 times in 0.647855257 seconds (generic) > vdso: 25000000 times in 0.601068605 seconds (LSX) > libc: 25000000 times in 6.948168864 seconds > syscall: 25000000 times in 6.990265548 seconds > > The vdso_test_getrandom bench-multi result: > > vdso: 25000000 x 256 times in 35.322187834 seconds (generic) > vdso: 25000000 x 256 times in 29.183885426 seconds (LSX) > libc: 25000000 x 256 times in 356.628428409 seconds > syscall: 25000000 x 256 times in 334.764602866 seconds I don't see significant improvements about LSX here, so I prefer to just use the generic version to avoid complexity (I remember Linus said the whole of __vdso_getrandom is not very useful). Huacai > > [1]:https://lore.kernel.org/all/20240712014009.281406-1-Jason@xxxxxxxxx/ > [2]:https://github.com/xry111/linux/commits/xry111/la-vdso-v3/ > > [v2]->v3: > - Add a generic LoongArch implementation for which LSX isn't needed. > > v1->v2: > - Properly send the series to the list. > > [v2]:https://lore.kernel.org/all/20240815133357.35829-1-xry111@xxxxxxxxxxx/ > > Xi Ruoyao (3): > LoongArch: vDSO: Wire up getrandom() vDSO implementation > LoongArch: Perform alternative runtime patching on vDSO > LoongArch: vDSO: Add LSX implementation of vDSO getrandom() > > arch/loongarch/Kconfig | 1 + > arch/loongarch/include/asm/vdso/getrandom.h | 47 ++++ > arch/loongarch/include/asm/vdso/vdso.h | 8 + > arch/loongarch/kernel/asm-offsets.c | 10 + > arch/loongarch/kernel/vdso.c | 14 +- > arch/loongarch/vdso/Makefile | 6 + > arch/loongarch/vdso/memset.S | 24 ++ > arch/loongarch/vdso/vdso.lds.S | 7 + > arch/loongarch/vdso/vgetrandom-chacha-lsx.S | 162 +++++++++++++ > arch/loongarch/vdso/vgetrandom-chacha.S | 252 ++++++++++++++++++++ > arch/loongarch/vdso/vgetrandom.c | 19 ++ > 11 files changed, 549 insertions(+), 1 deletion(-) > create mode 100644 arch/loongarch/include/asm/vdso/getrandom.h > create mode 100644 arch/loongarch/vdso/memset.S > create mode 100644 arch/loongarch/vdso/vgetrandom-chacha-lsx.S > create mode 100644 arch/loongarch/vdso/vgetrandom-chacha.S > create mode 100644 arch/loongarch/vdso/vgetrandom.c > > -- > 2.46.0 >
