Re: [PATCH v5 4/7] powerpc/qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32
From: Christophe Leroy <hidden>
Date: 2021-03-28 11:15:34
Also in:
linux-arch, linux-riscv, lkml, sparclinux
Le 28/03/2021 à 08:30, guoren@kernel.org a écrit :
From: Guo Ren <redacted> We don't have native hw xchg16 instruction, so let qspinlock generic code to deal with it.
We have lharx/sthcx pair on some versions of powerpc. See https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20201107032328.2454582-1-npiggin@gmail.com/ Christophe
quoted hunk ↗ jump to hunk
Using the full-word atomic xchg instructions implement xchg16 has the semantic risk for atomic operations. This patch cancels the dependency of on qspinlock generic code on architecture's xchg16. Signed-off-by: Guo Ren <redacted> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <redacted> --- arch/powerpc/Kconfig | 1 + 1 file changed, 1 insertion(+)diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 386ae12d8523..69ec4ade6521 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig@@ -151,6 +151,7 @@ config PPC select ARCH_USE_CMPXCHG_LOCKREF if PPC64 select ARCH_USE_QUEUED_RWLOCKS if PPC_QUEUED_SPINLOCKS select ARCH_USE_QUEUED_SPINLOCKS if PPC_QUEUED_SPINLOCKS + select ARCH_USE_QUEUED_SPINLOCKS_XCHG32 if PPC_QUEUED_SPINLOCKS select ARCH_WANT_IPC_PARSE_VERSION select ARCH_WANT_IRQS_OFF_ACTIVATE_MM select ARCH_WANT_LD_ORPHAN_WARN