[PATCH v5 4/7] powerpc/qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32
From: Guo Ren We don't have native hw xchg16 instruction, so let qspinlock generic code to deal with it. 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 Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras --- 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_SPINLOCKSif 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 -- 2.17.1
Re: [PATCH v5 4/7] powerpc/qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32
Le 28/03/2021 à 08:30, guo...@kernel.org a écrit : From: Guo Ren 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-npig...@gmail.com/ Christophe 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 Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras --- 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_SPINLOCKSif 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
Re: [PATCH v5 4/7] powerpc/qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32
On Sun, Mar 28, 2021 at 7:14 PM Christophe Leroy wrote: > > > > Le 28/03/2021 à 08:30, guo...@kernel.org a écrit : > > From: Guo Ren > > > > 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-npig...@gmail.com/ Got it, thx for the information. > > Christophe > > > > > 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 > > Cc: Michael Ellerman > > Cc: Benjamin Herrenschmidt > > Cc: Paul Mackerras > > --- > > 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_SPINLOCKSif 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 > > -- Best Regards Guo Ren ML: https://lore.kernel.org/linux-csky/
