From 40eb0cb4939e462acfedea8c8064571e886b9773 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 18 Aug 2020 07:31:30 +0200 Subject: [PATCH] x86/cpu: Fix typos and improve the comments in sync_core() - Fix typos. - Move the compiler barrier comment to the top, because it's valid for the whole function, not just the legacy branch. Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20200818053130.GA3161093@gmail.com Reviewed-by: Ricardo Neri --- arch/x86/include/asm/sync_core.h | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/sync_core.h b/arch/x86/include/asm/sync_core.h index 4631c0f969d4..0fd4a9dfb29c 100644 --- a/arch/x86/include/asm/sync_core.h +++ b/arch/x86/include/asm/sync_core.h @@ -47,16 +47,19 @@ static inline void iret_to_self(void) * * b) Text was modified on a different CPU, may subsequently be * executed on this CPU, and you want to make sure the new version - * gets executed. This generally means you're calling this in a IPI. + * gets executed. This generally means you're calling this in an IPI. * * If you're calling this for a different reason, you're probably doing * it wrong. + * + * Like all of Linux's memory ordering operations, this is a + * compiler barrier as well. */ static inline void sync_core(void) { /* * The SERIALIZE instruction is the most straightforward way to - * do this but it not universally available. + * do this, but it is not universally available. */ if (static_cpu_has(X86_FEATURE_SERIALIZE)) { serialize(); @@ -67,10 +70,10 @@ static inline void sync_core(void) * For all other processors, there are quite a few ways to do this. * IRET-to-self is nice because it works on every CPU, at any CPL * (so it's compatible with paravirtualization), and it never exits - * to a hypervisor. The only down sides are that it's a bit slow + * to a hypervisor. The only downsides are that it's a bit slow * (it seems to be a bit more than 2x slower than the fastest - * options) and that it unmasks NMIs. The "push %cs" is needed - * because, in paravirtual environments, __KERNEL_CS may not be a + * options) and that it unmasks NMIs. The "push %cs" is needed, + * because in paravirtual environments __KERNEL_CS may not be a * valid CS value when we do IRET directly. * * In case NMI unmasking or performance ever becomes a problem, @@ -81,9 +84,6 @@ static inline void sync_core(void) * CPUID is the conventional way, but it's nasty: it doesn't * exist on some 486-like CPUs, and it usually exits to a * hypervisor. - * - * Like all of Linux's memory ordering operations, this is a - * compiler barrier as well. */ iret_to_self(); }