Messages in this thread | | | Date | Wed, 12 Aug 2020 14:30:44 +0100 | From | Will Deacon <> | Subject | Re: [PATCH] arm64: Skip apply SSBS call for non SSBS system |
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On Tue, Aug 04, 2020 at 07:44:42PM +0530, Gaurav Kohli wrote: > In a system where no cpu's implement SSBS, for > them no need to set pstate. This might help to save > few cpu cycles during context switch. > > Signed-off-by: Gaurav Kohli <gkohli@codeaurora.org> > > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > index 6089638..79f80f1 100644 > --- a/arch/arm64/kernel/process.c > +++ b/arch/arm64/kernel/process.c > @@ -477,6 +477,13 @@ static void ssbs_thread_switch(struct task_struct *next) > struct pt_regs *regs = task_pt_regs(next); > > /* > + * For Targets which don't have SSBS support, they > + * can return from here. > + */ > + if (!IS_ENABLED(CONFIG_ARM64_SSBD)) > + return;
Does this actually make a measurable difference?
Will
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