From c474e50711aa79b7bd0ea30b44744baca5650375 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Fri, 14 Oct 2016 08:15:31 -0400 Subject: x86/fpu: Split old_fpu & new_fpu handling into separate functions By moving all of the new_fpu state handling into switch_fpu_finish(), the code can be simplified some more. This gets rid of the prefetch, but given the size of the FPU register state on modern CPUs, and the amount of work done by __switch_to() inbetween both functions, the value of a single cache line prefetch seems somewhat dubious anyway. Signed-off-by: Rik van Riel Acked-by: Dave Hansen Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Quentin Casasnovas Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1476447331-21566-3-git-send-email-riel@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/process_64.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'arch/x86/kernel/process_64.c') diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index ee944bd2310d..705669efb762 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -264,9 +264,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) int cpu = smp_processor_id(); struct tss_struct *tss = &per_cpu(cpu_tss, cpu); unsigned prev_fsindex, prev_gsindex; - fpu_switch_t fpu_switch; - fpu_switch = switch_fpu_prepare(prev_fpu, next_fpu, cpu); + switch_fpu_prepare(prev_fpu, cpu); /* We must save %fs and %gs before load_TLS() because * %fs and %gs may be cleared by load_TLS(). @@ -416,7 +415,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) prev->gsbase = 0; prev->gsindex = prev_gsindex; - switch_fpu_finish(next_fpu, fpu_switch); + switch_fpu_finish(next_fpu, cpu); /* * Switch the PDA and FPU contexts. -- cgit v1.2.3