From 317b622cb2fda1812d8646e211cdb23dce2564d0 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Fri, 14 Oct 2016 08:15:30 -0400 Subject: [PATCH] x86/fpu: Remove 'cpu' argument from __cpu_invalidate_fpregs_state() The __{fpu,cpu}_invalidate_fpregs_state() functions can only be used to invalidate a resource they control. Document that, and change the API a little bit to reflect that. Go back to open coding the fpu_fpregs_owner_ctx write in the CPU hotplug code, which should be the exception, and move __kernel_fpu_begin() to this API. This patch has no functional changes to the current code. 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/1476447331-21566-2-git-send-email-riel@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/fpu/internal.h | 13 +++++++------ arch/x86/kernel/fpu/core.c | 2 +- arch/x86/kernel/smpboot.c | 2 +- 3 files changed, 9 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 1dcb29e8d92c..590f27488fca 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -488,15 +488,16 @@ DECLARE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx); * * Any code that clobbers the FPU registers or updates the in-memory * FPU state for a task MUST let the rest of the kernel know that the - * FPU registers are no longer valid for this task. Calling either of - * these two invalidate functions is enough, use whichever is convenient. + * FPU registers are no longer valid for this task. * - * Must be run with preemption disabled: this clears the fpu_fpregs_owner_ctx, - * on this CPU. + * Either one of these invalidation functions is enough. Invalidate + * a resource you control: CPU if using the CPU for something else + * (with preemption disabled), FPU for the current task, or a task that + * is prevented from running by the current task. */ -static inline void __cpu_invalidate_fpregs_state(unsigned int cpu) +static inline void __cpu_invalidate_fpregs_state(void) { - per_cpu(fpu_fpregs_owner_ctx, cpu) = NULL; + __this_cpu_write(fpu_fpregs_owner_ctx, NULL); } static inline void __fpu_invalidate_fpregs_state(struct fpu *fpu) diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 25a45ddfdbcf..30f11ab6c07e 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -106,7 +106,7 @@ void __kernel_fpu_begin(void) */ copy_fpregs_to_fpstate(fpu); } else { - this_cpu_write(fpu_fpregs_owner_ctx, NULL); + __cpu_invalidate_fpregs_state(); } } EXPORT_SYMBOL(__kernel_fpu_begin); diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index ca4c4ca2f6af..5cb801acc2e5 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1111,7 +1111,7 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle) return err; /* the FPU context is blank, nobody can own it */ - __cpu_invalidate_fpregs_state(cpu); + per_cpu(fpu_fpregs_owner_ctx, cpu) = NULL; common_cpu_up(cpu, tidle); -- 2.30.2