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Commit 317b622c authored by Rik van Riel's avatar Rik van Riel Committed by Ingo Molnar
Browse files

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: default avatarRik van Riel <riel@redhat.com>
Acked-by: default avatarDave Hansen <dave.hansen@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1476447331-21566-2-git-send-email-riel@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 9ad93fe3

arch/x86/include/asm/fpu/internal.h

+7 −6
Original line number Diff line number Diff line
@@ -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 * FPU registers are no longer valid for this task.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 * FPU registers are no longer valid for this task.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)

arch/x86/kernel/fpu/core.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

arch/x86/kernel/smpboot.c

+1 −1
Original line number Diff line number Diff line
@@ -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);