Commit-ID: 317b622cb2fda1812d8646e211cdb23dce2564d0
Gitweb: http://git.kernel.org/tip/317b622cb2fda1812d8646e211cdb23dce2564d0
Author: Rik van Riel <riel@xxxxxxxxxx>
AuthorDate: Fri, 14 Oct 2016 08:15:30 -0400
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sun, 16 Oct 2016 11:38:31 +0200
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 <riel@xxxxxxxxxx>
Acked-by: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Quentin Casasnovas <quentin.casasnovas@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1476447331-21566-2-git-send-email-riel@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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 1dcb29e..590f274 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- * FPU registers are no longer valid for this task.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+ * FPU registers are no longer valid for this task.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 25a45dd..30f11ab 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 ca4c4ca..5cb801a 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);
--
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