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Subject[PATCH 11/23] x86/fpu: Add (__)make_fpregs_active helpers
Date
From: Rik van Riel <riel@surriel.com>

Add helper function that ensures the floating point registers for
the current task are active. Use with preemption disabled.

Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
arch/x86/include/asm/fpu/api.h | 11 +++++++++++
arch/x86/include/asm/fpu/internal.h | 26 ++++++++++++++++----------
2 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index a9caac9d4a729..8c03b42416656 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -10,6 +10,7 @@

#ifndef _ASM_X86_FPU_API_H
#define _ASM_X86_FPU_API_H
+#include <linux/preempt.h>

/*
* Careful: __kernel_fpu_begin/end() must be called with preempt disabled
@@ -27,6 +28,16 @@ extern void kernel_fpu_begin(void);
extern void kernel_fpu_end(void);
extern bool irq_fpu_usable(void);

+static inline void __fpregs_changes_begin(void)
+{
+ preempt_disable();
+}
+
+static inline void __fpregs_changes_end(void)
+{
+ preempt_enable();
+}
+
/*
* Query the presence of one or more xfeatures. Works on any legacy CPU as well.
*
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index d7f9e14c73c19..260cd4f4ba2bb 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -512,6 +512,20 @@ static inline void fpregs_activate(struct fpu *fpu)
trace_x86_fpu_regs_activated(fpu);
}

+/*
+ * Load the FPU state for the current task. Call with preemption disabled.
+ */
+static inline void __fpregs_load_activate(struct fpu *fpu, int cpu)
+{
+ if (!fpregs_state_valid(fpu, cpu)) {
+ if (current->mm)
+ copy_kernel_to_fpregs(&fpu->state);
+ else
+ copy_kernel_to_fpregs(&init_fpstate);
+ }
+ fpregs_activate(fpu);
+}
+
/*
* FPU state switching for scheduling.
*
@@ -547,16 +561,8 @@ switch_fpu_prepare(struct fpu *old_fpu, int cpu)
*/
static inline void switch_fpu_finish(struct fpu *new_fpu, int cpu)
{
- if (static_cpu_has(X86_FEATURE_FPU)) {
- if (!fpregs_state_valid(new_fpu, cpu)) {
- if (current->mm)
- copy_kernel_to_fpregs(&new_fpu->state);
- else
- copy_kernel_to_fpregs(&init_fpstate);
- }
-
- fpregs_activate(new_fpu);
- }
+ if (static_cpu_has(X86_FEATURE_FPU))
+ __fpregs_load_activate(new_fpu, cpu);
}

/*
--
2.19.1
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