[patch 24/31] x86/fpu: Move fpregs_restore_userregs() to core

Thomas Gleixner
2021-10-12T00:06:38Z

Only used core internaly.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/include/asm/fpu/internal.h | 83 -----------------------------------
arch/x86/kernel/fpu/context.h | 85 ++++++++++++++++++++++++++++++++++++
arch/x86/kernel/fpu/core.c | 1
arch/x86/kernel/fpu/regset.c | 1
arch/x86/kernel/fpu/signal.c | 1
5 files changed, 88 insertions(+), 83 deletions(-)

--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -55,89 +55,6 @@ extern void restore_fpregs_from_fpstate(

extern bool copy_fpstate_to_sigframe(void __user *buf, void __user *fp, int size);

-/*
- * FPU context switch related helper methods:
- */
-
DECLARE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx);

-/*
- * The in-register FPU state for an FPU context on a CPU is assumed to be
- * valid if the fpu->last_cpu matches the CPU, and the fpu_fpregs_owner_ctx
- * matches the FPU.
- *
- * If the FPU register state is valid, the kernel can skip restoring the
- * FPU state from memory.
- *
- * 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- * FPU registers are no longer valid for this task.
- *
- * 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(void)
-{
- __this_cpu_write(fpu_fpregs_owner_ctx, NULL);
-}
-
-static inline void __fpu_invalidate_fpregs_state(struct fpu *fpu)
-{
- fpu->last_cpu = -1;
-}
-
-static inline int fpregs_state_valid(struct fpu *fpu, unsigned int cpu)
-{
- return fpu == this_cpu_read(fpu_fpregs_owner_ctx) && cpu == fpu->last_cpu;
-}
-
-/*
- * These generally need preemption protection to work,
- * do try to avoid using these on their own:
- */
-static inline void fpregs_deactivate(struct fpu *fpu)
-{
- this_cpu_write(fpu_fpregs_owner_ctx, NULL);
- trace_x86_fpu_regs_deactivated(fpu);
-}
-
-static inline void fpregs_activate(struct fpu *fpu)
-{
- this_cpu_write(fpu_fpregs_owner_ctx, fpu);
- trace_x86_fpu_regs_activated(fpu);
-}
-
-/* Internal helper for switch_fpu_return() and signal frame setup */
-static inline void fpregs_restore_userregs(void)
-{
- struct fpu *fpu = &current->thread.fpu;
- int cpu = smp_processor_id();
-
- if (WARN_ON_ONCE(current->flags & PF_KTHREAD))
- return;
-
- if (!fpregs_state_valid(fpu, cpu)) {
- u64 mask;
-
- /*
- * This restores _all_ xstate which has not been
- * established yet.
- *
- * If PKRU is enabled, then the PKRU value is already
- * correct because it was either set in switch_to() or in
- * flush_thread(). So it is excluded because it might be
- * not up to date in current->thread.fpu.xsave state.
- */
- mask = xfeatures_mask_restore_user() |
- xfeatures_mask_supervisor();
- restore_fpregs_from_fpstate(&fpu->state, mask);
-
- fpregs_activate(fpu);
- fpu->last_cpu = cpu;
- }
- clear_thread_flag(TIF_NEED_FPU_LOAD);
-}
-
#endif /* _ASM_X86_FPU_INTERNAL_H */
--- /dev/null
+++ b/arch/x86/kernel/fpu/context.h
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __X86_KERNEL_FPU_CONTEXT_H
+#define __X86_KERNEL_FPU_CONTEXT_H
+
+#include <asm/fpu/xstate.h>
+#include <asm/trace/fpu.h>
+
+/* Functions related to FPU context tracking */
+
+/*
+ * The in-register FPU state for an FPU context on a CPU is assumed to be
+ * valid if the fpu->last_cpu matches the CPU, and the fpu_fpregs_owner_ctx
+ * matches the FPU.
+ *
+ * If the FPU register state is valid, the kernel can skip restoring the
+ * FPU state from memory.
+ *
+ * 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.
+ *
+ * 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(void)
+{
+ __this_cpu_write(fpu_fpregs_owner_ctx, NULL);
+}
+
+static inline void __fpu_invalidate_fpregs_state(struct fpu *fpu)
+{
+ fpu->last_cpu = -1;
+}
+
+static inline int fpregs_state_valid(struct fpu *fpu, unsigned int cpu)
+{
+ return fpu == this_cpu_read(fpu_fpregs_owner_ctx) && cpu == fpu->last_cpu;
+}
+
+static inline void fpregs_deactivate(struct fpu *fpu)
+{
+ __this_cpu_write(fpu_fpregs_owner_ctx, NULL);
+ trace_x86_fpu_regs_deactivated(fpu);
+}
+
+static inline void fpregs_activate(struct fpu *fpu)
+{
+ __this_cpu_write(fpu_fpregs_owner_ctx, fpu);
+ trace_x86_fpu_regs_activated(fpu);
+}
+
+/* Internal helper for switch_fpu_return() and signal frame setup */
+static inline void fpregs_restore_userregs(void)
+{
+ struct fpu *fpu = &current->thread.fpu;
+ int cpu = smp_processor_id();
+
+ if (WARN_ON_ONCE(current->flags & PF_KTHREAD))
+ return;
+
+ if (!fpregs_state_valid(fpu, cpu)) {
+ u64 mask;
+
+ /*
+ * This restores _all_ xstate which has not been
+ * established yet.
+ *
+ * If PKRU is enabled, then the PKRU value is already
+ * correct because it was either set in switch_to() or in
+ * flush_thread(). So it is excluded because it might be
+ * not up to date in current->thread.fpu.xsave state.
+ */
+ mask = xfeatures_mask_restore_user() |
+ xfeatures_mask_supervisor();
+ restore_fpregs_from_fpstate(&fpu->state, mask);
+
+ fpregs_activate(fpu);
+ fpu->last_cpu = cpu;
+ }
+ clear_thread_flag(TIF_NEED_FPU_LOAD);
+}
+
+#endif
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -17,6 +17,7 @@
#include <linux/hardirq.h>
#include <linux/pkeys.h>

+#include "context.h"
#include "internal.h"
#include "legacy.h"
#include "xstate.h"
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -10,6 +10,7 @@
#include <asm/fpu/regset.h>
#include <asm/fpu/xstate.h>

+#include "context.h"
#include "internal.h"

/*
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -16,6 +16,7 @@
#include <asm/trapnr.h>
#include <asm/trace/fpu.h>

+#include "context.h"
#include "internal.h"
#include "legacy.h"
#include "xstate.h"