[patch 18/31] x86/fpu: Move context switch and exit to user inlines into sched.h

Thomas Gleixner
2021-10-12T00:06:45Z

internal.h is a kitchen sink which needs to get out of the way to prepare
for the upcoming changes.

Move the context switch and exit to user inlines into a separate header,
which is all that code needs.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/include/asm/fpu/internal.h | 60 -------------------------------
arch/x86/include/asm/fpu/sched.h | 68 ++++++++++++++++++++++++++++++++++++
arch/x86/kernel/fpu/core.c | 1
arch/x86/kernel/process.c | 2 -
arch/x86/kernel/process_32.c | 2 -
arch/x86/kernel/process_64.c | 2 -
6 files changed, 72 insertions(+), 63 deletions(-)

--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -27,16 +27,11 @@
* High level FPU state handling functions:
*/
extern bool fpu__restore_sig(void __user *buf, int ia32_frame);
-extern void fpu__drop(struct fpu *fpu);
extern void fpu__clear_user_states(struct fpu *fpu);
extern int fpu__exception_code(struct fpu *fpu, int trap_nr);

extern void fpu_sync_fpstate(struct fpu *fpu);

-/* Clone and exit operations */
-extern int fpu_clone(struct task_struct *dst, unsigned long clone_flags);
-extern void fpu_flush_thread(void);
-
/*
* Boot time FPU initialization functions:
*/
@@ -82,7 +77,6 @@ extern void fpstate_init_soft(struct swr
#else
static inline void fpstate_init_soft(struct swregs_state *soft) {}
#endif
-extern void save_fpregs_to_fpstate(struct fpu *fpu);

/*
* Returns 0 on success or the trap number when the operation raises an
@@ -464,58 +458,4 @@ static inline void fpregs_restore_userre
clear_thread_flag(TIF_NEED_FPU_LOAD);
}

-/*
- * FPU state switching for scheduling.
- *
- * This is a two-stage process:
- *
- * - switch_fpu_prepare() saves the old state.
- * This is done within the context of the old process.
- *
- * - switch_fpu_finish() sets TIF_NEED_FPU_LOAD; the floating point state
- * will get loaded on return to userspace, or when the kernel needs it.
- *
- * If TIF_NEED_FPU_LOAD is cleared then the CPU's FPU registers
- * are saved in the current thread's FPU register state.
- *
- * If TIF_NEED_FPU_LOAD is set then CPU's FPU registers may not
- * hold current()'s FPU registers. It is required to load the
- * registers before returning to userland or using the content
- * otherwise.
- *
- * The FPU context is only stored/restored for a user task and
- * PF_KTHREAD is used to distinguish between kernel and user threads.
- */
-static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu)
-{
- if (static_cpu_has(X86_FEATURE_FPU) && !(current->flags & PF_KTHREAD)) {
- save_fpregs_to_fpstate(old_fpu);
- /*
- * The save operation preserved register state, so the
- * fpu_fpregs_owner_ctx is still @old_fpu. Store the
- * current CPU number in @old_fpu, so the next return
- * to user space can avoid the FPU register restore
- * when is returns on the same CPU and still owns the
- * context.
- */
- old_fpu->last_cpu = cpu;
-
- trace_x86_fpu_regs_deactivated(old_fpu);
- }
-}
-
-/*
- * Misc helper functions:
- */
-
-/*
- * Delay loading of the complete FPU state until the return to userland.
- * PKRU is handled separately.
- */
-static inline void switch_fpu_finish(void)
-{
- if (cpu_feature_enabled(X86_FEATURE_FPU))
- set_thread_flag(TIF_NEED_FPU_LOAD);
-}
-
#endif /* _ASM_X86_FPU_INTERNAL_H */
--- /dev/null
+++ b/arch/x86/include/asm/fpu/sched.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_FPU_SCHED_H
+#define _ASM_X86_FPU_SCHED_H
+
+#include <linux/sched.h>
+
+#include <asm/cpufeature.h>
+#include <asm/fpu/types.h>
+
+#include <asm/trace/fpu.h>
+
+extern void save_fpregs_to_fpstate(struct fpu *fpu);
+extern void fpu__drop(struct fpu *fpu);
+extern int fpu_clone(struct task_struct *dst, unsigned long clone_flags);
+extern void fpu_flush_thread(void);
+
+/*
+ * FPU state switching for scheduling.
+ *
+ * This is a two-stage process:
+ *
+ * - switch_fpu_prepare() saves the old state.
+ * This is done within the context of the old process.
+ *
+ * - switch_fpu_finish() sets TIF_NEED_FPU_LOAD; the floating point state
+ * will get loaded on return to userspace, or when the kernel needs it.
+ *
+ * If TIF_NEED_FPU_LOAD is cleared then the CPU's FPU registers
+ * are saved in the current thread's FPU register state.
+ *
+ * If TIF_NEED_FPU_LOAD is set then CPU's FPU registers may not
+ * hold current()'s FPU registers. It is required to load the
+ * registers before returning to userland or using the content
+ * otherwise.
+ *
+ * The FPU context is only stored/restored for a user task and
+ * PF_KTHREAD is used to distinguish between kernel and user threads.
+ */
+static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu)
+{
+ if (cpu_feature_enabled(X86_FEATURE_FPU) &&
+ !(current->flags & PF_KTHREAD)) {
+ save_fpregs_to_fpstate(old_fpu);
+ /*
+ * The save operation preserved register state, so the
+ * fpu_fpregs_owner_ctx is still @old_fpu. Store the
+ * current CPU number in @old_fpu, so the next return
+ * to user space can avoid the FPU register restore
+ * when is returns on the same CPU and still owns the
+ * context.
+ */
+ old_fpu->last_cpu = cpu;
+
+ trace_x86_fpu_regs_deactivated(old_fpu);
+ }
+}
+
+/*
+ * Delay loading of the complete FPU state until the return to userland.
+ * PKRU is handled separately.
+ */
+static inline void switch_fpu_finish(void)
+{
+ if (cpu_feature_enabled(X86_FEATURE_FPU))
+ set_thread_flag(TIF_NEED_FPU_LOAD);
+}
+
+#endif /* _ASM_X86_FPU_SCHED_H */
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -8,6 +8,7 @@
*/
#include <asm/fpu/internal.h>
#include <asm/fpu/regset.h>
+#include <asm/fpu/sched.h>
#include <asm/fpu/signal.h>
#include <asm/fpu/types.h>
#include <asm/traps.h>
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -30,7 +30,7 @@
#include <asm/apic.h>
#include <linux/uaccess.h>
#include <asm/mwait.h>
-#include <asm/fpu/internal.h>
+#include <asm/fpu/sched.h>
#include <asm/debugreg.h>
#include <asm/nmi.h>
#include <asm/tlbflush.h>
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -41,7 +41,7 @@

#include <asm/ldt.h>
#include <asm/processor.h>
-#include <asm/fpu/internal.h>
+#include <asm/fpu/sched.h>
#include <asm/desc.h>

#include <linux/err.h>
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -42,7 +42,7 @@

#include <asm/processor.h>
#include <asm/pkru.h>
-#include <asm/fpu/internal.h>
+#include <asm/fpu/sched.h>
#include <asm/mmu_context.h>
#include <asm/prctl.h>
#include <asm/desc.h>