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x86/fpu: Move context switch and exit to user inlines into sched.h 

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>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211015011539.349132461@linutronix.de
This commit is contained in:
Thomas Gleixner 2021-10-15 03:16:20 +02:00 committed by Borislav Petkov
parent 9603445549
commit 63e81807c1
6 changed files with 72 additions and 63 deletions
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60
arch/x86/include/asm/fpu/internal.h
View File

@ -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);
extern void fpu_flush_thread(void);
/*
* Boot time FPU initialization functions:
*/
@ -82,7 +77,6 @@ extern void fpstate_init_soft(struct swregs_state *soft);
#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_userregs(void)
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 */

68
arch/x86/include/asm/fpu/sched.h Normal file
View File

@ -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);
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 */

1
arch/x86/kernel/fpu/core.c
View File

@ -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>

2
arch/x86/kernel/process.c
View File

@ -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>

2
arch/x86/kernel/process_32.c
View File

@ -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>

2
arch/x86/kernel/process_64.c
View File

@ -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>