FM / fpu

/usr/src/linux-headers-5.15.0-190/arch/x86/include/asm/fpu/

/usr/src/linux-headers-5.15.0-190/arch/x86/include/asm/fpu

Name	Size	Mode	Actions
api.h	5039	0644	edit dl rm
internal.h	0	0644	edit dl rm
regset.h	637	0644	edit dl rm
sched.h	2065	0644	edit dl rm
signal.h	1494	0644	edit dl rm
types.h	13797	0644	edit dl rm
xcr.h	483	0644	edit dl rm
xstate.h	4136	0644	edit dl rm

Edit: /usr/src/linux-headers-5.15.0-190/arch/x86/include/asm/fpu/sched.h (2065B)

/* 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 */

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