linux/arch/x86/kernel/fpu/context.h

/* 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 * FPU registers are no longer valid for this task.
 *
 * 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)
{ … }

static inline void __fpu_invalidate_fpregs_state(struct fpu *fpu)
{ … }

static inline int fpregs_state_valid(struct fpu *fpu, unsigned int cpu)
{ … }

static inline void fpregs_deactivate(struct fpu *fpu)
{ … }

static inline void fpregs_activate(struct fpu *fpu)
{ … }

/* Internal helper for switch_fpu_return() and signal frame setup */
static inline void fpregs_restore_userregs(void)
{ … }

#endif