linux/arch/x86/kernel/fpu/regset.c

// SPDX-License-Identifier: GPL-2.0
/*
 * FPU register's regset abstraction, for ptrace, core dumps, etc.
 */
#include <linux/sched/task_stack.h>
#include <linux/vmalloc.h>

#include <asm/fpu/api.h>
#include <asm/fpu/signal.h>
#include <asm/fpu/regset.h>
#include <asm/prctl.h>

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

/*
 * The xstateregs_active() routine is the same as the regset_fpregs_active() routine,
 * as the "regset->n" for the xstate regset will be updated based on the feature
 * capabilities supported by the xsave.
 */
int regset_fpregs_active(struct task_struct *target, const struct user_regset *regset)
{ … }

int regset_xregset_fpregs_active(struct task_struct *target, const struct user_regset *regset)
{ … }

/*
 * The regset get() functions are invoked from:
 *
 *   - coredump to dump the current task's fpstate. If the current task
 *     owns the FPU then the memory state has to be synchronized and the
 *     FPU register state preserved. Otherwise fpstate is already in sync.
 *
 *   - ptrace to dump fpstate of a stopped task, in which case the registers
 *     have already been saved to fpstate on context switch.
 */
static void sync_fpstate(struct fpu *fpu)
{ … }

/*
 * Invalidate cached FPU registers before modifying the stopped target
 * task's fpstate.
 *
 * This forces the target task on resume to restore the FPU registers from
 * modified fpstate. Otherwise the task might skip the restore and operate
 * with the cached FPU registers which discards the modifications.
 */
static void fpu_force_restore(struct fpu *fpu)
{ … }

int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
		struct membuf to)
{ … }

int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
		unsigned int pos, unsigned int count,
		const void *kbuf, const void __user *ubuf)
{ … }

int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
		struct membuf to)
{ … }

int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
		  unsigned int pos, unsigned int count,
		  const void *kbuf, const void __user *ubuf)
{ … }

#ifdef CONFIG_X86_USER_SHADOW_STACK
int ssp_active(struct task_struct *target, const struct user_regset *regset)
{ … }

int ssp_get(struct task_struct *target, const struct user_regset *regset,
	    struct membuf to)
{ … }

int ssp_set(struct task_struct *target, const struct user_regset *regset,
	    unsigned int pos, unsigned int count,
	    const void *kbuf, const void __user *ubuf)
{ … }
#endif /* CONFIG_X86_USER_SHADOW_STACK */

#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION

/*
 * FPU tag word conversions.
 */

static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
{ … }

#define FPREG_ADDR(f, n) …
#define FP_EXP_TAG_VALID …
#define FP_EXP_TAG_ZERO …
#define FP_EXP_TAG_SPECIAL …
#define FP_EXP_TAG_EMPTY …

static inline u32 twd_fxsr_to_i387(struct fxregs_state *fxsave)
{ … }

/*
 * FXSR floating point environment conversions.
 */

static void __convert_from_fxsr(struct user_i387_ia32_struct *env,
				struct task_struct *tsk,
				struct fxregs_state *fxsave)
{ … }

void
convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk)
{ … }

void convert_to_fxsr(struct fxregs_state *fxsave,
		     const struct user_i387_ia32_struct *env)

{ … }

int fpregs_get(struct task_struct *target, const struct user_regset *regset,
	       struct membuf to)
{ … }

int fpregs_set(struct task_struct *target, const struct user_regset *regset,
	       unsigned int pos, unsigned int count,
	       const void *kbuf, const void __user *ubuf)
{ … }

#endif	/* CONFIG_X86_32 || CONFIG_IA32_EMULATION */