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

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __X86_KERNEL_FPU_XSTATE_H
#define __X86_KERNEL_FPU_XSTATE_H

#include <asm/cpufeature.h>
#include <asm/fpu/xstate.h>
#include <asm/fpu/xcr.h>

#ifdef CONFIG_X86_64
DECLARE_PER_CPU(u64, xfd_state);
#endif

static inline void xstate_init_xcomp_bv(struct xregs_state *xsave, u64 mask)
{ … }

static inline u64 xstate_get_group_perm(bool guest)
{ … }

static inline u64 xstate_get_host_group_perm(void)
{ … }

enum xstate_copy_mode { … };

struct membuf;
extern void __copy_xstate_to_uabi_buf(struct membuf to, struct fpstate *fpstate,
				      u64 xfeatures, u32 pkru_val,
				      enum xstate_copy_mode copy_mode);
extern void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk,
				    enum xstate_copy_mode mode);
extern int copy_uabi_from_kernel_to_xstate(struct fpstate *fpstate, const void *kbuf, u32 *pkru);
extern int copy_sigframe_from_user_to_xstate(struct task_struct *tsk, const void __user *ubuf);


extern void fpu__init_cpu_xstate(void);
extern void fpu__init_system_xstate(unsigned int legacy_size);

extern void __user *get_xsave_addr_user(struct xregs_state __user *xsave, int xfeature_nr);

static inline u64 xfeatures_mask_supervisor(void)
{ … }

static inline u64 xfeatures_mask_independent(void)
{ … }

/* XSAVE/XRSTOR wrapper functions */

#ifdef CONFIG_X86_64
#define REX_PREFIX …
#else
#define REX_PREFIX
#endif

/* These macros all use (%edi)/(%rdi) as the single memory argument. */
#define XSAVE …
#define XSAVEOPT …
#define XSAVEC …
#define XSAVES …
#define XRSTOR …
#define XRSTORS …

/*
 * After this @err contains 0 on success or the trap number when the
 * operation raises an exception.
 */
#define XSTATE_OP(op, st, lmask, hmask, err) …

/*
 * If XSAVES is enabled, it replaces XSAVEC because it supports supervisor
 * states in addition to XSAVEC.
 *
 * Otherwise if XSAVEC is enabled, it replaces XSAVEOPT because it supports
 * compacted storage format in addition to XSAVEOPT.
 *
 * Otherwise, if XSAVEOPT is enabled, XSAVEOPT replaces XSAVE because XSAVEOPT
 * supports modified optimization which is not supported by XSAVE.
 *
 * Use XSAVE as a fallback.
 */
#define XSTATE_XSAVE(st, lmask, hmask, err) …

/*
 * Use XRSTORS to restore context if it is enabled. XRSTORS supports compact
 * XSAVE area format.
 */
#define XSTATE_XRESTORE(st, lmask, hmask) …

#if defined(CONFIG_X86_64) && defined(CONFIG_X86_DEBUG_FPU)
extern void xfd_validate_state(struct fpstate *fpstate, u64 mask, bool rstor);
#else
static inline void xfd_validate_state(struct fpstate *fpstate, u64 mask, bool rstor) { }
#endif

#ifdef CONFIG_X86_64
static inline void xfd_set_state(u64 xfd)
{ … }

static inline void xfd_update_state(struct fpstate *fpstate)
{ … }

extern int __xfd_enable_feature(u64 which, struct fpu_guest *guest_fpu);
#else
static inline void xfd_set_state(u64 xfd) { }

static inline void xfd_update_state(struct fpstate *fpstate) { }

static inline int __xfd_enable_feature(u64 which, struct fpu_guest *guest_fpu) {
	return -EPERM;
}
#endif

/*
 * Save processor xstate to xsave area.
 *
 * Uses either XSAVE or XSAVEOPT or XSAVES depending on the CPU features
 * and command line options. The choice is permanent until the next reboot.
 */
static inline void os_xsave(struct fpstate *fpstate)
{ … }

/*
 * Restore processor xstate from xsave area.
 *
 * Uses XRSTORS when XSAVES is used, XRSTOR otherwise.
 */
static inline void os_xrstor(struct fpstate *fpstate, u64 mask)
{ … }

/* Restore of supervisor state. Does not require XFD */
static inline void os_xrstor_supervisor(struct fpstate *fpstate)
{ … }

/*
 * XSAVE itself always writes all requested xfeatures.  Removing features
 * from the request bitmap reduces the features which are written.
 * Generate a mask of features which must be written to a sigframe.  The
 * unset features can be optimized away and not written.
 *
 * This optimization is user-visible.  Only use for states where
 * uninitialized sigframe contents are tolerable, like dynamic features.
 *
 * Users of buffers produced with this optimization must check XSTATE_BV
 * to determine which features have been optimized out.
 */
static inline u64 xfeatures_need_sigframe_write(void)
{ … }

/*
 * Save xstate to user space xsave area.
 *
 * We don't use modified optimization because xrstor/xrstors might track
 * a different application.
 *
 * We don't use compacted format xsave area for backward compatibility for
 * old applications which don't understand the compacted format of the
 * xsave area.
 *
 * The caller has to zero buf::header before calling this because XSAVE*
 * does not touch the reserved fields in the header.
 */
static inline int xsave_to_user_sigframe(struct xregs_state __user *buf)
{ … }

/*
 * Restore xstate from user space xsave area.
 */
static inline int xrstor_from_user_sigframe(struct xregs_state __user *buf, u64 mask)
{ … }

/*
 * Restore xstate from kernel space xsave area, return an error code instead of
 * an exception.
 */
static inline int os_xrstor_safe(struct fpstate *fpstate, u64 mask)
{ … }


#endif