root/arch/x86/include/asm/xsave.h

INCLUDED FROM

DEFINITIONS

1. xsave_state_booting
2. xrstor_state_booting
3. xsave_state
4. xrstor_state
5. fpu_xsave
6. fpu_xrstor_checking
7. xsave_user
8. xrestore_user

#ifndef __ASM_X86_XSAVE_H
#define __ASM_X86_XSAVE_H

#include <linux/types.h>
#include <asm/processor.h>

#define XSTATE_CPUID            0x0000000d

#define XSTATE_FP               0x1
#define XSTATE_SSE              0x2
#define XSTATE_YMM              0x4
#define XSTATE_BNDREGS          0x8
#define XSTATE_BNDCSR           0x10
#define XSTATE_OPMASK           0x20
#define XSTATE_ZMM_Hi256        0x40
#define XSTATE_Hi16_ZMM         0x80

#define XSTATE_FPSSE    (XSTATE_FP | XSTATE_SSE)
/* Bit 63 of XCR0 is reserved for future expansion */
#define XSTATE_EXTEND_MASK      (~(XSTATE_FPSSE | (1ULL << 63)))

#define FXSAVE_SIZE     512

#define XSAVE_HDR_SIZE      64
#define XSAVE_HDR_OFFSET    FXSAVE_SIZE

#define XSAVE_YMM_SIZE      256
#define XSAVE_YMM_OFFSET    (XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET)

/* Supported features which support lazy state saving */
#define XSTATE_LAZY     (XSTATE_FP | XSTATE_SSE | XSTATE_YMM                  \
                        | XSTATE_OPMASK | XSTATE_ZMM_Hi256 | XSTATE_Hi16_ZMM)

/* Supported features which require eager state saving */
#define XSTATE_EAGER    (XSTATE_BNDREGS | XSTATE_BNDCSR)

/* All currently supported features */
#define XCNTXT_MASK     (XSTATE_LAZY | XSTATE_EAGER)

#ifdef CONFIG_X86_64
#define REX_PREFIX      "0x48, "
#else
#define REX_PREFIX
#endif

extern unsigned int xstate_size;
extern u64 pcntxt_mask;
extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
extern struct xsave_struct *init_xstate_buf;

extern void xsave_init(void);
extern void update_regset_xstate_info(unsigned int size, u64 xstate_mask);
extern int init_fpu(struct task_struct *child);

/* These macros all use (%edi)/(%rdi) as the single memory argument. */
#define XSAVE           ".byte " REX_PREFIX "0x0f,0xae,0x27"
#define XSAVEOPT        ".byte " REX_PREFIX "0x0f,0xae,0x37"
#define XSAVES          ".byte " REX_PREFIX "0x0f,0xc7,0x2f"
#define XRSTOR          ".byte " REX_PREFIX "0x0f,0xae,0x2f"
#define XRSTORS         ".byte " REX_PREFIX "0x0f,0xc7,0x1f"

#define xstate_fault    ".section .fixup,\"ax\"\n"      \
                        "3:  movl $-1,%[err]\n"         \
                        "    jmp  2b\n"                 \
                        ".previous\n"                   \
                        _ASM_EXTABLE(1b, 3b)            \
                        : [err] "=r" (err)

/*
 * This function is called only during boot time when x86 caps are not set
 * up and alternative can not be used yet.
 */
static inline int xsave_state_booting(struct xsave_struct *fx, u64 mask)
{
        u32 lmask = mask;
        u32 hmask = mask >> 32;
        int err = 0;

        WARN_ON(system_state != SYSTEM_BOOTING);

        if (boot_cpu_has(X86_FEATURE_XSAVES))
                asm volatile("1:"XSAVES"\n\t"
                        "2:\n\t"
                        : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
                        :   "memory");
        else
                asm volatile("1:"XSAVE"\n\t"
                        "2:\n\t"
                        : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
                        :   "memory");

        asm volatile(xstate_fault
                     : "0" (0)
                     : "memory");

        return err;
}

/*
 * This function is called only during boot time when x86 caps are not set
 * up and alternative can not be used yet.
 */
static inline int xrstor_state_booting(struct xsave_struct *fx, u64 mask)
{
        u32 lmask = mask;
        u32 hmask = mask >> 32;
        int err = 0;

        WARN_ON(system_state != SYSTEM_BOOTING);

        if (boot_cpu_has(X86_FEATURE_XSAVES))
                asm volatile("1:"XRSTORS"\n\t"
                        "2:\n\t"
                        : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
                        :   "memory");
        else
                asm volatile("1:"XRSTOR"\n\t"
                        "2:\n\t"
                        : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
                        :   "memory");

        asm volatile(xstate_fault
                     : "0" (0)
                     : "memory");

        return err;
}

/*
 * Save processor xstate to xsave area.
 */
static inline int xsave_state(struct xsave_struct *fx, u64 mask)
{
        u32 lmask = mask;
        u32 hmask = mask >> 32;
        int err = 0;

        /*
         * If xsaves is enabled, xsaves replaces xsaveopt because
         * it supports compact format and supervisor states in addition to
         * modified optimization in xsaveopt.
         *
         * Otherwise, if xsaveopt is enabled, xsaveopt replaces xsave
         * because xsaveopt supports modified optimization which is not
         * supported by xsave.
         *
         * If none of xsaves and xsaveopt is enabled, use xsave.
         */
        alternative_input_2(
                "1:"XSAVE,
                "1:"XSAVEOPT,
                X86_FEATURE_XSAVEOPT,
                "1:"XSAVES,
                X86_FEATURE_XSAVES,
                [fx] "D" (fx), "a" (lmask), "d" (hmask) :
                "memory");
        asm volatile("2:\n\t"
                     xstate_fault
                     : "0" (0)
                     : "memory");

        return err;
}

/*
 * Restore processor xstate from xsave area.
 */
static inline int xrstor_state(struct xsave_struct *fx, u64 mask)
{
        int err = 0;
        u32 lmask = mask;
        u32 hmask = mask >> 32;

        /*
         * Use xrstors to restore context if it is enabled. xrstors supports
         * compacted format of xsave area which is not supported by xrstor.
         */
        alternative_input(
                "1: " XRSTOR,
                "1: " XRSTORS,
                X86_FEATURE_XSAVES,
                "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
                : "memory");

        asm volatile("2:\n"
                     xstate_fault
                     : "0" (0)
                     : "memory");

        return err;
}

/*
 * Save xstate context for old process during context switch.
 */
static inline void fpu_xsave(struct fpu *fpu)
{
        xsave_state(&fpu->state->xsave, -1);
}

/*
 * Restore xstate context for new process during context switch.
 */
static inline int fpu_xrstor_checking(struct xsave_struct *fx)
{
        return xrstor_state(fx, -1);
}

/*
 * 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
 * compacted format of xsave area.
 */
static inline int xsave_user(struct xsave_struct __user *buf)
{
        int err;

        /*
         * Clear the xsave header first, so that reserved fields are
         * initialized to zero.
         */
        err = __clear_user(&buf->xsave_hdr, sizeof(buf->xsave_hdr));
        if (unlikely(err))
                return -EFAULT;

        __asm__ __volatile__(ASM_STAC "\n"
                             "1:"XSAVE"\n"
                             "2: " ASM_CLAC "\n"
                             xstate_fault
                             : "D" (buf), "a" (-1), "d" (-1), "0" (0)
                             : "memory");
        return err;
}

/*
 * Restore xstate from user space xsave area.
 */
static inline int xrestore_user(struct xsave_struct __user *buf, u64 mask)
{
        int err = 0;
        struct xsave_struct *xstate = ((__force struct xsave_struct *)buf);
        u32 lmask = mask;
        u32 hmask = mask >> 32;

        __asm__ __volatile__(ASM_STAC "\n"
                             "1:"XRSTOR"\n"
                             "2: " ASM_CLAC "\n"
                             xstate_fault
                             : "D" (xstate), "a" (lmask), "d" (hmask), "0" (0)
                             : "memory");       /* memory required? */
        return err;
}

void *get_xsave_addr(struct xsave_struct *xsave, int xstate);
void setup_xstate_comp(void);

#endif