xsave.h

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#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_FPSSE    (XSTATE_FP | XSTATE_SSE)

#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)

/*
 * These are the features that the OS can handle currently.
 */
#define XCNTXT_MASK (XSTATE_FP | XSTATE_SSE | XSTATE_YMM)

#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);

static inline int fpu_xrstor_checking(struct xsave_struct *fx)
{
    int err;

    asm volatile("1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
             "2:\n"
             ".section .fixup,\"ax\"\n"
             "3:  movl $-1,%[err]\n"
             "    jmp  2b\n"
             ".previous\n"
             _ASM_EXTABLE(1b, 3b)
             : [err] "=r" (err)
             : "D" (fx), "m" (*fx), "a" (-1), "d" (-1), "0" (0)
             : "memory");

    return err;
}

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: .byte " REX_PREFIX "0x0f,0xae,0x27\n"
                 "2: " ASM_CLAC "\n"
                 ".section .fixup,\"ax\"\n"
                 "3:  movl $-1,%[err]\n"
                 "    jmp  2b\n"
                 ".previous\n"
                 _ASM_EXTABLE(1b,3b)
                 : [err] "=r" (err)
                 : "D" (buf), "a" (-1), "d" (-1), "0" (0)
                 : "memory");
    return err;
}

static inline int xrestore_user(struct xsave_struct __user *buf, u64 mask)
{
    int err;
    struct xsave_struct *xstate = ((__force struct xsave_struct *)buf);
    u32 lmask = mask;
    u32 hmask = mask >> 32;

    __asm__ __volatile__(ASM_STAC "\n"
                 "1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n"
                 "2: " ASM_CLAC "\n"
                 ".section .fixup,\"ax\"\n"
                 "3:  movl $-1,%[err]\n"
                 "    jmp  2b\n"
                 ".previous\n"
                 _ASM_EXTABLE(1b,3b)
                 : [err] "=r" (err)
                 : "D" (xstate), "a" (lmask), "d" (hmask), "0" (0)
                 : "memory");   /* memory required? */
    return err;
}

static inline void xrstor_state(struct xsave_struct *fx, u64 mask)
{
    u32 lmask = mask;
    u32 hmask = mask >> 32;

    asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
             : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
             :   "memory");
}

static inline void xsave_state(struct xsave_struct *fx, u64 mask)
{
    u32 lmask = mask;
    u32 hmask = mask >> 32;

    asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x27\n\t"
             : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
             :   "memory");
}

static inline void fpu_xsave(struct fpu *fpu)
{
    /* This, however, we can work around by forcing the compiler to select
       an addressing mode that doesn't require extended registers. */
    alternative_input(
        ".byte " REX_PREFIX "0x0f,0xae,0x27",
        ".byte " REX_PREFIX "0x0f,0xae,0x37",
        X86_FEATURE_XSAVEOPT,
        [fx] "D" (&fpu->state->xsave), "a" (-1), "d" (-1) :
        "memory");
}
#endif