/* SPDX-License-Identifier: GPL-2.0 */
/*
 * FPU data structures:
 */
#ifndef _ASM_X86_FPU_H
#define _ASM_X86_FPU_H

/*
 * The legacy x87 FPU state format, as saved by FSAVE and
 * restored by the FRSTOR instructions:
 */
struct fregs_state {
        u32                     cwd;    /* FPU Control Word             */
        u32                     swd;    /* FPU Status Word              */
        u32                     twd;    /* FPU Tag Word                 */
        u32                     fip;    /* FPU IP Offset                */
        u32                     fcs;    /* FPU IP Selector              */
        u32                     foo;    /* FPU Operand Pointer Offset   */
        u32                     fos;    /* FPU Operand Pointer Selector */

        /* 8*10 bytes for each FP-reg = 80 bytes:                       */
        u32                     st_space[20];

        /* Software status information [not touched by FSAVE]:          */
        u32                     status;
};

/*
 * The legacy fx SSE/MMX FPU state format, as saved by FXSAVE and
 * restored by the FXRSTOR instructions. It's similar to the FSAVE
 * format, but differs in some areas, plus has extensions at
 * the end for the XMM registers.
 */
struct fxregs_state {
        u16                     cwd; /* Control Word                    */
        u16                     swd; /* Status Word                     */
        u16                     twd; /* Tag Word                        */
        u16                     fop; /* Last Instruction Opcode         */
        union {
                struct {
                        u64     rip; /* Instruction Pointer             */
                        u64     rdp; /* Data Pointer                    */
                };
                struct {
                        u32     fip; /* FPU IP Offset                   */
                        u32     fcs; /* FPU IP Selector                 */
                        u32     foo; /* FPU Operand Offset              */
                        u32     fos; /* FPU Operand Selector            */
                };
        };
        u32                     mxcsr;          /* MXCSR Register State */
        u32                     mxcsr_mask;     /* MXCSR Mask           */

        /* 8*16 bytes for each FP-reg = 128 bytes:                      */
        u32                     st_space[32];

        /* 16*16 bytes for each XMM-reg = 256 bytes:                    */
        u32                     xmm_space[64];

        u32                     padding[12];

        union {
                u32             padding1[12];
                u32             sw_reserved[12];
        };

} __attribute__((aligned(16)));

/* Default value for fxregs_state.mxcsr: */
#define MXCSR_DEFAULT           0x1f80

/* Copy both mxcsr & mxcsr_flags with a single u64 memcpy: */
#define MXCSR_AND_FLAGS_SIZE sizeof(u64)

/*
 * Software based FPU emulation state. This is arbitrary really,
 * it matches the x87 format to make it easier to understand:
 */
struct swregs_state {
        u32                     cwd;
        u32                     swd;
        u32                     twd;
        u32                     fip;
        u32                     fcs;
        u32                     foo;
        u32                     fos;
        /* 8*10 bytes for each FP-reg = 80 bytes: */
        u32                     st_space[20];
        u8                      ftop;
        u8                      changed;
        u8                      lookahead;
        u8                      no_update;
        u8                      rm;
        u8                      alimit;
        struct math_emu_info    *info;
        u32                     entry_eip;
};

/*
 * List of XSAVE features Linux knows about:
 */
enum xfeature {
        XFEATURE_FP,
        XFEATURE_SSE,
        /*
         * Values above here are "legacy states".
         * Those below are "extended states".
         */
        XFEATURE_YMM,
        XFEATURE_BNDREGS,
        XFEATURE_BNDCSR,
        XFEATURE_OPMASK,
        XFEATURE_ZMM_Hi256,
        XFEATURE_Hi16_ZMM,
        XFEATURE_PT_UNIMPLEMENTED_SO_FAR,
        XFEATURE_PKRU,

        XFEATURE_MAX,
};

#define XFEATURE_MASK_FP                (1 << XFEATURE_FP)
#define XFEATURE_MASK_SSE               (1 << XFEATURE_SSE)
#define XFEATURE_MASK_YMM               (1 << XFEATURE_YMM)
#define XFEATURE_MASK_BNDREGS           (1 << XFEATURE_BNDREGS)
#define XFEATURE_MASK_BNDCSR            (1 << XFEATURE_BNDCSR)
#define XFEATURE_MASK_OPMASK            (1 << XFEATURE_OPMASK)
#define XFEATURE_MASK_ZMM_Hi256         (1 << XFEATURE_ZMM_Hi256)
#define XFEATURE_MASK_Hi16_ZMM          (1 << XFEATURE_Hi16_ZMM)
#define XFEATURE_MASK_PT                (1 << XFEATURE_PT_UNIMPLEMENTED_SO_FAR)
#define XFEATURE_MASK_PKRU              (1 << XFEATURE_PKRU)

#define XFEATURE_MASK_FPSSE             (XFEATURE_MASK_FP | XFEATURE_MASK_SSE)
#define XFEATURE_MASK_AVX512            (XFEATURE_MASK_OPMASK \
                                         | XFEATURE_MASK_ZMM_Hi256 \
                                         | XFEATURE_MASK_Hi16_ZMM)

#define FIRST_EXTENDED_XFEATURE XFEATURE_YMM

struct reg_128_bit {
        u8      regbytes[128/8];
};
struct reg_256_bit {
        u8      regbytes[256/8];
};
struct reg_512_bit {
        u8      regbytes[512/8];
};

/*
 * State component 2:
 *
 * There are 16x 256-bit AVX registers named YMM0-YMM15.
 * The low 128 bits are aliased to the 16 SSE registers (XMM0-XMM15)
 * and are stored in 'struct fxregs_state::xmm_space[]' in the
 * "legacy" area.
 *
 * The high 128 bits are stored here.
 */
struct ymmh_struct {
        struct reg_128_bit              hi_ymm[16];
} __packed;

/* Intel MPX support: */

struct mpx_bndreg {
        u64                             lower_bound;
        u64                             upper_bound;
} __packed;
/*
 * State component 3 is used for the 4 128-bit bounds registers
 */
struct mpx_bndreg_state {
        struct mpx_bndreg               bndreg[4];
} __packed;

/*
 * State component 4 is used for the 64-bit user-mode MPX
 * configuration register BNDCFGU and the 64-bit MPX status
 * register BNDSTATUS.  We call the pair "BNDCSR".
 */
struct mpx_bndcsr {
        u64                             bndcfgu;
        u64                             bndstatus;
} __packed;

/*
 * The BNDCSR state is padded out to be 64-bytes in size.
 */
struct mpx_bndcsr_state {
        union {
                struct mpx_bndcsr               bndcsr;
                u8                              pad_to_64_bytes[64];
        };
} __packed;

/* AVX-512 Components: */

/*
 * State component 5 is used for the 8 64-bit opmask registers
 * k0-k7 (opmask state).
 */
struct avx_512_opmask_state {
        u64                             opmask_reg[8];
} __packed;

/*
 * State component 6 is used for the upper 256 bits of the
 * registers ZMM0-ZMM15. These 16 256-bit values are denoted
 * ZMM0_H-ZMM15_H (ZMM_Hi256 state).
 */
struct avx_512_zmm_uppers_state {
        struct reg_256_bit              zmm_upper[16];
} __packed;

/*
 * State component 7 is used for the 16 512-bit registers
 * ZMM16-ZMM31 (Hi16_ZMM state).
 */
struct avx_512_hi16_state {
        struct reg_512_bit              hi16_zmm[16];
} __packed;

/*
 * State component 9: 32-bit PKRU register.  The state is
 * 8 bytes long but only 4 bytes is used currently.
 */
struct pkru_state {
        u32                             pkru;
        u32                             pad;
} __packed;

struct xstate_header {
        u64                             xfeatures;
        u64                             xcomp_bv;
        u64                             reserved[6];
} __attribute__((packed));

/*
 * xstate_header.xcomp_bv[63] indicates that the extended_state_area
 * is in compacted format.
 */
#define XCOMP_BV_COMPACTED_FORMAT ((u64)1 << 63)

/*
 * This is our most modern FPU state format, as saved by the XSAVE
 * and restored by the XRSTOR instructions.
 *
 * It consists of a legacy fxregs portion, an xstate header and
 * subsequent areas as defined by the xstate header.  Not all CPUs
 * support all the extensions, so the size of the extended area
 * can vary quite a bit between CPUs.
 */
struct xregs_state {
        struct fxregs_state             i387;
        struct xstate_header            header;
        u8                              extended_state_area[0];
} __attribute__ ((packed, aligned (64)));

/*
 * This is a union of all the possible FPU state formats
 * put together, so that we can pick the right one runtime.
 *
 * The size of the structure is determined by the largest
 * member - which is the xsave area.  The padding is there
 * to ensure that statically-allocated task_structs (just
 * the init_task today) have enough space.
 */
union fpregs_state {
        struct fregs_state              fsave;
        struct fxregs_state             fxsave;
        struct swregs_state             soft;
        struct xregs_state              xsave;
        u8 __padding[PAGE_SIZE];
};

/*
 * Highest level per task FPU state data structure that
 * contains the FPU register state plus various FPU
 * state fields:
 */
struct fpu {
        /*
         * @last_cpu:
         *
         * Records the last CPU on which this context was loaded into
         * FPU registers. (In the lazy-restore case we might be
         * able to reuse FPU registers across multiple context switches
         * this way, if no intermediate task used the FPU.)
         *
         * A value of -1 is used to indicate that the FPU state in context
         * memory is newer than the FPU state in registers, and that the
         * FPU state should be reloaded next time the task is run.
         */
        unsigned int                    last_cpu;

        /*
         * @initialized:
         *
         * This flag indicates whether this context is initialized: if the task
         * is not running then we can restore from this context, if the task
         * is running then we should save into this context.
         */
        unsigned char                   initialized;

        /*
         * @state:
         *
         * In-memory copy of all FPU registers that we save/restore
         * over context switches. If the task is using the FPU then
         * the registers in the FPU are more recent than this state
         * copy. If the task context-switches away then they get
         * saved here and represent the FPU state.
         */
        union fpregs_state              state;
        /*
         * WARNING: 'state' is dynamically-sized.  Do not put
         * anything after it here.
         */
};

#endif /* _ASM_X86_FPU_H */