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

#include <linux/bits.h>
#include <asm/gpr-num.h>

#define EX_TYPE_NONE                    0
#define EX_TYPE_BPF                     1
#define EX_TYPE_UACCESS_ERR_ZERO        2
#define EX_TYPE_KACCESS_ERR_ZERO        3
#define EX_TYPE_UACCESS_CPY             4
#define EX_TYPE_LOAD_UNALIGNED_ZEROPAD  5

/* Data fields for EX_TYPE_UACCESS_ERR_ZERO */
#define EX_DATA_REG_ERR_SHIFT   0
#define EX_DATA_REG_ERR         GENMASK(4, 0)
#define EX_DATA_REG_ZERO_SHIFT  5
#define EX_DATA_REG_ZERO        GENMASK(9, 5)

/* Data fields for EX_TYPE_LOAD_UNALIGNED_ZEROPAD */
#define EX_DATA_REG_DATA_SHIFT  0
#define EX_DATA_REG_DATA        GENMASK(4, 0)
#define EX_DATA_REG_ADDR_SHIFT  5
#define EX_DATA_REG_ADDR        GENMASK(9, 5)

/* Data fields for EX_TYPE_UACCESS_CPY */
#define EX_DATA_UACCESS_WRITE   BIT(0)

#ifdef __ASSEMBLER__

#define __ASM_EXTABLE_RAW(insn, fixup, type, data)      \
        .pushsection    __ex_table, "a";                \
        .align          2;                              \
        .long           ((insn) - .);                   \
        .long           ((fixup) - .);                  \
        .short          (type);                         \
        .short          (data);                         \
        .popsection;

#define EX_DATA_REG(reg, gpr)   \
        (.L__gpr_num_##gpr << EX_DATA_REG_##reg##_SHIFT)

#define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)           \
        __ASM_EXTABLE_RAW(insn, fixup,                                  \
                          EX_TYPE_UACCESS_ERR_ZERO,                     \
                          (                                             \
                            EX_DATA_REG(ERR, err) |                     \
                            EX_DATA_REG(ZERO, zero)                     \
                          ))

#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err)                      \
        _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)

#define _ASM_EXTABLE_UACCESS(insn, fixup)                               \
        _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)

/*
 * Create an exception table entry for uaccess `insn`, which will branch to `fixup`
 * when an unhandled fault is taken.
 */
        .macro          _asm_extable_uaccess, insn, fixup
        _ASM_EXTABLE_UACCESS(\insn, \fixup)
        .endm

/*
 * Create an exception table entry for `insn` if `fixup` is provided. Otherwise
 * do nothing.
 */
        .macro          _cond_uaccess_extable, insn, fixup
        .ifnc                   \fixup,
        _asm_extable_uaccess    \insn, \fixup
        .endif
        .endm

        .macro          _asm_extable_uaccess_cpy, insn, fixup, uaccess_is_write
        __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_UACCESS_CPY, \uaccess_is_write)
        .endm

#else /* __ASSEMBLER__ */

#include <linux/stringify.h>

#define __ASM_EXTABLE_RAW(insn, fixup, type, data)      \
        ".pushsection   __ex_table, \"a\"\n"            \
        ".align         2\n"                            \
        ".long          ((" insn ") - .)\n"             \
        ".long          ((" fixup ") - .)\n"            \
        ".short         (" type ")\n"                   \
        ".short         (" data ")\n"                   \
        ".popsection\n"

#define EX_DATA_REG(reg, gpr)                                           \
        "((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")"

#define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)           \
        __DEFINE_ASM_GPR_NUMS                                           \
        __ASM_EXTABLE_RAW(#insn, #fixup,                                \
                          __stringify(EX_TYPE_UACCESS_ERR_ZERO),        \
                          "("                                           \
                            EX_DATA_REG(ERR, err) " | "                 \
                            EX_DATA_REG(ZERO, zero)                     \
                          ")")

#define _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, zero)           \
        __DEFINE_ASM_GPR_NUMS                                           \
        __ASM_EXTABLE_RAW(#insn, #fixup,                                \
                          __stringify(EX_TYPE_KACCESS_ERR_ZERO),        \
                          "("                                           \
                            EX_DATA_REG(ERR, err) " | "                 \
                            EX_DATA_REG(ZERO, zero)                     \
                          ")")

#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err)                      \
        _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)

#define _ASM_EXTABLE_UACCESS(insn, fixup)                               \
        _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)

#define _ASM_EXTABLE_KACCESS_ERR(insn, fixup, err)                      \
        _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, wzr)

#define _ASM_EXTABLE_KACCESS(insn, fixup)                               \
        _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, wzr, wzr)

#define _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(insn, fixup, data, addr)            \
        __DEFINE_ASM_GPR_NUMS                                                   \
        __ASM_EXTABLE_RAW(#insn, #fixup,                                        \
                          __stringify(EX_TYPE_LOAD_UNALIGNED_ZEROPAD),          \
                          "("                                                   \
                            EX_DATA_REG(DATA, data) " | "                       \
                            EX_DATA_REG(ADDR, addr)                             \
                          ")")

#endif /* __ASSEMBLER__ */

#endif /* __ASM_ASM_EXTABLE_H */