LXR linux/arch/arm64/include/asm/asm-extable.h

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2#ifndef __ASM_ASM_EXTABLE_H
   3#define __ASM_ASM_EXTABLE_H
   4
   5#define EX_TYPE_NONE                    0
   6#define EX_TYPE_FIXUP                   1
   7#define EX_TYPE_BPF                     2
   8#define EX_TYPE_UACCESS_ERR_ZERO        3
   9#define EX_TYPE_LOAD_UNALIGNED_ZEROPAD  4
  10
  11#ifdef __ASSEMBLY__
  12
  13#define __ASM_EXTABLE_RAW(insn, fixup, type, data)      \
  14        .pushsection    __ex_table, "a";                \
  15        .align          2;                              \
  16        .long           ((insn) - .);                   \
  17        .long           ((fixup) - .);                  \
  18        .short          (type);                         \
  19        .short          (data);                         \
  20        .popsection;
  21
  22/*
  23 * Create an exception table entry for `insn`, which will branch to `fixup`
  24 * when an unhandled fault is taken.
  25 */
  26        .macro          _asm_extable, insn, fixup
  27        __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0)
  28        .endm
  29
  30/*
  31 * Create an exception table entry for `insn` if `fixup` is provided. Otherwise
  32 * do nothing.
  33 */
  34        .macro          _cond_extable, insn, fixup
  35        .ifnc           \fixup,
  36        _asm_extable    \insn, \fixup
  37        .endif
  38        .endm
  39
  40#else /* __ASSEMBLY__ */
  41
  42#include <linux/bits.h>
  43#include <linux/stringify.h>
  44
  45#include <asm/gpr-num.h>
  46
  47#define __ASM_EXTABLE_RAW(insn, fixup, type, data)      \
  48        ".pushsection   __ex_table, \"a\"\n"            \
  49        ".align         2\n"                            \
  50        ".long          ((" insn ") - .)\n"             \
  51        ".long          ((" fixup ") - .)\n"            \
  52        ".short         (" type ")\n"                   \
  53        ".short         (" data ")\n"                   \
  54        ".popsection\n"
  55
  56#define _ASM_EXTABLE(insn, fixup) \
  57        __ASM_EXTABLE_RAW(#insn, #fixup, __stringify(EX_TYPE_FIXUP), "0")
  58
  59#define EX_DATA_REG_ERR_SHIFT   0
  60#define EX_DATA_REG_ERR         GENMASK(4, 0)
  61#define EX_DATA_REG_ZERO_SHIFT  5
  62#define EX_DATA_REG_ZERO        GENMASK(9, 5)
  63
  64#define EX_DATA_REG(reg, gpr)                                           \
  65        "((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")"
  66
  67#define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)           \
  68        __DEFINE_ASM_GPR_NUMS                                           \
  69        __ASM_EXTABLE_RAW(#insn, #fixup,                                \
  70                          __stringify(EX_TYPE_UACCESS_ERR_ZERO),        \
  71                          "("                                           \
  72                            EX_DATA_REG(ERR, err) " | "                 \
  73                            EX_DATA_REG(ZERO, zero)                     \
  74                          ")")
  75
  76#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err)                      \
  77        _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
  78
  79#define EX_DATA_REG_DATA_SHIFT  0
  80#define EX_DATA_REG_DATA        GENMASK(4, 0)
  81#define EX_DATA_REG_ADDR_SHIFT  5
  82#define EX_DATA_REG_ADDR        GENMASK(9, 5)
  83
  84#define _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(insn, fixup, data, addr)            \
  85        __DEFINE_ASM_GPR_NUMS                                                   \
  86        __ASM_EXTABLE_RAW(#insn, #fixup,                                        \
  87                          __stringify(EX_TYPE_LOAD_UNALIGNED_ZEROPAD),          \
  88                          "("                                                   \
  89                            EX_DATA_REG(DATA, data) " | "                       \
  90                            EX_DATA_REG(ADDR, addr)                             \
  91                          ")")
  92
  93#endif /* __ASSEMBLY__ */
  94
  95#endif /* __ASM_ASM_EXTABLE_H */
  96