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 #include <linux/bits.h>
   6 #include <asm/gpr-num.h>
   7
   8 #define EX_TYPE_NONE                    0
   9 #define EX_TYPE_BPF                     1
  10 #define EX_TYPE_UACCESS_ERR_ZERO        2
  11 #define EX_TYPE_KACCESS_ERR_ZERO        3
  12 #define EX_TYPE_LOAD_UNALIGNED_ZEROPAD  4
  13
  14 /* Data fields for EX_TYPE_UACCESS_ERR_ZERO */
  15 #define EX_DATA_REG_ERR_SHIFT   0
  16 #define EX_DATA_REG_ERR         GENMASK(4, 0)
  17 #define EX_DATA_REG_ZERO_SHIFT  5
  18 #define EX_DATA_REG_ZERO        GENMASK(9, 5)
  19
  20 /* Data fields for EX_TYPE_LOAD_UNALIGNED_ZEROPAD */
  21 #define EX_DATA_REG_DATA_SHIFT  0
  22 #define EX_DATA_REG_DATA        GENMASK(4, 0)
  23 #define EX_DATA_REG_ADDR_SHIFT  5
  24 #define EX_DATA_REG_ADDR        GENMASK(9, 5)
  25
  26 #ifdef __ASSEMBLY__
  27
  28 #define __ASM_EXTABLE_RAW(insn, fixup, type, data)      \
  29         .pushsection    __ex_table, "a";                \
  30         .align          2;                              \
  31         .long           ((insn) - .);                   \
  32         .long           ((fixup) - .);                  \
  33         .short          (type);                         \
  34         .short          (data);                         \
  35         .popsection;
  36
  37 #define EX_DATA_REG(reg, gpr)   \
  38         (.L__gpr_num_##gpr << EX_DATA_REG_##reg##_SHIFT)
  39
  40 #define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)           \
  41         __ASM_EXTABLE_RAW(insn, fixup,                                  \
  42                           EX_TYPE_UACCESS_ERR_ZERO,                     \
  43                           (                                             \
  44                             EX_DATA_REG(ERR, err) |                     \
  45                             EX_DATA_REG(ZERO, zero)                     \
  46                           ))
  47
  48 #define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err)                      \
  49         _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
  50
  51 #define _ASM_EXTABLE_UACCESS(insn, fixup)                               \
  52         _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
  53
  54 /*
  55  * Create an exception table entry for uaccess `insn`, which will branch to `fixup`
  56  * when an unhandled fault is taken.
  57  */
  58         .macro          _asm_extable_uaccess, insn, fixup
  59         _ASM_EXTABLE_UACCESS(\insn, \fixup)
  60         .endm
  61
  62 /*
  63  * Create an exception table entry for `insn` if `fixup` is provided. Otherwise
  64  * do nothing.
  65  */
  66         .macro          _cond_uaccess_extable, insn, fixup
  67         .ifnc                   \fixup,
  68         _asm_extable_uaccess    \insn, \fixup
  69         .endif
  70         .endm
  71
  72 #else /* __ASSEMBLY__ */
  73
  74 #include <linux/stringify.h>
  75
  76 #define __ASM_EXTABLE_RAW(insn, fixup, type, data)      \
  77         ".pushsection   __ex_table, \"a\"\n"            \
  78         ".align         2\n"                            \
  79         ".long          ((" insn ") - .)\n"             \
  80         ".long          ((" fixup ") - .)\n"            \
  81         ".short         (" type ")\n"                   \
  82         ".short         (" data ")\n"                   \
  83         ".popsection\n"
  84
  85 #define EX_DATA_REG(reg, gpr)                                           \
  86         "((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")"
  87
  88 #define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)           \
  89         __DEFINE_ASM_GPR_NUMS                                           \
  90         __ASM_EXTABLE_RAW(#insn, #fixup,                                \
  91                           __stringify(EX_TYPE_UACCESS_ERR_ZERO),        \
  92                           "("                                           \
  93                             EX_DATA_REG(ERR, err) " | "                 \
  94                             EX_DATA_REG(ZERO, zero)                     \
  95                           ")")
  96
  97 #define _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, zero)           \
  98         __DEFINE_ASM_GPR_NUMS                                           \
  99         __ASM_EXTABLE_RAW(#insn, #fixup,                                \
 100                           __stringify(EX_TYPE_KACCESS_ERR_ZERO),        \
 101                           "("                                           \
 102                             EX_DATA_REG(ERR, err) " | "                 \
 103                             EX_DATA_REG(ZERO, zero)                     \
 104                           ")")
 105
 106 #define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err)                      \
 107         _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
 108
 109 #define _ASM_EXTABLE_UACCESS(insn, fixup)                               \
 110         _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
 111
 112 #define _ASM_EXTABLE_KACCESS_ERR(insn, fixup, err)                      \
 113         _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, wzr)
 114
 115 #define _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(insn, fixup, data, addr)            \
 116         __DEFINE_ASM_GPR_NUMS                                                   \
 117         __ASM_EXTABLE_RAW(#insn, #fixup,                                        \
 118                           __stringify(EX_TYPE_LOAD_UNALIGNED_ZEROPAD),          \
 119                           "("                                                   \
 120                             EX_DATA_REG(DATA, data) " | "                       \
 121                             EX_DATA_REG(ADDR, addr)                             \
 122                           ")")
 123
 124 #endif /* __ASSEMBLY__ */
 125
 126 #endif /* __ASM_ASM_EXTABLE_H */