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 */