sysdeps/x86_64/sysdep.h

   1 /* Assembler macros for x86-64.
   2    Copyright (C) 2001-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _X86_64_SYSDEP_H
  20 #define _X86_64_SYSDEP_H 1
  21
  22 #include <sysdeps/x86/sysdep.h>
  23 #include <x86-lp_size.h>
  24
  25 /* __CET__ is defined by GCC with Control-Flow Protection values:
  26
  27 enum cf_protection_level
  28 {
  29   CF_NONE = 0,
  30   CF_BRANCH = 1 << 0,
  31   CF_RETURN = 1 << 1,
  32   CF_FULL = CF_BRANCH | CF_RETURN,
  33   CF_SET = 1 << 2
  34 };
  35 */
  36
  37 /* Set if CF_BRANCH (IBT) is enabled.  */
  38 #define X86_FEATURE_1_IBT       (1U << 0)
  39 /* Set if CF_RETURN (SHSTK) is enabled.  */
  40 #define X86_FEATURE_1_SHSTK     (1U << 1)
  41
  42 #ifdef __CET__
  43 # define CET_ENABLED    1
  44 # define SHSTK_ENABLED  (__CET__ & X86_FEATURE_1_SHSTK)
  45 #else
  46 # define CET_ENABLED    0
  47 # define SHSTK_ENABLED  0
  48 #endif
  49
  50 #ifdef  __ASSEMBLER__
  51
  52 /* Syntactic details of assembler.  */
  53
  54 #ifdef _CET_ENDBR
  55 # define _CET_NOTRACK notrack
  56 #else
  57 # define _CET_ENDBR
  58 # define _CET_NOTRACK
  59 #endif
  60
  61 /* Define an entry point visible from C.  */
  62 #define ENTRY_P2ALIGN(name, alignment)                                        \
  63   .globl C_SYMBOL_NAME(name);                                                 \
  64   .type C_SYMBOL_NAME(name),@function;                                        \
  65   .align ALIGNARG(alignment);                                                 \
  66   C_LABEL(name)                                                               \
  67   cfi_startproc;                                                              \
  68   _CET_ENDBR;                                                                 \
  69   CALL_MCOUNT
  70
  71 /* This macro is for setting proper CFI with DW_CFA_expression describing
  72    the register as saved relative to %rsp instead of relative to the CFA.
  73    Expression is DW_OP_drop, DW_OP_breg7 (%rsp is register 7), sleb128 offset
  74    from %rsp.  */
  75 #define cfi_offset_rel_rsp(regn, off)   .cfi_escape 0x10, regn, 0x4, 0x13, \
  76                                         0x77, off & 0x7F | 0x80, off >> 7
  77
  78 /* If compiled for profiling, call `mcount' at the start of each function.  */
  79 #ifdef  PROF
  80 /* The mcount code relies on a normal frame pointer being on the stack
  81    to locate our caller, so push one just for its benefit.  */
  82 #define CALL_MCOUNT                                                          \
  83   pushq %rbp;                                                                \
  84   cfi_adjust_cfa_offset(8);                                                  \
  85   movq %rsp, %rbp;                                                           \
  86   cfi_def_cfa_register(%rbp);                                                \
  87   call JUMPTARGET(mcount);                                                   \
  88   popq %rbp;                                                                 \
  89   cfi_def_cfa(rsp,8);
  90 #else
  91 #define CALL_MCOUNT             /* Do nothing.  */
  92 #endif
  93
  94 #define PSEUDO(name, syscall_name, args)                                      \
  95 lose:                                                                         \
  96   jmp JUMPTARGET(syscall_error)                                               \
  97   .globl syscall_error;                                                       \
  98   ENTRY (name)                                                                \
  99   DO_CALL (syscall_name, args);                                               \
 100   jb lose
 101
 102 #undef JUMPTARGET
 103 #ifdef SHARED
 104 # ifdef BIND_NOW
 105 #  define JUMPTARGET(name)      *name##@GOTPCREL(%rip)
 106 # else
 107 #  define JUMPTARGET(name)      name##@PLT
 108 # endif
 109 #else
 110 /* For static archives, branch to target directly.  */
 111 # define JUMPTARGET(name)       name
 112 #endif
 113
 114 /* Instruction to operate on long and pointer.  */
 115 #define LP_OP(insn) insn##q
 116
 117 /* Assembler address directive. */
 118 #define ASM_ADDR .quad
 119
 120 /* Registers to hold long and pointer.  */
 121 #define RAX_LP  rax
 122 #define RBP_LP  rbp
 123 #define RBX_LP  rbx
 124 #define RCX_LP  rcx
 125 #define RDI_LP  rdi
 126 #define RDX_LP  rdx
 127 #define RSI_LP  rsi
 128 #define RSP_LP  rsp
 129 #define R8_LP   r8
 130 #define R9_LP   r9
 131 #define R10_LP  r10
 132 #define R11_LP  r11
 133 #define R12_LP  r12
 134 #define R13_LP  r13
 135 #define R14_LP  r14
 136 #define R15_LP  r15
 137
 138 /* Zero upper vector registers and return with xtest.  NB: Use VZEROALL
 139    to avoid RTM abort triggered by VZEROUPPER inside transactionally.  */
 140 #define ZERO_UPPER_VEC_REGISTERS_RETURN_XTEST \
 141         xtest;                                                  \
 142         jnz     1f;                                             \
 143         vzeroupper;                                             \
 144         ret;                                                    \
 145 1:                                                              \
 146         vzeroall;                                               \
 147         ret
 148
 149 /* Can be used to replace vzeroupper that is not directly before a
 150    return.  This is useful when hoisting a vzeroupper from multiple
 151    return paths to decrease the total number of vzerouppers and code
 152    size.  */
 153 #define COND_VZEROUPPER_XTEST                                                   \
 154     xtest;                                                      \
 155     jz 1f;                                                      \
 156     vzeroall;                                                   \
 157     jmp 2f;                                                     \
 158 1:                                                      \
 159     vzeroupper;                                                 \
 160 2:
 161
 162 /* In RTM define this as COND_VZEROUPPER_XTEST.  */
 163 #ifndef COND_VZEROUPPER
 164 # define COND_VZEROUPPER vzeroupper
 165 #endif
 166
 167 /* Zero upper vector registers and return.  */
 168 #ifndef ZERO_UPPER_VEC_REGISTERS_RETURN
 169 # define ZERO_UPPER_VEC_REGISTERS_RETURN \
 170         VZEROUPPER;                                             \
 171         ret
 172 #endif
 173
 174 #ifndef VZEROUPPER_RETURN
 175 # define VZEROUPPER_RETURN      VZEROUPPER; ret
 176 #endif
 177
 178 #else   /* __ASSEMBLER__ */
 179
 180 /* Instruction to operate on long and pointer.  */
 181 #define LP_OP(insn) #insn "q"
 182
 183 /* Assembler address directive. */
 184 #define ASM_ADDR ".quad"
 185
 186 /* Registers to hold long and pointer.  */
 187 #define RAX_LP  "rax"
 188 #define RBP_LP  "rbp"
 189 #define RBX_LP  "rbx"
 190 #define RCX_LP  "rcx"
 191 #define RDI_LP  "rdi"
 192 #define RDX_LP  "rdx"
 193 #define RSI_LP  "rsi"
 194 #define RSP_LP  "rsp"
 195 #define R8_LP   "r8"
 196 #define R9_LP   "r9"
 197 #define R10_LP  "r10"
 198 #define R11_LP  "r11"
 199 #define R12_LP  "r12"
 200 #define R13_LP  "r13"
 201 #define R14_LP  "r14"
 202 #define R15_LP  "r15"
 203
 204 #endif  /* __ASSEMBLER__ */
 205
 206 #endif  /* _X86_64_SYSDEP_H */