sysdeps/aarch64/sysdep.h

   1 /* Copyright (C) 1997-2024 Free Software Foundation, Inc.
   2
   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 License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    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 _AARCH64_SYSDEP_H
  20 #define _AARCH64_SYSDEP_H
  21
  22 #include <sysdeps/generic/sysdep.h>
  23
  24 #ifdef __LP64__
  25 # define AARCH64_R(NAME)        R_AARCH64_ ## NAME
  26 # define PTR_REG(n)             x##n
  27 # define PTR_LOG_SIZE           3
  28 # define PTR_ARG(n)
  29 # define SIZE_ARG(n)
  30 #else
  31 # define AARCH64_R(NAME)        R_AARCH64_P32_ ## NAME
  32 # define PTR_REG(n)             w##n
  33 # define PTR_LOG_SIZE           2
  34 # define PTR_ARG(n)             mov     w##n, w##n
  35 # define SIZE_ARG(n)            mov     w##n, w##n
  36 #endif
  37
  38 #define PTR_SIZE        (1<<PTR_LOG_SIZE)
  39
  40 #ifndef __ASSEMBLER__
  41 /* Strip pointer authentication code from pointer p.  */
  42 static inline void *
  43 strip_pac (void *p)
  44 {
  45   register void *ra asm ("x30") = (p);
  46   asm ("hint 7 // xpaclri" : "+r"(ra));
  47   return ra;
  48 }
  49
  50 /* This is needed when glibc is built with -mbranch-protection=pac-ret
  51    with a gcc that is affected by PR target/94891.  */
  52 # if HAVE_AARCH64_PAC_RET
  53 #  undef RETURN_ADDRESS
  54 #  define RETURN_ADDRESS(n) strip_pac (__builtin_return_address (n))
  55 # endif
  56 #endif
  57
  58 #ifdef  __ASSEMBLER__
  59
  60 /* Syntactic details of assembler.  */
  61
  62 #define ASM_SIZE_DIRECTIVE(name) .size name,.-name
  63
  64 /* Branch Target Identitication support.  */
  65 #if HAVE_AARCH64_BTI
  66 # define BTI_C          hint    34
  67 # define BTI_J          hint    36
  68 #else
  69 # define BTI_C          nop
  70 # define BTI_J          nop
  71 #endif
  72
  73 /* Return address signing support (pac-ret).  */
  74 #define PACIASP         hint    25
  75 #define AUTIASP         hint    29
  76
  77 /* GNU_PROPERTY_AARCH64_* macros from elf.h for use in asm code.  */
  78 #define FEATURE_1_AND 0xc0000000
  79 #define FEATURE_1_BTI 1
  80 #define FEATURE_1_PAC 2
  81
  82 /* Add a NT_GNU_PROPERTY_TYPE_0 note.  */
  83 #define GNU_PROPERTY(type, value)       \
  84   .section .note.gnu.property, "a";     \
  85   .p2align 3;                           \
  86   .word 4;                              \
  87   .word 16;                             \
  88   .word 5;                              \
  89   .asciz "GNU";                         \
  90   .word type;                           \
  91   .word 4;                              \
  92   .word value;                          \
  93   .word 0;                              \
  94   .text
  95
  96 /* Add GNU property note with the supported features to all asm code
  97    where sysdep.h is included.  */
  98 #if HAVE_AARCH64_BTI && HAVE_AARCH64_PAC_RET
  99 GNU_PROPERTY (FEATURE_1_AND, FEATURE_1_BTI|FEATURE_1_PAC)
 100 #elif HAVE_AARCH64_BTI
 101 GNU_PROPERTY (FEATURE_1_AND, FEATURE_1_BTI)
 102 #endif
 103
 104 /* Define an entry point visible from C.  */
 105 #define ENTRY(name)                                             \
 106   .globl C_SYMBOL_NAME(name);                                   \
 107   .type C_SYMBOL_NAME(name),%function;                          \
 108   .p2align 6;                                                   \
 109   C_LABEL(name)                                                 \
 110   cfi_startproc;                                                \
 111   BTI_C;                                                        \
 112   CALL_MCOUNT
 113
 114 /* Define an entry point visible from C.  */
 115 #define ENTRY_ALIGN(name, align)                                \
 116   .globl C_SYMBOL_NAME(name);                                   \
 117   .type C_SYMBOL_NAME(name),%function;                          \
 118   .p2align align;                                               \
 119   C_LABEL(name)                                                 \
 120   cfi_startproc;                                                \
 121   BTI_C;                                                        \
 122   CALL_MCOUNT
 123
 124 /* Define an entry point visible from C with a specified alignment and
 125    pre-padding with NOPs.  This can be used to ensure that a critical
 126    loop within a function is cache line aligned.  Note this version
 127    does not adjust the padding if CALL_MCOUNT is defined. */
 128
 129 #define ENTRY_ALIGN_AND_PAD(name, align, padding)               \
 130   .globl C_SYMBOL_NAME(name);                                   \
 131   .type C_SYMBOL_NAME(name),%function;                          \
 132   .p2align align;                                               \
 133   .rep padding - 1; /* -1 for bti c.  */                        \
 134   nop;                                                          \
 135   .endr;                                                        \
 136   C_LABEL(name)                                                 \
 137   cfi_startproc;                                                \
 138   BTI_C;                                                        \
 139   CALL_MCOUNT
 140
 141 #undef  END
 142 #define END(name)                                               \
 143   cfi_endproc;                                                  \
 144   ASM_SIZE_DIRECTIVE(name)
 145
 146 /* If compiled for profiling, call `mcount' at the start of each function.  */
 147 #ifdef  PROF
 148 # define CALL_MCOUNT                                            \
 149         str     x30, [sp, #-80]!;                               \
 150         cfi_adjust_cfa_offset (80);                             \
 151         cfi_rel_offset (x30, 0);                                \
 152         stp     x0, x1, [sp, #16];                              \
 153         cfi_rel_offset (x0, 16);                                \
 154         cfi_rel_offset (x1, 24);                                \
 155         stp     x2, x3, [sp, #32];                              \
 156         cfi_rel_offset (x2, 32);                                \
 157         cfi_rel_offset (x3, 40);                                \
 158         stp     x4, x5, [sp, #48];                              \
 159         cfi_rel_offset (x4, 48);                                \
 160         cfi_rel_offset (x5, 56);                                \
 161         stp     x6, x7, [sp, #64];                              \
 162         cfi_rel_offset (x6, 64);                                \
 163         cfi_rel_offset (x7, 72);                                \
 164         mov     x0, x30;                                        \
 165         bl      mcount;                                         \
 166         ldp     x0, x1, [sp, #16];                              \
 167         cfi_restore (x0);                                       \
 168         cfi_restore (x1);                                       \
 169         ldp     x2, x3, [sp, #32];                              \
 170         cfi_restore (x2);                                       \
 171         cfi_restore (x3);                                       \
 172         ldp     x4, x5, [sp, #48];                              \
 173         cfi_restore (x4);                                       \
 174         cfi_restore (x5);                                       \
 175         ldp     x6, x7, [sp, #64];                              \
 176         cfi_restore (x6);                                       \
 177         cfi_restore (x7);                                       \
 178         ldr     x30, [sp], #80;                                 \
 179         cfi_adjust_cfa_offset (-80);                            \
 180         cfi_restore (x30);
 181 #else
 182 # define CALL_MCOUNT            /* Do nothing.  */
 183 #endif
 184
 185 /* Local label name for asm code.  */
 186 #ifndef L
 187 # define L(name)         .L##name
 188 #endif
 189
 190 /* Load or store to/from a pc-relative EXPR into/from R, using T.
 191    Note R and T are register numbers and not register names.  */
 192 #define LDST_PCREL(OP, R, T, EXPR)                      \
 193         adrp    x##T, EXPR;                             \
 194         OP      PTR_REG (R), [x##T, #:lo12:EXPR];       \
 195
 196 /* Load or store to/from a got-relative EXPR into/from R, using T.
 197    Note R and T are register numbers and not register names.  */
 198 #define LDST_GLOBAL(OP, R, T,  EXPR)                    \
 199         adrp    x##T, :got:EXPR;                        \
 200         ldr     PTR_REG (T), [x##T, #:got_lo12:EXPR];   \
 201         OP      PTR_REG (R), [x##T];
 202
 203 /* Load an immediate into R.
 204    Note R is a register number and not a register name.  */
 205 #ifdef __LP64__
 206 # define MOVL(R, NAME)                                  \
 207         movz    PTR_REG (R), #:abs_g3:NAME;             \
 208         movk    PTR_REG (R), #:abs_g2_nc:NAME;          \
 209         movk    PTR_REG (R), #:abs_g1_nc:NAME;          \
 210         movk    PTR_REG (R), #:abs_g0_nc:NAME;
 211 #else
 212 # define MOVL(R, NAME)                                  \
 213         movz    PTR_REG (R), #:abs_g1:NAME;             \
 214         movk    PTR_REG (R), #:abs_g0_nc:NAME;
 215 #endif
 216
 217 /* Since C identifiers are not normally prefixed with an underscore
 218    on this system, the asm identifier `syscall_error' intrudes on the
 219    C name space.  Make sure we use an innocuous name.  */
 220 #define syscall_error   __syscall_error
 221 #define mcount          _mcount
 222
 223 #endif  /* __ASSEMBLER__ */
 224
 225 #endif  /* _AARCH64_SYSDEP_H */