arch/arm64/include/asm/compiler.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_COMPILER_H
   3 #define __ASM_COMPILER_H
   4
   5 #ifdef ARM64_ASM_ARCH
   6 #define ARM64_ASM_PREAMBLE ".arch " ARM64_ASM_ARCH "\n"
   7 #else
   8 #define ARM64_ASM_PREAMBLE
   9 #endif
  10
  11 /*
  12  * The EL0/EL1 pointer bits used by a pointer authentication code.
  13  * This is dependent on TBI0/TBI1 being enabled, or bits 63:56 would also apply.
  14  */
  15 #define ptrauth_user_pac_mask()         GENMASK_ULL(54, vabits_actual)
  16 #define ptrauth_kernel_pac_mask()       GENMASK_ULL(63, vabits_actual)
  17
  18 /* Valid for EL0 TTBR0 and EL1 TTBR1 instruction pointers */
  19 #define ptrauth_clear_pac(ptr)                                          \
  20         ((ptr & BIT_ULL(55)) ? (ptr | ptrauth_kernel_pac_mask()) :      \
  21                                (ptr & ~ptrauth_user_pac_mask()))
  22
  23 #define __builtin_return_address(val)                                   \
  24         (void *)(ptrauth_clear_pac((unsigned long)__builtin_return_address(val)))
  25
  26 #ifdef CONFIG_CFI_CLANG
  27 /*
  28  * With CONFIG_CFI_CLANG, the compiler replaces function address
  29  * references with the address of the function's CFI jump table
  30  * entry. The function_nocfi macro always returns the address of the
  31  * actual function instead.
  32  */
  33 #define function_nocfi(x) ({                                            \
  34         void *addr;                                                     \
  35         asm("adrp %0, " __stringify(x) "\n\t"                           \
  36             "add  %0, %0, :lo12:" __stringify(x)                        \
  37             : "=r" (addr));                                             \
  38         addr;                                                           \
  39 })
  40 #endif
  41
  42 #endif /* __ASM_COMPILER_H */