LXR linux/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 */
  43