arch/arm64/include/asm/linkage.h

   1 #ifndef __ASM_LINKAGE_H
   2 #define __ASM_LINKAGE_H
   3
   4 #define __ALIGN         .align 2
   5 #define __ALIGN_STR     ".align 2"
   6
   7 #if defined(CONFIG_ARM64_BTI_KERNEL) && defined(__aarch64__)
   8
   9 /*
  10  * Since current versions of gas reject the BTI instruction unless we
  11  * set the architecture version to v8.5 we use the hint instruction
  12  * instead.
  13  */
  14 #define BTI_C hint 34 ;
  15
  16 /*
  17  * When using in-kernel BTI we need to ensure that PCS-conformant assembly
  18  * functions have suitable annotations.  Override SYM_FUNC_START to insert
  19  * a BTI landing pad at the start of everything.
  20  */
  21 #define SYM_FUNC_START(name)                            \
  22         SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)      \
  23         BTI_C
  24
  25 #define SYM_FUNC_START_NOALIGN(name)                    \
  26         SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)       \
  27         BTI_C
  28
  29 #define SYM_FUNC_START_LOCAL(name)                      \
  30         SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN)       \
  31         BTI_C
  32
  33 #define SYM_FUNC_START_LOCAL_NOALIGN(name)              \
  34         SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)        \
  35         BTI_C
  36
  37 #define SYM_FUNC_START_WEAK(name)                       \
  38         SYM_START(name, SYM_L_WEAK, SYM_A_ALIGN)        \
  39         BTI_C
  40
  41 #define SYM_FUNC_START_WEAK_NOALIGN(name)               \
  42         SYM_START(name, SYM_L_WEAK, SYM_A_NONE)         \
  43         BTI_C
  44
  45 #endif
  46
  47 /*
  48  * Annotate a function as position independent, i.e., safe to be called before
  49  * the kernel virtual mapping is activated.
  50  */
  51 #define SYM_FUNC_START_PI(x)                    \
  52                 SYM_FUNC_START_ALIAS(__pi_##x); \
  53                 SYM_FUNC_START(x)
  54
  55 #define SYM_FUNC_START_WEAK_PI(x)               \
  56                 SYM_FUNC_START_ALIAS(__pi_##x); \
  57                 SYM_FUNC_START_WEAK(x)
  58
  59 #define SYM_FUNC_END_PI(x)                      \
  60                 SYM_FUNC_END(x);                \
  61                 SYM_FUNC_END_ALIAS(__pi_##x)
  62
  63 #endif