diff options
Diffstat (limited to 'sys/arm64/include/profile.h')
| -rw-r--r-- | sys/arm64/include/profile.h | 45 |
1 files changed, 44 insertions, 1 deletions
diff --git a/sys/arm64/include/profile.h b/sys/arm64/include/profile.h index afbfbdb44c0b..0b117d0ff442 100644 --- a/sys/arm64/include/profile.h +++ b/sys/arm64/include/profile.h @@ -72,8 +72,51 @@ void mcount(uintfptr_t frompc, uintfptr_t selfpc); typedef __uintfptr_t uintfptr_t; -#define _MCOUNT_DECL void mcount +#define _MCOUNT_DECL \ +static void _mcount(uintfptr_t frompc, uintfptr_t selfpc) __used; \ +static void _mcount + +#ifdef __GNUCLIKE_ASM +/* + * Call into _mcount. On arm64 the .mcount is a function so callers will + * handle caller saved registers. As we don't directly touch any callee + * saved registers we can just load the two arguments and use a tail call + * into the MI _mcount function. + * + * When building with gcc frompc will be in x0, however this is not the + * case on clang. As such we need to load it from the stack. As long as + * the caller follows the ABI this will load the correct value. + */ +#define MCOUNT __asm( \ +" .text \n" \ +" .align 6 \n" \ +" .type .mcount,#function \n" \ +" .globl .mcount \n" \ +" .mcount: \n" \ +" .cfi_startproc \n" \ + /* Load the caller return address as frompc */ \ +" ldr x0, [x29, #8] \n" \ + /* Use our return address as selfpc */ \ +" mov x1, lr \n" \ +" b _mcount \n" \ +" .cfi_endproc \n" \ +" .size .mcount, . - .mcount \n" \ + ); +#if 0 +/* + * If clang passed frompc correctly we could implement it like this, however + * all clang versions we care about would need to be fixed before we could + * make this change. + */ +void +mcount(uintfptr_t frompc) +{ + _mcount(frompc, __builtin_return_address(0)); +} +#endif +#else #define MCOUNT +#endif #endif /* _KERNEL */ |