xref: /linux/arch/arm64/include/asm/compiler.h (revision bb5b94f5bbe75470912b70fb08880fc5273aa62d)
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