1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_RUNTIME_CONST_H 3 #define _ASM_RUNTIME_CONST_H 4 5 #ifdef MODULE 6 #error "Cannot use runtime-const infrastructure from modules" 7 #endif 8 9 #ifdef __ASSEMBLY__ 10 11 .macro RUNTIME_CONST_PTR sym reg 12 movq $0x0123456789abcdef, %\reg 13 1: 14 .pushsection runtime_ptr_\sym, "a" 15 .long 1b - 8 - . 16 .popsection 17 .endm 18 19 #else /* __ASSEMBLY__ */ 20 21 #define runtime_const_ptr(sym) ({ \ 22 typeof(sym) __ret; \ 23 asm_inline("mov %1,%0\n1:\n" \ 24 ".pushsection runtime_ptr_" #sym ",\"a\"\n\t" \ 25 ".long 1b - %c2 - .\n" \ 26 ".popsection" \ 27 :"=r" (__ret) \ 28 :"i" ((unsigned long)0x0123456789abcdefull), \ 29 "i" (sizeof(long))); \ 30 __ret; }) 31 32 // The 'typeof' will create at _least_ a 32-bit type, but 33 // will happily also take a bigger type and the 'shrl' will 34 // clear the upper bits 35 #define runtime_const_shift_right_32(val, sym) ({ \ 36 typeof(0u+(val)) __ret = (val); \ 37 asm_inline("shrl $12,%k0\n1:\n" \ 38 ".pushsection runtime_shift_" #sym ",\"a\"\n\t" \ 39 ".long 1b - 1 - .\n" \ 40 ".popsection" \ 41 :"+r" (__ret)); \ 42 __ret; }) 43 44 #define runtime_const_init(type, sym) do { \ 45 extern s32 __start_runtime_##type##_##sym[]; \ 46 extern s32 __stop_runtime_##type##_##sym[]; \ 47 runtime_const_fixup(__runtime_fixup_##type, \ 48 (unsigned long)(sym), \ 49 __start_runtime_##type##_##sym, \ 50 __stop_runtime_##type##_##sym); \ 51 } while (0) 52 53 /* 54 * The text patching is trivial - you can only do this at init time, 55 * when the text section hasn't been marked RO, and before the text 56 * has ever been executed. 57 */ 58 static inline void __runtime_fixup_ptr(void *where, unsigned long val) 59 { 60 *(unsigned long *)where = val; 61 } 62 63 static inline void __runtime_fixup_shift(void *where, unsigned long val) 64 { 65 *(unsigned char *)where = val; 66 } 67 68 static inline void runtime_const_fixup(void (*fn)(void *, unsigned long), 69 unsigned long val, s32 *start, s32 *end) 70 { 71 while (start < end) { 72 fn(*start + (void *)start, val); 73 start++; 74 } 75 } 76 77 #endif /* __ASSEMBLY__ */ 78 #endif 79