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