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