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 */
54static inline void __runtime_fixup_ptr(void *where, unsigned long val)
55{
56 *(unsigned long *)where = val;
57}
58
59static inline void __runtime_fixup_shift(void *where, unsigned long val)
60{
61 *(unsigned char *)where = val;
62}
63
64static 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