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"				\
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"				\
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 */
42static inline void __runtime_fixup_ptr(void *where, unsigned long val)
43{
44	*(unsigned long *)where = val;
45}
46
47static inline void __runtime_fixup_shift(void *where, unsigned long val)
48{
49	*(unsigned char *)where = val;
50}
51
52static 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