mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-08-05 16:54:27 +00:00
bd72baff22
Add an assembly macro to refer runtime cost. It hides linker magic and makes assembly more readable. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250304153342.2016569-1-kirill.shutemov@linux.intel.com
74 lines
1.9 KiB
C
74 lines
1.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _ASM_RUNTIME_CONST_H
|
|
#define _ASM_RUNTIME_CONST_H
|
|
|
|
#ifdef __ASSEMBLY__
|
|
|
|
.macro RUNTIME_CONST_PTR sym reg
|
|
movq $0x0123456789abcdef, %\reg
|
|
1:
|
|
.pushsection runtime_ptr_\sym, "a"
|
|
.long 1b - 8 - .
|
|
.popsection
|
|
.endm
|
|
|
|
#else /* __ASSEMBLY__ */
|
|
|
|
#define runtime_const_ptr(sym) ({ \
|
|
typeof(sym) __ret; \
|
|
asm_inline("mov %1,%0\n1:\n" \
|
|
".pushsection runtime_ptr_" #sym ",\"a\"\n\t" \
|
|
".long 1b - %c2 - .\n" \
|
|
".popsection" \
|
|
:"=r" (__ret) \
|
|
:"i" ((unsigned long)0x0123456789abcdefull), \
|
|
"i" (sizeof(long))); \
|
|
__ret; })
|
|
|
|
// The 'typeof' will create at _least_ a 32-bit type, but
|
|
// will happily also take a bigger type and the 'shrl' will
|
|
// clear the upper bits
|
|
#define runtime_const_shift_right_32(val, sym) ({ \
|
|
typeof(0u+(val)) __ret = (val); \
|
|
asm_inline("shrl $12,%k0\n1:\n" \
|
|
".pushsection runtime_shift_" #sym ",\"a\"\n\t" \
|
|
".long 1b - 1 - .\n" \
|
|
".popsection" \
|
|
:"+r" (__ret)); \
|
|
__ret; })
|
|
|
|
#define runtime_const_init(type, sym) do { \
|
|
extern s32 __start_runtime_##type##_##sym[]; \
|
|
extern s32 __stop_runtime_##type##_##sym[]; \
|
|
runtime_const_fixup(__runtime_fixup_##type, \
|
|
(unsigned long)(sym), \
|
|
__start_runtime_##type##_##sym, \
|
|
__stop_runtime_##type##_##sym); \
|
|
} while (0)
|
|
|
|
/*
|
|
* The text patching is trivial - you can only do this at init time,
|
|
* when the text section hasn't been marked RO, and before the text
|
|
* has ever been executed.
|
|
*/
|
|
static inline void __runtime_fixup_ptr(void *where, unsigned long val)
|
|
{
|
|
*(unsigned long *)where = val;
|
|
}
|
|
|
|
static inline void __runtime_fixup_shift(void *where, unsigned long val)
|
|
{
|
|
*(unsigned char *)where = val;
|
|
}
|
|
|
|
static inline void runtime_const_fixup(void (*fn)(void *, unsigned long),
|
|
unsigned long val, s32 *start, s32 *end)
|
|
{
|
|
while (start < end) {
|
|
fn(*start + (void *)start, val);
|
|
start++;
|
|
}
|
|
}
|
|
|
|
#endif /* __ASSEMBLY__ */
|
|
#endif
|