1 /* SPDX-License-Identifier: GPL-2.0 */ 1
2 #ifndef _ASM_STATIC_CALL_H
3 #define _ASM_STATIC_CALL_H
4
5 #include <asm/text-patching.h>
6
7 /*
8 * For CONFIG_HAVE_STATIC_CALL_INLINE, this is
9 * uses the current value of the key->func poi
10 * the function. This trampoline is only used
11 * sites get patched by static_call_update().
12 * a magical aspect: objtool uses it to find s
13 * the .static_call_sites section.
14 *
15 * For CONFIG_HAVE_STATIC_CALL, this is a perm
16 * does a direct jump to the function. The di
17 * static_call_update().
18 *
19 * Having the trampoline in a special section
20 * it does tail-call optimization on the call;
21 * relative displacement across sections.
22 */
23
24 /*
25 * The trampoline is 8 bytes and of the genera
26 *
27 * jmp.d32 \func
28 * ud1 %esp, %ecx
29 *
30 * That trailing #UD provides both a speculati
31 * 3 byte signature identifying static call tr
32 * and __static_call_fixup().
33 */
34 #define __ARCH_DEFINE_STATIC_CALL_TRAMP(name,
35 asm(".pushsection .static_call.text, \
36 ".align 4
37 ".globl " STATIC_CALL_TRAMP_STR(na
38 STATIC_CALL_TRAMP_STR(name) ":
39 ANNOTATE_NOENDBR
40 insns "
41 ".byte 0x0f, 0xb9, 0xcc
42 ".type " STATIC_CALL_TRAMP_STR(nam
43 ".size " STATIC_CALL_TRAMP_STR(nam
44 ".popsection
45
46 #define ARCH_DEFINE_STATIC_CALL_TRAMP(name, fu
47 __ARCH_DEFINE_STATIC_CALL_TRAMP(name,
48
49 #ifdef CONFIG_MITIGATION_RETHUNK
50 #define ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(nam
51 __ARCH_DEFINE_STATIC_CALL_TRAMP(name,
52 #else
53 #define ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(nam
54 __ARCH_DEFINE_STATIC_CALL_TRAMP(name,
55 #endif
56
57 #define ARCH_DEFINE_STATIC_CALL_RET0_TRAMP(nam
58 ARCH_DEFINE_STATIC_CALL_TRAMP(name, __
59
60 #define ARCH_ADD_TRAMP_KEY(name)
61 asm(".pushsection .static_call_tramp_k
62 ".long " STATIC_CALL_TRAMP_STR(nam
63 ".long " STATIC_CALL_KEY_STR(name)
64 ".popsection
65
66 extern bool __static_call_fixup(void *tramp, u
67
68 #endif /* _ASM_STATIC_CALL_H */
69
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.