livepatch_helpers.h

 1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _LINUX_LIVEPATCH_HELPERS_H
 3#define _LINUX_LIVEPATCH_HELPERS_H
 4
 5/*
 6 * Interfaces for use by livepatch patches
 7 */
 8
 9#include <linux/syscalls.h>
10#include <linux/livepatch.h>
11
12#ifdef MODULE
13#define KLP_OBJNAME __KBUILD_MODNAME
14#else
15#define KLP_OBJNAME vmlinux
16#endif
17
18/* Livepatch callback registration */
19
20#define KLP_CALLBACK_PTRS ".discard.klp_callback_ptrs"
21
22#define KLP_PRE_PATCH_CALLBACK(func)						\
23	klp_pre_patch_t __used __section(KLP_CALLBACK_PTRS)			\
24		__PASTE(__KLP_PRE_PATCH_PREFIX, KLP_OBJNAME) = func
25
26#define KLP_POST_PATCH_CALLBACK(func)						\
27	klp_post_patch_t __used __section(KLP_CALLBACK_PTRS)			\
28		__PASTE(__KLP_POST_PATCH_PREFIX, KLP_OBJNAME) = func
29
30#define KLP_PRE_UNPATCH_CALLBACK(func)						\
31	klp_pre_unpatch_t __used __section(KLP_CALLBACK_PTRS)			\
32		__PASTE(__KLP_PRE_UNPATCH_PREFIX, KLP_OBJNAME) = func
33
34#define KLP_POST_UNPATCH_CALLBACK(func)						\
35	klp_post_unpatch_t __used __section(KLP_CALLBACK_PTRS)			\
36		__PASTE(__KLP_POST_UNPATCH_PREFIX, KLP_OBJNAME) = func
37
38/*
39 * Replace static_call() usage with this macro when create-diff-object
40 * recommends it due to the original static call key living in a module.
41 *
42 * This converts the static call to a regular indirect call.
43 */
44#define KLP_STATIC_CALL(name) \
45	((typeof(STATIC_CALL_TRAMP(name))*)(STATIC_CALL_KEY(name).func))
46
47/* Syscall patching */
48
49#define KLP_SYSCALL_DEFINE1(name, ...) KLP_SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
50#define KLP_SYSCALL_DEFINE2(name, ...) KLP_SYSCALL_DEFINEx(2, _##name, __VA_ARGS__)
51#define KLP_SYSCALL_DEFINE3(name, ...) KLP_SYSCALL_DEFINEx(3, _##name, __VA_ARGS__)
52#define KLP_SYSCALL_DEFINE4(name, ...) KLP_SYSCALL_DEFINEx(4, _##name, __VA_ARGS__)
53#define KLP_SYSCALL_DEFINE5(name, ...) KLP_SYSCALL_DEFINEx(5, _##name, __VA_ARGS__)
54#define KLP_SYSCALL_DEFINE6(name, ...) KLP_SYSCALL_DEFINEx(6, _##name, __VA_ARGS__)
55
56#define KLP_SYSCALL_DEFINEx(x, sname, ...)				\
57	__KLP_SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
58
59#ifdef CONFIG_X86_64
60// TODO move this to arch/x86/include/asm/syscall_wrapper.h and share code
61#define __KLP_SYSCALL_DEFINEx(x, name, ...)			\
62	static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__));	\
63	static inline long __klp_do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
64	__X64_SYS_STUBx(x, name, __VA_ARGS__)				\
65	__IA32_SYS_STUBx(x, name, __VA_ARGS__)				\
66	static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))	\
67	{								\
68		long ret = __klp_do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\
69		__MAP(x,__SC_TEST,__VA_ARGS__);				\
70		__PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__));	\
71		return ret;						\
72	}								\
73	static inline long __klp_do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
74
75#endif
76
77#endif /* _LINUX_LIVEPATCH_HELPERS_H */