1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* thread_info.h: common low-level thread information accessors
3 *
4 * Copyright (C) 2002 David Howells (dhowells@redhat.com)
5 * - Incorporating suggestions made by Linus Torvalds
6 */
7
8 #ifndef _LINUX_THREAD_INFO_H
9 #define _LINUX_THREAD_INFO_H
10
11 #include <linux/types.h>
12 #include <linux/bug.h>
13 #include <linux/restart_block.h>
14
15 #ifdef CONFIG_THREAD_INFO_IN_TASK
16 /*
17 * For CONFIG_THREAD_INFO_IN_TASK kernels we need <asm/current.h> for the
18 * definition of current, but for !CONFIG_THREAD_INFO_IN_TASK kernels,
19 * including <asm/current.h> can cause a circular dependency on some platforms.
20 */
21 #include <asm/current.h>
22 #define current_thread_info() ((struct thread_info *)current)
23 #endif
24
25 #include <linux/bitops.h>
26
27 /*
28 * For per-arch arch_within_stack_frames() implementations, defined in
29 * asm/thread_info.h.
30 */
31 enum {
32 BAD_STACK = -1,
33 NOT_STACK = 0,
34 GOOD_FRAME,
35 GOOD_STACK,
36 };
37
38 #include <asm/thread_info.h>
39
40 #ifdef __KERNEL__
41
42 #ifndef THREAD_ALIGN
43 #define THREAD_ALIGN THREAD_SIZE
44 #endif
45
46 #define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_ZERO)
47
48 /*
49 * flag set/clear/test wrappers
50 * - pass TIF_xxxx constants to these functions
51 */
52
set_ti_thread_flag(struct thread_info * ti,int flag)53 static inline void set_ti_thread_flag(struct thread_info *ti, int flag)
54 {
55 set_bit(flag, (unsigned long *)&ti->flags);
56 }
57
clear_ti_thread_flag(struct thread_info * ti,int flag)58 static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
59 {
60 clear_bit(flag, (unsigned long *)&ti->flags);
61 }
62
update_ti_thread_flag(struct thread_info * ti,int flag,bool value)63 static inline void update_ti_thread_flag(struct thread_info *ti, int flag,
64 bool value)
65 {
66 if (value)
67 set_ti_thread_flag(ti, flag);
68 else
69 clear_ti_thread_flag(ti, flag);
70 }
71
test_and_set_ti_thread_flag(struct thread_info * ti,int flag)72 static inline int test_and_set_ti_thread_flag(struct thread_info *ti, int flag)
73 {
74 return test_and_set_bit(flag, (unsigned long *)&ti->flags);
75 }
76
test_and_clear_ti_thread_flag(struct thread_info * ti,int flag)77 static inline int test_and_clear_ti_thread_flag(struct thread_info *ti, int flag)
78 {
79 return test_and_clear_bit(flag, (unsigned long *)&ti->flags);
80 }
81
test_ti_thread_flag(struct thread_info * ti,int flag)82 static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
83 {
84 return test_bit(flag, (unsigned long *)&ti->flags);
85 }
86
87 #define set_thread_flag(flag) \
88 set_ti_thread_flag(current_thread_info(), flag)
89 #define clear_thread_flag(flag) \
90 clear_ti_thread_flag(current_thread_info(), flag)
91 #define update_thread_flag(flag, value) \
92 update_ti_thread_flag(current_thread_info(), flag, value)
93 #define test_and_set_thread_flag(flag) \
94 test_and_set_ti_thread_flag(current_thread_info(), flag)
95 #define test_and_clear_thread_flag(flag) \
96 test_and_clear_ti_thread_flag(current_thread_info(), flag)
97 #define test_thread_flag(flag) \
98 test_ti_thread_flag(current_thread_info(), flag)
99
100 #define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)
101
102 #ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
arch_within_stack_frames(const void * const stack,const void * const stackend,const void * obj,unsigned long len)103 static inline int arch_within_stack_frames(const void * const stack,
104 const void * const stackend,
105 const void *obj, unsigned long len)
106 {
107 return 0;
108 }
109 #endif
110
111 #ifdef CONFIG_HARDENED_USERCOPY
112 extern void __check_object_size(const void *ptr, unsigned long n,
113 bool to_user);
114
check_object_size(const void * ptr,unsigned long n,bool to_user)115 static __always_inline void check_object_size(const void *ptr, unsigned long n,
116 bool to_user)
117 {
118 if (!__builtin_constant_p(n))
119 __check_object_size(ptr, n, to_user);
120 }
121 #else
check_object_size(const void * ptr,unsigned long n,bool to_user)122 static inline void check_object_size(const void *ptr, unsigned long n,
123 bool to_user)
124 { }
125 #endif /* CONFIG_HARDENED_USERCOPY */
126
127 extern void __compiletime_error("copy source size is too small")
128 __bad_copy_from(void);
129 extern void __compiletime_error("copy destination size is too small")
130 __bad_copy_to(void);
131
copy_overflow(int size,unsigned long count)132 static inline void copy_overflow(int size, unsigned long count)
133 {
134 WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
135 }
136
137 static __always_inline __must_check bool
check_copy_size(const void * addr,size_t bytes,bool is_source)138 check_copy_size(const void *addr, size_t bytes, bool is_source)
139 {
140 int sz = __compiletime_object_size(addr);
141 if (unlikely(sz >= 0 && sz < bytes)) {
142 if (!__builtin_constant_p(bytes))
143 copy_overflow(sz, bytes);
144 else if (is_source)
145 __bad_copy_from();
146 else
147 __bad_copy_to();
148 return false;
149 }
150 if (WARN_ON_ONCE(bytes > INT_MAX))
151 return false;
152 check_object_size(addr, bytes, is_source);
153 return true;
154 }
155
156 #ifndef arch_setup_new_exec
arch_setup_new_exec(void)157 static inline void arch_setup_new_exec(void) { }
158 #endif
159
160 #endif /* __KERNEL__ */
161
162 #endif /* _LINUX_THREAD_INFO_H */
163
