include/linux/thread_info.h

   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/limits.h>
  13 #include <linux/bug.h>
  14 #include <linux/restart_block.h>
  15 #include <linux/errno.h>
  16
  17 #ifdef CONFIG_THREAD_INFO_IN_TASK
  18 /*
  19  * For CONFIG_THREAD_INFO_IN_TASK kernels we need <asm/current.h> for the
  20  * definition of current, but for !CONFIG_THREAD_INFO_IN_TASK kernels,
  21  * including <asm/current.h> can cause a circular dependency on some platforms.
  22  */
  23 #include <asm/current.h>
  24 #define current_thread_info() ((struct thread_info *)current)
  25 #endif
  26
  27 #include <linux/bitops.h>
  28
  29 /*
  30  * For per-arch arch_within_stack_frames() implementations, defined in
  31  * asm/thread_info.h.
  32  */
  33 enum {
  34         BAD_STACK = -1,
  35         NOT_STACK = 0,
  36         GOOD_FRAME,
  37         GOOD_STACK,
  38 };
  39
  40 #ifdef CONFIG_GENERIC_ENTRY
  41 enum syscall_work_bit {
  42         SYSCALL_WORK_BIT_SECCOMP,
  43         SYSCALL_WORK_BIT_SYSCALL_TRACEPOINT,
  44         SYSCALL_WORK_BIT_SYSCALL_TRACE,
  45         SYSCALL_WORK_BIT_SYSCALL_EMU,
  46         SYSCALL_WORK_BIT_SYSCALL_AUDIT,
  47         SYSCALL_WORK_BIT_SYSCALL_USER_DISPATCH,
  48         SYSCALL_WORK_BIT_SYSCALL_EXIT_TRAP,
  49 };
  50
  51 #define SYSCALL_WORK_SECCOMP            BIT(SYSCALL_WORK_BIT_SECCOMP)
  52 #define SYSCALL_WORK_SYSCALL_TRACEPOINT BIT(SYSCALL_WORK_BIT_SYSCALL_TRACEPOINT)
  53 #define SYSCALL_WORK_SYSCALL_TRACE      BIT(SYSCALL_WORK_BIT_SYSCALL_TRACE)
  54 #define SYSCALL_WORK_SYSCALL_EMU        BIT(SYSCALL_WORK_BIT_SYSCALL_EMU)
  55 #define SYSCALL_WORK_SYSCALL_AUDIT      BIT(SYSCALL_WORK_BIT_SYSCALL_AUDIT)
  56 #define SYSCALL_WORK_SYSCALL_USER_DISPATCH BIT(SYSCALL_WORK_BIT_SYSCALL_USER_DISPATCH)
  57 #define SYSCALL_WORK_SYSCALL_EXIT_TRAP  BIT(SYSCALL_WORK_BIT_SYSCALL_EXIT_TRAP)
  58 #endif
  59
  60 #include <asm/thread_info.h>
  61
  62 #ifdef __KERNEL__
  63
  64 #ifndef arch_set_restart_data
  65 #define arch_set_restart_data(restart) do { } while (0)
  66 #endif
  67
  68 static inline long set_restart_fn(struct restart_block *restart,
  69                                         long (*fn)(struct restart_block *))
  70 {
  71         restart->fn = fn;
  72         arch_set_restart_data(restart);
  73         return -ERESTART_RESTARTBLOCK;
  74 }
  75
  76 #ifndef THREAD_ALIGN
  77 #define THREAD_ALIGN    THREAD_SIZE
  78 #endif
  79
  80 #define THREADINFO_GFP          (GFP_KERNEL_ACCOUNT | __GFP_ZERO)
  81
  82 /*
  83  * flag set/clear/test wrappers
  84  * - pass TIF_xxxx constants to these functions
  85  */
  86
  87 static inline void set_ti_thread_flag(struct thread_info *ti, int flag)
  88 {
  89         set_bit(flag, (unsigned long *)&ti->flags);
  90 }
  91
  92 static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
  93 {
  94         clear_bit(flag, (unsigned long *)&ti->flags);
  95 }
  96
  97 static inline void update_ti_thread_flag(struct thread_info *ti, int flag,
  98                                          bool value)
  99 {
 100         if (value)
 101                 set_ti_thread_flag(ti, flag);
 102         else
 103                 clear_ti_thread_flag(ti, flag);
 104 }
 105
 106 static inline int test_and_set_ti_thread_flag(struct thread_info *ti, int flag)
 107 {
 108         return test_and_set_bit(flag, (unsigned long *)&ti->flags);
 109 }
 110
 111 static inline int test_and_clear_ti_thread_flag(struct thread_info *ti, int flag)
 112 {
 113         return test_and_clear_bit(flag, (unsigned long *)&ti->flags);
 114 }
 115
 116 static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
 117 {
 118         return test_bit(flag, (unsigned long *)&ti->flags);
 119 }
 120
 121 /*
 122  * This may be used in noinstr code, and needs to be __always_inline to prevent
 123  * inadvertent instrumentation.
 124  */
 125 static __always_inline unsigned long read_ti_thread_flags(struct thread_info *ti)
 126 {
 127         return READ_ONCE(ti->flags);
 128 }
 129
 130 #define set_thread_flag(flag) \
 131         set_ti_thread_flag(current_thread_info(), flag)
 132 #define clear_thread_flag(flag) \
 133         clear_ti_thread_flag(current_thread_info(), flag)
 134 #define update_thread_flag(flag, value) \
 135         update_ti_thread_flag(current_thread_info(), flag, value)
 136 #define test_and_set_thread_flag(flag) \
 137         test_and_set_ti_thread_flag(current_thread_info(), flag)
 138 #define test_and_clear_thread_flag(flag) \
 139         test_and_clear_ti_thread_flag(current_thread_info(), flag)
 140 #define test_thread_flag(flag) \
 141         test_ti_thread_flag(current_thread_info(), flag)
 142 #define read_thread_flags() \
 143         read_ti_thread_flags(current_thread_info())
 144
 145 #define read_task_thread_flags(t) \
 146         read_ti_thread_flags(task_thread_info(t))
 147
 148 #ifdef CONFIG_GENERIC_ENTRY
 149 #define set_syscall_work(fl) \
 150         set_bit(SYSCALL_WORK_BIT_##fl, &current_thread_info()->syscall_work)
 151 #define test_syscall_work(fl) \
 152         test_bit(SYSCALL_WORK_BIT_##fl, &current_thread_info()->syscall_work)
 153 #define clear_syscall_work(fl) \
 154         clear_bit(SYSCALL_WORK_BIT_##fl, &current_thread_info()->syscall_work)
 155
 156 #define set_task_syscall_work(t, fl) \
 157         set_bit(SYSCALL_WORK_BIT_##fl, &task_thread_info(t)->syscall_work)
 158 #define test_task_syscall_work(t, fl) \
 159         test_bit(SYSCALL_WORK_BIT_##fl, &task_thread_info(t)->syscall_work)
 160 #define clear_task_syscall_work(t, fl) \
 161         clear_bit(SYSCALL_WORK_BIT_##fl, &task_thread_info(t)->syscall_work)
 162
 163 #else /* CONFIG_GENERIC_ENTRY */
 164
 165 #define set_syscall_work(fl)                                            \
 166         set_ti_thread_flag(current_thread_info(), TIF_##fl)
 167 #define test_syscall_work(fl) \
 168         test_ti_thread_flag(current_thread_info(), TIF_##fl)
 169 #define clear_syscall_work(fl) \
 170         clear_ti_thread_flag(current_thread_info(), TIF_##fl)
 171
 172 #define set_task_syscall_work(t, fl) \
 173         set_ti_thread_flag(task_thread_info(t), TIF_##fl)
 174 #define test_task_syscall_work(t, fl) \
 175         test_ti_thread_flag(task_thread_info(t), TIF_##fl)
 176 #define clear_task_syscall_work(t, fl) \
 177         clear_ti_thread_flag(task_thread_info(t), TIF_##fl)
 178 #endif /* !CONFIG_GENERIC_ENTRY */
 179
 180 #define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)
 181
 182 #ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
 183 static inline int arch_within_stack_frames(const void * const stack,
 184                                            const void * const stackend,
 185                                            const void *obj, unsigned long len)
 186 {
 187         return 0;
 188 }
 189 #endif
 190
 191 #ifdef CONFIG_HARDENED_USERCOPY
 192 extern void __check_object_size(const void *ptr, unsigned long n,
 193                                         bool to_user);
 194
 195 static __always_inline void check_object_size(const void *ptr, unsigned long n,
 196                                               bool to_user)
 197 {
 198         if (!__builtin_constant_p(n))
 199                 __check_object_size(ptr, n, to_user);
 200 }
 201 #else
 202 static inline void check_object_size(const void *ptr, unsigned long n,
 203                                      bool to_user)
 204 { }
 205 #endif /* CONFIG_HARDENED_USERCOPY */
 206
 207 extern void __compiletime_error("copy source size is too small")
 208 __bad_copy_from(void);
 209 extern void __compiletime_error("copy destination size is too small")
 210 __bad_copy_to(void);
 211
 212 void __copy_overflow(int size, unsigned long count);
 213
 214 static inline void copy_overflow(int size, unsigned long count)
 215 {
 216         if (IS_ENABLED(CONFIG_BUG))
 217                 __copy_overflow(size, count);
 218 }
 219
 220 static __always_inline __must_check bool
 221 check_copy_size(const void *addr, size_t bytes, bool is_source)
 222 {
 223         int sz = __builtin_object_size(addr, 0);
 224         if (unlikely(sz >= 0 && sz < bytes)) {
 225                 if (!__builtin_constant_p(bytes))
 226                         copy_overflow(sz, bytes);
 227                 else if (is_source)
 228                         __bad_copy_from();
 229                 else
 230                         __bad_copy_to();
 231                 return false;
 232         }
 233         if (WARN_ON_ONCE(bytes > INT_MAX))
 234                 return false;
 235         check_object_size(addr, bytes, is_source);
 236         return true;
 237 }
 238
 239 #ifndef arch_setup_new_exec
 240 static inline void arch_setup_new_exec(void) { }
 241 #endif
 242
 243 #endif  /* __KERNEL__ */
 244
 245 #endif /* _LINUX_THREAD_INFO_H */