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 #ifndef TIF_NEED_RESCHED_LAZY
  63 #ifdef CONFIG_ARCH_HAS_PREEMPT_LAZY
  64 #error Inconsistent PREEMPT_LAZY
  65 #endif
  66 #define TIF_NEED_RESCHED_LAZY TIF_NEED_RESCHED
  67 #define _TIF_NEED_RESCHED_LAZY _TIF_NEED_RESCHED
  68 #endif
  69
  70 #ifdef __KERNEL__
  71
  72 #ifndef arch_set_restart_data
  73 #define arch_set_restart_data(restart) do { } while (0)
  74 #endif
  75
  76 static inline long set_restart_fn(struct restart_block *restart,
  77                                         long (*fn)(struct restart_block *))
  78 {
  79         restart->fn = fn;
  80         arch_set_restart_data(restart);
  81         return -ERESTART_RESTARTBLOCK;
  82 }
  83
  84 #ifndef THREAD_ALIGN
  85 #define THREAD_ALIGN    THREAD_SIZE
  86 #endif
  87
  88 #define THREADINFO_GFP          (GFP_KERNEL_ACCOUNT | __GFP_ZERO)
  89
  90 /*
  91  * flag set/clear/test wrappers
  92  * - pass TIF_xxxx constants to these functions
  93  */
  94
  95 static inline void set_ti_thread_flag(struct thread_info *ti, int flag)
  96 {
  97         set_bit(flag, (unsigned long *)&ti->flags);
  98 }
  99
 100 static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
 101 {
 102         clear_bit(flag, (unsigned long *)&ti->flags);
 103 }
 104
 105 static inline void update_ti_thread_flag(struct thread_info *ti, int flag,
 106                                          bool value)
 107 {
 108         if (value)
 109                 set_ti_thread_flag(ti, flag);
 110         else
 111                 clear_ti_thread_flag(ti, flag);
 112 }
 113
 114 static inline int test_and_set_ti_thread_flag(struct thread_info *ti, int flag)
 115 {
 116         return test_and_set_bit(flag, (unsigned long *)&ti->flags);
 117 }
 118
 119 static inline int test_and_clear_ti_thread_flag(struct thread_info *ti, int flag)
 120 {
 121         return test_and_clear_bit(flag, (unsigned long *)&ti->flags);
 122 }
 123
 124 static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
 125 {
 126         return test_bit(flag, (unsigned long *)&ti->flags);
 127 }
 128
 129 /*
 130  * This may be used in noinstr code, and needs to be __always_inline to prevent
 131  * inadvertent instrumentation.
 132  */
 133 static __always_inline unsigned long read_ti_thread_flags(struct thread_info *ti)
 134 {
 135         return READ_ONCE(ti->flags);
 136 }
 137
 138 #define set_thread_flag(flag) \
 139         set_ti_thread_flag(current_thread_info(), flag)
 140 #define clear_thread_flag(flag) \
 141         clear_ti_thread_flag(current_thread_info(), flag)
 142 #define update_thread_flag(flag, value) \
 143         update_ti_thread_flag(current_thread_info(), flag, value)
 144 #define test_and_set_thread_flag(flag) \
 145         test_and_set_ti_thread_flag(current_thread_info(), flag)
 146 #define test_and_clear_thread_flag(flag) \
 147         test_and_clear_ti_thread_flag(current_thread_info(), flag)
 148 #define test_thread_flag(flag) \
 149         test_ti_thread_flag(current_thread_info(), flag)
 150 #define read_thread_flags() \
 151         read_ti_thread_flags(current_thread_info())
 152
 153 #define read_task_thread_flags(t) \
 154         read_ti_thread_flags(task_thread_info(t))
 155
 156 #ifdef CONFIG_GENERIC_ENTRY
 157 #define set_syscall_work(fl) \
 158         set_bit(SYSCALL_WORK_BIT_##fl, &current_thread_info()->syscall_work)
 159 #define test_syscall_work(fl) \
 160         test_bit(SYSCALL_WORK_BIT_##fl, &current_thread_info()->syscall_work)
 161 #define clear_syscall_work(fl) \
 162         clear_bit(SYSCALL_WORK_BIT_##fl, &current_thread_info()->syscall_work)
 163
 164 #define set_task_syscall_work(t, fl) \
 165         set_bit(SYSCALL_WORK_BIT_##fl, &task_thread_info(t)->syscall_work)
 166 #define test_task_syscall_work(t, fl) \
 167         test_bit(SYSCALL_WORK_BIT_##fl, &task_thread_info(t)->syscall_work)
 168 #define clear_task_syscall_work(t, fl) \
 169         clear_bit(SYSCALL_WORK_BIT_##fl, &task_thread_info(t)->syscall_work)
 170
 171 #else /* CONFIG_GENERIC_ENTRY */
 172
 173 #define set_syscall_work(fl)                                            \
 174         set_ti_thread_flag(current_thread_info(), TIF_##fl)
 175 #define test_syscall_work(fl) \
 176         test_ti_thread_flag(current_thread_info(), TIF_##fl)
 177 #define clear_syscall_work(fl) \
 178         clear_ti_thread_flag(current_thread_info(), TIF_##fl)
 179
 180 #define set_task_syscall_work(t, fl) \
 181         set_ti_thread_flag(task_thread_info(t), TIF_##fl)
 182 #define test_task_syscall_work(t, fl) \
 183         test_ti_thread_flag(task_thread_info(t), TIF_##fl)
 184 #define clear_task_syscall_work(t, fl) \
 185         clear_ti_thread_flag(task_thread_info(t), TIF_##fl)
 186 #endif /* !CONFIG_GENERIC_ENTRY */
 187
 188 #ifdef _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H
 189
 190 static __always_inline bool tif_test_bit(int bit)
 191 {
 192         return arch_test_bit(bit,
 193                              (unsigned long *)(&current_thread_info()->flags));
 194 }
 195
 196 #else
 197
 198 static __always_inline bool tif_test_bit(int bit)
 199 {
 200         return test_bit(bit,
 201                         (unsigned long *)(&current_thread_info()->flags));
 202 }
 203
 204 #endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H */
 205
 206 static __always_inline bool tif_need_resched(void)
 207 {
 208         return tif_test_bit(TIF_NEED_RESCHED);
 209 }
 210
 211 #ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
 212 static inline int arch_within_stack_frames(const void * const stack,
 213                                            const void * const stackend,
 214                                            const void *obj, unsigned long len)
 215 {
 216         return 0;
 217 }
 218 #endif
 219
 220 #ifdef CONFIG_HARDENED_USERCOPY
 221 extern void __check_object_size(const void *ptr, unsigned long n,
 222                                         bool to_user);
 223
 224 static __always_inline void check_object_size(const void *ptr, unsigned long n,
 225                                               bool to_user)
 226 {
 227         if (!__builtin_constant_p(n))
 228                 __check_object_size(ptr, n, to_user);
 229 }
 230 #else
 231 static inline void check_object_size(const void *ptr, unsigned long n,
 232                                      bool to_user)
 233 { }
 234 #endif /* CONFIG_HARDENED_USERCOPY */
 235
 236 extern void __compiletime_error("copy source size is too small")
 237 __bad_copy_from(void);
 238 extern void __compiletime_error("copy destination size is too small")
 239 __bad_copy_to(void);
 240
 241 void __copy_overflow(int size, unsigned long count);
 242
 243 static inline void copy_overflow(int size, unsigned long count)
 244 {
 245         if (IS_ENABLED(CONFIG_BUG))
 246                 __copy_overflow(size, count);
 247 }
 248
 249 static __always_inline __must_check bool
 250 check_copy_size(const void *addr, size_t bytes, bool is_source)
 251 {
 252         int sz = __builtin_object_size(addr, 0);
 253         if (unlikely(sz >= 0 && sz < bytes)) {
 254                 if (!__builtin_constant_p(bytes))
 255                         copy_overflow(sz, bytes);
 256                 else if (is_source)
 257                         __bad_copy_from();
 258                 else
 259                         __bad_copy_to();
 260                 return false;
 261         }
 262         if (WARN_ON_ONCE(bytes > INT_MAX))
 263                 return false;
 264         check_object_size(addr, bytes, is_source);
 265         return true;
 266 }
 267
 268 #ifndef arch_setup_new_exec
 269 static inline void arch_setup_new_exec(void) { }
 270 #endif
 271
 272 void arch_task_cache_init(void); /* for CONFIG_SH */
 273 void arch_release_task_struct(struct task_struct *tsk);
 274 int arch_dup_task_struct(struct task_struct *dst,
 275                                 struct task_struct *src);
 276
 277 #endif  /* __KERNEL__ */
 278
 279 #endif /* _LINUX_THREAD_INFO_H */