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 CONFIG_PREEMPT_BUILD_AUTO
  63 # define TIF_NEED_RESCHED_LAZY          TIF_ARCH_RESCHED_LAZY
  64 # define _TIF_NEED_RESCHED_LAZY         _TIF_ARCH_RESCHED_LAZY
  65 # define TIF_NEED_RESCHED_LAZY_OFFSET   (TIF_NEED_RESCHED_LAZY - TIF_NEED_RESCHED)
  66 #else
  67 # define TIF_NEED_RESCHED_LAZY          TIF_NEED_RESCHED
  68 # define _TIF_NEED_RESCHED_LAZY         _TIF_NEED_RESCHED
  69 # define TIF_NEED_RESCHED_LAZY_OFFSET   0
  70 #endif
  71
  72 #ifdef __KERNEL__
  73
  74 #ifndef arch_set_restart_data
  75 #define arch_set_restart_data(restart) do { } while (0)
  76 #endif
  77
  78 static inline long set_restart_fn(struct restart_block *restart,
  79                                         long (*fn)(struct restart_block *))
  80 {
  81         restart->fn = fn;
  82         arch_set_restart_data(restart);
  83         return -ERESTART_RESTARTBLOCK;
  84 }
  85
  86 #ifndef THREAD_ALIGN
  87 #define THREAD_ALIGN    THREAD_SIZE
  88 #endif
  89
  90 #define THREADINFO_GFP          (GFP_KERNEL_ACCOUNT | __GFP_ZERO)
  91
  92 /*
  93  * flag set/clear/test wrappers
  94  * - pass TIF_xxxx constants to these functions
  95  */
  96
  97 static inline void set_ti_thread_flag(struct thread_info *ti, int flag)
  98 {
  99         set_bit(flag, (unsigned long *)&ti->flags);
 100 }
 101
 102 static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
 103 {
 104         clear_bit(flag, (unsigned long *)&ti->flags);
 105 }
 106
 107 static inline void update_ti_thread_flag(struct thread_info *ti, int flag,
 108                                          bool value)
 109 {
 110         if (value)
 111                 set_ti_thread_flag(ti, flag);
 112         else
 113                 clear_ti_thread_flag(ti, flag);
 114 }
 115
 116 static inline int test_and_set_ti_thread_flag(struct thread_info *ti, int flag)
 117 {
 118         return test_and_set_bit(flag, (unsigned long *)&ti->flags);
 119 }
 120
 121 static inline int test_and_clear_ti_thread_flag(struct thread_info *ti, int flag)
 122 {
 123         return test_and_clear_bit(flag, (unsigned long *)&ti->flags);
 124 }
 125
 126 static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
 127 {
 128         return test_bit(flag, (unsigned long *)&ti->flags);
 129 }
 130
 131 /*
 132  * This may be used in noinstr code, and needs to be __always_inline to prevent
 133  * inadvertent instrumentation.
 134  */
 135 static __always_inline unsigned long read_ti_thread_flags(struct thread_info *ti)
 136 {
 137         return READ_ONCE(ti->flags);
 138 }
 139
 140 #define set_thread_flag(flag) \
 141         set_ti_thread_flag(current_thread_info(), flag)
 142 #define clear_thread_flag(flag) \
 143         clear_ti_thread_flag(current_thread_info(), flag)
 144 #define update_thread_flag(flag, value) \
 145         update_ti_thread_flag(current_thread_info(), flag, value)
 146 #define test_and_set_thread_flag(flag) \
 147         test_and_set_ti_thread_flag(current_thread_info(), flag)
 148 #define test_and_clear_thread_flag(flag) \
 149         test_and_clear_ti_thread_flag(current_thread_info(), flag)
 150 #define test_thread_flag(flag) \
 151         test_ti_thread_flag(current_thread_info(), flag)
 152 #define read_thread_flags() \
 153         read_ti_thread_flags(current_thread_info())
 154
 155 #define read_task_thread_flags(t) \
 156         read_ti_thread_flags(task_thread_info(t))
 157
 158 #ifdef CONFIG_GENERIC_ENTRY
 159 #define set_syscall_work(fl) \
 160         set_bit(SYSCALL_WORK_BIT_##fl, &current_thread_info()->syscall_work)
 161 #define test_syscall_work(fl) \
 162         test_bit(SYSCALL_WORK_BIT_##fl, &current_thread_info()->syscall_work)
 163 #define clear_syscall_work(fl) \
 164         clear_bit(SYSCALL_WORK_BIT_##fl, &current_thread_info()->syscall_work)
 165
 166 #define set_task_syscall_work(t, fl) \
 167         set_bit(SYSCALL_WORK_BIT_##fl, &task_thread_info(t)->syscall_work)
 168 #define test_task_syscall_work(t, fl) \
 169         test_bit(SYSCALL_WORK_BIT_##fl, &task_thread_info(t)->syscall_work)
 170 #define clear_task_syscall_work(t, fl) \
 171         clear_bit(SYSCALL_WORK_BIT_##fl, &task_thread_info(t)->syscall_work)
 172
 173 #else /* CONFIG_GENERIC_ENTRY */
 174
 175 #define set_syscall_work(fl)                                            \
 176         set_ti_thread_flag(current_thread_info(), TIF_##fl)
 177 #define test_syscall_work(fl) \
 178         test_ti_thread_flag(current_thread_info(), TIF_##fl)
 179 #define clear_syscall_work(fl) \
 180         clear_ti_thread_flag(current_thread_info(), TIF_##fl)
 181
 182 #define set_task_syscall_work(t, fl) \
 183         set_ti_thread_flag(task_thread_info(t), TIF_##fl)
 184 #define test_task_syscall_work(t, fl) \
 185         test_ti_thread_flag(task_thread_info(t), TIF_##fl)
 186 #define clear_task_syscall_work(t, fl) \
 187         clear_ti_thread_flag(task_thread_info(t), TIF_##fl)
 188 #endif /* !CONFIG_GENERIC_ENTRY */
 189
 190 #ifdef _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H
 191
 192 static __always_inline bool tif_need_resched(void)
 193 {
 194         return arch_test_bit(TIF_NEED_RESCHED,
 195                              (unsigned long *)(&current_thread_info()->flags));
 196 }
 197
 198 static __always_inline bool tif_need_resched_lazy(void)
 199 {
 200         return IS_ENABLED(CONFIG_PREEMPT_BUILD_AUTO) &&
 201                 arch_test_bit(TIF_NEED_RESCHED_LAZY,
 202                               (unsigned long *)(&current_thread_info()->flags));
 203 }
 204
 205 #else
 206
 207 static __always_inline bool tif_need_resched(void)
 208 {
 209         return test_bit(TIF_NEED_RESCHED,
 210                         (unsigned long *)(&current_thread_info()->flags));
 211 }
 212
 213 static __always_inline bool tif_need_resched_lazy(void)
 214 {
 215         return IS_ENABLED(CONFIG_PREEMPT_BUILD_AUTO) &&
 216                 test_bit(TIF_NEED_RESCHED_LAZY,
 217                          (unsigned long *)(&current_thread_info()->flags));
 218 }
 219
 220 #endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H */
 221
 222 #ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
 223 static inline int arch_within_stack_frames(const void * const stack,
 224                                            const void * const stackend,
 225                                            const void *obj, unsigned long len)
 226 {
 227         return 0;
 228 }
 229 #endif
 230
 231 #ifdef CONFIG_HARDENED_USERCOPY
 232 extern void __check_object_size(const void *ptr, unsigned long n,
 233                                         bool to_user);
 234
 235 static __always_inline void check_object_size(const void *ptr, unsigned long n,
 236                                               bool to_user)
 237 {
 238         if (!__builtin_constant_p(n))
 239                 __check_object_size(ptr, n, to_user);
 240 }
 241 #else
 242 static inline void check_object_size(const void *ptr, unsigned long n,
 243                                      bool to_user)
 244 { }
 245 #endif /* CONFIG_HARDENED_USERCOPY */
 246
 247 extern void __compiletime_error("copy source size is too small")
 248 __bad_copy_from(void);
 249 extern void __compiletime_error("copy destination size is too small")
 250 __bad_copy_to(void);
 251
 252 void __copy_overflow(int size, unsigned long count);
 253
 254 static inline void copy_overflow(int size, unsigned long count)
 255 {
 256         if (IS_ENABLED(CONFIG_BUG))
 257                 __copy_overflow(size, count);
 258 }
 259
 260 static __always_inline __must_check bool
 261 check_copy_size(const void *addr, size_t bytes, bool is_source)
 262 {
 263         int sz = __builtin_object_size(addr, 0);
 264         if (unlikely(sz >= 0 && sz < bytes)) {
 265                 if (!__builtin_constant_p(bytes))
 266                         copy_overflow(sz, bytes);
 267                 else if (is_source)
 268                         __bad_copy_from();
 269                 else
 270                         __bad_copy_to();
 271                 return false;
 272         }
 273         if (WARN_ON_ONCE(bytes > INT_MAX))
 274                 return false;
 275         check_object_size(addr, bytes, is_source);
 276         return true;
 277 }
 278
 279 #ifndef arch_setup_new_exec
 280 static inline void arch_setup_new_exec(void) { }
 281 #endif
 282
 283 void arch_task_cache_init(void); /* for CONFIG_SH */
 284 void arch_release_task_struct(struct task_struct *tsk);
 285 int arch_dup_task_struct(struct task_struct *dst,
 286                                 struct task_struct *src);
 287
 288 #endif  /* __KERNEL__ */
 289
 290 #endif /* _LINUX_THREAD_INFO_H */