LXR linux/include/linux/thread

   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 */
  33enum {
  34        BAD_STACK = -1,
  35        NOT_STACK = 0,
  36        GOOD_FRAME,
  37        GOOD_STACK,
  38};
  39
  40#ifdef CONFIG_GENERIC_ENTRY
  41enum 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
  68static 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
  87static inline void set_ti_thread_flag(struct thread_info *ti, int flag)
  88{
  89        set_bit(flag, (unsigned long *)&ti->flags);
  90}
  91
  92static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
  93{
  94        clear_bit(flag, (unsigned long *)&ti->flags);
  95}
  96
  97static 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
 106static 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
 111static 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
 116static 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 */
 125static __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
 183static 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
 192extern void __check_object_size(const void *ptr, unsigned long n,
 193                                        bool to_user);
 194
 195static __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
 202static inline void check_object_size(const void *ptr, unsigned long n,
 203                                     bool to_user)
 204{ }
 205#endif /* CONFIG_HARDENED_USERCOPY */
 206
 207extern void __compiletime_error("copy source size is too small")
 208__bad_copy_from(void);
 209extern void __compiletime_error("copy destination size is too small")
 210__bad_copy_to(void);
 211
 212static inline void copy_overflow(int size, unsigned long count)
 213{
 214        WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
 215}
 216
 217static __always_inline __must_check bool
 218check_copy_size(const void *addr, size_t bytes, bool is_source)
 219{
 220        int sz = __builtin_object_size(addr, 0);
 221        if (unlikely(sz >= 0 && sz < bytes)) {
 222                if (!__builtin_constant_p(bytes))
 223                        copy_overflow(sz, bytes);
 224                else if (is_source)
 225                        __bad_copy_from();
 226                else
 227                        __bad_copy_to();
 228                return false;
 229        }
 230        if (WARN_ON_ONCE(bytes > INT_MAX))
 231                return false;
 232        check_object_size(addr, bytes, is_source);
 233        return true;
 234}
 235
 236#ifndef arch_setup_new_exec
 237static inline void arch_setup_new_exec(void) { }
 238#endif
 239
 240#endif  /* __KERNEL__ */
 241
 242#endif /* _LINUX_THREAD_INFO_H */
 243