include/linux/rseq.h

   1 /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
   2 #ifndef _LINUX_RSEQ_H
   3 #define _LINUX_RSEQ_H
   4
   5 #ifdef CONFIG_RSEQ
   6
   7 #include <linux/preempt.h>
   8 #include <linux/sched.h>
   9
  10 /*
  11  * Map the event mask on the user-space ABI enum rseq_cs_flags
  12  * for direct mask checks.
  13  */
  14 enum rseq_event_mask_bits {
  15         RSEQ_EVENT_PREEMPT_BIT  = RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT,
  16         RSEQ_EVENT_SIGNAL_BIT   = RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT,
  17         RSEQ_EVENT_MIGRATE_BIT  = RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT,
  18 };
  19
  20 enum rseq_event_mask {
  21         RSEQ_EVENT_PREEMPT      = (1U << RSEQ_EVENT_PREEMPT_BIT),
  22         RSEQ_EVENT_SIGNAL       = (1U << RSEQ_EVENT_SIGNAL_BIT),
  23         RSEQ_EVENT_MIGRATE      = (1U << RSEQ_EVENT_MIGRATE_BIT),
  24 };
  25
  26 static inline void rseq_set_notify_resume(struct task_struct *t)
  27 {
  28         if (t->rseq)
  29                 set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
  30 }
  31
  32 void __rseq_handle_notify_resume(struct ksignal *sig, struct pt_regs *regs);
  33
  34 static inline void rseq_handle_notify_resume(struct ksignal *ksig,
  35                                              struct pt_regs *regs)
  36 {
  37         if (current->rseq)
  38                 __rseq_handle_notify_resume(ksig, regs);
  39 }
  40
  41 static inline void rseq_signal_deliver(struct ksignal *ksig,
  42                                        struct pt_regs *regs)
  43 {
  44         preempt_disable();
  45         __set_bit(RSEQ_EVENT_SIGNAL_BIT, &current->rseq_event_mask);
  46         preempt_enable();
  47         rseq_handle_notify_resume(ksig, regs);
  48 }
  49
  50 /* rseq_preempt() requires preemption to be disabled. */
  51 static inline void rseq_preempt(struct task_struct *t)
  52 {
  53         __set_bit(RSEQ_EVENT_PREEMPT_BIT, &t->rseq_event_mask);
  54         rseq_set_notify_resume(t);
  55 }
  56
  57 /* rseq_migrate() requires preemption to be disabled. */
  58 static inline void rseq_migrate(struct task_struct *t)
  59 {
  60         __set_bit(RSEQ_EVENT_MIGRATE_BIT, &t->rseq_event_mask);
  61         rseq_set_notify_resume(t);
  62 }
  63
  64 /*
  65  * If parent process has a registered restartable sequences area, the
  66  * child inherits. Unregister rseq for a clone with CLONE_VM set.
  67  */
  68 static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
  69 {
  70         if (clone_flags & CLONE_VM) {
  71                 t->rseq = NULL;
  72                 t->rseq_len = 0;
  73                 t->rseq_sig = 0;
  74                 t->rseq_event_mask = 0;
  75         } else {
  76                 t->rseq = current->rseq;
  77                 t->rseq_len = current->rseq_len;
  78                 t->rseq_sig = current->rseq_sig;
  79                 t->rseq_event_mask = current->rseq_event_mask;
  80         }
  81 }
  82
  83 static inline void rseq_execve(struct task_struct *t)
  84 {
  85         t->rseq = NULL;
  86         t->rseq_len = 0;
  87         t->rseq_sig = 0;
  88         t->rseq_event_mask = 0;
  89 }
  90
  91 #else
  92
  93 static inline void rseq_set_notify_resume(struct task_struct *t)
  94 {
  95 }
  96 static inline void rseq_handle_notify_resume(struct ksignal *ksig,
  97                                              struct pt_regs *regs)
  98 {
  99 }
 100 static inline void rseq_signal_deliver(struct ksignal *ksig,
 101                                        struct pt_regs *regs)
 102 {
 103 }
 104 static inline void rseq_preempt(struct task_struct *t)
 105 {
 106 }
 107 static inline void rseq_migrate(struct task_struct *t)
 108 {
 109 }
 110 static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
 111 {
 112 }
 113 static inline void rseq_execve(struct task_struct *t)
 114 {
 115 }
 116
 117 #endif
 118
 119 #ifdef CONFIG_DEBUG_RSEQ
 120
 121 void rseq_syscall(struct pt_regs *regs);
 122
 123 #else
 124
 125 static inline void rseq_syscall(struct pt_regs *regs)
 126 {
 127 }
 128
 129 #endif
 130
 131 #endif /* _LINUX_RSEQ_H */