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/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
#ifndef _LINUX_RSEQ_H
#define _LINUX_RSEQ_H
#ifdef CONFIG_RSEQ
#include <linux/sched.h>
void __rseq_handle_notify_resume(struct ksignal *sig, struct pt_regs *regs);
static inline void rseq_handle_notify_resume(struct pt_regs *regs)
{
if (current->rseq.event.has_rseq)
__rseq_handle_notify_resume(NULL, regs);
}
static inline void rseq_signal_deliver(struct ksignal *ksig, struct pt_regs *regs)
{
if (current->rseq.event.has_rseq) {
current->rseq.event.sched_switch = true;
__rseq_handle_notify_resume(ksig, regs);
}
}
static inline void rseq_sched_switch_event(struct task_struct *t)
{
if (t->rseq.event.has_rseq) {
t->rseq.event.sched_switch = true;
set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
}
}
/*
* KVM/HYPERV invoke resume_user_mode_work() before entering guest mode,
* which clears TIF_NOTIFY_RESUME. To avoid updating user space RSEQ in
* that case just to do it eventually again before returning to user space,
* the entry resume_user_mode_work() invocation is ignored as the register
* argument is NULL.
*
* After returning from guest mode, they have to invoke this function to
* re-raise TIF_NOTIFY_RESUME if necessary.
*/
static inline void rseq_virt_userspace_exit(void)
{
if (current->rseq.event.sched_switch)
set_tsk_thread_flag(current, TIF_NOTIFY_RESUME);
}
static inline void rseq_reset(struct task_struct *t)
{
memset(&t->rseq, 0, sizeof(t->rseq));
t->rseq.ids.cpu_cid = ~0ULL;
}
static inline void rseq_execve(struct task_struct *t)
{
rseq_reset(t);
}
/*
* If parent process has a registered restartable sequences area, the
* child inherits. Unregister rseq for a clone with CLONE_VM set.
*/
static inline void rseq_fork(struct task_struct *t, u64 clone_flags)
{
if (clone_flags & CLONE_VM) {
rseq_reset(t);
} else {
t->rseq = current->rseq;
t->rseq.ids.cpu_cid = ~0ULL;
}
}
#else /* CONFIG_RSEQ */
static inline void rseq_handle_notify_resume(struct pt_regs *regs) { }
static inline void rseq_signal_deliver(struct ksignal *ksig, struct pt_regs *regs) { }
static inline void rseq_sched_switch_event(struct task_struct *t) { }
static inline void rseq_virt_userspace_exit(void) { }
static inline void rseq_fork(struct task_struct *t, u64 clone_flags) { }
static inline void rseq_execve(struct task_struct *t) { }
#endif /* !CONFIG_RSEQ */
#ifdef CONFIG_DEBUG_RSEQ
void rseq_syscall(struct pt_regs *regs);
#else /* CONFIG_DEBUG_RSEQ */
static inline void rseq_syscall(struct pt_regs *regs) { }
#endif /* !CONFIG_DEBUG_RSEQ */
#endif /* _LINUX_RSEQ_H */
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