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https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git
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4b7de6df20
In preparation for rewriting RSEQ exit to user space handling provide storage to cache the CPU ID and MM CID values which were written to user space. That prepares for a quick check, which avoids the update when nothing changed. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://patch.msgid.link/20251027084306.841964081@linutronix.de
99 lines
2.8 KiB
C
99 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
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#ifndef _LINUX_RSEQ_H
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#define _LINUX_RSEQ_H
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#ifdef CONFIG_RSEQ
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#include <linux/sched.h>
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void __rseq_handle_notify_resume(struct ksignal *sig, struct pt_regs *regs);
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static inline void rseq_handle_notify_resume(struct pt_regs *regs)
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{
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if (current->rseq.event.has_rseq)
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__rseq_handle_notify_resume(NULL, regs);
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}
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static inline void rseq_signal_deliver(struct ksignal *ksig, struct pt_regs *regs)
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{
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if (current->rseq.event.has_rseq) {
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current->rseq.event.sched_switch = true;
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__rseq_handle_notify_resume(ksig, regs);
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}
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}
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static inline void rseq_sched_switch_event(struct task_struct *t)
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{
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if (t->rseq.event.has_rseq) {
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t->rseq.event.sched_switch = true;
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set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
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}
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}
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static __always_inline void rseq_exit_to_user_mode(void)
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{
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if (IS_ENABLED(CONFIG_DEBUG_RSEQ)) {
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if (WARN_ON_ONCE(current->rseq.event.has_rseq &&
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current->rseq.event.events))
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current->rseq.event.events = 0;
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}
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}
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/*
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* KVM/HYPERV invoke resume_user_mode_work() before entering guest mode,
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* which clears TIF_NOTIFY_RESUME. To avoid updating user space RSEQ in
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* that case just to do it eventually again before returning to user space,
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* the entry resume_user_mode_work() invocation is ignored as the register
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* argument is NULL.
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*
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* After returning from guest mode, they have to invoke this function to
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* re-raise TIF_NOTIFY_RESUME if necessary.
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*/
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static inline void rseq_virt_userspace_exit(void)
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{
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if (current->rseq.event.sched_switch)
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set_tsk_thread_flag(current, TIF_NOTIFY_RESUME);
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}
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static inline void rseq_reset(struct task_struct *t)
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{
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memset(&t->rseq, 0, sizeof(t->rseq));
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t->rseq.ids.cpu_cid = ~0ULL;
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}
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static inline void rseq_execve(struct task_struct *t)
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{
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rseq_reset(t);
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}
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/*
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* If parent process has a registered restartable sequences area, the
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* child inherits. Unregister rseq for a clone with CLONE_VM set.
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*/
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static inline void rseq_fork(struct task_struct *t, u64 clone_flags)
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{
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if (clone_flags & CLONE_VM) {
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rseq_reset(t);
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} else {
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t->rseq = current->rseq;
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t->rseq.ids.cpu_cid = ~0ULL;
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}
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}
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#else /* CONFIG_RSEQ */
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static inline void rseq_handle_notify_resume(struct pt_regs *regs) { }
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static inline void rseq_signal_deliver(struct ksignal *ksig, struct pt_regs *regs) { }
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static inline void rseq_sched_switch_event(struct task_struct *t) { }
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static inline void rseq_virt_userspace_exit(void) { }
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static inline void rseq_fork(struct task_struct *t, u64 clone_flags) { }
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static inline void rseq_execve(struct task_struct *t) { }
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static inline void rseq_exit_to_user_mode(void) { }
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#endif /* !CONFIG_RSEQ */
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#ifdef CONFIG_DEBUG_RSEQ
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void rseq_syscall(struct pt_regs *regs);
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#else /* CONFIG_DEBUG_RSEQ */
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static inline void rseq_syscall(struct pt_regs *regs) { }
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#endif /* !CONFIG_DEBUG_RSEQ */
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#endif /* _LINUX_RSEQ_H */
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