3 files changed, 76 insertions, 37 deletions

diff --git a/include/linux/rseq.h b/include/linux/rseq.h
index c6267f70c746..ab91b1e6bb4a 100644
--- a/include/linux/rseq.h
+++ b/include/linux/rseq.h
@@ -9,22 +9,22 @@ 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)
+	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) {
-		current->rseq_event_pending = true;
+	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) {
-		t->rseq_event_pending = true;
+	if (t->rseq.event.has_rseq) {
+		t->rseq.event.sched_switch = true;
 		set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
 	}
 }
@@ -32,8 +32,9 @@ static inline void rseq_sched_switch_event(struct task_struct *t)
 static __always_inline void rseq_exit_to_user_mode(void)
 {
 	if (IS_ENABLED(CONFIG_DEBUG_RSEQ)) {
-		if (WARN_ON_ONCE(current->rseq && current->rseq_event_pending))
-			current->rseq_event_pending = false;
+		if (WARN_ON_ONCE(current->rseq.event.has_rseq &&
+				 current->rseq.event.events))
+			current->rseq.event.events = 0;
 	}
 }
 
@@ -49,35 +50,30 @@ static __always_inline void rseq_exit_to_user_mode(void)
  */
 static inline void rseq_virt_userspace_exit(void)
 {
-	if (current->rseq_event_pending)
+	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));
+}
+
+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) {
-		t->rseq = NULL;
-		t->rseq_len = 0;
-		t->rseq_sig = 0;
-		t->rseq_event_pending = false;
-	} else {
+	if (clone_flags & CLONE_VM)
+		rseq_reset(t);
+	else
 		t->rseq = current->rseq;
-		t->rseq_len = current->rseq_len;
-		t->rseq_sig = current->rseq_sig;
-		t->rseq_event_pending = current->rseq_event_pending;
-	}
-}
-
-static inline void rseq_execve(struct task_struct *t)
-{
-	t->rseq = NULL;
-	t->rseq_len = 0;
-	t->rseq_sig = 0;
-	t->rseq_event_pending = false;
 }
 
 #else /* CONFIG_RSEQ */
diff --git a/include/linux/rseq_types.h b/include/linux/rseq_types.h
new file mode 100644
index 000000000000..f7a60c8eddc9
--- /dev/null
+++ b/include/linux/rseq_types.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_RSEQ_TYPES_H
+#define _LINUX_RSEQ_TYPES_H
+
+#include <linux/types.h>
+
+#ifdef CONFIG_RSEQ
+struct rseq;
+
+/**
+ * struct rseq_event - Storage for rseq related event management
+ * @all:		Compound to initialize and clear the data efficiently
+ * @events:		Compound to access events with a single load/store
+ * @sched_switch:	True if the task was scheduled out
+ * @has_rseq:		True if the task has a rseq pointer installed
+ */
+struct rseq_event {
+	union {
+		u32				all;
+		struct {
+			union {
+				u16		events;
+				struct {
+					u8	sched_switch;
+				};
+			};
+
+			u8			has_rseq;
+		};
+	};
+};
+
+/**
+ * struct rseq_data - Storage for all rseq related data
+ * @usrptr:	Pointer to the registered user space RSEQ memory
+ * @len:	Length of the RSEQ region
+ * @sig:	Signature of critial section abort IPs
+ * @event:	Storage for event management
+ */
+struct rseq_data {
+	struct rseq __user		*usrptr;
+	u32				len;
+	u32				sig;
+	struct rseq_event		event;
+};
+
+#else /* CONFIG_RSEQ */
+struct rseq_data { };
+#endif /* !CONFIG_RSEQ */
+
+#endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6627c527c2c7..15627769409d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -41,6 +41,7 @@
 #include <linux/task_io_accounting.h>
 #include <linux/posix-timers_types.h>
 #include <linux/restart_block.h>
+#include <linux/rseq_types.h>
 #include <uapi/linux/rseq.h>
 #include <linux/seqlock_types.h>
 #include <linux/kcsan.h>
@@ -1406,16 +1407,8 @@ struct task_struct {
 	unsigned long			numa_pages_migrated;
 #endif /* CONFIG_NUMA_BALANCING */
 
-#ifdef CONFIG_RSEQ
-	struct rseq __user		*rseq;
-	u32				rseq_len;
-	u32				rseq_sig;
-	/*
-	 * RmW on rseq_event_pending must be performed atomically
-	 * with respect to preemption.
-	 */
-	bool				rseq_event_pending;
-# ifdef CONFIG_DEBUG_RSEQ
+	struct rseq_data		rseq;
+#ifdef CONFIG_DEBUG_RSEQ
 	/*
 	 * This is a place holder to save a copy of the rseq fields for
 	 * validation of read-only fields. The struct rseq has a
@@ -1423,7 +1416,6 @@ struct task_struct {
 	 * directly. Reserve a size large enough for the known fields.
 	 */
 	char				rseq_fields[sizeof(struct rseq)];
-# endif
 #endif
 
 #ifdef CONFIG_SCHED_MM_CID