rseq: Split out rseq.h from sched.h

We're trying to get sched.h down to more or less just types only, not
code - rseq can live in its own header.

This helps us kill the dependency on preempt.h in sched.h.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

arch/arm64/kernel/ptrace.c

@@ -28,6 +28,7 @@
 #include <linux/hw_breakpoint.h>
 #include <linux/regset.h>
 #include <linux/elf.h>
+#include <linux/rseq.h>
 
 #include <asm/compat.h>
 #include <asm/cpufeature.h>

arch/powerpc/kernel/interrupt.c

@@ -3,6 +3,7 @@
 #include <linux/context_tracking.h>
 #include <linux/err.h>
 #include <linux/compat.h>
+#include <linux/rseq.h>
 #include <linux/sched/debug.h> /* for show_regs */
 
 #include <asm/kup.h>

arch/s390/kernel/signal.c

@@ -12,6 +12,7 @@
 
 #include <linux/sched.h>
 #include <linux/sched/task_stack.h>
+#include <linux/rseq.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
 #include <linux/kernel.h>

arch/x86/kernel/signal.c

@@ -27,6 +27,7 @@
 #include <linux/context_tracking.h>
 #include <linux/entry-common.h>
 #include <linux/syscalls.h>
+#include <linux/rseq.h>
 
 #include <asm/processor.h>
 #include <asm/ucontext.h>

fs/exec.c

@@ -66,6 +66,7 @@
 #include <linux/coredump.h>
 #include <linux/time_namespace.h>
 #include <linux/user_events.h>
+#include <linux/rseq.h>
 
 #include <linux/uaccess.h>
 #include <asm/mmu_context.h>

include/linux/resume_user_mode.h

@@ -6,6 +6,7 @@
 #include <linux/sched.h>
 #include <linux/task_work.h>
 #include <linux/memcontrol.h>
+#include <linux/rseq.h>
 #include <linux/blk-cgroup.h>
 
 /**

include/linux/rseq.h

+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+#ifndef _LINUX_RSEQ_H
+#define _LINUX_RSEQ_H
+
+#ifdef CONFIG_RSEQ
+
+#include <linux/preempt.h>
+#include <linux/sched.h>
+
+/*
+ * Map the event mask on the user-space ABI enum rseq_cs_flags
+ * for direct mask checks.
+ */
+enum rseq_event_mask_bits {
+	RSEQ_EVENT_PREEMPT_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT,
+	RSEQ_EVENT_SIGNAL_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT,
+	RSEQ_EVENT_MIGRATE_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT,
+};
+
+enum rseq_event_mask {
+	RSEQ_EVENT_PREEMPT	= (1U << RSEQ_EVENT_PREEMPT_BIT),
+	RSEQ_EVENT_SIGNAL	= (1U << RSEQ_EVENT_SIGNAL_BIT),
+	RSEQ_EVENT_MIGRATE	= (1U << RSEQ_EVENT_MIGRATE_BIT),
+};
+
+static inline void rseq_set_notify_resume(struct task_struct *t)
+{
+	if (t->rseq)
+		set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
+}
+
+void __rseq_handle_notify_resume(struct ksignal *sig, struct pt_regs *regs);
+
+static inline void rseq_handle_notify_resume(struct ksignal *ksig,
+					     struct pt_regs *regs)
+{
+	if (current->rseq)
+		__rseq_handle_notify_resume(ksig, regs);
+}
+
+static inline void rseq_signal_deliver(struct ksignal *ksig,
+				       struct pt_regs *regs)
+{
+	preempt_disable();
+	__set_bit(RSEQ_EVENT_SIGNAL_BIT, &current->rseq_event_mask);
+	preempt_enable();
+	rseq_handle_notify_resume(ksig, regs);
+}
+
+/* rseq_preempt() requires preemption to be disabled. */
+static inline void rseq_preempt(struct task_struct *t)
+{
+	__set_bit(RSEQ_EVENT_PREEMPT_BIT, &t->rseq_event_mask);
+	rseq_set_notify_resume(t);
+}
+
+/* rseq_migrate() requires preemption to be disabled. */
+static inline void rseq_migrate(struct task_struct *t)
+{
+	__set_bit(RSEQ_EVENT_MIGRATE_BIT, &t->rseq_event_mask);
+	rseq_set_notify_resume(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, unsigned long clone_flags)
+{
+	if (clone_flags & CLONE_VM) {
+		t->rseq = NULL;
+		t->rseq_len = 0;
+		t->rseq_sig = 0;
+		t->rseq_event_mask = 0;
+	} else {
+		t->rseq = current->rseq;
+		t->rseq_len = current->rseq_len;
+		t->rseq_sig = current->rseq_sig;
+		t->rseq_event_mask = current->rseq_event_mask;
+	}
+}
+
+static inline void rseq_execve(struct task_struct *t)
+{
+	t->rseq = NULL;
+	t->rseq_len = 0;
+	t->rseq_sig = 0;
+	t->rseq_event_mask = 0;
+}
+
+#else
+
+static inline void rseq_set_notify_resume(struct task_struct *t)
+{
+}
+static inline void rseq_handle_notify_resume(struct ksignal *ksig,
+					     struct pt_regs *regs)
+{
+}
+static inline void rseq_signal_deliver(struct ksignal *ksig,
+				       struct pt_regs *regs)
+{
+}
+static inline void rseq_preempt(struct task_struct *t)
+{
+}
+static inline void rseq_migrate(struct task_struct *t)
+{
+}
+static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
+{
+}
+static inline void rseq_execve(struct task_struct *t)
+{
+}
+
+#endif
+
+#ifdef CONFIG_DEBUG_RSEQ
+
+void rseq_syscall(struct pt_regs *regs);
+
+#else
+
+static inline void rseq_syscall(struct pt_regs *regs)
+{
+}
+
+#endif
+
+#endif /* _LINUX_RSEQ_H */

include/linux/sched.h

@@ -35,7 +35,7 @@
 #include <linux/task_io_accounting.h>
 #include <linux/posix-timers_types.h>
 #include <linux/restart_block.h>
-#include <linux/rseq.h>
+#include <uapi/linux/rseq.h>
 #include <linux/seqlock_types.h>
 #include <linux/kcsan.h>
 #include <linux/rv.h>
@@ -2181,129 +2181,6 @@ static inline bool owner_on_cpu(struct task_struct *owner)
 unsigned long sched_cpu_util(int cpu);
 #endif /* CONFIG_SMP */
 
-#ifdef CONFIG_RSEQ
-
-/*
- * Map the event mask on the user-space ABI enum rseq_cs_flags
- * for direct mask checks.
- */
-enum rseq_event_mask_bits {
-	RSEQ_EVENT_PREEMPT_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT,
-	RSEQ_EVENT_SIGNAL_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT,
-	RSEQ_EVENT_MIGRATE_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT,
-};
-
-enum rseq_event_mask {
-	RSEQ_EVENT_PREEMPT	= (1U << RSEQ_EVENT_PREEMPT_BIT),
-	RSEQ_EVENT_SIGNAL	= (1U << RSEQ_EVENT_SIGNAL_BIT),
-	RSEQ_EVENT_MIGRATE	= (1U << RSEQ_EVENT_MIGRATE_BIT),
-};
-
-static inline void rseq_set_notify_resume(struct task_struct *t)
-{
-	if (t->rseq)
-		set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
-}
-
-void __rseq_handle_notify_resume(struct ksignal *sig, struct pt_regs *regs);
-
-static inline void rseq_handle_notify_resume(struct ksignal *ksig,
-					     struct pt_regs *regs)
-{
-	if (current->rseq)
-		__rseq_handle_notify_resume(ksig, regs);
-}
-
-static inline void rseq_signal_deliver(struct ksignal *ksig,
-				       struct pt_regs *regs)
-{
-	preempt_disable();
-	__set_bit(RSEQ_EVENT_SIGNAL_BIT, &current->rseq_event_mask);
-	preempt_enable();
-	rseq_handle_notify_resume(ksig, regs);
-}
-
-/* rseq_preempt() requires preemption to be disabled. */
-static inline void rseq_preempt(struct task_struct *t)
-{
-	__set_bit(RSEQ_EVENT_PREEMPT_BIT, &t->rseq_event_mask);
-	rseq_set_notify_resume(t);
-}
-
-/* rseq_migrate() requires preemption to be disabled. */
-static inline void rseq_migrate(struct task_struct *t)
-{
-	__set_bit(RSEQ_EVENT_MIGRATE_BIT, &t->rseq_event_mask);
-	rseq_set_notify_resume(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, unsigned long clone_flags)
-{
-	if (clone_flags & CLONE_VM) {
-		t->rseq = NULL;
-		t->rseq_len = 0;
-		t->rseq_sig = 0;
-		t->rseq_event_mask = 0;
-	} else {
-		t->rseq = current->rseq;
-		t->rseq_len = current->rseq_len;
-		t->rseq_sig = current->rseq_sig;
-		t->rseq_event_mask = current->rseq_event_mask;
-	}
-}
-
-static inline void rseq_execve(struct task_struct *t)
-{
-	t->rseq = NULL;
-	t->rseq_len = 0;
-	t->rseq_sig = 0;
-	t->rseq_event_mask = 0;
-}
-
-#else
-
-static inline void rseq_set_notify_resume(struct task_struct *t)
-{
-}
-static inline void rseq_handle_notify_resume(struct ksignal *ksig,
-					     struct pt_regs *regs)
-{
-}
-static inline void rseq_signal_deliver(struct ksignal *ksig,
-				       struct pt_regs *regs)
-{
-}
-static inline void rseq_preempt(struct task_struct *t)
-{
-}
-static inline void rseq_migrate(struct task_struct *t)
-{
-}
-static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
-{
-}
-static inline void rseq_execve(struct task_struct *t)
-{
-}
-
-#endif
-
-#ifdef CONFIG_DEBUG_RSEQ
-
-void rseq_syscall(struct pt_regs *regs);
-
-#else
-
-static inline void rseq_syscall(struct pt_regs *regs)
-{
-}
-
-#endif
-
 #ifdef CONFIG_SCHED_CORE
 extern void sched_core_free(struct task_struct *tsk);
 extern void sched_core_fork(struct task_struct *p);

kernel/fork.c

@@ -100,6 +100,7 @@
 #include <linux/stackprotector.h>
 #include <linux/user_events.h>
 #include <linux/iommu.h>
+#include <linux/rseq.h>
 
 #include <asm/pgalloc.h>
 #include <linux/uaccess.h>

kernel/sched/core.c

@@ -57,6 +57,7 @@
 #include <linux/profile.h>
 #include <linux/psi.h>
 #include <linux/rcuwait_api.h>
+#include <linux/rseq.h>
 #include <linux/sched/wake_q.h>
 #include <linux/scs.h>
 #include <linux/slab.h>