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Diffstat (limited to 'arch/arm64/include/asm/preempt.h')
-rw-r--r--arch/arm64/include/asm/preempt.h89
1 files changed, 89 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/preempt.h b/arch/arm64/include/asm/preempt.h
new file mode 100644
index 000000000000..d49951647014
--- /dev/null
+++ b/arch/arm64/include/asm/preempt.h
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_PREEMPT_H
+#define __ASM_PREEMPT_H
+
+#include <linux/thread_info.h>
+
+#define PREEMPT_NEED_RESCHED BIT(32)
+#define PREEMPT_ENABLED (PREEMPT_NEED_RESCHED)
+
+static inline int preempt_count(void)
+{
+ return READ_ONCE(current_thread_info()->preempt.count);
+}
+
+static inline void preempt_count_set(u64 pc)
+{
+ /* Preserve existing value of PREEMPT_NEED_RESCHED */
+ WRITE_ONCE(current_thread_info()->preempt.count, pc);
+}
+
+#define init_task_preempt_count(p) do { \
+ task_thread_info(p)->preempt_count = FORK_PREEMPT_COUNT; \
+} while (0)
+
+#define init_idle_preempt_count(p, cpu) do { \
+ task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \
+} while (0)
+
+static inline void set_preempt_need_resched(void)
+{
+ current_thread_info()->preempt.need_resched = 0;
+}
+
+static inline void clear_preempt_need_resched(void)
+{
+ current_thread_info()->preempt.need_resched = 1;
+}
+
+static inline bool test_preempt_need_resched(void)
+{
+ return !current_thread_info()->preempt.need_resched;
+}
+
+static inline void __preempt_count_add(int val)
+{
+ u32 pc = READ_ONCE(current_thread_info()->preempt.count);
+ pc += val;
+ WRITE_ONCE(current_thread_info()->preempt.count, pc);
+}
+
+static inline void __preempt_count_sub(int val)
+{
+ u32 pc = READ_ONCE(current_thread_info()->preempt.count);
+ pc -= val;
+ WRITE_ONCE(current_thread_info()->preempt.count, pc);
+}
+
+static inline bool __preempt_count_dec_and_test(void)
+{
+ struct thread_info *ti = current_thread_info();
+ u64 pc = READ_ONCE(ti->preempt_count);
+
+ /* Update only the count field, leaving need_resched unchanged */
+ WRITE_ONCE(ti->preempt.count, --pc);
+
+ /*
+ * If we wrote back all zeroes, then we're preemptible and in
+ * need of a reschedule. Otherwise, we need to reload the
+ * preempt_count in case the need_resched flag was cleared by an
+ * interrupt occurring between the non-atomic READ_ONCE/WRITE_ONCE
+ * pair.
+ */
+ return !pc || !READ_ONCE(ti->preempt_count);
+}
+
+static inline bool should_resched(int preempt_offset)
+{
+ u64 pc = READ_ONCE(current_thread_info()->preempt_count);
+ return pc == preempt_offset;
+}
+
+#ifdef CONFIG_PREEMPT
+void preempt_schedule(void);
+#define __preempt_schedule() preempt_schedule()
+void preempt_schedule_notrace(void);
+#define __preempt_schedule_notrace() preempt_schedule_notrace()
+#endif /* CONFIG_PREEMPT */
+
+#endif /* __ASM_PREEMPT_H */