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-rw-r--r--arch/loongarch/include/asm/switch_to.h41
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/loongarch/include/asm/switch_to.h b/arch/loongarch/include/asm/switch_to.h
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+++ b/arch/loongarch/include/asm/switch_to.h
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+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_SWITCH_TO_H
+#define _ASM_SWITCH_TO_H
+
+#include <asm/cpu-features.h>
+#include <asm/fpu.h>
+
+struct task_struct;
+
+/**
+ * __switch_to - switch execution of a task
+ * @prev: The task previously executed.
+ * @next: The task to begin executing.
+ * @next_ti: task_thread_info(next).
+ * @sched_ra: __schedule return address.
+ * @sched_cfa: __schedule call frame address.
+ *
+ * This function is used whilst scheduling to save the context of prev & load
+ * the context of next. Returns prev.
+ */
+extern asmlinkage struct task_struct *__switch_to(struct task_struct *prev,
+ struct task_struct *next, struct thread_info *next_ti,
+ void *sched_ra, void *sched_cfa);
+
+/*
+ * For newly created kernel threads switch_to() will return to
+ * ret_from_kernel_thread, newly created user threads to ret_from_fork.
+ * That is, everything following __switch_to() will be skipped for new threads.
+ * So everything that matters to new threads should be placed before __switch_to().
+ */
+#define switch_to(prev, next, last) \
+do { \
+ lose_fpu_inatomic(1, prev); \
+ (last) = __switch_to(prev, next, task_thread_info(next), \
+ __builtin_return_address(0), __builtin_frame_address(0)); \
+} while (0)
+
+#endif /* _ASM_SWITCH_TO_H */