Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 44 insertions, 0 deletions

diff --git a/arch/loongarch/include/asm/switch_to.h b/arch/loongarch/include/asm/switch_to.h
new file mode 100644
index 0000000000..5b225aff3b
--- /dev/null
+++ b/arch/loongarch/include/asm/switch_to.h
@@ -0,0 +1,44 @@
+/* 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>
+#include <asm/lbt.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);						\
+	lose_lbt_inatomic(1, prev);						\
+	hw_breakpoint_thread_switch(next);					\
+	(last) = __switch_to(prev, next, task_thread_info(next),		\
+		 __builtin_return_address(0), __builtin_frame_address(0));	\
+} while (0)
+
+#endif /* _ASM_SWITCH_TO_H */