Adding upstream version 4.19.249.upstream/4.19.249

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

1 files changed, 32 insertions, 0 deletions

diff --git a/arch/arm/include/asm/switch_to.h b/arch/arm/include/asm/switch_to.h
new file mode 100644
index 000000000..d3e937dce
--- /dev/null
+++ b/arch/arm/include/asm/switch_to.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_ARM_SWITCH_TO_H
+#define __ASM_ARM_SWITCH_TO_H
+
+#include <linux/thread_info.h>
+
+/*
+ * For v7 SMP cores running a preemptible kernel we may be pre-empted
+ * during a TLB maintenance operation, so execute an inner-shareable dsb
+ * to ensure that the maintenance completes in case we migrate to another
+ * CPU.
+ */
+#if defined(CONFIG_PREEMPT) && defined(CONFIG_SMP) && defined(CONFIG_CPU_V7)
+#define __complete_pending_tlbi()	dsb(ish)
+#else
+#define __complete_pending_tlbi()
+#endif
+
+/*
+ * switch_to(prev, next) should switch from task `prev' to `next'
+ * `prev' will never be the same as `next'.  schedule() itself
+ * contains the memory barrier to tell GCC not to cache `current'.
+ */
+extern struct task_struct *__switch_to(struct task_struct *, struct thread_info *, struct thread_info *);
+
+#define switch_to(prev,next,last)					\
+do {									\
+	__complete_pending_tlbi();					\
+	last = __switch_to(prev,task_thread_info(prev), task_thread_info(next));	\
+} while (0)
+
+#endif /* __ASM_ARM_SWITCH_TO_H */