ARC: [plat-eznps] handle extra aux regs #1: save/restore on context switch

save EFLAGS, and GPA1 auxiliary registers during context switch,
since they may be changed by the new task in kernel mode, while using atomic
ops e.g. cmpxchg.

Signed-off-by: Noam Camus <noamc@ezchip.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/arch/arc/plat-eznps/ctop.c b/arch/arc/plat-eznps/ctop.c
new file mode 100644
index 000000000000..030bcd070a1b
--- /dev/null
+++ b/arch/arc/plat-eznps/ctop.c
@@ -0,0 +1,32 @@
+/*
+ * Copyright(c) 2015 EZchip Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * The full GNU General Public License is included in this distribution in
+ * the file called "COPYING".
+ */
+
+#include <linux/sched.h>
+#include <asm/processor.h>
+#include <plat/ctop.h>
+
+void dp_save_restore(struct task_struct *prev, struct task_struct *next)
+{
+	struct eznps_dp *prev_task_dp = &prev->thread.dp;
+	struct eznps_dp *next_task_dp = &next->thread.dp;
+
+	/* Here we save all Data Plane related auxiliary registers */
+	prev_task_dp->eflags = read_aux_reg(CTOP_AUX_EFLAGS);
+	write_aux_reg(CTOP_AUX_EFLAGS, next_task_dp->eflags);
+
+	prev_task_dp->gpa1 = read_aux_reg(CTOP_AUX_GPA1);
+	write_aux_reg(CTOP_AUX_GPA1, next_task_dp->gpa1);
+}