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-rw-r--r--arch/mn10300/kernel/switch_to.S71
1 files changed, 71 insertions, 0 deletions
diff --git a/arch/mn10300/kernel/switch_to.S b/arch/mn10300/kernel/switch_to.S
new file mode 100644
index 000000000000..630aad71b946
--- /dev/null
+++ b/arch/mn10300/kernel/switch_to.S
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+###############################################################################
+#
+# MN10300 Context switch operation
+#
+# Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+# Written by David Howells (dhowells@redhat.com)
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public Licence
+# as published by the Free Software Foundation; either version
+# 2 of the Licence, or (at your option) any later version.
+#
+###############################################################################
+#include <linux/sys.h>
+#include <linux/linkage.h>
+#include <asm/thread_info.h>
+#include <asm/cpu-regs.h>
+
+ .text
+
+###############################################################################
+#
+# struct task_struct *__switch_to(struct thread_struct *prev,
+# struct thread_struct *next,
+# struct task_struct *prev_task)
+#
+###############################################################################
+ENTRY(__switch_to)
+ movm [d2,d3,a2,a3,exreg1],(sp)
+ or EPSW_NMID,epsw
+
+ mov (44,sp),d2
+
+ mov d0,a0
+ mov d1,a1
+
+ # save prev context
+ mov (__frame),d0
+ mov d0,(THREAD_FRAME,a0)
+ mov __switch_back,d0
+ mov d0,(THREAD_PC,a0)
+ mov sp,a2
+ mov a2,(THREAD_SP,a0)
+ mov a3,(THREAD_A3,a0)
+
+ mov (THREAD_A3,a1),a3
+ mov (THREAD_SP,a1),a2
+
+ # switch
+ mov a2,sp
+
+ # load next context
+ GET_THREAD_INFO a2
+ mov a2,(__current_ti)
+ mov (TI_task,a2),a2
+ mov a2,(__current)
+#ifdef CONFIG_MN10300_CURRENT_IN_E2
+ mov a2,e2
+#endif
+
+ mov (THREAD_FRAME,a1),a2
+ mov a2,(__frame)
+ mov (THREAD_PC,a1),a2
+ mov d2,d0 # for ret_from_fork
+ mov d0,a0 # for __switch_to
+
+ jmp (a2)
+
+__switch_back:
+ and ~EPSW_NMID,epsw
+ ret [d2,d3,a2,a3,exreg1],32