MN10300: Save frame pointer in thread_info struct rather than global var
[linux-2.6-block.git] / arch / mn10300 / kernel / switch_to.S
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1###############################################################################
2#
3# MN10300 Context switch operation
4#
5# Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
6# Written by David Howells (dhowells@redhat.com)
7#
8# This program is free software; you can redistribute it and/or
9# modify it under the terms of the GNU General Public Licence
10# as published by the Free Software Foundation; either version
11# 2 of the Licence, or (at your option) any later version.
12#
13###############################################################################
14#include <linux/sys.h>
15#include <linux/linkage.h>
16#include <asm/thread_info.h>
17#include <asm/cpu-regs.h>
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18#ifdef CONFIG_SMP
19#include <proc/smp-regs.h>
20#endif /* CONFIG_SMP */
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21
22 .text
23
24###############################################################################
25#
26# struct task_struct *__switch_to(struct thread_struct *prev,
27# struct thread_struct *next,
28# struct task_struct *prev_task)
29#
30###############################################################################
31ENTRY(__switch_to)
32 movm [d2,d3,a2,a3,exreg1],(sp)
33 or EPSW_NMID,epsw
34
35 mov (44,sp),d2
36
37 mov d0,a0
38 mov d1,a1
39
40 # save prev context
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41 mov __switch_back,d0
42 mov d0,(THREAD_PC,a0)
43 mov sp,a2
44 mov a2,(THREAD_SP,a0)
45 mov a3,(THREAD_A3,a0)
46
47 mov (THREAD_A3,a1),a3
48 mov (THREAD_SP,a1),a2
49
50 # switch
51 mov a2,sp
52
53 # load next context
54 GET_THREAD_INFO a2
55 mov a2,(__current_ti)
56 mov (TI_task,a2),a2
57 mov a2,(__current)
58#ifdef CONFIG_MN10300_CURRENT_IN_E2
59 mov a2,e2
60#endif
61
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62 mov (THREAD_PC,a1),a2
63 mov d2,d0 # for ret_from_fork
64 mov d0,a0 # for __switch_to
65
66 jmp (a2)
67
68__switch_back:
69 and ~EPSW_NMID,epsw
70 ret [d2,d3,a2,a3,exreg1],32