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bf90e1ea VG |
1 | /* |
2 | * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * Vineetg: Aug 2009 | |
9 | * -Moved core context switch macro out of entry.S into this file. | |
10 | * -This is the more "natural" hand written assembler | |
11 | */ | |
12 | ||
13 | #include <asm/entry.h> /* For the SAVE_* macros */ | |
14 | #include <asm/asm-offsets.h> | |
15 | #include <asm/linkage.h> | |
16 | ||
17 | ;################### Low Level Context Switch ########################## | |
18 | ||
19 | .section .sched.text,"ax",@progbits | |
20 | .align 4 | |
21 | .global __switch_to | |
22 | .type __switch_to, @function | |
23 | __switch_to: | |
24 | ||
25 | /* Save regs on kernel mode stack of task */ | |
26 | st.a blink, [sp, -4] | |
27 | st.a fp, [sp, -4] | |
28 | SAVE_CALLEE_SAVED_KERNEL | |
29 | ||
30 | /* Save the now KSP in task->thread.ksp */ | |
31 | st.as sp, [r0, (TASK_THREAD + THREAD_KSP)/4] | |
32 | ||
33 | /* | |
34 | * Return last task in r0 (return reg) | |
35 | * On ARC, Return reg = First Arg reg = r0. | |
36 | * Since we already have last task in r0, | |
37 | * don't need to do anything special to return it | |
38 | */ | |
39 | ||
40 | /* hardware memory barrier */ | |
41 | sync | |
42 | ||
43 | /* | |
44 | * switch to new task, contained in r1 | |
45 | * Temp reg r3 is required to get the ptr to store val | |
46 | */ | |
47 | SET_CURR_TASK_ON_CPU r1, r3 | |
48 | ||
49 | /* reload SP with kernel mode stack pointer in task->thread.ksp */ | |
50 | ld.as sp, [r1, (TASK_THREAD + THREAD_KSP)/4] | |
51 | ||
52 | /* restore the registers */ | |
53 | RESTORE_CALLEE_SAVED_KERNEL | |
54 | ld.ab fp, [sp, 4] | |
55 | ld.ab blink, [sp, 4] | |
56 | j [blink] | |
57 | ||
58 | ARC_EXIT __switch_to |