| 1 | /* SPDX-License-Identifier: GPL-2.0-only */
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| 2 | /*
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| 3 | * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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| 4 | *
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| 5 | * Vineetg: Aug 2009
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| 6 | * -Moved core context switch macro out of entry.S into this file.
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| 7 | * -This is the more "natural" hand written assembler
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| 8 | */
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| 9 |
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| 10 | |
| 11 | |
| 12 | |
| 13 |
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| 14 | ; IN
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| 15 | ; - r0: prev task (also current)
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| 16 | ; - r1: next task
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| 17 | ; OUT
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| 18 | ; - r0: prev task (so r0 not touched)
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| 19 |
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| 20 | .section .sched.text,"ax",@progbits
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| 21 | ENTRY_CFI(__switch_to)
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| 22 |
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| 23 | /* save kernel stack frame regs of @prev task */
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| 24 | push blink
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| 25 | CFI_DEF_CFA_OFFSET 4
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| 26 | CFI_OFFSET r31, -4
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| 27 |
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| 28 | push fp
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| 29 | CFI_DEF_CFA_OFFSET 8
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| 30 | CFI_OFFSET r27, -8
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| 31 |
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| 32 | mov fp, sp
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| 33 | CFI_DEF_CFA_REGISTER r27
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| 34 |
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| 35 | /* kernel mode callee regs of @prev */
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| 36 | SAVE_CALLEE_SAVED_KERNEL
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| 37 |
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| 38 | /*
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| 39 | * save final SP to @prev->thread_info.ksp
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| 40 | * @prev is "current" so thread_info derived from SP
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| 41 | */
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| 42 | GET_CURR_THR_INFO_FROM_SP r10
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| 43 | st sp, [r10, THREAD_INFO_KSP]
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| 44 |
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| 45 | /* update @next in _current_task[] and GP register caching it */
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| 46 | SET_CURR_TASK_ON_CPU r1, r10
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| 47 |
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| 48 | /* load SP from @next->thread_info.ksp */
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| 49 | ld r10, [r1, TASK_THREAD_INFO]
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| 50 | ld sp, [r10, THREAD_INFO_KSP]
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| 51 |
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| 52 | /* restore callee regs, stack frame regs of @next */
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| 53 | RESTORE_CALLEE_SAVED_KERNEL
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| 54 |
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| 55 | pop fp
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| 56 | CFI_RESTORE r27
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| 57 | CFI_DEF_CFA r28, 4
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| 58 |
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| 59 | pop blink
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| 60 | CFI_RESTORE r31
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| 61 | CFI_DEF_CFA_OFFSET 0
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| 62 |
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| 63 | j [blink]
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| 64 | END_CFI(__switch_to)
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