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60 lines
1.5 KiB
60 lines
1.5 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) |
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* |
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* Vineetg: Aug 2009 |
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* -Moved core context switch macro out of entry.S into this file. |
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* -This is the more "natural" hand written assembler |
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*/ |
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#include <linux/linkage.h> |
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#include <asm/entry.h> /* For the SAVE_* macros */ |
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#include <asm/asm-offsets.h> |
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#define KSP_WORD_OFF ((TASK_THREAD + THREAD_KSP) / 4) |
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;################### Low Level Context Switch ########################## |
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.section .sched.text,"ax",@progbits |
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.align 4 |
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.global __switch_to |
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.type __switch_to, @function |
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__switch_to: |
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CFI_STARTPROC |
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/* Save regs on kernel mode stack of task */ |
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st.a blink, [sp, -4] |
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st.a fp, [sp, -4] |
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SAVE_CALLEE_SAVED_KERNEL |
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/* Save the now KSP in task->thread.ksp */ |
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#if KSP_WORD_OFF <= 255 |
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st.as sp, [r0, KSP_WORD_OFF] |
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#else |
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/* Workaround for NR_CPUS=4k as ST.as can only take s9 offset */ |
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add2 r24, r0, KSP_WORD_OFF |
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st sp, [r24] |
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#endif |
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/* |
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* Return last task in r0 (return reg) |
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* On ARC, Return reg = First Arg reg = r0. |
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* Since we already have last task in r0, |
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* don't need to do anything special to return it |
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*/ |
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/* |
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* switch to new task, contained in r1 |
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* Temp reg r3 is required to get the ptr to store val |
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*/ |
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SET_CURR_TASK_ON_CPU r1, r3 |
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/* reload SP with kernel mode stack pointer in task->thread.ksp */ |
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ld.as sp, [r1, (TASK_THREAD + THREAD_KSP)/4] |
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/* restore the registers */ |
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RESTORE_CALLEE_SAVED_KERNEL |
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ld.ab fp, [sp, 4] |
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ld.ab blink, [sp, 4] |
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j [blink] |
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END_CFI(__switch_to)
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