diff options
Diffstat (limited to 'arch/arc/kernel/ctx_sw_asm.S')
| -rw-r--r-- | arch/arc/kernel/ctx_sw_asm.S | 76 |
1 files changed, 41 insertions, 35 deletions
diff --git a/arch/arc/kernel/ctx_sw_asm.S b/arch/arc/kernel/ctx_sw_asm.S index d8972345e4c2..48e1f21976ed 100644 --- a/arch/arc/kernel/ctx_sw_asm.S +++ b/arch/arc/kernel/ctx_sw_asm.S @@ -1,58 +1,64 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * * Vineetg: Aug 2009 * -Moved core context switch macro out of entry.S into this file. * -This is the more "natural" hand written assembler */ +#include <linux/linkage.h> #include <asm/entry.h> /* For the SAVE_* macros */ #include <asm/asm-offsets.h> -#include <asm/linkage.h> -;################### Low Level Context Switch ########################## +; IN +; - r0: prev task (also current) +; - r1: next task +; OUT +; - r0: prev task (so r0 not touched) .section .sched.text,"ax",@progbits - .align 4 - .global __switch_to - .type __switch_to, @function -__switch_to: - - /* Save regs on kernel mode stack of task */ - st.a blink, [sp, -4] - st.a fp, [sp, -4] - SAVE_CALLEE_SAVED_KERNEL +ENTRY_CFI(__switch_to) - /* Save the now KSP in task->thread.ksp */ - st.as sp, [r0, (TASK_THREAD + THREAD_KSP)/4] + /* save kernel stack frame regs of @prev task */ + push blink + CFI_DEF_CFA_OFFSET 4 + CFI_OFFSET r31, -4 - /* - * Return last task in r0 (return reg) - * On ARC, Return reg = First Arg reg = r0. - * Since we already have last task in r0, - * don't need to do anything special to return it - */ + push fp + CFI_DEF_CFA_OFFSET 8 + CFI_OFFSET r27, -8 + + mov fp, sp + CFI_DEF_CFA_REGISTER r27 - /* hardware memory barrier */ - sync + /* kernel mode callee regs of @prev */ + SAVE_CALLEE_SAVED_KERNEL /* - * switch to new task, contained in r1 - * Temp reg r3 is required to get the ptr to store val + * save final SP to @prev->thread_info.ksp + * @prev is "current" so thread_info derived from SP */ - SET_CURR_TASK_ON_CPU r1, r3 + GET_CURR_THR_INFO_FROM_SP r10 + st sp, [r10, THREAD_INFO_KSP] + + /* update @next in _current_task[] and GP register caching it */ + SET_CURR_TASK_ON_CPU r1, r10 - /* reload SP with kernel mode stack pointer in task->thread.ksp */ - ld.as sp, [r1, (TASK_THREAD + THREAD_KSP)/4] + /* load SP from @next->thread_info.ksp */ + ld r10, [r1, TASK_THREAD_INFO] + ld sp, [r10, THREAD_INFO_KSP] - /* restore the registers */ + /* restore callee regs, stack frame regs of @next */ RESTORE_CALLEE_SAVED_KERNEL - ld.ab fp, [sp, 4] - ld.ab blink, [sp, 4] - j [blink] -ARC_EXIT __switch_to + pop fp + CFI_RESTORE r27 + CFI_DEF_CFA r28, 4 + + pop blink + CFI_RESTORE r31 + CFI_DEF_CFA_OFFSET 0 + + j [blink] +END_CFI(__switch_to) |