diff options
Diffstat (limited to 'arch/mn10300/kernel/switch_to.S')
| -rw-r--r-- | arch/mn10300/kernel/switch_to.S | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/arch/mn10300/kernel/switch_to.S b/arch/mn10300/kernel/switch_to.S new file mode 100644 index 00000000..de3e74fc --- /dev/null +++ b/arch/mn10300/kernel/switch_to.S @@ -0,0 +1,179 @@ +############################################################################### +# +# MN10300 Context switch operation +# +# Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. +# Written by David Howells (dhowells@redhat.com) +# +# This program is free software; you can redistribute it and/or +# modify it under the terms of the GNU General Public Licence +# as published by the Free Software Foundation; either version +# 2 of the Licence, or (at your option) any later version. +# +############################################################################### +#include <linux/sys.h> +#include <linux/linkage.h> +#include <asm/thread_info.h> +#include <asm/cpu-regs.h> +#ifdef CONFIG_SMP +#include <proc/smp-regs.h> +#endif /* CONFIG_SMP */ + + .text + +############################################################################### +# +# struct task_struct *__switch_to(struct thread_struct *prev, +# struct thread_struct *next, +# struct task_struct *prev_task) +# +############################################################################### +ENTRY(__switch_to) + movm [d2,d3,a2,a3,exreg1],(sp) + or EPSW_NMID,epsw + + mov (44,sp),d2 + + mov d0,a0 + mov d1,a1 + + # save prev context + mov __switch_back,d0 + mov sp,a2 + mov a2,(THREAD_SP,a0) + mov a3,(THREAD_A3,a0) + +#ifdef CONFIG_KGDB + btst 0xff,(kgdb_single_step) + bne __switch_to__lift_sstep_bp +__switch_to__continue: +#endif + mov d0,(THREAD_PC,a0) + + mov (THREAD_A3,a1),a3 + mov (THREAD_SP,a1),a2 + + # switch + mov a2,sp + + # load next context + GET_THREAD_INFO a2 + mov a2,(__current_ti) + mov (TI_task,a2),a2 + mov a2,(__current) +#ifdef CONFIG_MN10300_CURRENT_IN_E2 + mov a2,e2 +#endif + + mov (THREAD_PC,a1),a2 + mov d2,d0 # for ret_from_fork + mov d0,a0 # for __switch_to + + jmp (a2) + +__switch_back: + and ~EPSW_NMID,epsw + ret [d2,d3,a2,a3,exreg1],32 + +#ifdef CONFIG_KGDB +############################################################################### +# +# Lift the single-step breakpoints when the task being traced is switched out +# A0 = prev +# A1 = next +# +############################################################################### +__switch_to__lift_sstep_bp: + add -12,sp + mov a0,e4 + mov a1,e5 + + # Clear the single-step flag to prevent us coming this way until we get + # switched back in + bclr 0xff,(kgdb_single_step) + + # Remove first breakpoint + mov (kgdb_sstep_bp_addr),a2 + cmp 0,a2 + beq 1f + movbu (kgdb_sstep_bp),d0 + movbu d0,(a2) +#if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE) + mov a2,d0 + mov a2,d1 + add 1,d1 + calls flush_icache_range +#endif +1: + + # Remove second breakpoint + mov (kgdb_sstep_bp_addr+4),a2 + cmp 0,a2 + beq 2f + movbu (kgdb_sstep_bp+1),d0 + movbu d0,(a2) +#if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE) + mov a2,d0 + mov a2,d1 + add 1,d1 + calls flush_icache_range +#endif +2: + + # Change the resumption address and return + mov __switch_back__reinstall_sstep_bp,d0 + mov e4,a0 + mov e5,a1 + add 12,sp + bra __switch_to__continue + +############################################################################### +# +# Reinstall the single-step breakpoints when the task being traced is switched +# back in (A1 points to the new thread_struct). +# +############################################################################### +__switch_back__reinstall_sstep_bp: + add -12,sp + mov a0,e4 # save the return value + mov 0xff,d3 + + # Reinstall first breakpoint + mov (kgdb_sstep_bp_addr),a2 + cmp 0,a2 + beq 1f + movbu (a2),d0 + movbu d0,(kgdb_sstep_bp) + movbu d3,(a2) +#if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE) + mov a2,d0 + mov a2,d1 + add 1,d1 + calls flush_icache_range +#endif +1: + + # Reinstall second breakpoint + mov (kgdb_sstep_bp_addr+4),a2 + cmp 0,a2 + beq 2f + movbu (a2),d0 + movbu d0,(kgdb_sstep_bp+1) + movbu d3,(a2) +#if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE) + mov a2,d0 + mov a2,d1 + add 1,d1 + calls flush_icache_range +#endif +2: + + mov d3,(kgdb_single_step) + + # Restore the return value (the previous thread_struct pointer) + mov e4,a0 + mov a0,d0 + add 12,sp + bra __switch_back + +#endif /* CONFIG_KGDB */ |