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