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###############################################################################
#
# MN10300 Exception and interrupt entry points
#
# Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
# Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
# Modified 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/smp.h>
#include <asm/system.h>
#include <asm/irqflags.h>
#include <asm/thread_info.h>
#include <asm/intctl-regs.h>
#include <asm/busctl-regs.h>
#include <asm/timer-regs.h>
#include <unit/leds.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/errno.h>
#include <asm/asm-offsets.h>
#include <asm/frame.inc>
#if defined(CONFIG_SMP) && defined(CONFIG_GDBSTUB)
#include <asm/gdb-stub.h>
#endif /* CONFIG_SMP && CONFIG_GDBSTUB */
#ifdef CONFIG_PREEMPT
#define preempt_stop LOCAL_IRQ_DISABLE
#else
#define preempt_stop
#define resume_kernel restore_all
#endif
.am33_2
###############################################################################
#
# the return path for a forked child
# - on entry, D0 holds the address of the previous task to run
#
###############################################################################
ENTRY(ret_from_fork)
call schedule_tail[],0
GET_THREAD_INFO a2
# return 0 to indicate child process
clr d0
mov d0,(REG_D0,fp)
jmp syscall_exit
###############################################################################
#
# system call handler
#
###############################################################################
ENTRY(system_call)
add -4,sp
SAVE_ALL
mov d0,(REG_ORIG_D0,fp)
GET_THREAD_INFO a2
cmp nr_syscalls,d0
bcc syscall_badsys
btst _TIF_SYSCALL_TRACE,(TI_flags,a2)
bne syscall_entry_trace
syscall_call:
add d0,d0,a1
add a1,a1
mov (REG_A0,fp),d0
mov (sys_call_table,a1),a0
calls (a0)
mov d0,(REG_D0,fp)
syscall_exit:
# make sure we don't miss an interrupt setting need_resched or
# sigpending between sampling and the rti
LOCAL_IRQ_DISABLE
mov (TI_flags,a2),d2
btst _TIF_ALLWORK_MASK,d2
bne syscall_exit_work
restore_all:
RESTORE_ALL
###############################################################################
#
# perform work that needs to be done immediately before resumption and syscall
# tracing
#
###############################################################################
ALIGN
syscall_exit_work:
btst _TIF_SYSCALL_TRACE,d2
beq work_pending
LOCAL_IRQ_ENABLE # could let syscall_trace_exit() call
# schedule() instead
mov fp,d0
call syscall_trace_exit[],0 # do_syscall_trace(regs)
jmp resume_userspace
ALIGN
work_pending:
btst _TIF_NEED_RESCHED,d2
beq work_notifysig
work_resched:
call schedule[],0
# make sure we don't miss an interrupt setting need_resched or
# sigpending between sampling and the rti
LOCAL_IRQ_DISABLE
# is there any work to be done other than syscall tracing?
mov (TI_flags,a2),d2
btst _TIF_WORK_MASK,d2
beq restore_all
btst _TIF_NEED_RESCHED,d2
bne work_resched
# deal with pending signals and notify-resume requests
work_notifysig:
mov fp,d0
mov d2,d1
call do_notify_resume[],0
jmp resume_userspace
# perform syscall entry tracing
syscall_entry_trace:
mov -ENOSYS,d0
mov d0,(REG_D0,fp)
mov fp,d0
call syscall_trace_entry[],0 # returns the syscall number to actually use
mov (REG_D1,fp),d1
cmp nr_syscalls,d0
bcs syscall_call
jmp syscall_exit
syscall_badsys:
mov -ENOSYS,d0
mov d0,(REG_D0,fp)
jmp resume_userspace
# userspace resumption stub bypassing syscall exit tracing
.globl ret_from_exception, ret_from_intr
ALIGN
ret_from_exception:
preempt_stop
ret_from_intr:
GET_THREAD_INFO a2
mov (REG_EPSW,fp),d0 # need to deliver signals before
# returning to userspace
and EPSW_nSL,d0
beq resume_kernel # returning to supervisor mode
ENTRY(resume_userspace)
# make sure we don't miss an interrupt setting need_resched or
# sigpending between sampling and the rti
LOCAL_IRQ_DISABLE
# is there any work to be done on int/exception return?
mov (TI_flags,a2),d2
btst _TIF_WORK_MASK,d2
bne work_pending
jmp restore_all
#ifdef CONFIG_PREEMPT
ENTRY(resume_kernel)
LOCAL_IRQ_DISABLE
mov (TI_preempt_count,a2),d0 # non-zero preempt_count ?
cmp 0,d0
bne restore_all
need_resched:
btst _TIF_NEED_RESCHED,(TI_flags,a2)
beq restore_all
mov (REG_EPSW,fp),d0
and EPSW_IM,d0
cmp EPSW_IM_7,d0 # interrupts off (exception path) ?
bne restore_all
call preempt_schedule_irq[],0
jmp need_resched
#endif
###############################################################################
#
# IRQ handler entry point
# - intended to be entered at multiple priorities
#
###############################################################################
ENTRY(irq_handler)
add -4,sp
SAVE_ALL
# it's not a syscall
mov 0xffffffff,d0
mov d0,(REG_ORIG_D0,fp)
mov fp,d0
call do_IRQ[],0 # do_IRQ(regs)
jmp ret_from_intr
###############################################################################
#
# Double Fault handler entry point
# - note that there will not be a stack, D0/A0 will hold EPSW/PC as were
#
###############################################################################
.section .bss
.balign THREAD_SIZE
.space THREAD_SIZE
__df_stack:
.previous
ENTRY(double_fault)
mov a0,(__df_stack-4) # PC as was
mov d0,(__df_stack-8) # EPSW as was
mn10300_set_dbfleds # display 'db-f' on the LEDs
mov 0xaa55aa55,d0
mov d0,(__df_stack-12) # no ORIG_D0
mov sp,a0 # save corrupted SP
mov __df_stack-12,sp # emergency supervisor stack
SAVE_ALL
mov a0,(REG_A0,fp) # save corrupted SP as A0 (which got
# clobbered by the CPU)
mov fp,d0
calls do_double_fault
double_fault_loop:
bra double_fault_loop
###############################################################################
#
# Bus Error handler entry point
# - handle external (async) bus errors separately
#
###############################################################################
ENTRY(raw_bus_error)
add -4,sp
mov d0,(sp)
#if defined(CONFIG_ERRATUM_NEED_TO_RELOAD_MMUCTR)
mov (MMUCTR),d0
mov d0,(MMUCTR)
#endif
mov (BCBERR),d0 # what
btst BCBERR_BEMR_DMA,d0 # see if it was an external bus error
beq __common_exception_aux # it wasn't
SAVE_ALL
mov (BCBEAR),d1 # destination of erroneous access
mov (REG_ORIG_D0,fp),d2
mov d2,(REG_D0,fp)
mov -1,d2
mov d2,(REG_ORIG_D0,fp)
add -4,sp
mov fp,(12,sp) # frame pointer
call io_bus_error[],0
jmp restore_all
###############################################################################
#
# Miscellaneous exception entry points
#
###############################################################################
ENTRY(nmi_handler)
add -4,sp
mov d0,(sp)
mov (TBR),d0
#ifdef CONFIG_SMP
add -4,sp
mov d0,(sp) # save d0(TBR)
movhu (NMIAGR),d0
and NMIAGR_GN,d0
lsr 0x2,d0
cmp CALL_FUNCTION_NMI_IPI,d0
bne 5f # if not call function, jump
# function call nmi ipi
add 4,sp # no need to store TBR
mov GxICR_DETECT,d0 # clear NMI request
movbu d0,(GxICR(CALL_FUNCTION_NMI_IPI))
movhu (GxICR(CALL_FUNCTION_NMI_IPI)),d0
and ~EPSW_NMID,epsw
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