Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*
 *  linux/arch/m68knommu/platform/68360/entry.S
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2001 SED Systems, a Division of Calian Ltd.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file README.legal in the main directory of this archive
 * for more details.
 *
 * Linux/m68k support by Hamish Macdonald
 * M68360 Port by SED Systems, and Lineo.
 */

#include <linux/sys.h>
#include <linux/linkage.h>
#include <asm/thread_info.h>
#include <asm/unistd.h>
#include <asm/errno.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/traps.h>
#include <asm/asm-offsets.h>
#include <asm/entry.h>

.text

.globl system_call
.globl resume
.globl ret_from_exception
.globl ret_from_signal
.globl sys_call_table
.globl ret_from_interrupt
.globl bad_interrupt
.globl inthandler

badsys:
        movel   #-ENOSYS,%sp@(PT_D0)
        jra     ret_from_exception

do_trace:
        movel   #-ENOSYS,%sp@(PT_D0)    /* needed for strace*/
        subql   #4,%sp
        SAVE_SWITCH_STACK
        jbsr    syscall_trace
        RESTORE_SWITCH_STACK
        addql   #4,%sp
        movel   %sp@(PT_ORIG_D0),%d1
        movel   #-ENOSYS,%d0
        cmpl    #NR_syscalls,%d1
        jcc     1f
        lsl     #2,%d1
        lea     sys_call_table, %a0
        jbsr    %a0@(%d1)

1:      movel   %d0,%sp@(PT_D0)         /* save the return value */
        subql   #4,%sp                  /* dummy return address */
        SAVE_SWITCH_STACK
        jbsr    syscall_trace

ret_from_signal:
        RESTORE_SWITCH_STACK
        addql   #4,%sp
        jra     ret_from_exception

ENTRY(system_call)
        SAVE_ALL

        /* save top of frame*/
        pea     %sp@
        jbsr    set_esp0
        addql   #4,%sp

        btst    #PF_TRACESYS_BIT,%a2@(TASK_FLAGS+PF_TRACESYS_OFF)
        jne     do_trace
        cmpl    #NR_syscalls,%d0
        jcc     badsys
        lsl     #2,%d0
        lea     sys_call_table,%a0
        movel   %a0@(%d0), %a0
        jbsr    %a0@
        movel   %d0,%sp@(PT_D0)         /* save the return value*/

ret_from_exception:
        btst    #5,%sp@(PT_SR)          /* check if returning to kernel*/
        jeq     Luser_return            /* if so, skip resched, signals*/

Lkernel_return:
        RESTORE_ALL

Luser_return:
        /* only allow interrupts when we are really the last one on the*/
        /* kernel stack, otherwise stack overflow can occur during*/
        /* heavy interrupt load*/
        andw    #ALLOWINT,%sr

        movel   %sp,%d1                 /* get thread_info pointer */
        andl    #-THREAD_SIZE,%d1
        movel   %d1,%a2
        move    %a2@(TI_FLAGS),%d1      /* thread_info->flags */
        andl    #_TIF_WORK_MASK,%d1
        jne     Lwork_to_do
        RESTORE_ALL

Lwork_to_do:
        movel   %a2@(TI_FLAGS),%d1      /* thread_info->flags */
        btst    #TIF_NEED_RESCHED,%d1
        jne     reschedule

Lsignal_return:
        subql   #4,%sp                  /* dummy return address*/
        SAVE_SWITCH_STACK
        pea     %sp@(SWITCH_STACK_SIZE)
        clrl    %sp@-
        bsrw    do_signal
        addql   #8,%sp
        RESTORE_SWITCH_STACK
        addql   #4,%sp
Lreturn:
        RESTORE_ALL

/*
 * This is the main interrupt handler, responsible for calling do_IRQ()
 */
inthandler:
        SAVE_ALL
        movew   %sp@(PT_VECTOR), %d0
        and.l   #0x3ff, %d0
        lsr.l   #0x02,  %d0

        movel   %sp,%sp@-
        movel   %d0,%sp@-               /*  put vector # on stack*/
        jbsr    do_IRQ                  /*  process the IRQ*/
3:      addql   #8,%sp                  /*  pop parameters off stack*/
        bra     ret_from_interrupt

ret_from_interrupt:
        jeq     1f
2:
        RESTORE_ALL
1:
        moveb   %sp@(PT_SR), %d0
        and     #7, %d0
        jhi     2b
        /* check if we need to do software interrupts */

        movel   irq_stat+CPUSTAT_SOFTIRQ_PENDING,%d0
        jeq     ret_from_exception

        pea     ret_from_exception
        jra     do_softirq


/*
 * Handler for uninitialized and spurious interrupts.
 */
bad_interrupt:
        addql   #1,num_spurious
        rte

/*
 * Beware - when entering resume, prev (the current task) is
 * in a0, next (the new task) is in a1,so don't change these
 * registers until their contents are no longer needed.
 */
ENTRY(resume)
        movel   %a0,%d1                         /* save prev thread in d1 */
        movew   %sr,%a0@(TASK_THREAD+THREAD_SR) /* save sr */
        movel   %usp,%a2                        /* save usp */
        movel   %a2,%a0@(TASK_THREAD+THREAD_USP)

        SAVE_SWITCH_STACK
        movel   %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack */
        movel   %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new thread stack */
        RESTORE_SWITCH_STACK

        movel   %a1@(TASK_THREAD+THREAD_USP),%a0 /* restore user stack */
        movel   %a0,%usp
        movew   %a1@(TASK_THREAD+THREAD_SR),%sr /* restore thread status reg */
        rts