LXR linux/arch/m68knommu/platform/68360/entry.S

   1/*
   2 *  linux/arch/m68knommu/platform/68360/entry.S
   3 *
   4 *  Copyright (C) 1991, 1992  Linus Torvalds
   5 *  Copyright (C) 2001 SED Systems, a Division of Calian Ltd.
   6 *
   7 * This file is subject to the terms and conditions of the GNU General Public
   8 * License.  See the file README.legal in the main directory of this archive
   9 * for more details.
  10 *
  11 * Linux/m68k support by Hamish Macdonald
  12 * M68360 Port by SED Systems, and Lineo.
  13 */
  14
  15#include <linux/sys.h>
  16#include <linux/linkage.h>
  17#include <asm/thread_info.h>
  18#include <asm/unistd.h>
  19#include <asm/errno.h>
  20#include <asm/setup.h>
  21#include <asm/segment.h>
  22#include <asm/traps.h>
  23#include <asm/asm-offsets.h>
  24#include <asm/entry.h>
  25
  26.text
  27
  28.globl system_call
  29.globl resume
  30.globl ret_from_exception
  31.globl ret_from_signal
  32.globl sys_call_table
  33.globl ret_from_interrupt
  34.globl bad_interrupt
  35.globl inthandler
  36
  37badsys:
  38        movel   #-ENOSYS,%sp@(PT_OFF_D0)
  39        jra     ret_from_exception
  40
  41do_trace:
  42        movel   #-ENOSYS,%sp@(PT_OFF_D0) /* needed for strace*/
  43        subql   #4,%sp
  44        SAVE_SWITCH_STACK
  45        jbsr    syscall_trace
  46        RESTORE_SWITCH_STACK
  47        addql   #4,%sp
  48        movel   %sp@(PT_OFF_ORIG_D0),%d1
  49        movel   #-ENOSYS,%d0
  50        cmpl    #NR_syscalls,%d1
  51        jcc     1f
  52        lsl     #2,%d1
  53        lea     sys_call_table, %a0
  54        jbsr    %a0@(%d1)
  55
  561:      movel   %d0,%sp@(PT_OFF_D0)     /* save the return value */
  57        subql   #4,%sp                  /* dummy return address */
  58        SAVE_SWITCH_STACK
  59        jbsr    syscall_trace
  60
  61ret_from_signal:
  62        RESTORE_SWITCH_STACK
  63        addql   #4,%sp
  64        jra     ret_from_exception
  65
  66ENTRY(system_call)
  67        SAVE_ALL
  68
  69        /* save top of frame*/
  70        pea     %sp@
  71        jbsr    set_esp0
  72        addql   #4,%sp
  73
  74        btst    #PF_TRACESYS_BIT,%a2@(TASK_FLAGS+PF_TRACESYS_OFF)
  75        jne     do_trace
  76        cmpl    #NR_syscalls,%d0
  77        jcc     badsys
  78        lsl     #2,%d0
  79        lea     sys_call_table,%a0
  80        movel   %a0@(%d0), %a0
  81        jbsr    %a0@
  82        movel   %d0,%sp@(PT_OFF_D0)     /* save the return value*/
  83
  84ret_from_exception:
  85        btst    #5,%sp@(PT_OFF_SR)      /* check if returning to kernel*/
  86        jeq     Luser_return            /* if so, skip resched, signals*/
  87
  88Lkernel_return:
  89        RESTORE_ALL
  90
  91Luser_return:
  92        /* only allow interrupts when we are really the last one on the*/
  93        /* kernel stack, otherwise stack overflow can occur during*/
  94        /* heavy interrupt load*/
  95        andw    #ALLOWINT,%sr
  96
  97        movel   %sp,%d1                 /* get thread_info pointer */
  98        andl    #-THREAD_SIZE,%d1
  99        movel   %d1,%a2
 100        move    %a2@(TI_FLAGS),%d1      /* thread_info->flags */
 101        andl    #_TIF_WORK_MASK,%d1
 102        jne     Lwork_to_do
 103        RESTORE_ALL
 104
 105Lwork_to_do:
 106        movel   %a2@(TI_FLAGS),%d1      /* thread_info->flags */
 107        btst    #TIF_NEED_RESCHED,%d1
 108        jne     reschedule
 109
 110Lsignal_return:
 111        subql   #4,%sp                  /* dummy return address*/
 112        SAVE_SWITCH_STACK
 113        pea     %sp@(SWITCH_STACK_SIZE)
 114        clrl    %sp@-
 115        bsrw    do_signal
 116        addql   #8,%sp
 117        RESTORE_SWITCH_STACK
 118        addql   #4,%sp
 119Lreturn:
 120        RESTORE_ALL
 121
 122/*
 123 * This is the main interrupt handler, responsible for calling do_IRQ()
 124 */
 125inthandler:
 126        SAVE_ALL
 127        movew   %sp@(PT_OFF_VECTOR), %d0
 128        and.l   #0x3ff, %d0
 129        lsr.l   #0x02,  %d0
 130
 131        movel   %sp,%sp@-
 132        movel   %d0,%sp@-               /*  put vector # on stack*/
 133        jbsr    do_IRQ                  /*  process the IRQ*/
 1343:      addql   #8,%sp                  /*  pop parameters off stack*/
 135        bra     ret_from_interrupt
 136
 137ret_from_interrupt:
 138        jeq     1f
 1392:
 140        RESTORE_ALL
 1411:
 142        moveb   %sp@(PT_OFF_SR), %d0
 143        and     #7, %d0
 144        jhi     2b
 145        /* check if we need to do software interrupts */
 146
 147        movel   irq_stat+CPUSTAT_SOFTIRQ_PENDING,%d0
 148        jeq     ret_from_exception
 149
 150        pea     ret_from_exception
 151        jra     do_softirq
 152
 153
 154/*
 155 * Handler for uninitialized and spurious interrupts.
 156 */
 157bad_interrupt:
 158        addql   #1,num_spurious
 159        rte
 160
 161/*
 162 * Beware - when entering resume, prev (the current task) is
 163 * in a0, next (the new task) is in a1,so don't change these
 164 * registers until their contents are no longer needed.
 165 */
 166ENTRY(resume)
 167        movel   %a0,%d1                         /* save prev thread in d1 */
 168        movew   %sr,%a0@(TASK_THREAD+THREAD_SR) /* save sr */
 169        movel   %usp,%a2                        /* save usp */
 170        movel   %a2,%a0@(TASK_THREAD+THREAD_USP)
 171
 172        SAVE_SWITCH_STACK
 173        movel   %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack */
 174        movel   %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new thread stack */
 175        RESTORE_SWITCH_STACK
 176
 177        movel   %a1@(TASK_THREAD+THREAD_USP),%a0 /* restore user stack */
 178        movel   %a0,%usp
 179        movew   %a1@(TASK_THREAD+THREAD_SR),%sr /* restore thread status reg */
 180        rts
 181
 182