LXR linux/arch/m68k/68000/entry.S

   1/*
   2 *  entry.S -- non-mmu 68000 interrupt and exception entry points
   3 *
   4 *  Copyright (C) 1991, 1992  Linus Torvalds
   5 *
   6 * This file is subject to the terms and conditions of the GNU General Public
   7 * License.  See the file README.legal in the main directory of this archive
   8 * for more details.
   9 *
  10 * Linux/m68k support by Hamish Macdonald
  11 */
  12
  13#include <linux/linkage.h>
  14#include <asm/thread_info.h>
  15#include <asm/unistd.h>
  16#include <asm/errno.h>
  17#include <asm/setup.h>
  18#include <asm/traps.h>
  19#include <asm/asm-offsets.h>
  20#include <asm/entry.h>
  21
  22.text
  23
  24.globl system_call
  25.globl resume
  26.globl ret_from_exception
  27.globl sys_call_table
  28.globl bad_interrupt
  29.globl inthandler1
  30.globl inthandler2
  31.globl inthandler3
  32.globl inthandler4
  33.globl inthandler5
  34.globl inthandler6
  35.globl inthandler7
  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_enter
  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_leave
  60        RESTORE_SWITCH_STACK
  61        addql   #4,%sp
  62        jra     ret_from_exception
  63
  64ENTRY(system_call)
  65        SAVE_ALL_SYS
  66
  67        /* save top of frame*/
  68        pea     %sp@
  69        jbsr    set_esp0
  70        addql   #4,%sp
  71
  72        movel   %sp@(PT_OFF_ORIG_D0),%d0
  73
  74        movel   %sp,%d1                 /* get thread_info pointer */
  75        andl    #-THREAD_SIZE,%d1
  76        movel   %d1,%a2
  77        btst    #(TIF_SYSCALL_TRACE%8),%a2@(TINFO_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
  78        jne     do_trace
  79        cmpl    #NR_syscalls,%d0
  80        jcc     badsys
  81        lsl     #2,%d0
  82        lea     sys_call_table,%a0
  83        movel   %a0@(%d0), %a0
  84        jbsr    %a0@
  85        movel   %d0,%sp@(PT_OFF_D0)     /* save the return value*/
  86
  87ret_from_exception:
  88        btst    #5,%sp@(PT_OFF_SR)      /* check if returning to kernel*/
  89        jeq     Luser_return            /* if so, skip resched, signals*/
  90
  91Lkernel_return:
  92        RESTORE_ALL
  93
  94Luser_return:
  95        /* only allow interrupts when we are really the last one on the*/
  96        /* kernel stack, otherwise stack overflow can occur during*/
  97        /* heavy interrupt load*/
  98        andw    #ALLOWINT,%sr
  99
 100        movel   %sp,%d1                 /* get thread_info pointer */
 101        andl    #-THREAD_SIZE,%d1
 102        movel   %d1,%a2
 1031:
 104        move    %a2@(TINFO_FLAGS),%d1   /* thread_info->flags */
 105        jne     Lwork_to_do
 106        RESTORE_ALL
 107
 108Lwork_to_do:
 109        movel   %a2@(TINFO_FLAGS),%d1   /* thread_info->flags */
 110        btst    #TIF_NEED_RESCHED,%d1
 111        jne     reschedule
 112
 113Lsignal_return:
 114        subql   #4,%sp                  /* dummy return address*/
 115        SAVE_SWITCH_STACK
 116        pea     %sp@(SWITCH_STACK_SIZE)
 117        bsrw    do_notify_resume
 118        addql   #4,%sp
 119        RESTORE_SWITCH_STACK
 120        addql   #4,%sp
 121        jra     1b
 122
 123/*
 124 * This is the main interrupt handler, responsible for calling process_int()
 125 */
 126inthandler1:
 127        SAVE_ALL_INT
 128        movew   %sp@(PT_OFF_FORMATVEC), %d0
 129        and     #0x3ff, %d0
 130
 131        movel   %sp,%sp@-
 132        movel   #65,%sp@-               /*  put vector # on stack*/
 133        jbsr    process_int             /*  process the IRQ*/
 1343:      addql   #8,%sp                  /*  pop parameters off stack*/
 135        bra     ret_from_exception
 136
 137inthandler2:
 138        SAVE_ALL_INT
 139        movew   %sp@(PT_OFF_FORMATVEC), %d0
 140        and     #0x3ff, %d0
 141
 142        movel   %sp,%sp@-
 143        movel   #66,%sp@-               /*  put vector # on stack*/
 144        jbsr    process_int             /*  process the IRQ*/
 1453:      addql   #8,%sp                  /*  pop parameters off stack*/
 146        bra     ret_from_exception
 147
 148inthandler3:
 149        SAVE_ALL_INT
 150        movew   %sp@(PT_OFF_FORMATVEC), %d0
 151        and     #0x3ff, %d0
 152
 153        movel   %sp,%sp@-
 154        movel   #67,%sp@-               /*  put vector # on stack*/
 155        jbsr    process_int             /*  process the IRQ*/
 1563:      addql   #8,%sp                  /*  pop parameters off stack*/
 157        bra     ret_from_exception
 158
 159inthandler4:
 160        SAVE_ALL_INT
 161        movew   %sp@(PT_OFF_FORMATVEC), %d0
 162        and     #0x3ff, %d0
 163
 164        movel   %sp,%sp@-
 165        movel   #68,%sp@-               /*  put vector # on stack*/
 166        jbsr    process_int             /*  process the IRQ*/
 1673:      addql   #8,%sp                  /*  pop parameters off stack*/
 168        bra     ret_from_exception
 169
 170inthandler5:
 171        SAVE_ALL_INT
 172        movew   %sp@(PT_OFF_FORMATVEC), %d0
 173        and     #0x3ff, %d0
 174
 175        movel   %sp,%sp@-
 176        movel   #69,%sp@-               /*  put vector # on stack*/
 177        jbsr    process_int             /*  process the IRQ*/
 1783:      addql   #8,%sp                  /*  pop parameters off stack*/
 179        bra     ret_from_exception
 180
 181inthandler6:
 182        SAVE_ALL_INT
 183        movew   %sp@(PT_OFF_FORMATVEC), %d0
 184        and     #0x3ff, %d0
 185
 186        movel   %sp,%sp@-
 187        movel   #70,%sp@-               /*  put vector # on stack*/
 188        jbsr    process_int             /*  process the IRQ*/
 1893:      addql   #8,%sp                  /*  pop parameters off stack*/
 190        bra     ret_from_exception
 191
 192inthandler7:
 193        SAVE_ALL_INT
 194        movew   %sp@(PT_OFF_FORMATVEC), %d0
 195        and     #0x3ff, %d0
 196
 197        movel   %sp,%sp@-
 198        movel   #71,%sp@-               /*  put vector # on stack*/
 199        jbsr    process_int             /*  process the IRQ*/
 2003:      addql   #8,%sp                  /*  pop parameters off stack*/
 201        bra     ret_from_exception
 202
 203inthandler:
 204        SAVE_ALL_INT
 205        movew   %sp@(PT_OFF_FORMATVEC), %d0
 206        and     #0x3ff, %d0
 207
 208        movel   %sp,%sp@-
 209        movel   %d0,%sp@-               /*  put vector # on stack*/
 210        jbsr    process_int             /*  process the IRQ*/
 2113:      addql   #8,%sp                  /*  pop parameters off stack*/
 212        bra     ret_from_exception
 213
 214/*
 215 * Handler for uninitialized and spurious interrupts.
 216 */
 217ENTRY(bad_interrupt)
 218        addql   #1,irq_err_count
 219        rte
 220
 221/*
 222 * Beware - when entering resume, prev (the current task) is
 223 * in a0, next (the new task) is in a1, so don't change these
 224 * registers until their contents are no longer needed.
 225 */
 226ENTRY(resume)
 227        movel   %a0,%d1                         /* save prev thread in d1 */
 228        movew   %sr,%a0@(TASK_THREAD+THREAD_SR) /* save sr */
 229        SAVE_SWITCH_STACK
 230        movel   %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack */
 231        movel   %usp,%a3                        /* save usp */
 232        movel   %a3,%a0@(TASK_THREAD+THREAD_USP)
 233
 234        movel   %a1@(TASK_THREAD+THREAD_USP),%a3 /* restore user stack */
 235        movel   %a3,%usp
 236        movel   %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new thread stack */
 237        RESTORE_SWITCH_STACK
 238        movew   %a1@(TASK_THREAD+THREAD_SR),%sr /* restore thread status reg */
 239        rts
 240
 241