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/config.h>
  16 #include <linux/sys.h>
  17 #include <linux/linkage.h>
  18 #include <asm/thread_info.h>
  19 #include <asm/unistd.h>
  20 #include <asm/errno.h>
  21 #include <asm/setup.h>
  22 #include <asm/segment.h>
  23 #include <asm/traps.h>
  24 #include <asm/asm-offsets.h>
  25 #include <asm/entry.h>
  26
  27 .text
  28
  29 .globl system_call
  30 .globl resume
  31 .globl ret_from_exception
  32 .globl ret_from_signal
  33 .globl sys_call_table
  34 .globl ret_from_interrupt
  35 .globl bad_interrupt
  36 .globl inthandler
  37
  38 badsys:
  39         movel   #-ENOSYS,%sp@(PT_D0)
  40         jra     ret_from_exception
  41
  42 do_trace:
  43         movel   #-ENOSYS,%sp@(PT_D0)    /* needed for strace*/
  44         subql   #4,%sp
  45         SAVE_SWITCH_STACK
  46         jbsr    syscall_trace
  47         RESTORE_SWITCH_STACK
  48         addql   #4,%sp
  49         movel   %sp@(PT_ORIG_D0),%d1
  50         movel   #-ENOSYS,%d0
  51         cmpl    #NR_syscalls,%d1
  52         jcc     1f
  53         lsl     #2,%d1
  54         lea     sys_call_table, %a0
  55         jbsr    %a0@(%d1)
  56
  57 1:      movel   %d0,%sp@(PT_D0)         /* save the return value */
  58         subql   #4,%sp                  /* dummy return address */
  59         SAVE_SWITCH_STACK
  60         jbsr    syscall_trace
  61
  62 ret_from_signal:
  63         RESTORE_SWITCH_STACK
  64         addql   #4,%sp
  65         jra     ret_from_exception
  66
  67 ENTRY(system_call)
  68         SAVE_ALL
  69
  70         /* save top of frame*/
  71         pea     %sp@
  72         jbsr    set_esp0
  73         addql   #4,%sp
  74
  75         btst    #PF_TRACESYS_BIT,%a2@(TASK_FLAGS+PF_TRACESYS_OFF)
  76         jne     do_trace
  77         cmpl    #NR_syscalls,%d0
  78         jcc     badsys
  79         lsl     #2,%d0
  80         lea     sys_call_table,%a0
  81         movel   %a0@(%d0), %a0
  82         jbsr    %a0@
  83         movel   %d0,%sp@(PT_D0)         /* save the return value*/
  84
  85 ret_from_exception:
  86         btst    #5,%sp@(PT_SR)          /* check if returning to kernel*/
  87         jeq     Luser_return            /* if so, skip resched, signals*/
  88
  89 Lkernel_return:
  90         RESTORE_ALL
  91
  92 Luser_return:
  93         /* only allow interrupts when we are really the last one on the*/
  94         /* kernel stack, otherwise stack overflow can occur during*/
  95         /* heavy interrupt load*/
  96         andw    #ALLOWINT,%sr
  97
  98         movel   %sp,%d1                 /* get thread_info pointer */
  99         andl    #0xffffe000,%d1
 100         movel   %d1,%a2
 101         move    %a2@(TI_FLAGS),%d1      /* thread_info->flags */
 102         andl    #_TIF_WORK_MASK,%d1
 103         jne     Lwork_to_do
 104         RESTORE_ALL
 105
 106 Lwork_to_do:
 107         movel   %a2@(TI_FLAGS),%d1      /* thread_info->flags */
 108         btst    #TIF_NEED_RESCHED,%d1
 109         jne     reschedule
 110
 111 Lsignal_return:
 112         subql   #4,%sp                  /* dummy return address*/
 113         SAVE_SWITCH_STACK
 114         pea     %sp@(SWITCH_STACK_SIZE)
 115         clrl    %sp@-
 116         bsrw    do_signal
 117         addql   #8,%sp
 118         RESTORE_SWITCH_STACK
 119         addql   #4,%sp
 120 Lreturn:
 121         RESTORE_ALL
 122
 123 /*
 124  * This is the main interrupt handler, responsible for calling process_int()
 125  */
 126 inthandler:
 127         SAVE_ALL
 128         addql   #1,local_irq_count      /*  put exception # in d0*/
 129         movew   %sp@(PT_VECTOR), %d0
 130         and.l   #0x3ff, %d0
 131         lsr.l   #0x02,  %d0
 132
 133         movel   %sp,%sp@-
 134         movel   %d0,%sp@-               /*  put vector # on stack*/
 135         jbsr    process_int             /*  process the IRQ*/
 136 3:      addql   #8,%sp                  /*  pop parameters off stack*/
 137         bra     ret_from_interrupt
 138
 139 ret_from_interrupt:
 140         subql   #1,local_irq_count
 141         jeq     1f
 142 2:
 143         RESTORE_ALL
 144 1:
 145         moveb   %sp@(PT_SR), %d0
 146         and     #7, %d0
 147         jhi     2b
 148         /* check if we need to do software interrupts */
 149
 150         movel   irq_stat+CPUSTAT_SOFTIRQ_PENDING,%d0
 151         jeq     ret_from_exception
 152
 153         pea     ret_from_exception
 154         jra     do_softirq
 155
 156
 157 /*
 158  * Handler for uninitialized and spurious interrupts.
 159  */
 160 bad_interrupt:
 161         addql   #1,num_spurious
 162         rte
 163
 164 /*
 165  * Beware - when entering resume, prev (the current task) is
 166  * in a0, next (the new task) is in a1,so don't change these
 167  * registers until their contents are no longer needed.
 168  */
 169 ENTRY(resume)
 170         movel   %a0,%d1                         /* save prev thread in d1 */
 171         movew   %sr,%a0@(TASK_THREAD+THREAD_SR) /* save sr */
 172         movel   %usp,%a2                        /* save usp */
 173         movel   %a2,%a0@(TASK_THREAD+THREAD_USP)
 174
 175         SAVE_SWITCH_STACK
 176         movel   %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack */
 177         movel   %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new thread stack */
 178         RESTORE_SWITCH_STACK
 179
 180         movel   %a1@(TASK_THREAD+THREAD_USP),%a0 /* restore user stack */
 181         movel   %a0,%usp
 182         movew   %a1@(TASK_THREAD+THREAD_SR),%sr /* restore thread status reg */
 183         rts
 184