arch/m68k/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
  37 badsys:
  38         movel   #-ENOSYS,%sp@(PT_OFF_D0)
  39         jra     ret_from_exception
  40
  41 do_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
  56 1:      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
  61 ret_from_signal:
  62         RESTORE_SWITCH_STACK
  63         addql   #4,%sp
  64         jra     ret_from_exception
  65
  66 ENTRY(system_call)
  67         SAVE_ALL
  68
  69         /* save top of frame*/
  70         pea     %sp@
  71         jbsr    set_esp0
  72         addql   #4,%sp
  73
  74         movel   %sp@(PT_OFF_ORIG_D0),%d0
  75
  76         movel   %sp,%d1                 /* get thread_info pointer */
  77         andl    #-THREAD_SIZE,%d1
  78         movel   %d1,%a2
  79         btst    #(TIF_SYSCALL_TRACE%8),%a2@(TINFO_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
  80         jne     do_trace
  81         cmpl    #NR_syscalls,%d0
  82         jcc     badsys
  83         lsl     #2,%d0
  84         lea     sys_call_table,%a0
  85         movel   %a0@(%d0), %a0
  86         jbsr    %a0@
  87         movel   %d0,%sp@(PT_OFF_D0)     /* save the return value*/
  88
  89 ret_from_exception:
  90         btst    #5,%sp@(PT_OFF_SR)      /* check if returning to kernel*/
  91         jeq     Luser_return            /* if so, skip resched, signals*/
  92
  93 Lkernel_return:
  94         RESTORE_ALL
  95
  96 Luser_return:
  97         /* only allow interrupts when we are really the last one on the*/
  98         /* kernel stack, otherwise stack overflow can occur during*/
  99         /* heavy interrupt load*/
 100         andw    #ALLOWINT,%sr
 101
 102         movel   %sp,%d1                 /* get thread_info pointer */
 103         andl    #-THREAD_SIZE,%d1
 104         movel   %d1,%a2
 105 1:
 106         move    %a2@(TINFO_FLAGS),%d1   /* thread_info->flags */
 107         jne     Lwork_to_do
 108         RESTORE_ALL
 109
 110 Lwork_to_do:
 111         movel   %a2@(TINFO_FLAGS),%d1   /* thread_info->flags */
 112         btst    #TIF_NEED_RESCHED,%d1
 113         jne     reschedule
 114
 115 Lsignal_return:
 116         subql   #4,%sp                  /* dummy return address*/
 117         SAVE_SWITCH_STACK
 118         pea     %sp@(SWITCH_STACK_SIZE)
 119         bsrw    do_signal
 120         addql   #4,%sp
 121         RESTORE_SWITCH_STACK
 122         addql   #4,%sp
 123         jra     1b
 124
 125 /*
 126  * This is the main interrupt handler, responsible for calling do_IRQ()
 127  */
 128 inthandler:
 129         SAVE_ALL
 130         movew   %sp@(PT_OFF_FORMATVEC), %d0
 131         and.l   #0x3ff, %d0
 132         lsr.l   #0x02,  %d0
 133
 134         movel   %sp,%sp@-
 135         movel   %d0,%sp@-               /*  put vector # on stack*/
 136         jbsr    do_IRQ                  /*  process the IRQ*/
 137 3:      addql   #8,%sp                  /*  pop parameters off stack*/
 138         bra     ret_from_interrupt
 139
 140 ret_from_interrupt:
 141         jeq     1f
 142 2:
 143         RESTORE_ALL
 144 1:
 145         moveb   %sp@(PT_OFF_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