linux/arch/m68k/coldfire/entry.S
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   1/*
   2 *  entry.S  -- interrupt and exception processing for ColdFire
   3 *
   4 *  Copyright (C) 1999-2007, Greg Ungerer (gerg@snapgear.com)
   5 *  Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
   6 *                      Kenneth Albanowski <kjahds@kjahds.com>,
   7 *  Copyright (C) 2000  Lineo Inc. (www.lineo.com)
   8 *  Copyright (C) 2004-2006  Macq Electronique SA. (www.macqel.com)
   9 *
  10 * Based on:
  11 *
  12 *  linux/arch/m68k/kernel/entry.S
  13 *
  14 *  Copyright (C) 1991, 1992  Linus Torvalds
  15 *
  16 * This file is subject to the terms and conditions of the GNU General Public
  17 * License.  See the file README.legal in the main directory of this archive
  18 * for more details.
  19 *
  20 * Linux/m68k support by Hamish Macdonald
  21 *
  22 * 68060 fixes by Jesper Skov
  23 * ColdFire support by Greg Ungerer (gerg@snapgear.com)
  24 * 5307 fixes by David W. Miller
  25 * linux 2.4 support David McCullough <davidm@snapgear.com>
  26 * Bug, speed and maintainability fixes by Philippe De Muyter <phdm@macqel.be>
  27 */
  28
  29#include <linux/linkage.h>
  30#include <asm/unistd.h>
  31#include <asm/thread_info.h>
  32#include <asm/errno.h>
  33#include <asm/setup.h>
  34#include <asm/segment.h>
  35#include <asm/asm-offsets.h>
  36#include <asm/entry.h>
  37
  38#ifdef CONFIG_COLDFIRE_SW_A7
  39/*
  40 *      Define software copies of the supervisor and user stack pointers.
  41 */
  42.bss
  43sw_ksp:
  44.long   0
  45sw_usp:
  46.long   0
  47#endif /* CONFIG_COLDFIRE_SW_A7 */
  48
  49.text
  50
  51.globl system_call
  52.globl resume
  53.globl ret_from_exception
  54.globl ret_from_signal
  55.globl sys_call_table
  56.globl inthandler
  57
  58enosys:
  59        mov.l   #sys_ni_syscall,%d3
  60        bra     1f
  61
  62ENTRY(system_call)
  63        SAVE_ALL_SYS
  64        move    #0x2000,%sr             /* enable intrs again */
  65        GET_CURRENT(%d2)
  66
  67        cmpl    #NR_syscalls,%d0
  68        jcc     enosys
  69        lea     sys_call_table,%a0
  70        lsll    #2,%d0                  /* movel %a0@(%d0:l:4),%d3 */
  71        movel   %a0@(%d0),%d3
  72        jeq     enosys
  73
  741:
  75        movel   %sp,%d2                 /* get thread_info pointer */
  76        andl    #-THREAD_SIZE,%d2       /* at start of kernel stack */
  77        movel   %d2,%a0
  78        movel   %a0@,%a1                /* save top of frame */
  79        movel   %sp,%a1@(TASK_THREAD+THREAD_ESP0)
  80        btst    #(TIF_SYSCALL_TRACE%8),%a0@(TINFO_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
  81        bnes    1f
  82
  83        movel   %d3,%a0
  84        jbsr    %a0@
  85        movel   %d0,%sp@(PT_OFF_D0)     /* save the return value */
  86        jra     ret_from_exception
  871:
  88        movel   #-ENOSYS,%d2            /* strace needs -ENOSYS in PT_OFF_D0 */
  89        movel   %d2,PT_OFF_D0(%sp)      /* on syscall entry */
  90        subql   #4,%sp
  91        SAVE_SWITCH_STACK
  92        jbsr    syscall_trace_enter
  93        RESTORE_SWITCH_STACK
  94        addql   #4,%sp
  95        movel   %d3,%a0
  96        jbsr    %a0@
  97        movel   %d0,%sp@(PT_OFF_D0)             /* save the return value */
  98        subql   #4,%sp                  /* dummy return address */
  99        SAVE_SWITCH_STACK
 100        jbsr    syscall_trace_leave
 101
 102ret_from_signal:
 103        RESTORE_SWITCH_STACK
 104        addql   #4,%sp
 105
 106ret_from_exception:
 107        move    #0x2700,%sr             /* disable intrs */
 108        btst    #5,%sp@(PT_OFF_SR)      /* check if returning to kernel */
 109        jeq     Luser_return            /* if so, skip resched, signals */
 110
 111#ifdef CONFIG_PREEMPT
 112        movel   %sp,%d1                 /* get thread_info pointer */
 113        andl    #-THREAD_SIZE,%d1       /* at base of kernel stack */
 114        movel   %d1,%a0
 115        movel   %a0@(TINFO_FLAGS),%d1   /* get thread_info->flags */
 116        andl    #(1<<TIF_NEED_RESCHED),%d1
 117        jeq     Lkernel_return
 118
 119        movel   %a0@(TINFO_PREEMPT),%d1
 120        cmpl    #0,%d1
 121        jne     Lkernel_return
 122
 123        pea     Lkernel_return
 124        jmp     preempt_schedule_irq    /* preempt the kernel */
 125#endif
 126
 127Lkernel_return:
 128        moveml  %sp@,%d1-%d5/%a0-%a2
 129        lea     %sp@(32),%sp            /* space for 8 regs */
 130        movel   %sp@+,%d0
 131        addql   #4,%sp                  /* orig d0 */
 132        addl    %sp@+,%sp               /* stk adj */
 133        rte
 134
 135Luser_return:
 136        movel   %sp,%d1                 /* get thread_info pointer */
 137        andl    #-THREAD_SIZE,%d1       /* at base of kernel stack */
 138        movel   %d1,%a0
 139        moveb   %a0@(TINFO_FLAGS+3),%d1 /* thread_info->flags (low 8 bits) */
 140        jne     Lwork_to_do             /* still work to do */
 141
 142Lreturn:
 143        RESTORE_USER
 144
 145Lwork_to_do:
 146        movel   %a0@(TINFO_FLAGS),%d1   /* get thread_info->flags */
 147        move    #0x2000,%sr             /* enable intrs again */
 148        btst    #TIF_NEED_RESCHED,%d1
 149        jne     reschedule
 150
 151Lsignal_return:
 152        subql   #4,%sp                  /* dummy return address */
 153        SAVE_SWITCH_STACK
 154        pea     %sp@(SWITCH_STACK_SIZE)
 155        jsr     do_notify_resume
 156        addql   #4,%sp
 157        RESTORE_SWITCH_STACK
 158        addql   #4,%sp
 159        jmp     Luser_return
 160
 161/*
 162 * This is the generic interrupt handler (for all hardware interrupt
 163 * sources). Calls up to high level code to do all the work.
 164 */
 165ENTRY(inthandler)
 166        SAVE_ALL_INT
 167        GET_CURRENT(%d2)
 168
 169        movew   %sp@(PT_OFF_FORMATVEC),%d0 /* put exception # in d0 */
 170        andl    #0x03fc,%d0             /* mask out vector only */
 171
 172        movel   %sp,%sp@-               /* push regs arg */
 173        lsrl    #2,%d0                  /* calculate real vector # */
 174        movel   %d0,%sp@-               /* push vector number */
 175        jbsr    do_IRQ                  /* call high level irq handler */
 176        lea     %sp@(8),%sp             /* pop args off stack */
 177
 178        bra     ret_from_exception
 179
 180/*
 181 * Beware - when entering resume, prev (the current task) is
 182 * in a0, next (the new task) is in a1, so don't change these
 183 * registers until their contents are no longer needed.
 184 */
 185ENTRY(resume)
 186        movew   %sr,%d1                          /* save current status */
 187        movew   %d1,%a0@(TASK_THREAD+THREAD_SR)
 188        movel   %a0,%d1                          /* get prev thread in d1 */
 189        SAVE_SWITCH_STACK
 190        movel   %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack pointer */
 191        RDUSP                                    /* movel %usp,%a3 */
 192        movel   %a3,%a0@(TASK_THREAD+THREAD_USP) /* save thread user stack */
 193#ifdef CONFIG_MMU
 194        movel   %a1,%a2                          /* set new current */
 195#endif
 196        movel   %a1@(TASK_THREAD+THREAD_USP),%a3 /* restore thread user stack */
 197        WRUSP                                    /* movel %a3,%usp */
 198        movel   %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new kernel stack */
 199        movew   %a1@(TASK_THREAD+THREAD_SR),%d7  /* restore new status */
 200        movew   %d7,%sr
 201        RESTORE_SWITCH_STACK
 202        rts
 203
 204
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