root/arch/m68k/coldfire/entry.S

   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
  43 sw_ksp:
  44 .long   0
  45 sw_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 
  58 enosys:
  59         mov.l   #sys_ni_syscall,%d3
  60         bra     1f
  61 
  62 ENTRY(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 
  74 1:
  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
  87 1:
  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 
 102 ret_from_signal:
 103         RESTORE_SWITCH_STACK
 104         addql   #4,%sp
 105 
 106 ret_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 
 127 Lkernel_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 
 135 Luser_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 
 142 Lreturn:
 143         RESTORE_USER
 144 
 145 Lwork_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 
 151 Lsignal_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  */
 165 ENTRY(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  */
 185 ENTRY(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