arch/m68knommu/platform/5307/entry.S

   1 /*
   2  *  linux/arch/m68knommu/platform/5307/entry.S
   3  *
   4  *  Copyright (C) 1999-2002, 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  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/config.h>
  30 #include <linux/sys.h>
  31 #include <linux/linkage.h>
  32 #include <asm/unistd.h>
  33 #include <asm/thread_info.h>
  34 #include <asm/errno.h>
  35 #include <asm/setup.h>
  36 #include <asm/segment.h>
  37 #include <asm/asm-offsets.h>
  38 #include <asm/entry.h>
  39
  40 .bss
  41
  42 sw_ksp:
  43 .long   0
  44
  45 sw_usp:
  46 .long   0
  47
  48 .text
  49
  50 .globl system_call
  51 .globl resume
  52 .globl ret_from_exception
  53 .globl ret_from_signal
  54 .globl sys_call_table
  55 .globl ret_from_interrupt
  56 .globl inthandler
  57 .globl fasthandler
  58
  59 ENTRY(system_call)
  60         SAVE_ALL
  61         move    #0x2000,%sr             /* enable intrs again */
  62
  63         movel   #-LENOSYS,%d2
  64         movel   %d2,PT_D0(%sp)          /* default return value in d0 */
  65                                         /* original D0 is in orig_d0 */
  66         movel   %d0,%d2
  67
  68         /* save top of frame */
  69         pea     %sp@
  70         jbsr    set_esp0
  71         addql   #4,%sp
  72
  73         cmpl    #NR_syscalls,%d2
  74         jcc     ret_from_exception
  75         lea     sys_call_table,%a0
  76         lsll    #2,%d2                  /* movel %a0@(%d2:l:4),%d3 */
  77         movel   %a0@(%d2),%d3
  78         jeq     ret_from_exception
  79         lsrl    #2,%d2
  80
  81         movel   %sp,%d2                 /* get thread_info pointer */
  82         andl    #-THREAD_SIZE,%d2       /* at start of kernel stack */
  83         movel   %d2,%a0
  84         btst    #TIF_SYSCALL_TRACE,%a0@(TI_FLAGS)
  85         bnes    1f
  86
  87         movel   %d3,%a0
  88         jbsr    %a0@
  89         movel   %d0,%sp@(PT_D0)         /* save the return value */
  90         jra     ret_from_exception
  91 1:
  92         subql   #4,%sp
  93         SAVE_SWITCH_STACK
  94         jbsr    syscall_trace
  95         RESTORE_SWITCH_STACK
  96         addql   #4,%sp
  97         movel   %d3,%a0
  98         jbsr    %a0@
  99         movel   %d0,%sp@(PT_D0)         /* save the return value */
 100         subql   #4,%sp                  /* dummy return address */
 101         SAVE_SWITCH_STACK
 102         jbsr    syscall_trace
 103
 104 ret_from_signal:
 105         RESTORE_SWITCH_STACK
 106         addql   #4,%sp
 107
 108 ret_from_exception:
 109         btst    #5,%sp@(PT_SR)          /* check if returning to kernel */
 110         jeq     Luser_return            /* if so, skip resched, signals */
 111
 112 Lkernel_return:
 113         moveml  %sp@,%d1-%d5/%a0-%a2
 114         lea     %sp@(32),%sp            /* space for 8 regs */
 115         movel   %sp@+,%d0
 116         addql   #4,%sp                  /* orig d0 */
 117         addl    %sp@+,%sp               /* stk adj */
 118         rte
 119
 120 Luser_return:
 121         movel   %sp,%d1                 /* get thread_info pointer */
 122         andl    #-THREAD_SIZE,%d1       /* at base of kernel stack */
 123         movel   %d1,%a0
 124         movel   %a0@(TI_FLAGS),%d1      /* get thread_info->flags */
 125         andl    #_TIF_WORK_MASK,%d1
 126         jne     Lwork_to_do             /* still work to do */
 127
 128 Lreturn:
 129         move    #0x2700,%sr             /* disable intrs */
 130         movel   sw_usp,%a0              /* get usp */
 131         movel   %sp@(PT_PC),%a0@-       /* copy exception program counter */
 132         movel   %sp@(PT_FORMATVEC),%a0@-/* copy exception format/vector/sr */
 133         moveml  %sp@,%d1-%d5/%a0-%a2
 134         lea     %sp@(32),%sp            /* space for 8 regs */
 135         movel   %sp@+,%d0
 136         addql   #4,%sp                  /* orig d0 */
 137         addl    %sp@+,%sp               /* stk adj */
 138         addql   #8,%sp                  /* remove exception */
 139         movel   %sp,sw_ksp              /* save ksp */
 140         subql   #8,sw_usp               /* set exception */
 141         movel   sw_usp,%sp              /* restore usp */
 142         rte
 143
 144 Lwork_to_do:
 145         movel   %a0@(TI_FLAGS),%d1      /* get thread_info->flags */
 146         btst    #TIF_NEED_RESCHED,%d1
 147         jne     reschedule
 148
 149         /* GERG: do we need something here for TRACEing?? */
 150
 151 Lsignal_return:
 152         subql   #4,%sp                  /* dummy return address */
 153         SAVE_SWITCH_STACK
 154         pea     %sp@(SWITCH_STACK_SIZE)
 155         clrl    %sp@-
 156         jsr     do_signal
 157         addql   #8,%sp
 158         RESTORE_SWITCH_STACK
 159         addql   #4,%sp
 160         jmp     Lreturn
 161
 162 /*
 163  * This is the generic interrupt handler (for all hardware interrupt
 164  * sources). It figures out the vector number and calls the appropriate
 165  * interrupt service routine directly.
 166  */
 167 ENTRY(inthandler)
 168         SAVE_ALL
 169         moveq   #-1,%d0
 170         movel   %d0,%sp@(PT_ORIG_D0)
 171         addql   #1,local_irq_count
 172
 173         movew   %sp@(PT_FORMATVEC),%d0  /* put exception # in d0 */
 174         andl    #0x03fc,%d0             /* mask out vector only */
 175
 176         leal    per_cpu__kstat+STAT_IRQ,%a0
 177         addql   #1,%a0@(%d0)
 178
 179         lsrl    #2,%d0                  /* calculate real vector # */
 180         movel   %d0,%d1                 /* calculate array offset */
 181         lsll    #4,%d1
 182         lea     irq_list,%a0
 183         addl    %d1,%a0                 /* pointer to array struct */
 184
 185         movel   %sp,%sp@-               /* push regs arg onto stack */
 186         movel   %a0@(8),%sp@-           /* push devid arg */
 187         movel   %d0,%sp@-               /* push vector # on stack */
 188
 189         movel   %a0@,%a0                /* get function to call */
 190         jbsr    %a0@                    /* call vector handler */
 191         lea     %sp@(12),%sp            /* pop parameters off stack */
 192
 193         bra     ret_from_interrupt      /* this was fallthrough */
 194
 195 /*
 196  * This is the fast interrupt handler (for certain hardware interrupt
 197  * sources). Unlike the normal interrupt handler it just uses the
 198  * current stack (doesn't care if it is user or kernel). It also
 199  * doesn't bother doing the bottom half handlers.
 200  */
 201 ENTRY(fasthandler)
 202         SAVE_LOCAL
 203
 204         movew   %sp@(PT_FORMATVEC),%d0
 205         andl    #0x03fc,%d0             /* mask out vector only */
 206
 207         leal    per_cpu__kstat+STAT_IRQ,%a0
 208         addql   #1,%a0@(%d0)
 209
 210         movel   %sp,%sp@-               /* push regs arg onto stack */
 211         clrl    %sp@-                   /* push devid arg */
 212         lsrl    #2,%d0                  /* calculate real vector # */
 213         movel   %d0,%sp@-               /* push vector # on stack */
 214
 215         lsll    #4,%d0                  /* adjust for array offset */
 216         lea     irq_list,%a0
 217         movel   %a0@(%d0),%a0           /* get function to call */
 218         jbsr    %a0@                    /* call vector handler */
 219         lea     %sp@(12),%sp            /* pop parameters off stack */
 220
 221         RESTORE_LOCAL
 222
 223 ENTRY(ret_from_interrupt)
 224         subql   #1,local_irq_count
 225         jeq     2f
 226 1:
 227         RESTORE_ALL
 228 2:
 229         moveb   %sp@(PT_SR),%d0
 230         andl    #0x7,%d0
 231         jhi     1b
 232
 233         /* check if we need to do software interrupts */
 234         movel   irq_stat+CPUSTAT_SOFTIRQ_PENDING,%d0
 235         jeq     ret_from_exception
 236
 237         pea     ret_from_exception
 238         jmp     do_softirq
 239
 240 /*
 241  * Beware - when entering resume, prev (the current task) is
 242  * in a0, next (the new task) is in a1,so don't change these
 243  * registers until their contents are no longer needed.
 244  */
 245 ENTRY(resume)
 246         movel   %a0, %d1                        /* get prev thread in d1 */
 247
 248         movew   %sr,%d0                         /* save thread status reg */
 249         movew   %d0,%a0@(TASK_THREAD+THREAD_SR)
 250
 251         oril    #0x700,%d0                      /* disable interrupts */
 252         move    %d0,%sr
 253
 254         movel   sw_usp,%d0                      /* save usp */
 255         movel   %d0,%a0@(TASK_THREAD+THREAD_USP)
 256
 257         SAVE_SWITCH_STACK
 258         movel   %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack pointer */
 259         movel   %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new thread stack */
 260         RESTORE_SWITCH_STACK
 261
 262         movel   %a1@(TASK_THREAD+THREAD_USP),%a0 /* restore thread user stack */
 263         movel   %a0, sw_usp
 264
 265         movew   %a1@(TASK_THREAD+THREAD_SR),%d0 /* restore thread status reg */
 266         movew   %d0, %sr
 267         rts
 268