2 * entry.S -- interrupt and exception processing for ColdFire
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)
12 * linux/arch/m68k/kernel/entry.S
14 * Copyright (C) 1991, 1992 Linus Torvalds
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
20 * Linux/m68k support by Hamish Macdonald
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>
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>
38 #ifdef CONFIG_COLDFIRE_SW_A7
40 * Define software copies of the supervisor and user stack pointers.
47 #endif /* CONFIG_COLDFIRE_SW_A7 */
53 .globl ret_from_exception
54 .globl ret_from_signal
59 mov.l #sys_ni_syscall,%d3
64 move #0x2000,%sr /* enable intrs again */
69 lea sys_call_table,%a0
70 lsll #2,%d0 /* movel %a0@(%d0:l:4),%d3 */
75 movel %sp,%d2 /* get thread_info pointer */
76 andl #-THREAD_SIZE,%d2 /* at start of kernel stack */
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)
85 movel %d0,%sp@(PT_OFF_D0) /* save the return value */
86 jra ret_from_exception
88 movel #-ENOSYS,%d2 /* strace needs -ENOSYS in PT_OFF_D0 */
89 movel %d2,PT_OFF_D0(%sp) /* on syscall entry */
92 jbsr syscall_trace_enter
96 jeq ret_from_exception
99 movel %d0,%sp@(PT_OFF_D0) /* save the return value */
100 subql #4,%sp /* dummy return address */
102 jbsr syscall_trace_leave
109 move #0x2700,%sr /* disable intrs */
110 btst #5,%sp@(PT_OFF_SR) /* check if returning to kernel */
111 jeq Luser_return /* if so, skip resched, signals */
113 #ifdef CONFIG_PREEMPT
114 movel %sp,%d1 /* get thread_info pointer */
115 andl #-THREAD_SIZE,%d1 /* at base of kernel stack */
117 movel %a0@(TINFO_FLAGS),%d1 /* get thread_info->flags */
118 andl #(1<<TIF_NEED_RESCHED),%d1
121 movel %a0@(TINFO_PREEMPT),%d1
126 jmp preempt_schedule_irq /* preempt the kernel */
130 moveml %sp@,%d1-%d5/%a0-%a2
131 lea %sp@(32),%sp /* space for 8 regs */
133 addql #4,%sp /* orig d0 */
134 addl %sp@+,%sp /* stk adj */
138 movel %sp,%d1 /* get thread_info pointer */
139 andl #-THREAD_SIZE,%d1 /* at base of kernel stack */
141 moveb %a0@(TINFO_FLAGS+3),%d1 /* thread_info->flags (low 8 bits) */
142 jne Lwork_to_do /* still work to do */
148 movel %a0@(TINFO_FLAGS),%d1 /* get thread_info->flags */
149 move #0x2000,%sr /* enable intrs again */
150 btst #TIF_NEED_RESCHED,%d1
154 subql #4,%sp /* dummy return address */
156 pea %sp@(SWITCH_STACK_SIZE)
164 * This is the generic interrupt handler (for all hardware interrupt
165 * sources). Calls up to high level code to do all the work.
171 movew %sp@(PT_OFF_FORMATVEC),%d0 /* put exception # in d0 */
172 andl #0x03fc,%d0 /* mask out vector only */
174 movel %sp,%sp@- /* push regs arg */
175 lsrl #2,%d0 /* calculate real vector # */
176 movel %d0,%sp@- /* push vector number */
177 jbsr do_IRQ /* call high level irq handler */
178 lea %sp@(8),%sp /* pop args off stack */
180 bra ret_from_exception
183 * Beware - when entering resume, prev (the current task) is
184 * in a0, next (the new task) is in a1, so don't change these
185 * registers until their contents are no longer needed.
188 movew %sr,%d1 /* save current status */
189 movew %d1,%a0@(TASK_THREAD+THREAD_SR)
190 movel %a0,%d1 /* get prev thread in d1 */
192 movel %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack pointer */
193 RDUSP /* movel %usp,%a3 */
194 movel %a3,%a0@(TASK_THREAD+THREAD_USP) /* save thread user stack */
196 movel %a1,%a2 /* set new current */
198 movel %a1@(TASK_THREAD+THREAD_USP),%a3 /* restore thread user stack */
199 WRUSP /* movel %a3,%usp */
200 movel %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new kernel stack */
201 movew %a1@(TASK_THREAD+THREAD_SR),%d7 /* restore new status */