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-rw-r--r--arch/m68k/68000/entry.S244
1 files changed, 244 insertions, 0 deletions
diff --git a/arch/m68k/68000/entry.S b/arch/m68k/68000/entry.S
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+++ b/arch/m68k/68000/entry.S
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+/*
+ * entry.S -- non-mmu 68000 interrupt and exception entry points
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file README.legal in the main directory of this archive
+ * for more details.
+ *
+ * Linux/m68k support by Hamish Macdonald
+ */
+
+#include <linux/linkage.h>
+#include <asm/thread_info.h>
+#include <asm/unistd.h>
+#include <asm/errno.h>
+#include <asm/setup.h>
+#include <asm/segment.h>
+#include <asm/traps.h>
+#include <asm/asm-offsets.h>
+#include <asm/entry.h>
+
+.text
+
+.globl system_call
+.globl resume
+.globl ret_from_exception
+.globl ret_from_signal
+.globl sys_call_table
+.globl bad_interrupt
+.globl inthandler1
+.globl inthandler2
+.globl inthandler3
+.globl inthandler4
+.globl inthandler5
+.globl inthandler6
+.globl inthandler7
+
+badsys:
+ movel #-ENOSYS,%sp@(PT_OFF_D0)
+ jra ret_from_exception
+
+do_trace:
+ movel #-ENOSYS,%sp@(PT_OFF_D0) /* needed for strace*/
+ subql #4,%sp
+ SAVE_SWITCH_STACK
+ jbsr syscall_trace_enter
+ RESTORE_SWITCH_STACK
+ addql #4,%sp
+ movel %sp@(PT_OFF_ORIG_D0),%d1
+ movel #-ENOSYS,%d0
+ cmpl #NR_syscalls,%d1
+ jcc 1f
+ lsl #2,%d1
+ lea sys_call_table, %a0
+ jbsr %a0@(%d1)
+
+1: movel %d0,%sp@(PT_OFF_D0) /* save the return value */
+ subql #4,%sp /* dummy return address */
+ SAVE_SWITCH_STACK
+ jbsr syscall_trace_leave
+
+ret_from_signal:
+ RESTORE_SWITCH_STACK
+ addql #4,%sp
+ jra ret_from_exception
+
+ENTRY(system_call)
+ SAVE_ALL_SYS
+
+ /* save top of frame*/
+ pea %sp@
+ jbsr set_esp0
+ addql #4,%sp
+
+ movel %sp@(PT_OFF_ORIG_D0),%d0
+
+ movel %sp,%d1 /* get thread_info pointer */
+ andl #-THREAD_SIZE,%d1
+ movel %d1,%a2
+ btst #(TIF_SYSCALL_TRACE%8),%a2@(TINFO_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
+ jne do_trace
+ cmpl #NR_syscalls,%d0
+ jcc badsys
+ lsl #2,%d0
+ lea sys_call_table,%a0
+ movel %a0@(%d0), %a0
+ jbsr %a0@
+ movel %d0,%sp@(PT_OFF_D0) /* save the return value*/
+
+ret_from_exception:
+ btst #5,%sp@(PT_OFF_SR) /* check if returning to kernel*/
+ jeq Luser_return /* if so, skip resched, signals*/
+
+Lkernel_return:
+ RESTORE_ALL
+
+Luser_return:
+ /* only allow interrupts when we are really the last one on the*/
+ /* kernel stack, otherwise stack overflow can occur during*/
+ /* heavy interrupt load*/
+ andw #ALLOWINT,%sr
+
+ movel %sp,%d1 /* get thread_info pointer */
+ andl #-THREAD_SIZE,%d1
+ movel %d1,%a2
+1:
+ move %a2@(TINFO_FLAGS),%d1 /* thread_info->flags */
+ jne Lwork_to_do
+ RESTORE_ALL
+
+Lwork_to_do:
+ movel %a2@(TINFO_FLAGS),%d1 /* thread_info->flags */
+ btst #TIF_NEED_RESCHED,%d1
+ jne reschedule
+
+Lsignal_return:
+ subql #4,%sp /* dummy return address*/
+ SAVE_SWITCH_STACK
+ pea %sp@(SWITCH_STACK_SIZE)
+ bsrw do_notify_resume
+ addql #4,%sp
+ RESTORE_SWITCH_STACK
+ addql #4,%sp
+ jra 1b
+
+/*
+ * This is the main interrupt handler, responsible for calling process_int()
+ */
+inthandler1:
+ SAVE_ALL_INT
+ movew %sp@(PT_OFF_FORMATVEC), %d0
+ and #0x3ff, %d0
+
+ movel %sp,%sp@-
+ movel #65,%sp@- /* put vector # on stack*/
+ jbsr process_int /* process the IRQ*/
+3: addql #8,%sp /* pop parameters off stack*/
+ bra ret_from_exception
+
+inthandler2:
+ SAVE_ALL_INT
+ movew %sp@(PT_OFF_FORMATVEC), %d0
+ and #0x3ff, %d0
+
+ movel %sp,%sp@-
+ movel #66,%sp@- /* put vector # on stack*/
+ jbsr process_int /* process the IRQ*/
+3: addql #8,%sp /* pop parameters off stack*/
+ bra ret_from_exception
+
+inthandler3:
+ SAVE_ALL_INT
+ movew %sp@(PT_OFF_FORMATVEC), %d0
+ and #0x3ff, %d0
+
+ movel %sp,%sp@-
+ movel #67,%sp@- /* put vector # on stack*/
+ jbsr process_int /* process the IRQ*/
+3: addql #8,%sp /* pop parameters off stack*/
+ bra ret_from_exception
+
+inthandler4:
+ SAVE_ALL_INT
+ movew %sp@(PT_OFF_FORMATVEC), %d0
+ and #0x3ff, %d0
+
+ movel %sp,%sp@-
+ movel #68,%sp@- /* put vector # on stack*/
+ jbsr process_int /* process the IRQ*/
+3: addql #8,%sp /* pop parameters off stack*/
+ bra ret_from_exception
+
+inthandler5:
+ SAVE_ALL_INT
+ movew %sp@(PT_OFF_FORMATVEC), %d0
+ and #0x3ff, %d0
+
+ movel %sp,%sp@-
+ movel #69,%sp@- /* put vector # on stack*/
+ jbsr process_int /* process the IRQ*/
+3: addql #8,%sp /* pop parameters off stack*/
+ bra ret_from_exception
+
+inthandler6:
+ SAVE_ALL_INT
+ movew %sp@(PT_OFF_FORMATVEC), %d0
+ and #0x3ff, %d0
+
+ movel %sp,%sp@-
+ movel #70,%sp@- /* put vector # on stack*/
+ jbsr process_int /* process the IRQ*/
+3: addql #8,%sp /* pop parameters off stack*/
+ bra ret_from_exception
+
+inthandler7:
+ SAVE_ALL_INT
+ movew %sp@(PT_OFF_FORMATVEC), %d0
+ and #0x3ff, %d0
+
+ movel %sp,%sp@-
+ movel #71,%sp@- /* put vector # on stack*/
+ jbsr process_int /* process the IRQ*/
+3: addql #8,%sp /* pop parameters off stack*/
+ bra ret_from_exception
+
+inthandler:
+ SAVE_ALL_INT
+ movew %sp@(PT_OFF_FORMATVEC), %d0
+ and #0x3ff, %d0
+
+ movel %sp,%sp@-
+ movel %d0,%sp@- /* put vector # on stack*/
+ jbsr process_int /* process the IRQ*/
+3: addql #8,%sp /* pop parameters off stack*/
+ bra ret_from_exception
+
+/*
+ * Handler for uninitialized and spurious interrupts.
+ */
+ENTRY(bad_interrupt)
+ addql #1,irq_err_count
+ rte
+
+/*
+ * Beware - when entering resume, prev (the current task) is
+ * in a0, next (the new task) is in a1, so don't change these
+ * registers until their contents are no longer needed.
+ */
+ENTRY(resume)
+ movel %a0,%d1 /* save prev thread in d1 */
+ movew %sr,%a0@(TASK_THREAD+THREAD_SR) /* save sr */
+ SAVE_SWITCH_STACK
+ movel %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack */
+ movel %usp,%a3 /* save usp */
+ movel %a3,%a0@(TASK_THREAD+THREAD_USP)
+
+ movel %a1@(TASK_THREAD+THREAD_USP),%a3 /* restore user stack */
+ movel %a3,%usp
+ movel %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new thread stack */
+ RESTORE_SWITCH_STACK
+ movew %a1@(TASK_THREAD+THREAD_SR),%sr /* restore thread status reg */
+ rts
+