entry.s

microwindows移植到S3C44B0的源码

/* -*- mode: asm -*-
 *
 *  linux/arch/m68knommu/platform/68360/entry.S
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2001 SED Systems, a Division of Calian Ltd.
 *
 * 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
 * M68360 Port by SED Systems, and Lineo.
 *
 */

/*
 * entry.S  contains the system-call and fault low-level handling routines.
 * This also contains the timer-interrupt handler, as well as all interrupts
 * and faults that can result in a task-switch.
 *
 * NOTE: This code handles signal-recognition, which happens every time
 * after a timer-interrupt and after each system call.
 *
 */

/*
 * 12/03/96 Jes: Currently we only support m68k single-cpu systems, so
 *               all pointers that used to be 'current' are now entry
 *               number 0 in the 'current_set' list.
 */

#include <linux/sys.h>
#include <linux/config.h>
#include <linux/linkage.h>
#include <asm/setup.h>
#include <asm/segment.h>

#include <asm/entry.h>
#include <asm/errno.h>
#include <asm/traps.h>

#include "m68k_defs.h"

#define IMMED #
#define DBG_PUTC(x) moveb IMMED x,0xfffff907; \
					moveb IMMED '\r',0xfffff907; \
					moveb IMMED '\n',0xfffff907
LD0         =   0x20
LORIG_D0    =   0x24

.globl SYMBOL_NAME(system_call)
.globl SYMBOL_NAME(buserr)
.globl SYMBOL_NAME(trap)
.globl SYMBOL_NAME(resume)
.globl SYMBOL_NAME(ret_from_exception)
.globl SYMBOL_NAME(ret_from_signal)
.globl SYMBOL_NAME(sys_call_table)
.globl SYMBOL_NAME(sys_fork)
.globl SYMBOL_NAME(sys_clone)
.globl SYMBOL_NAME(sys_vfork)
.globl SYMBOL_NAME(ret_from_interrupt)
.globl SYMBOL_NAME(bad_interrupt)
.globl SYMBOL_NAME(inthandler)

.text
ENTRY(buserr)
	SAVE_ALL_INT
	/* GET_CURRENT(%d0) */
	movel	%sp,%sp@- 		/* stack frame pointer argument*/
	bsrw	SYMBOL_NAME(buserr_c)
	addql	#4,%sp
	jra	SYMBOL_NAME(ret_from_exception)

ENTRY(trap)
	SAVE_ALL_INT
	GET_CURRENT(%d0)
    moveq.l #-1,%d0
    move.l  %d0,%sp@(LORIG_D0)
/* may have to test for LFORMATVEC here as was done in teh 2.0 module */
	movel	%sp,%sp@- 		/* stack frame pointer argument*/
	bsrw	SYMBOL_NAME(trap_c)
	addql	#4,%sp
	jra	SYMBOL_NAME(ret_from_exception)


ENTRY(reschedule)

	/* save top of frame*/
	movel   SYMBOL_NAME(_current_task),%a2
	movel	%sp,%a2@(TASK_THREAD+THREAD_ESP0)

	pea	SYMBOL_NAME(ret_from_exception)
	jmp	SYMBOL_NAME(schedule)

	/* After a fork we jump here directly from resume,*/
	/* so that %d1 contains the previous task*/
	/* Theoretically only needed on SMP, but let's watch*/
	/* what happens in schedule_tail() in future...*/
ENTRY(ret_from_fork)
	movel	%d1,%sp@-
	jsr	SYMBOL_NAME(schedule_tail)
	addql	#4,%sp
	jra	SYMBOL_NAME(ret_from_exception)

badsys:
	movel	#-ENOSYS,%sp@(PT_D0)
	jra	SYMBOL_NAME(ret_from_exception)

do_trace:
	movel	#-ENOSYS,%sp@(PT_D0)	/* needed for strace*/
	subql	#4,%sp
	SAVE_SWITCH_STACK
	jbsr	SYMBOL_NAME(syscall_trace)
	RESTORE_SWITCH_STACK
	addql	#4,%sp
	movel	%sp@(PT_ORIG_D0),%d1
	movel	#-ENOSYS,%d0
	cmpl	#NR_syscalls,%d1
	jcc	1f
/*	jbsr	@(SYMBOL_NAME(sys_call_table),%d1:l:4)@(0) */
	lsl	#2,%d1
#if 1
	lea	SYMBOL_NAME(sys_call_table), %a0
	jbsr	%a0@(%d1)
#else
	bsrw	SYMBOL_NAME(sys_call_table)@(%d1)
#endif

1:	movel	%d0,%sp@(PT_D0)		/* save the return value*/
	subql	#4,%sp			/* dummy return address*/
	SAVE_SWITCH_STACK
	jbsr	SYMBOL_NAME(syscall_trace)

SYMBOL_NAME_LABEL(ret_from_signal)
	RESTORE_SWITCH_STACK
	addql	#4,%sp
	jra	SYMBOL_NAME(ret_from_exception)

ENTRY(system_call)
	SAVE_ALL_SYS

	GET_CURRENT(%d1)
	/* save top of frame*/
	movel   SYMBOL_NAME(_current_task),%a2
	movel	%sp,%a2@(TASK_THREAD+THREAD_ESP0)

	btst	#PF_TRACESYS_BIT,%a2@(TASK_FLAGS+PF_TRACESYS_OFF)
	jne	do_trace
	cmpl	#NR_syscalls,%d0
	jcc	badsys
/*	jbsr	@(SYMBOL_NAME(sys_call_table),%d0:l:4)@(0) */
	lsl	#2,%d0
#if 1
	lea	SYMBOL_NAME(sys_call_table),%a0
	movel	%a0@(%d0), %a0
	jbsr	%a0@
#else
	jbsr	SYMBOL_NAME(sys_call_table)@(%d0)
#endif
	movel	%d0,%sp@(PT_D0)		/* save the return value*/

SYMBOL_NAME_LABEL(ret_from_exception)
	btst	#5,%sp@(PT_SR)		/* check if returning to kernel*/
	bnes	2f			/* if so, skip resched, signals*/
	/* only allow interrupts when we are really the last one on the*/
	/* kernel stack, otherwise stack overflow can occur during*/
	/* heavy interupt load*/
	andw	#ALLOWINT,%sr
	movel   SYMBOL_NAME(_current_task),%a2
	tstl	%a2@(TASK_NEEDRESCHED)
	jne	SYMBOL_NAME(reschedule)
#if 0
	cmpl	#SYMBOL_NAME(task),%a2	/* task[0] cannot have signals*/
	jeq	2f
#endif
					/* check for delayed trace*/
	bclr	#PF_DTRACE_BIT,%a2@(TASK_FLAGS+PF_DTRACE_OFF)
	jne	do_delayed_trace
5:
	tstl	%a2@(TASK_STATE)	/* state*/
	jne	SYMBOL_NAME(reschedule)

	tstl	%a2@(TASK_SIGPENDING)
	jne	Lsignal_return
2:	RESTORE_ALL

Lsignal_return:
	subql	#4,%sp			/* dummy return address*/
	SAVE_SWITCH_STACK
	pea	%sp@(SWITCH_STACK_SIZE)
	clrl	%sp@-
	bsrw	SYMBOL_NAME(do_signal)
	addql	#8,%sp
	RESTORE_SWITCH_STACK
	addql	#4,%sp

	/*
	 * if an app is getting tricky and using "a5",  the signal handler
	 * may trigger while "a5" is invalid,  so we have to set it here
	 */
	jbsr 	SYMBOL_NAME(get_pic_a5)
	movel	%d0, %a5

	RESTORE_ALL

do_delayed_trace:
	bclr	#7,%sp@(PT_SR)		/* clear trace bit in SR*/
	pea	1			/* send SIGTRAP*/
	movel	%a2,%sp@-
	pea	LSIGTRAP
	jbsr	SYMBOL_NAME(send_sig)
	addql	#8,%sp
	addql	#4,%sp
	jra	5b
/*
** This is the main interrupt handler, responsible for calling process_int()
*/

SYMBOL_NAME_LABEL(inthandler)
	SAVE_ALL_INT
	GET_CURRENT(%d0)
	addql	#1,SYMBOL_NAME(irq_stat)+CPUSTAT_LOCAL_IRQ_COUNT
					/*  put exception # in d0*/
/*	bfextu %sp@(PT_VECTOR){#4,#10},%d0 */
	movew	%sp@(PT_VECTOR), %d0
	and.l	#0x3ff, %d0
    lsr.l   #0x02,  %d0

	movel	%sp,%sp@-
	movel	%d0,%sp@- 		/*  put vector # on stack*/
	jbsr	SYMBOL_NAME(process_int)/*  process the IRQ*/
3:     	addql	#8,%sp			/*  pop parameters off stack*/
	bra	ret_from_interrupt

SYMBOL_NAME_LABEL(ret_from_interrupt)
	subql	#1,SYMBOL_NAME(irq_stat)+CPUSTAT_LOCAL_IRQ_COUNT
	jeq	1f
2:
	RESTORE_ALL
1:
#if 1
/*	bfextu  %sp@(PT_SR){#5,#3},%d0 */	/* Check for nested interrupt.*/
	moveb	%sp@(PT_SR), %d0
	and	#7, %d0

#if MAX_NOINT_IPL > 0
	cmpiw	#MAX_NOINT_IPL,%d0
#endif
	jhi	2b
#endif
	/* check if we need to do software interrupts */

	movel	SYMBOL_NAME(irq_stat)+CPUSTAT_SOFTIRQ_PENDING,%d0
	jeq	SYMBOL_NAME(ret_from_exception)

	pea	SYMBOL_NAME(ret_from_exception)
	jra	SYMBOL_NAME(do_softirq)


/* Handler for uninitialized and spurious interrupts */

SYMBOL_NAME_LABEL(bad_interrupt)
	addql	#1,SYMBOL_NAME(num_spurious)
	rte

ENTRY(sys_fork)
	SAVE_SWITCH_STACK	
	pea	%sp@(SWITCH_STACK_SIZE)
	jbsr	SYMBOL_NAME(m68k_fork)
	addql	#4,%sp
	RESTORE_SWITCH_STACK
	rts

ENTRY(sys_clone)
	SAVE_SWITCH_STACK
	pea	%sp@(SWITCH_STACK_SIZE)
	jbsr	SYMBOL_NAME(m68k_clone)
	addql	#4,%sp
	RESTORE_SWITCH_STACK
	rts

ENTRY(sys_vfork)
	SAVE_SWITCH_STACK	
	pea	%sp@(SWITCH_STACK_SIZE)
	jbsr	SYMBOL_NAME(m68k_vfork)
	addql	#4,%sp
	RESTORE_SWITCH_STACK
	rts

ENTRY(sys_sigsuspend)
	SAVE_SWITCH_STACK
	pea	%sp@(SWITCH_STACK_SIZE)
	jbsr	SYMBOL_NAME(do_sigsuspend)
	addql	#4,%sp
	RESTORE_SWITCH_STACK
	rts

ENTRY(sys_rt_sigsuspend)
	SAVE_SWITCH_STACK
	pea	%sp@(SWITCH_STACK_SIZE)
	jbsr	SYMBOL_NAME(do_rt_sigsuspend)