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linux/arch/m68knommu/platform/coldfire/entry.S
Sebastian Siewior c7bcd0df1f m68knommu: use one exist from execption 
Part of the code that did not make sense to me got removed by Greg.
This is part two:

The first compare is to check whether the interrupts are disabled or not.
Depending on the result we exectute the RESTORE_ALL macro is not only
restoring the stack but also returning to caller.
The test for pending softirq has been removed because it is allready done
in irq_exit().
Since system_call() is allso using the SAVE_ALL macro and returning via
ret_from_exception label I see no reason why we could not do this here
as well. This is also handy because if we return from the timer interrupt
and we need to resched than we check for this :)

Signed-off-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
2009-01-27 16:42:00 +10:00

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/*
* linux/arch/m68knommu/platform/5307/entry.S
*
* Copyright (C) 1999-2007, Greg Ungerer (gerg@snapgear.com)
* Copyright (C) 1998 D. Jeff Dionne <jeff@lineo.ca>,
* Kenneth Albanowski <kjahds@kjahds.com>,
* Copyright (C) 2000 Lineo Inc. (www.lineo.com)
* Copyright (C) 2004-2006 Macq Electronique SA. (www.macqel.com)
*
* Based on:
*
* linux/arch/m68k/kernel/entry.S
*
* 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
*
* 68060 fixes by Jesper Skov
* ColdFire support by Greg Ungerer (gerg@snapgear.com)
* 5307 fixes by David W. Miller
* linux 2.4 support David McCullough <davidm@snapgear.com>
* Bug, speed and maintainability fixes by Philippe De Muyter <phdm@macqel.be>
*/
#include <linux/sys.h>
#include <linux/linkage.h>
#include <asm/unistd.h>
#include <asm/thread_info.h>
#include <asm/errno.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/asm-offsets.h>
#include <asm/entry.h>
.bss
sw_ksp:
.long 0
sw_usp:
.long 0
.text
.globl system_call
.globl resume
.globl ret_from_exception
.globl ret_from_signal
.globl sys_call_table
.globl ret_from_interrupt
.globl inthandler
.globl fasthandler
enosys:
mov.l #sys_ni_syscall,%d3
bra 1f
ENTRY(system_call)
SAVE_ALL
move #0x2000,%sr /* enable intrs again */
cmpl #NR_syscalls,%d0
jcc enosys
lea sys_call_table,%a0
lsll #2,%d0 /* movel %a0@(%d0:l:4),%d3 */
movel %a0@(%d0),%d3
jeq enosys
1:
movel %sp,%d2 /* get thread_info pointer */
andl #-THREAD_SIZE,%d2 /* at start of kernel stack */
movel %d2,%a0
movel %a0@,%a1 /* save top of frame */
movel %sp,%a1@(TASK_THREAD+THREAD_ESP0)
btst #(TIF_SYSCALL_TRACE%8),%a0@(TI_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
bnes 1f
movel %d3,%a0
jbsr %a0@
movel %d0,%sp@(PT_D0) /* save the return value */
jra ret_from_exception
1:
movel #-ENOSYS,%d2 /* strace needs -ENOSYS in PT_D0 */
movel %d2,PT_D0(%sp) /* on syscall entry */
subql #4,%sp
SAVE_SWITCH_STACK
jbsr syscall_trace
RESTORE_SWITCH_STACK
addql #4,%sp
movel %d3,%a0
jbsr %a0@
movel %d0,%sp@(PT_D0) /* save the return value */
subql #4,%sp /* dummy return address */
SAVE_SWITCH_STACK
jbsr syscall_trace
ret_from_signal:
RESTORE_SWITCH_STACK
addql #4,%sp
ret_from_exception:
move #0x2700,%sr /* disable intrs */
btst #5,%sp@(PT_SR) /* check if returning to kernel */
jeq Luser_return /* if so, skip resched, signals */
#ifdef CONFIG_PREEMPT
movel %sp,%d1 /* get thread_info pointer */
andl #-THREAD_SIZE,%d1 /* at base of kernel stack */
movel %d1,%a0
movel %a0@(TI_FLAGS),%d1 /* get thread_info->flags */
andl #_TIF_NEED_RESCHED,%d1
jeq Lkernel_return
movel %a0@(TI_PREEMPTCOUNT),%d1
cmpl #0,%d1
jne Lkernel_return
pea Lkernel_return
jmp preempt_schedule_irq /* preempt the kernel */
#endif
Lkernel_return:
moveml %sp@,%d1-%d5/%a0-%a2
lea %sp@(32),%sp /* space for 8 regs */
movel %sp@+,%d0
addql #4,%sp /* orig d0 */
addl %sp@+,%sp /* stk adj */
rte
Luser_return:
movel %sp,%d1 /* get thread_info pointer */
andl #-THREAD_SIZE,%d1 /* at base of kernel stack */
movel %d1,%a0
movel %a0@(TI_FLAGS),%d1 /* get thread_info->flags */
andl #_TIF_WORK_MASK,%d1
jne Lwork_to_do /* still work to do */
Lreturn:
move #0x2700,%sr /* disable intrs */
movel sw_usp,%a0 /* get usp */
movel %sp@(PT_PC),%a0@- /* copy exception program counter */
movel %sp@(PT_FORMATVEC),%a0@-/* copy exception format/vector/sr */
moveml %sp@,%d1-%d5/%a0-%a2
lea %sp@(32),%sp /* space for 8 regs */
movel %sp@+,%d0
addql #4,%sp /* orig d0 */
addl %sp@+,%sp /* stk adj */
addql #8,%sp /* remove exception */
movel %sp,sw_ksp /* save ksp */
subql #8,sw_usp /* set exception */
movel sw_usp,%sp /* restore usp */
rte
Lwork_to_do:
movel %a0@(TI_FLAGS),%d1 /* get thread_info->flags */
move #0x2000,%sr /* enable intrs again */
btst #TIF_NEED_RESCHED,%d1
jne reschedule
/* GERG: do we need something here for TRACEing?? */
Lsignal_return:
subql #4,%sp /* dummy return address */
SAVE_SWITCH_STACK
pea %sp@(SWITCH_STACK_SIZE)
clrl %sp@-
jsr do_signal
addql #8,%sp
RESTORE_SWITCH_STACK
addql #4,%sp
jmp Lreturn
/*
* This is the generic interrupt handler (for all hardware interrupt
* sources). Calls upto high level code to do all the work.
*/
ENTRY(inthandler)
SAVE_ALL
moveq #-1,%d0
movel %d0,%sp@(PT_ORIG_D0)
movew %sp@(PT_FORMATVEC),%d0 /* put exception # in d0 */
andl #0x03fc,%d0 /* mask out vector only */
movel %sp,%sp@- /* push regs arg */
lsrl #2,%d0 /* calculate real vector # */
movel %d0,%sp@- /* push vector number */
jbsr do_IRQ /* call high level irq handler */
lea %sp@(8),%sp /* pop args off stack */
bra ret_from_interrupt /* this was fallthrough */
/*
* This is the fast interrupt handler (for certain hardware interrupt
* sources). Unlike the normal interrupt handler it just uses the
* current stack (doesn't care if it is user or kernel). It also
* doesn't bother doing the bottom half handlers.
*/
ENTRY(fasthandler)
SAVE_LOCAL
movew %sp@(PT_FORMATVEC),%d0
andl #0x03fc,%d0 /* mask out vector only */
movel %sp,%sp@- /* push regs arg */
lsrl #2,%d0 /* calculate real vector # */
movel %d0,%sp@- /* push vector number */
jbsr do_IRQ /* call high level irq handler */
lea %sp@(8),%sp /* pop args off stack */
RESTORE_LOCAL
ENTRY(ret_from_interrupt)
/* the fasthandler is confusing me, haven't seen any user */
jmp ret_from_exception
/*
* 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.
* This is always called in supervisor mode, so don't bother to save
* and restore sr; user's process sr is actually in the stack.
*/
ENTRY(resume)
movel %a0, %d1 /* get prev thread in d1 */
movel sw_usp,%d0 /* save usp */
movel %d0,%a0@(TASK_THREAD+THREAD_USP)
SAVE_SWITCH_STACK
movel %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack pointer */
movel %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new thread stack */
RESTORE_SWITCH_STACK
movel %a1@(TASK_THREAD+THREAD_USP),%a0 /* restore thread user stack */
movel %a0, sw_usp
rts
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