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linux-sg2042/arch/m68k/kernel/entry.S

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m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
/* -*- mode: asm -*-
*
* 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
*
*/
/*
* 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.
*
* 6/05/00 RZ: addedd writeback completion after return from sighandler
* for 68040
*/
#include <linux/linkage.h>
#include <asm/errno.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/traps.h>
#include <asm/unistd.h>
#include <asm/asm-offsets.h>
#include <asm/entry.h>
.globl system_call, buserr, trap, resume
.globl sys_call_table
m68k: sanitize copy_thread(), fork/vfork/clone wrappers, switch to generic fork/vfork Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-22 04:41:46 +08:00
.globl __sys_fork, __sys_clone, __sys_vfork
m68k: Simplify low level interrupt handling code The low level interrupt entry code of m68k contains the following: add_preempt_count(HARDIRQ_OFFSET); do_IRQ(); irq_enter(); add_preempt_count(HARDIRQ_OFFSET); handle_interrupt(); irq_exit(); sub_preempt_count(HARDIRQ_OFFSET); if (in_interrupt()) return; <---- On m68k always taken! if (local_softirq_pending()) do_softirq(); sub_preempt_count(HARDIRQ_OFFSET); if (in_hardirq()) return; if (status_on_stack_has_interrupt_priority_mask > 0) return; if (local_softirq_pending()) do_softirq(); ret_from_exception: if (interrupted_context_is_kernel) return: .... I tried to find a proper explanation for this, but the changelog is sparse and there are no mails explaining it further. But obviously this relates to the interrupt priority levels of the m68k and tries to be extra clever with nested interrupts. Though this cleverness just adds code bloat to the interrupt hotpath. For the common case of non nested interrupts the code runs through two extra conditionals to the only important one, which checks whether the return is to kernel or user space. For the nested case the checks for in_hardirq() and the priority mask value on stack catch only the case where the nested interrupt happens inside the hard irq context of the first interrupt. If the nested interrupt happens while the first interrupt handles soft interrupts, then these extra checks buy nothing. The nested interrupt will fall through to the final kernel/user space return check at ret_from_exception. Changing the code flow in the following way: do_IRQ(); irq_enter(); add_preempt_count(HARDIRQ_OFFSET); handle_interrupt(); irq_exit(); sub_preempt_count(HARDIRQ_OFFSET); if (in_interrupt()) return; if (local_softirq_pending()) do_softirq(); ret_from_exception: if (interrupted_context_is_kernel) return: makes the region protected by the hardirq count slightly smaller and the softirq handling is invoked with a minimal deeper stack. But otherwise it's completely functional equivalent and saves 104 bytes of text in arch/m68k/kernel/entry.o. This modification allows us further to get rid of the limitations which m68k puts on the preempt_count layout, so we can make the preempt count bits completely generic. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Michael Schmitz <schmitz@biophys.uni-duesseldorf.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Linux/m68k <linux-m68k@vger.kernel.org> Cc: Andreas Schwab <schwab@linux-m68k.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1311112052360.30673@ionos.tec.linutronix.de
2013-11-12 04:01:03 +08:00
.globl bad_interrupt
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
.globl auto_irqhandler_fixup
.globl user_irqvec_fixup
.text
m68k: sanitize copy_thread(), fork/vfork/clone wrappers, switch to generic fork/vfork Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-22 04:41:46 +08:00
ENTRY(__sys_fork)
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
SAVE_SWITCH_STACK
m68k: sanitize copy_thread(), fork/vfork/clone wrappers, switch to generic fork/vfork Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-22 04:41:46 +08:00
jbsr sys_fork
lea %sp@(24),%sp
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
rts
m68k: sanitize copy_thread(), fork/vfork/clone wrappers, switch to generic fork/vfork Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-22 04:41:46 +08:00
ENTRY(__sys_clone)
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
SAVE_SWITCH_STACK
pea %sp@(SWITCH_STACK_SIZE)
jbsr m68k_clone
m68k: sanitize copy_thread(), fork/vfork/clone wrappers, switch to generic fork/vfork Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-22 04:41:46 +08:00
lea %sp@(28),%sp
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
rts
m68k: sanitize copy_thread(), fork/vfork/clone wrappers, switch to generic fork/vfork Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-22 04:41:46 +08:00
ENTRY(__sys_vfork)
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
SAVE_SWITCH_STACK
m68k: sanitize copy_thread(), fork/vfork/clone wrappers, switch to generic fork/vfork Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-22 04:41:46 +08:00
jbsr sys_vfork
lea %sp@(24),%sp
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
rts
ENTRY(sys_sigreturn)
SAVE_SWITCH_STACK
jbsr do_sigreturn
RESTORE_SWITCH_STACK
rts
ENTRY(sys_rt_sigreturn)
SAVE_SWITCH_STACK
jbsr do_rt_sigreturn
RESTORE_SWITCH_STACK
rts
ENTRY(buserr)
SAVE_ALL_INT
GET_CURRENT(%d0)
movel %sp,%sp@- | stack frame pointer argument
jbsr buserr_c
addql #4,%sp
jra ret_from_exception
ENTRY(trap)
SAVE_ALL_INT
GET_CURRENT(%d0)
movel %sp,%sp@- | stack frame pointer argument
jbsr trap_c
addql #4,%sp
jra ret_from_exception
| After a fork we jump here directly from resume,
| so that %d1 contains the previous task
| schedule_tail now used regardless of CONFIG_SMP
ENTRY(ret_from_fork)
movel %d1,%sp@-
jsr schedule_tail
addql #4,%sp
jra ret_from_exception
m68k: split ret_from_fork(), simplify kernel_thread() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-17 00:05:09 +08:00
ENTRY(ret_from_kernel_thread)
| a3 contains the kernel thread payload, d7 - its argument
movel %d1,%sp@-
jsr schedule_tail
movel %d7,(%sp)
jsr %a3@
addql #4,%sp
m68k: switch to generic sys_execve()/kernel_execve() The tricky part here is that task_pt_regs() on m68k works *only* for process inside do_signal(). However, we need something much simpler - pt_regs of a process inside do_signal() may be at different offsets from the stack bottom, depending on the way we'd entered the kernel, but for a task inside sys_execve() it *is* at constant offset. Moreover, for a kernel thread about to become a userland process the same location is also fine - setting sp to that will leave the kernel stack pointer at the very bottom of the kernel stack when we finally switch to userland. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-17 00:06:34 +08:00
jra ret_from_exception
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
#if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)
#ifdef TRAP_DBG_INTERRUPT
.globl dbginterrupt
ENTRY(dbginterrupt)
SAVE_ALL_INT
GET_CURRENT(%d0)
movel %sp,%sp@- /* stack frame pointer argument */
jsr dbginterrupt_c
addql #4,%sp
jra ret_from_exception
#endif
ENTRY(reschedule)
/* save top of frame */
pea %sp@
jbsr set_esp0
addql #4,%sp
pea ret_from_exception
jmp schedule
ENTRY(ret_from_user_signal)
moveq #__NR_sigreturn,%d0
trap #0
ENTRY(ret_from_user_rt_signal)
movel #__NR_rt_sigreturn,%d0
trap #0
m68k: merge m68k and m68knommu arch directories There is a lot of common code that could be shared between the m68k and m68knommu arch branches. It makes sense to merge the two branches into a single directory structure so that we can more easily share that common code. This is a brute force merge, based on a script from Stephen King <sfking@fdwdc.com>, which was originally written by Arnd Bergmann <arnd@arndb.de>. > The script was inspired by the script Sam Ravnborg used to merge the > includes from m68knommu. For those files common to both arches but > differing in content, the m68k version of the file is renamed to > <file>_mm.<ext> and the m68knommu version of the file is moved into the > corresponding m68k directory and renamed <file>_no.<ext> and a small > wrapper file <file>.<ext> is used to select between the two version. Files > that are common to both but don't differ are removed from the m68knommu > tree and files and directories that are unique to the m68knommu tree are > moved to the m68k tree. Finally, the arch/m68knommu tree is removed. > > To select between the the versions of the files, the wrapper uses > > #ifdef CONFIG_MMU > #include <file>_mm.<ext> > #else > #include <file>_no.<ext> > #endif On top of this file merge I have done a simplistic merge of m68k and m68knommu Kconfig, which primarily attempts to keep existing options and menus in place. Other than a handful of options being moved it produces identical .config outputs on m68k and m68knommu targets I tested it on. With this in place there is now quite a bit of scope for merge cleanups in future patches. Signed-off-by: Greg Ungerer <gerg@uclinux.org>
2011-03-22 11:39:27 +08:00
#else
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
do_trace_entry:
movel #-ENOSYS,%sp@(PT_OFF_D0)| needed for strace
subql #4,%sp
SAVE_SWITCH_STACK
jbsr syscall_trace
RESTORE_SWITCH_STACK
addql #4,%sp
movel %sp@(PT_OFF_ORIG_D0),%d0
cmpl #NR_syscalls,%d0
jcs syscall
badsys:
movel #-ENOSYS,%sp@(PT_OFF_D0)
jra ret_from_syscall
do_trace_exit:
subql #4,%sp
SAVE_SWITCH_STACK
jbsr syscall_trace
RESTORE_SWITCH_STACK
addql #4,%sp
jra .Lret_from_exception
ENTRY(ret_from_signal)
movel %curptr@(TASK_STACK),%a1
tstb %a1@(TINFO_FLAGS+2)
jge 1f
jbsr syscall_trace
1: RESTORE_SWITCH_STACK
addql #4,%sp
/* on 68040 complete pending writebacks if any */
#ifdef CONFIG_M68040
bfextu %sp@(PT_OFF_FORMATVEC){#0,#4},%d0
subql #7,%d0 | bus error frame ?
jbne 1f
movel %sp,%sp@-
jbsr berr_040cleanup
addql #4,%sp
1:
#endif
jra .Lret_from_exception
ENTRY(system_call)
SAVE_ALL_SYS
GET_CURRENT(%d1)
movel %d1,%a1
| save top of frame
movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
| syscall trace?
tstb %a1@(TINFO_FLAGS+2)
jmi do_trace_entry
cmpl #NR_syscalls,%d0
jcc badsys
syscall:
jbsr @(sys_call_table,%d0:l:4)@(0)
movel %d0,%sp@(PT_OFF_D0) | save the return value
ret_from_syscall:
|oriw #0x0700,%sr
movel %curptr@(TASK_STACK),%a1
movew %a1@(TINFO_FLAGS+2),%d0
jne syscall_exit_work
1: RESTORE_ALL
syscall_exit_work:
btst #5,%sp@(PT_OFF_SR) | check if returning to kernel
bnes 1b | if so, skip resched, signals
lslw #1,%d0
jcs do_trace_exit
jmi do_delayed_trace
lslw #8,%d0
jne do_signal_return
pea resume_userspace
jra schedule
ENTRY(ret_from_exception)
.Lret_from_exception:
btst #5,%sp@(PT_OFF_SR) | check if returning to kernel
bnes 1f | 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 interrupt load
andw #ALLOWINT,%sr
resume_userspace:
movel %curptr@(TASK_STACK),%a1
moveb %a1@(TINFO_FLAGS+3),%d0
jne exit_work
1: RESTORE_ALL
exit_work:
| save top of frame
movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
lslb #1,%d0
jne do_signal_return
pea resume_userspace
jra schedule
do_signal_return:
|andw #ALLOWINT,%sr
subql #4,%sp | dummy return address
SAVE_SWITCH_STACK
pea %sp@(SWITCH_STACK_SIZE)
bsrl do_notify_resume
addql #4,%sp
RESTORE_SWITCH_STACK
addql #4,%sp
jbra resume_userspace
do_delayed_trace:
bclr #7,%sp@(PT_OFF_SR) | clear trace bit in SR
pea 1 | send SIGTRAP
movel %curptr,%sp@-
pea LSIGTRAP
jbsr send_sig
addql #8,%sp
addql #4,%sp
jbra resume_userspace
/* This is the main interrupt handler for autovector interrupts */
ENTRY(auto_inthandler)
SAVE_ALL_INT
GET_CURRENT(%d0)
| put exception # in d0
bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
subw #VEC_SPUR,%d0
movel %sp,%sp@-
movel %d0,%sp@- | put vector # on stack
auto_irqhandler_fixup = . + 2
jsr do_IRQ | process the IRQ
addql #8,%sp | pop parameters off stack
m68k: Simplify low level interrupt handling code The low level interrupt entry code of m68k contains the following: add_preempt_count(HARDIRQ_OFFSET); do_IRQ(); irq_enter(); add_preempt_count(HARDIRQ_OFFSET); handle_interrupt(); irq_exit(); sub_preempt_count(HARDIRQ_OFFSET); if (in_interrupt()) return; <---- On m68k always taken! if (local_softirq_pending()) do_softirq(); sub_preempt_count(HARDIRQ_OFFSET); if (in_hardirq()) return; if (status_on_stack_has_interrupt_priority_mask > 0) return; if (local_softirq_pending()) do_softirq(); ret_from_exception: if (interrupted_context_is_kernel) return: .... I tried to find a proper explanation for this, but the changelog is sparse and there are no mails explaining it further. But obviously this relates to the interrupt priority levels of the m68k and tries to be extra clever with nested interrupts. Though this cleverness just adds code bloat to the interrupt hotpath. For the common case of non nested interrupts the code runs through two extra conditionals to the only important one, which checks whether the return is to kernel or user space. For the nested case the checks for in_hardirq() and the priority mask value on stack catch only the case where the nested interrupt happens inside the hard irq context of the first interrupt. If the nested interrupt happens while the first interrupt handles soft interrupts, then these extra checks buy nothing. The nested interrupt will fall through to the final kernel/user space return check at ret_from_exception. Changing the code flow in the following way: do_IRQ(); irq_enter(); add_preempt_count(HARDIRQ_OFFSET); handle_interrupt(); irq_exit(); sub_preempt_count(HARDIRQ_OFFSET); if (in_interrupt()) return; if (local_softirq_pending()) do_softirq(); ret_from_exception: if (interrupted_context_is_kernel) return: makes the region protected by the hardirq count slightly smaller and the softirq handling is invoked with a minimal deeper stack. But otherwise it's completely functional equivalent and saves 104 bytes of text in arch/m68k/kernel/entry.o. This modification allows us further to get rid of the limitations which m68k puts on the preempt_count layout, so we can make the preempt count bits completely generic. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Michael Schmitz <schmitz@biophys.uni-duesseldorf.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Linux/m68k <linux-m68k@vger.kernel.org> Cc: Andreas Schwab <schwab@linux-m68k.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1311112052360.30673@ionos.tec.linutronix.de
2013-11-12 04:01:03 +08:00
jra ret_from_exception
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
/* Handler for user defined interrupt vectors */
ENTRY(user_inthandler)
SAVE_ALL_INT
GET_CURRENT(%d0)
| put exception # in d0
bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
user_irqvec_fixup = . + 2
subw #VEC_USER,%d0
movel %sp,%sp@-
movel %d0,%sp@- | put vector # on stack
jsr do_IRQ | process the IRQ
addql #8,%sp | pop parameters off stack
m68k: Simplify low level interrupt handling code The low level interrupt entry code of m68k contains the following: add_preempt_count(HARDIRQ_OFFSET); do_IRQ(); irq_enter(); add_preempt_count(HARDIRQ_OFFSET); handle_interrupt(); irq_exit(); sub_preempt_count(HARDIRQ_OFFSET); if (in_interrupt()) return; <---- On m68k always taken! if (local_softirq_pending()) do_softirq(); sub_preempt_count(HARDIRQ_OFFSET); if (in_hardirq()) return; if (status_on_stack_has_interrupt_priority_mask > 0) return; if (local_softirq_pending()) do_softirq(); ret_from_exception: if (interrupted_context_is_kernel) return: .... I tried to find a proper explanation for this, but the changelog is sparse and there are no mails explaining it further. But obviously this relates to the interrupt priority levels of the m68k and tries to be extra clever with nested interrupts. Though this cleverness just adds code bloat to the interrupt hotpath. For the common case of non nested interrupts the code runs through two extra conditionals to the only important one, which checks whether the return is to kernel or user space. For the nested case the checks for in_hardirq() and the priority mask value on stack catch only the case where the nested interrupt happens inside the hard irq context of the first interrupt. If the nested interrupt happens while the first interrupt handles soft interrupts, then these extra checks buy nothing. The nested interrupt will fall through to the final kernel/user space return check at ret_from_exception. Changing the code flow in the following way: do_IRQ(); irq_enter(); add_preempt_count(HARDIRQ_OFFSET); handle_interrupt(); irq_exit(); sub_preempt_count(HARDIRQ_OFFSET); if (in_interrupt()) return; if (local_softirq_pending()) do_softirq(); ret_from_exception: if (interrupted_context_is_kernel) return: makes the region protected by the hardirq count slightly smaller and the softirq handling is invoked with a minimal deeper stack. But otherwise it's completely functional equivalent and saves 104 bytes of text in arch/m68k/kernel/entry.o. This modification allows us further to get rid of the limitations which m68k puts on the preempt_count layout, so we can make the preempt count bits completely generic. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Michael Schmitz <schmitz@biophys.uni-duesseldorf.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Linux/m68k <linux-m68k@vger.kernel.org> Cc: Andreas Schwab <schwab@linux-m68k.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1311112052360.30673@ionos.tec.linutronix.de
2013-11-12 04:01:03 +08:00
jra ret_from_exception
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
/* Handler for uninitialized and spurious interrupts */
ENTRY(bad_inthandler)
SAVE_ALL_INT
GET_CURRENT(%d0)
movel %sp,%sp@-
jsr handle_badint
addql #4,%sp
m68k: Simplify low level interrupt handling code The low level interrupt entry code of m68k contains the following: add_preempt_count(HARDIRQ_OFFSET); do_IRQ(); irq_enter(); add_preempt_count(HARDIRQ_OFFSET); handle_interrupt(); irq_exit(); sub_preempt_count(HARDIRQ_OFFSET); if (in_interrupt()) return; <---- On m68k always taken! if (local_softirq_pending()) do_softirq(); sub_preempt_count(HARDIRQ_OFFSET); if (in_hardirq()) return; if (status_on_stack_has_interrupt_priority_mask > 0) return; if (local_softirq_pending()) do_softirq(); ret_from_exception: if (interrupted_context_is_kernel) return: .... I tried to find a proper explanation for this, but the changelog is sparse and there are no mails explaining it further. But obviously this relates to the interrupt priority levels of the m68k and tries to be extra clever with nested interrupts. Though this cleverness just adds code bloat to the interrupt hotpath. For the common case of non nested interrupts the code runs through two extra conditionals to the only important one, which checks whether the return is to kernel or user space. For the nested case the checks for in_hardirq() and the priority mask value on stack catch only the case where the nested interrupt happens inside the hard irq context of the first interrupt. If the nested interrupt happens while the first interrupt handles soft interrupts, then these extra checks buy nothing. The nested interrupt will fall through to the final kernel/user space return check at ret_from_exception. Changing the code flow in the following way: do_IRQ(); irq_enter(); add_preempt_count(HARDIRQ_OFFSET); handle_interrupt(); irq_exit(); sub_preempt_count(HARDIRQ_OFFSET); if (in_interrupt()) return; if (local_softirq_pending()) do_softirq(); ret_from_exception: if (interrupted_context_is_kernel) return: makes the region protected by the hardirq count slightly smaller and the softirq handling is invoked with a minimal deeper stack. But otherwise it's completely functional equivalent and saves 104 bytes of text in arch/m68k/kernel/entry.o. This modification allows us further to get rid of the limitations which m68k puts on the preempt_count layout, so we can make the preempt count bits completely generic. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Michael Schmitz <schmitz@biophys.uni-duesseldorf.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Linux/m68k <linux-m68k@vger.kernel.org> Cc: Andreas Schwab <schwab@linux-m68k.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1311112052360.30673@ionos.tec.linutronix.de
2013-11-12 04:01:03 +08:00
jra ret_from_exception
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
resume:
/*
* 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.
*/
/* save sr */
movew %sr,%a0@(TASK_THREAD+THREAD_SR)
/* save fs (sfc,%dfc) (may be pointing to kernel memory) */
movec %sfc,%d0
movew %d0,%a0@(TASK_THREAD+THREAD_FS)
/* save usp */
/* it is better to use a movel here instead of a movew 8*) */
movec %usp,%d0
movel %d0,%a0@(TASK_THREAD+THREAD_USP)
/* save non-scratch registers on stack */
SAVE_SWITCH_STACK
/* save current kernel stack pointer */
movel %sp,%a0@(TASK_THREAD+THREAD_KSP)
/* save floating point context */
#ifndef CONFIG_M68KFPU_EMU_ONLY
#ifdef CONFIG_M68KFPU_EMU
tstl m68k_fputype
jeq 3f
#endif
fsave %a0@(TASK_THREAD+THREAD_FPSTATE)
#if defined(CONFIG_M68060)
#if !defined(CPU_M68060_ONLY)
btst #3,m68k_cputype+3
beqs 1f
#endif
/* The 060 FPU keeps status in bits 15-8 of the first longword */
tstb %a0@(TASK_THREAD+THREAD_FPSTATE+2)
jeq 3f
#if !defined(CPU_M68060_ONLY)
jra 2f
#endif
#endif /* CONFIG_M68060 */
#if !defined(CPU_M68060_ONLY)
1: tstb %a0@(TASK_THREAD+THREAD_FPSTATE)
jeq 3f
#endif
2: fmovemx %fp0-%fp7,%a0@(TASK_THREAD+THREAD_FPREG)
fmoveml %fpcr/%fpsr/%fpiar,%a0@(TASK_THREAD+THREAD_FPCNTL)
3:
#endif /* CONFIG_M68KFPU_EMU_ONLY */
/* Return previous task in %d1 */
movel %curptr,%d1
/* switch to new task (a1 contains new task) */
movel %a1,%curptr
/* restore floating point context */
#ifndef CONFIG_M68KFPU_EMU_ONLY
#ifdef CONFIG_M68KFPU_EMU
tstl m68k_fputype
jeq 4f
#endif
#if defined(CONFIG_M68060)
#if !defined(CPU_M68060_ONLY)
btst #3,m68k_cputype+3
beqs 1f
#endif
/* The 060 FPU keeps status in bits 15-8 of the first longword */
tstb %a1@(TASK_THREAD+THREAD_FPSTATE+2)
jeq 3f
#if !defined(CPU_M68060_ONLY)
jra 2f
#endif
#endif /* CONFIG_M68060 */
#if !defined(CPU_M68060_ONLY)
1: tstb %a1@(TASK_THREAD+THREAD_FPSTATE)
jeq 3f
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
#endif
m68k: merge the MMU and non-MMU versions of the entry.S code Some of the entry.S code is common to both MMU and non-MMU builds. So merge the entry_no.S and entry_mm.S files back into a single file. With a little code movement we only need a single #ifdef. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-05-09 15:05:24 +08:00
2: fmovemx %a1@(TASK_THREAD+THREAD_FPREG),%fp0-%fp7
fmoveml %a1@(TASK_THREAD+THREAD_FPCNTL),%fpcr/%fpsr/%fpiar
3: frestore %a1@(TASK_THREAD+THREAD_FPSTATE)
4:
#endif /* CONFIG_M68KFPU_EMU_ONLY */
/* restore the kernel stack pointer */
movel %a1@(TASK_THREAD+THREAD_KSP),%sp
/* restore non-scratch registers */
RESTORE_SWITCH_STACK
/* restore user stack pointer */
movel %a1@(TASK_THREAD+THREAD_USP),%a0
movel %a0,%usp
/* restore fs (sfc,%dfc) */
movew %a1@(TASK_THREAD+THREAD_FS),%a0
movec %a0,%sfc
movec %a0,%dfc
/* restore status register */
movew %a1@(TASK_THREAD+THREAD_SR),%sr
rts
#endif /* CONFIG_MMU && !CONFIG_COLDFIRE */