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
Pull m68k updates from Geert Uytterhoeven:
"Summary:
- __put_user_unaligned may/will be used by btrfs
- m68k part of a global cleanup"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
m68k: Remove deprecated IRQF_DISABLED
m68k/m68knommu: Implement __get_user_unaligned/__put_user_unaligned()
This patch proposes to remove the IRQF_DISABLED flag from m68k architecture
code. It's a NOOP since 2.6.35 and it will be removed one day.
Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Some functions that are only called (indirectly) from setup_arch() lack
__init annotations.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Pull m68k updates from Geert Uytterhoeven.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
m68k: Make sys_atomic_cmpxchg_32 work on classic m68k
m68k/apollo: Rename "timer" to "apollo_timer"
zorro: Remove unused zorro_bus.devices
m68k: Remove never used asm/shm.h
m68k/sun3: Remove unselectable code in prom_init()
m68k: Use asm-generic version of <asm/sections.h>
m68k: Replace m68k-specific _[se]bss by generic __bss_{start,stop}
mtd/uclinux: Use generic __bss_stop instead of _ebss
m68knommu: Allow ColdFire CPUs to use unaligned accesses
m68k: Remove five unused headers
m68k: CPU32 does not support unaligned accesses
m68k: Introduce config option CPU_HAS_NO_UNALIGNED
m68k: delay, muldi3 - Use CONFIG_CPU_HAS_NO_MULDIV64
m68k: Move CPU_HAS_* config options
m68k: Remove duplicate FPU config option
m68knommu: Clean up printing of sections
m68k: Use asm-generic version of <asm/types.h>
m68k: Use Kbuild logic to import asm-generic headers
BSS_SECTION() provides the __bss_{start,stop} symbols, so there's no need
to wrap our own _[se]bss around it.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Greg Ungerer<gerg@uclinux.org>
Compiling for 68360 based targets fails with:
arch/m68k/platform/68360/config.c: In function ‘hw_tick’:
arch/m68k/platform/68360/config.c:55:2: error: implicit declaration of function ‘arch_timer_interrupt’
arch/m68k/platform/68360/config.c: At top level:
arch/m68k/platform/68360/config.c:64:6: error: conflicting types for ‘hw_timer_init’
arch/m68k/include/asm/machdep.h:36:13: note: previous declaration of ‘hw_timer_init’ was here
Changes made to hw_timer_init() didn't get updated in the 68328 timer code.
So process and call the "handler" arg that is now passed into that
hw_timer_init() function.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
TIF_NOTIFY_RESUME added (as bit 5). That way nommu glue needs no changes at
all; mmu one needs just to replace jmi do_signal_return to jne do_signal_return
There we have flags shifted up, until bit 6 (SIGPENDING) is in MSBit; instead
of checking that MSBit is set (jmi) we check that MSBit or something below it
is set (jne); bits 0..4 are never set, so that's precisely "bit 6 or bit 5 is
set".
Usual handling of NOTIFY_RESUME/SIGPENDING is done in do_notify_resume(); glue
calls it instead of do_signal().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The read_persistent_clock() code is different on m68knommu, for really no
reason. With a few changes to support function names and some code
re-organization the code can be made the same.
This will make it easier to merge the arch/m68k/kernel/time.c for m68k and
m68knommu in a future patch.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
The base of the real RAM resident hardware vectors, _ramvec, is declared in
our asm/traps.h. No need to have local declarations spread around in other
files that use this. So remove them.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
The changes in the mmu version of entry.h (entry_mm.h) and the non-mmu
version (entry_no.h) are not about the presence or use of an MMU at all.
The main changes are to support the ColdFire processors. The code for
trap entry and exit for all types of 68k processor outside coldfire is
the same.
So merge the files back to a single entry.h and share the common 68k
entry/exit code. Some changes are required for the non-mmu entry
handlers to adopt the differing macros for system call and interrupt
entry, but this is quite strait forward. The changes for the ColdFire
remove a couple of instructions for the separate a7 register case, and
are no worse for the older single a7 register case.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Most of the build logic is the same for the mmu and non-mmu m68k targets.
Merge the top level architecture Makefiles back into a single Makefile.
For the most part this is just adding the non-mmu processor types and
their specific cflags and other options into the mmu Makefile.
Note that all the BOARD setting logic that was in the non-mmu Makefile
is completely removed. It was no longer being used at all.
This has been build and run tested on ColdFire targets and ARAnyM.
It has been build tested on all the m68k defconfig targets using a
gcc-4.5.1 based toolchain.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
commit 2502b667ea ("Change the m68knommu irq
handling to use the generic irq framework.") removed the reporting of spurious
interrupts on nommu (68328 and 68360).
Bring it back in a generic way, using "atomic_t irq_err_count", as that's what
most of the other architectures are using.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Currently trap_init() is an empty function for m68knommu. Instead
the vectors are being setup as part of the IRQ initialization.
This is inconsistent with m68k and other architectures.
Change the local init_vectors() to be trap_init(), and init the
vectors at the correct time during startup. This will help merge of
m68k and m68knommu trap code in the furture.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
The non-MMU m68k targets can use the same asm/system.h as the MMU
targets. So switch the current system_mm.h to be system.h and remove
system_no.h.
The assembly support code for the non-MMU resume functions needs to
be modified to match the now common switch_to() macro. Specifically
this means correctly saving and restoring the status flags in the case
of the ColdFire resume, and some reordering of the code to not use
registers before they are saved or after they are restored.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
It is strait forward to merge the mmu and non-mmu versions of
asm-offstes.c. Some name changes are required for the preempt and
thread_info.flags in the non-mmu entry.S assembler to make them
consistent for both setups.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
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>
