Booting a 3.2, 3.3, or 3.4-rc4 kernel on an Atari using the
`nfeth' ethernet device triggers a WARN_ONCE() in generic irq
handling code on the first irq for that device:

WARNING: at kernel/irq/handle.c:146 handle_irq_event_percpu+0x134/0x142()
irq 3 handler nfeth_interrupt+0x0/0x194 enabled interrupts
Modules linked in:
Call Trace: [<000299b2>] warn_slowpath_common+0x48/0x6a
 [<000299c0>] warn_slowpath_common+0x56/0x6a
 [<00029a4c>] warn_slowpath_fmt+0x2a/0x32
 [<0005b34c>] handle_irq_event_percpu+0x134/0x142
 [<0005b34c>] handle_irq_event_percpu+0x134/0x142
 [<0000a584>] nfeth_interrupt+0x0/0x194
 [<001ba0a8>] schedule_preempt_disabled+0x0/0xc
 [<0005b37a>] handle_irq_event+0x20/0x2c
 [<0005add4>] generic_handle_irq+0x2c/0x3a
 [<00002ab6>] do_IRQ+0x20/0x32
 [<0000289e>] auto_irqhandler_fixup+0x4/0x6
 [<00003144>] cpu_idle+0x22/0x2e
 [<001b8a78>] printk+0x0/0x18
 [<0024d112>] start_kernel+0x37a/0x386
 [<0003021d>] __do_proc_dointvec+0xb1/0x366
 [<0003021d>] __do_proc_dointvec+0xb1/0x366
 [<0024c31e>] _sinittext+0x31e/0x9c0

After invoking the irq's handler the kernel sees !irqs_disabled()
and concludes that the handler erroneously enabled interrupts.

However, debugging shows that !irqs_disabled() is true even before
the handler is invoked, which indicates a problem in the platform
code rather than the specific driver.

The warning does not occur in 3.1 or older kernels.

It turns out that the ALLOWINT definition for Atari is incorrect.

The Atari definition of ALLOWINT is ~0x400, the stated purpose of
that is to avoid taking HSYNC interrupts.  irqs_disabled() returns
true if the 3-bit ipl & 4 is non-zero.  The nfeth interrupt runs at
ipl 3 (it's autovector 3), but 3 & 4 is zero so irqs_disabled() is
false, and the warning above is generated.

When interrupts are explicitly disabled, ipl is set to 7.  When they
are enabled, ipl is masked with ALLOWINT.  On Atari this will result
in ipl = 3, which blocks interrupts at ipl 3 and below.  So how come
nfeth interrupts at ipl 3 are received at all?  That's because ipl
is reset to 2 by Atari-specific code in default_idle(), again with
the stated purpose of blocking HSYNC interrupts.  This discrepancy
means that ipl 3 can remain blocked for longer than intended.

Both default_idle() and falcon_hblhandler() identify HSYNC with
ipl 2, and the "Atari ST/.../F030 Hardware Register Listing" agrees,
but ALLOWINT is defined as if HSYNC was ipl 3.

[As an experiment I modified default_idle() to reset ipl to 3, and
as expected that resulted in all nfeth interrupts being blocked.]

The fix is simple: define ALLOWINT as ~0x500 instead.  This makes
arch_local_irq_enable() consistent with default_idle(), and prevents
the !irqs_disabled() problems for ipl 3 interrupts.

Tested on Atari running in an Aranym VM.
Signed-off-by: NMikael Pettersson <mikpe@it.uu.se>
Tested-by: Michael Schmitz <schmitzmic@googlemail.com> (on Falcon/CT60)
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>

Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>

Virtual memory m68k systems build with register a2 dedicated to being the
current proc pointer (non-MMU don't do this). Add code to the ColdFire
interrupt and exception processing to set this on entry, and at context
switch time. We use the same GET_CURRENT() macro that MMU enabled code
uses - modifying it so that the assembler is ColdFire clean.
Signed-off-by: NGreg Ungerer <gerg@uclinux.org>
Acked-by: NMatt Waddel <mwaddel@yahoo.com>
Acked-by: NKurt Mahan <kmahan@xmission.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.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: NGreg Ungerer <gerg@uclinux.org>

Merge header files for m68k and m68knommu to the single location:

    arch/m68k/include/asm

The majority of this patch was the result of the
script that is included in the changelog below.

The script was originally written by Arnd Bergman and
exten by me to cover a few more files.

When the header files differed the script uses the following:

The original m68k file is named <file>_mm.h  [mm for memory manager]
The m68knommu file is named <file>_no.h [no for no memory manager]

The files uses the following include guard:

This include gaurd works as the m68knommu toolchain set
the __uClinux__ symbol - so this should work in userspace too.

Merging the header files for m68k and m68knommu exposes the
(unexpected?) ABI differences thus it is easier to actually
identify these and thus to fix them.

The commit has been build tested with both a m68k and
a m68knommu toolchain - with success.

The commit has also been tested with "make headers_check"
and this patch fixes make headers_check for m68knommu.

The script used:
TARGET=arch/m68k/include/asm
SOURCE=arch/m68knommu/include/asm

INCLUDE="cachectl.h errno.h fcntl.h hwtest.h ioctls.h ipcbuf.h \
linkage.h math-emu.h md.h mman.h movs.h msgbuf.h openprom.h \
oplib.h poll.h posix_types.h resource.h rtc.h sembuf.h shmbuf.h \
shm.h shmparam.h socket.h sockios.h spinlock.h statfs.h stat.h \
termbits.h termios.h tlb.h types.h user.h"

EQUAL="auxvec.h cputime.h device.h emergency-restart.h futex.h \
ioctl.h irq_regs.h kdebug.h local.h mutex.h percpu.h \
sections.h topology.h"

NOMUUFILES="anchor.h bootstd.h coldfire.h commproc.h dbg.h \
elia.h flat.h m5206sim.h m520xsim.h m523xsim.h m5249sim.h \
m5272sim.h m527xsim.h m528xsim.h m5307sim.h m532xsim.h \
m5407sim.h m68360_enet.h m68360.h m68360_pram.h m68360_quicc.h \
m68360_regs.h MC68328.h MC68332.h MC68EZ328.h MC68VZ328.h \
mcfcache.h mcfdma.h mcfmbus.h mcfne.h mcfpci.h mcfpit.h \
mcfsim.h mcfsmc.h mcftimer.h mcfuart.h mcfwdebug.h \
nettel.h quicc_simple.h smp.h"

FILES="atomic.h bitops.h bootinfo.h bug.h bugs.h byteorder.h cache.h \
cacheflush.h checksum.h current.h delay.h div64.h \
dma-mapping.h dma.h elf.h entry.h fb.h fpu.h hardirq.h hw_irq.h io.h \
irq.h kmap_types.h machdep.h mc146818rtc.h mmu.h mmu_context.h \
module.h page.h page_offset.h param.h pci.h pgalloc.h \
pgtable.h processor.h ptrace.h scatterlist.h segment.h \
setup.h sigcontext.h siginfo.h signal.h string.h system.h swab.h \
thread_info.h timex.h tlbflush.h traps.h uaccess.h ucontext.h \
unaligned.h unistd.h"

mergefile() {
	BASE=${1%.h}
	git mv ${SOURCE}/$1 ${TARGET}/${BASE}_no.h
	git mv ${TARGET}/$1 ${TARGET}/${BASE}_mm.h

cat << EOF > ${TARGET}/$1
EOF

	git add ${TARGET}/$1
}

set -e

mkdir -p ${TARGET}

git mv include/asm-m68k/* ${TARGET}
rmdir include/asm-m68k

git rm ${SOURCE}/Kbuild
for F in $INCLUDE $EQUAL; do
	git rm ${SOURCE}/$F
done

for F in $NOMUUFILES; do
	git mv ${SOURCE}/$F ${TARGET}/$F
done

for F in $FILES ; do
	mergefile $F
done

rmdir arch/m68knommu/include/asm
rmdir arch/m68knommu/include

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NGreg Ungerer <gerg@uclinux.org>