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Have an explicit mm call to split higher order pages into individual pages.
Should help to avoid bugs and be more explicit about the code's intention.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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A careful reading of the recent changes to the system call entry/exit
paths revealed several problems, plus some things that could be
simplified and improved:
* 32-bit wasn't testing the _TIF_NOERROR bit in the syscall fast exit
path, so it was only doing anything with it once it saw some other
bit being set. In other words, the noerror behaviour would apply to
the next system call where we had to reschedule or deliver a signal,
which is not necessarily the current system call.
* 32-bit wasn't doing the call to ptrace_notify in the syscall exit
path when the _TIF_SINGLESTEP bit was set.
* _TIF_RESTOREALL was in both _TIF_USER_WORK_MASK and
_TIF_PERSYSCALL_MASK, which is odd since _TIF_RESTOREALL is only set
by system calls. I took it out of _TIF_USER_WORK_MASK.
* On 64-bit, _TIF_RESTOREALL wasn't causing the non-volatile registers
to be restored (unless perhaps a signal was delivered or the syscall
was traced or single-stepped). Thus the non-volatile registers
weren't restored on exit from a signal handler. We probably got
away with it mostly because signal handlers written in C wouldn't
alter the non-volatile registers.
* On 32-bit I simplified the code and made it more like 64-bit by
making the syscall exit path jump to ret_from_except to handle
preemption and signal delivery.
* 32-bit was calling do_signal unnecessarily when _TIF_RESTOREALL was
set - but I think because of that 32-bit was actually restoring the
non-volatile registers on exit from a signal handler.
* I changed the order of enabling interrupts and saving the
non-volatile registers before calling do_syscall_trace_leave; now we
enable interrupts first.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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altivec_unavailable_exception is called without setting r3... it looks like
the r3 that actually gets passed in as struct pt_regs *regs is the
undisturbed value of r3 at the time the altivec instruction was encountered.
The user actually gets to choose the pt_regs printed in the Oops!
This fixes the oops by passing the correct pt_regs pointer to
altivec_unavailable_exception.
Signed-off-by: Alan Curry <pacman@TheWorld.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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A few symbols are exported twice, remove them from ppc_ksyms.c
Remove users of sys_ctrler in arch/ppc/
WARNING: vmlinux: duplicate symbol '__delay' previous definition was in vmlinux
WARNING: vmlinux: duplicate symbol '__up' previous definition was in vmlinux
WARNING: vmlinux: duplicate symbol '__down' previous definition was in vmlinux
WARNING: vmlinux: duplicate symbol '__down_interruptible' previous definition was in vmlinux
WARNING: vmlinux: duplicate symbol 'sys_ctrler' previous definition was in vmlinux
WARNING: vmlinux: duplicate symbol 'strncat' previous definition was in vmlinux
WARNING: vmlinux: duplicate symbol 'strncmp' previous definition was in vmlinux
WARNING: vmlinux: duplicate symbol 'strchr' previous definition was in vmlinux
WARNING: vmlinux: duplicate symbol 'strrchr' previous definition was in vmlinux
WARNING: vmlinux: duplicate symbol 'strnlen' previous definition was in vmlinux
WARNING: vmlinux: duplicate symbol 'strpbrk' previous definition was in vmlinux
WARNING: vmlinux: duplicate symbol 'memscan' previous definition was in vmlinux
WARNING: vmlinux: duplicate symbol 'strstr' previous definition was in vmlinux
Signed-off-by: Olaf Hering <olh@suse.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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With this, new system calls only have to be wired up in one place
for ARCH=ppc and ARCH=powerpc, rather than 2.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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... so it should be exported only on non-SMP.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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The last two 8MB TLB entries are being incorrectly set by initial_mmu on 8xx.
The first entry is written with the same virtual/physical address, which
renders it invalid:
BDI>rms 792 0x00001e00
BDI>rms 824 1
BDI>rds 824
SPR 824 : 0xc08000c0 -1065353024
BDI>rds 825
SPR 825 : 0xc0800de0 -1065349664
BDI>rds 826
SPR 826 : 0x00000000 0
And the second entry, in addition, does not have its TLB index set
correctly.
Signed-off-by: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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When I removed the powermac support from arch/ppc/kernel/pci.c,
I overlooked the fact that that file is used in 32-bit ARCH=powerpc
builds. To prevent problems in future, restore the original version
of that file as arch/powerpc/kernel/pci_32.c, and use that.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This makes it possible to build kernels for PReP and/or CHRP
with ARCH=ppc by removing the (non-building) powermac support.
It's now also possible to select PReP and CHRP independently.
Powermac users should now build with ARCH=powerpc instead of
ARCH=ppc. (This does mean that it is no longer possible to
build a 32-bit kernel for a G5.)
Signed-off-by: Paul Mackerras <paulus@samba.org>
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The arch/powerpc version of process.c exports get_wchan itself. When
I moved ARCH=ppc over to using arch/powerpc/kernel/process.c the
get_wchan export in arch/ppc/kernel/ppc_ksyms.c became redundant, so
remove it.
Signed-off-by: Paul Mackerras <paulus@samba.org>
(cherry picked from 9871166ad692121d6b944159ef3f053570158ea8 commit)
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The following implements support for instantiation of 8MB D-TLB
entries for the kernel direct virtual mapping on 8xx, thus reducing TLB
space consumed for the kernel.
Test used: writing 40MB from /dev/zero to file in ext2fs over
RAMDISK.
$ time dd if=/dev/zero of=file bs=4k count=10000
VANILLA 8MB kernel data pages
real 0m11.485s real 0m11.267s
user 0m0.218s user 0m0.250s
sys 0m8.939s sys 0m9.108s
real 0m11.518s real 0m10.978s
user 0m0.203s user 0m0.222s
sys 0m9.585s sys 0m9.138s
real 0m11.554s real 0m10.967s
user 0m0.228s user 0m0.222s
sys 0m9.497s sys 0m9.127s
real 0m11.633s real 0m11.286s
user 0m0.214s user 0m0.196s
sys 0m9.529s sys 0m9.134s
and averages for both:
real 11.54750 real 11.12450
Which is a 3.6% improvement in execution time. More improvement is
expected for loads with larger kernel data footprint (real workloads).
Signed-off-by: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Fix up delete/modify conflict of arch/ppc/kernel/process.c by hand (it's
gone, gone, gone).
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Commit 5388fb1025443ec223ba556b10efc4c5f83f8682 made signal_32.c
use discard_lazy_cpu_state, which broke ARCH=ppc because that
uses the common signal_32.c but has its own process.c. Make ARCH=ppc
use the common process.c to fix this and to reduce the amount
of duplicated code.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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arch: Use <linux/capability.h> where capable() is used.
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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- In case of system crash, current state of cpu registers is saved in memory
in elf note format. So far memory for storing elf notes was being allocated
statically for NR_CPUS.
- This patch introduces dynamic allocation of memory for storing elf notes.
It uses alloc_percpu() interface. This should lead to better memory usage.
- Introduced based on Andi Kleen's and Eric W. Biederman's suggestions.
- This patch also moves memory allocation for elf notes from architecture
dependent portion to architecture independent portion. Now crash_notes is
architecture independent. The whole idea is that size of memory to be
allocated per cpu (MAX_NOTE_BYTES) can be architecture dependent and
allocation of this memory can be architecture independent.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Jiri Slaby <xslaby@fi.muni.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
arch/ppc/kernel/pci.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
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pci_address_to_pio is missing a closing curly brace
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This fixes pci_address_to_pio() to return an unsigned long (to be safe)
and fixes a bug in the implementation that caused it to return a bogus
IO port number
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Added the ability to determine if an outbound window in the PCI host
controller is for prefetchable memory and report it as such.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This updates the OF address parsers to return the IO flags
indicating the type of address obtained. It also adds a PCI
call for converting physical addresses that hit IO space into
into IO tokens, and add routines that return the translated
addresses into struct resource
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This makes ARCH=ppc build in your powerpc tree again, with the new
syscall entry/exit path.
Still doesn't actually boot on my Pegasos; the last thing I see is
'MMU:exit'. But at least it builds -- I'll look at why it doesn't boot
later, so that I can see if the mv643xx_eth actually works with ARCH=ppc
(it doesn't with ARCH=powerpc; two in every three packets I receive are
offset by 4 bytes).
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This patch unifies udbg for both ppc32 and ppc64 when building the
merged achitecture. xmon now has a single "back end". The powermac udbg
stuff gets enriched with some ADB capabilities and btext output. In
addition, the early_init callback is now called on ppc32 as well,
approx. in the same order as ppc64 regarding device-tree manipulations.
The init sequences of ppc32 and ppc64 are getting closer, I'll unify
them in a later patch.
For now, you can force udbg to the scc using "sccdbg" or to btext using
"btextdbg" on powermacs. I'll implement a cleaner way of forcing udbg
output to something else than the autodetected OF output device in a
later patch.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This moves the discovery of legacy serial ports to a separate file,
makes it common to ppc32 and ppc64, and reworks it to use the new OF
address translators to get to the ports early. This new version can also
detect some PCI serial cards using legacy chips and will probably match
those discovered port with the default console choice.
Only ppc64 gets udbg still yet, unifying udbg isn't finished yet.
It also adds some speed-probing code to udbg so that the default console
can come up at the same speed it was set to by the firmware.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This is the current version of the spu file system, used
for driving SPEs on the Cell Broadband Engine.
This release is almost identical to the version for the
2.6.14 kernel posted earlier, which is available as part
of the Cell BE Linux distribution from
http://www.bsc.es/projects/deepcomputing/linuxoncell/.
The first patch provides all the interfaces for running
spu application, but does not have any support for
debugging SPU tasks or for scheduling. Both these
functionalities are added in the subsequent patches.
See Documentation/filesystems/spufs.txt on how to use
spufs.
Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This patch merges, to some extent, the PPC32 and PPC64 kexec implementations.
We adopt the PPC32 approach of having ppc_md callbacks for the kexec functions.
The current PPC64 implementation becomes the "default" implementation for PPC64
which platforms can select if they need no special treatment.
I've added these default callbacks to pseries/maple/cell/powermac, this means
iSeries no longer supports kexec - but it never worked anyway.
I've renamed PPC32's machine_kexec_simple to default_machine_kexec, inline with
PPC64. Judging by the comments it might be better named machine_kexec_non_of,
or something, but at the moment it's the only implementation for PPC32 so it's
the "default".
Kexec requires machine_shutdown(), which is in machine_kexec.c on PPC32, but we
already have in setup-common.c on powerpc. All this does is call
ppc_md.nvram_sync, which only powermac implements, so instead make
machine_shutdown a ppc_md member and have it call core99_nvram_sync directly
on powermac.
I've also stuck relocate_kernel.S into misc_32.S for powerpc.
Built for ARCH=ppc, and 32 & 64 bit ARCH=powerpc, with KEXEC=y/n. Booted on
P5 LPAR and successfully kexec'ed.
Should apply on top of 493f25ef4087395891c99fcfe2c72e62e293e89f.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This patch removes the EXPORT_SYMBOL'ed but completely unused variable
ucSystemType and removes the unneeded EXPORT_SYMBOL(_prep_type).
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Tom Rini <trini@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Disable declaration of cpu variable in default_idle function when
building non-SMP kernels.
Signed-off-by: Otavio Salvador <otavio@debian.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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ppc32 kernel, when built with CONFIG_SMP and booted on a single CPU
machine, will not properly set smp_tb_synchronized, thus causing
gettimeofday() to not use the HW timebase and to be limited to jiffy
resolution. This, among others, causes unacceptable pauses when launching
X.org.
Signed-Off-By: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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I recently discovered a bug on PPC which causes the floating point
registers to get corrupted when CONFIG_PREEMPT=y.
The problem occurred while running a multi threaded Java application that
does floating point. The problem could be reproduced in anywhere from 2 to
6 hours. With the patch I have included below it ran for over a week
without failure.
Signed-off-by: Paolo Galtieri <pgaltieri@mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Tom Rini <trini@kernel.crashing.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Export symbol needed to allow MOL to run. This was changed to be inline
in past and forgot to be change here.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Signed-off-by: Paul Mackerras <paulus@samba.org>
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This patch merges align.c, the result isn't quite what was in ppc64 nor
what was in ppc32 :) It should implement all the functionalities of both
though. Kumar, since you played with that in the past, I suppose you
have some test cases for verifying that it works properly before I dig
out the 601 machine ? :)
Since it's likely that I won't be able to test all scenario, code
inspection is much welcome.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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The merge of machine types broke boot with yaboot & ARCH=ppc due to the
old code still retreiving the old-syle machine type passed in by yaboot.
This patch fixes it by translating those old numbers. Since that whole
mecanism is deprecated, this is a temporary fix until ARCH=ppc uses the
new prom_init that the merged architecture now uses for both ppc32 and
ppc64 (after 2.6.15)
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Changed jobs and the Freescale address is no longer valid.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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We needed the VDSO symbols in the arch/ppc asm-offsets.c, and there
were a few usages of _systemcfg still left lying around.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Move the PPC fixup for old NCR 810 controllers to generic quirks -
it's needed for Alpha, x86 and other architectures that use
setup-bus.c.
Thanks to Jay Estabrook for pointing out the issue.
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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This patch merges platform codes. systemcfg->platform is no longer used,
systemcfg use in general is deprecated as much as possible (and renamed
_systemcfg before it gets completely moved elsewhere in a future patch),
_machine is now used on ppc64 along as ppc32. Platform codes aren't gone
yet but we are getting a step closer. A bunch of asm code in head[_64].S
is also turned into C code.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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The ppc32 and ppc64 versions of cacheflush.h were almost identical.
The two versions of cache.h are fairly similar, except for a bunch of
register definitions in the ppc32 version which probably belong better
elsewhere. This patch, therefore, merges both headers. Notable
points:
- there are several functions in cacheflush.h which exist only
on ppc32 or only on ppc64. These are handled by #ifdef for now, but
these should probably be consolidated, along with the actual code
behind them later.
- Confusingly, both ppc32 and ppc64 have a
flush_dcache_range(), but they're subtly different: it uses dcbf on
ppc32 and dcbst on ppc64, ppc64 has a flush_inval_dcache_range() which
uses dcbf. These too should be merged and consolidated later.
- Also flush_dcache_range() was defined in cacheflush.h on
ppc64, and in cache.h on ppc32. In the merged version it's in
cacheflush.h
- On ppc32 flush_icache_range() is a normal function from
misc.S. On ppc64, it was wrapper, testing a feature bit before
calling __flush_icache_range() which does the actual flush. This
patch takes the ppc64 approach, which amounts to no change on ppc32,
since CPU_FTR_COHERENT_ICACHE will never be set there, but does mean
renaming flush_icache_range() to __flush_icache_range() in
arch/ppc/kernel/misc.S and arch/powerpc/kernel/misc_32.S
- The PReP register info from asm-ppc/cache.h has moved to
arch/ppc/platforms/prep_setup.c
- The 8xx register info from asm-ppc/cache.h has moved to a
new asm-powerpc/reg_8xx.h, included from reg.h
- flush_dcache_all() was defined on ppc32 (only), but was
never called (although it was exported). Thus this patch removes it
from cacheflush.h and from ARCH=powerpc (misc_32.S) entirely. It's
left in ARCH=ppc for now, with the prototype moved to ppc_ksyms.c.
Built for Walnut (ARCH=ppc), 32-bit multiplatform (pmac, CHRP and PReP
ARCH=ppc, pmac and CHRP ARCH=powerpc). Built and booted on POWER5
LPAR (ARCH=powerpc and ARCH=ppc64).
Built for 32-bit powermac (ARCH=ppc and ARCH=powerpc). Built and
booted on POWER5 LPAR (ARCH=powerpc and ARCH=ppc64). Built and booted
on G5 (ARCH=powerpc)
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Fixes ppc44x fpu support that broke from a bad arch/powerpc merge.
Instead of adding KernelFP back in (which duplicates code) we use
the same kernel fpu unavailable handler as classic PPC processors.
Signed-off-by: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Having already merged the ppc and ppc64 versions of signal.c, this
patch finishes the job by merging signal.h. The two versions were
almost identical already. Notable changes:
- We use BITS_PER_LONG to correctly size sigset_t
- Remove some uneeded #includes and struct forward
declarations. This does mean adding an include to signal_32.c which
relied on the indirect inclusion of sigcontext.h
- As the ppc64 version, the merged signal.h has prototypes for
do_signal() and do_signal32(). Thus remove extra prototypes from
ppc_ksyms.c which had them directly.
Built and booted on POWER5 LPAR (ARCH=ppc64 and ARCH=powerpc). Built
for 32-bit powermac (ARCH=ppc and ARCH=powerpc) and Walnut (ARCH=ppc).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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- Re-add a hunk lost during merge: ppc64 is missing the hunk that disables
preempt on the secondary CPUs before they call cpu_idle().
- ppc's cpu_idle() had the need_resched() test wrong.
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Make some changes to the NEED_RESCHED and POLLING_NRFLAG to reduce
confusion, and make their semantics rigid. Improves efficiency of
resched_task and some cpu_idle routines.
* In resched_task:
- TIF_NEED_RESCHED is only cleared with the task's runqueue lock held,
and as we hold it during resched_task, then there is no need for an
atomic test and set there. The only other time this should be set is
when the task's quantum expires, in the timer interrupt - this is
protected against because the rq lock is irq-safe.
- If TIF_NEED_RESCHED is set, then we don't need to do anything. It
won't get unset until the task get's schedule()d off.
- If we are running on the same CPU as the task we resched, then set
TIF_NEED_RESCHED and no further action is required.
- If we are running on another CPU, and TIF_POLLING_NRFLAG is *not* set
after TIF_NEED_RESCHED has been set, then we need to send an IPI.
Using these rules, we are able to remove the test and set operation in
resched_task, and make clear the previously vague semantics of
POLLING_NRFLAG.
* In idle routines:
- Enter cpu_idle with preempt disabled. When the need_resched() condition
becomes true, explicitly call schedule(). This makes things a bit clearer
(IMO), but haven't updated all architectures yet.
- Many do a test and clear of TIF_NEED_RESCHED for some reason. According
to the resched_task rules, this isn't needed (and actually breaks the
assumption that TIF_NEED_RESCHED is only cleared with the runqueue lock
held). So remove that. Generally one less locked memory op when switching
to the idle thread.
- Many idle routines clear TIF_POLLING_NRFLAG, and only set it in the inner
most polling idle loops. The above resched_task semantics allow it to be
set until before the last time need_resched() is checked before going into
a halt requiring interrupt wakeup.
Many idle routines simply never enter such a halt, and so POLLING_NRFLAG
can be always left set, completely eliminating resched IPIs when rescheduling
the idle task.
POLLING_NRFLAG width can be increased, to reduce the chance of resched IPIs.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Con Kolivas <kernel@kolivas.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Run idle threads with preempt disabled.
Also corrected a bugs in arm26's cpu_idle (make it actually call schedule()).
How did it ever work before?
Might fix the CPU hotplugging hang which Nigel Cunningham noted.
We think the bug hits if the idle thread is preempted after checking
need_resched() and before going to sleep, then the CPU offlined.
After calling stop_machine_run, the CPU eventually returns from preemption and
into the idle thread and goes to sleep. The CPU will continue executing
previous idle and have no chance to call play_dead.
By disabling preemption until we are ready to explicitly schedule, this bug is
fixed and the idle threads generally become more robust.
From: alexs <ashepard@u.washington.edu>
PPC build fix
From: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
MIPS build fix
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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xmon() prototype is inconsistent between ARCH=ppc and ARCH=powerpc,
thus causing ARCH=ppc build breakage.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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