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Sam Ravnborg pointed out that calling if_changed was redundant in the
rule since a prerequisite had to have changed for us to get there.
Signed-off-by: Kumar Gala <galak@kernel.crashing.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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Moved 83xx and QUICC Engine interrupt handling code into arch/powerpc
as a precursor of getting 83xx sub-arch building in arch/powerpc.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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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Commit 3e9e7c1d0b7a36fb8affb973a054c5098e27baa8 (ppc32: cleanup AMCC PPC40x
eval boards to support U-Boot) broke the kernel for ML300 / EP405.
It still compiles as there's a weak definition of the function in
misc-embedded.c, but the kernel crashes as the bd_t fixup isn't performed.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Some custom cards might not need PCI, without this patch, compilation fails.
Signed-off-by: Roger Blofeld <blofeldus@yahoo.com>
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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We were counting on the bootloader to init some stuff, like get the bus out of
reset and enable accesses.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch takes care of an errata of the MPC5200 by avoiding 32 bits access
in type 1 configuration accesses. All others accesses are still 32 bits wide.
It also adds some mb() since the simple out_be(...) are not sufficient in
this case.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The mpc52xx_pci_fixup_resources is not only called at init but also when there
is a pci hotplug like when a cardbus card is plugged in. So that function is
needed after init too.
Thanks to Asier Llano Palacios for reporting this.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The current iomapping used MBAR_SIZE for the size argument of
io_block_mapping, resulting in a call to setbat with a size argument of 64k
which is invalid.
This patch correct this and maps the whole 0xf0000000->0xffffffff range so
that devices on the local bus are also included in the BAT mapping.
Thanks to Bernhard Kuhn from Metrowerks for pointing this out.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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That file is a left-over of the 'old' OCP model that should have been erased
during the change to platform model but I forgot it ...
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.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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Remove the not needed anymore "jumbo" member from ocp_func_emac_data.
Jumbo frame support is handled by PPC4xx EMAC driver internally now.
Signed-off-by: Eugene Surovegin <ebs@ebshome.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The CPM2 interrupt handler does not return success to the IRQ subsystem, which
causes it to kill the IRQ line after 100,000 interrupts.
Signed-off-by: Edson Seabra <Edson.Seabra@cyclades.com>
Signed-off-by: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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DMA_MODE_{READ,WRITE} are declared in asm-powerpc/dma.h and their
declarations there match the definitions. Old declarations in
ppc4xx_dma.h are not right anymore (wrong type, to start with).
Killed them, added include of asm/dma.h where needed.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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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The code that sets the clock spreading feature of the Intrepid ASIC
must not be run on some machine models or those won't boot. This
fixes it.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This reverts commit da0825fd201a03294dbf7f8f030676d608da122c, making
it so that if you select CONFIG_PPC_MULTIPLATFORM you get support
for PMAC, PREP and CHRP built in.
The reason for not allowing PMAC, PREP and CHRP to be selected
individually for ARCH=ppc is that there is too much interdependency
between them in the platform support code. For example, CHRP uses
the PMAC nvram code.
Configuring with ARCH=powerpc does allow you to select support for
PMAC and CHRP separately. Support for PREP is not there yet but
should be there soon.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Correctly specify treeboot based image entrypoint. Currently makefile uses
$(ENTRYPOINT) which isn't defined anywhere. Each board port sets
entrypoint-$(CONFIG_BOARD_NAME) instead.
Without this patch I cannot boot Ocotea (PPC440GX eval board) anymore. I
was getting random "OS panic" errors from OpenBIOS for a while, but with
current kernel I get them all the time (probably because image became
bigger).
Signed-off-by: Eugene Surovegin <ebs@ebshome.net>
Acked-by: Tom Rini <trini@kernel.crashing.org>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The time to wait after deasserting PCI_RST has been counted with incorrect
value - this patch fixes the issue.
Signed-off-by: Vitaly Bordug <vbordug@ru.mvista.com>
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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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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When we moved things around in irq.h seq_file became an issue. Fix
warnings related to its usage.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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The SVRs for MPC8343/E were incorrect and really the SVRs
for MPC8347/E.
Signed-off-by: David Updegraff <dave@cray.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Building ARCH=ppc for multiplatforms with CONFIG_CHRP not set fails
due to some unshielded code in xmon
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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Currently 8xx fails to boot due to endless pagefaults.
Seems the bug is exposed by the change which avoids flushing the
TLB when not necessary (in case the pte has not changed), introduced
recently:
__handle_mm_fault():
entry = pte_mkyoung(entry);
if (!pte_same(old_entry, entry)) {
ptep_set_access_flags(vma, address, pte, entry, write_access);
update_mmu_cache(vma, address, entry);
lazy_mmu_prot_update(entry);
} else {
/*
* This is needed only for protection faults but the arch code
* is not yet telling us if this is a protection fault or not.
* This still avoids useless tlb flushes for .text page faults
* with threads.
*/
if (write_access)
flush_tlb_page(vma, address);
}
The "update_mmu_cache()" call was unconditional before, which caused the TLB
to be flushed by:
if (pfn_valid(pfn)) {
struct page *page = pfn_to_page(pfn);
if (!PageReserved(page)
&& !test_bit(PG_arch_1, &page->flags)) {
if (vma->vm_mm == current->active_mm) {
#ifdef CONFIG_8xx
/* On 8xx, cache control instructions (particularly
* "dcbst" from flush_dcache_icache) fault as write
* operation if there is an unpopulated TLB entry
* for the address in question. To workaround that,
* we invalidate the TLB here, thus avoiding dcbst
* misbehaviour.
*/
_tlbie(address);
#endif
__flush_dcache_icache((void *) address);
} else
flush_dcache_icache_page(page);
set_bit(PG_arch_1, &page->flags);
}
Which worked to due to pure luck: PG_arch_1 was always unset before, but
now it isnt.
The root of the problem are the changes against the 8xx TLB handlers introduced
during v2.6. What happens is the TLBMiss handlers load the zeroed pte into
the TLB, causing the TLBError handler to be invoked (thats two TLB faults per
pagefault), which then jumps to the generic MM code to setup the pte.
The bug is that the zeroed TLB is not invalidated (the same reason
for the "dcbst" misbehaviour), resulting in infinite TLBError faults.
The "two exception" approach requires a TLB flush (to nuke the zeroed TLB)
at each PTE update for correct behaviour:
Signed-off-by: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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The MPC8349 PIBs system has a expansion board with 6 PCI slots. We needed
to update the IDSEL interrupt mapping for it to work properly. However,
only PCI1 is supported as the first revision of this expansion board
doesn't function properly for PCI2. For the time being we have zero'd out
the entries for the IDSELs related to PCI2. When a functioning expansion
board exists we can fix the table.
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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Enablement patch for the new PowerBooks (late 2005 edition).
This enables the ATA controller, Gigabit ethernet and basic AGP setup.
Bluetooth works out-of-the box after running hid2hci.
Still remaining is to get the touchpad to work, the simple change of just
adding the new USB ids isn't enough.
Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.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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The bit position in the status register corresponding to the
PCI DMA interrupt was incorrect. Additionally, we did not
have a define for the PCI DMA interrupt.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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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This patch consolidates macros used to generate assembly for
compatibility across different CPUs or configs. A new header,
asm-powerpc/asm-compat.h contains the main compatibility macros. It
uses some preprocessor magic to make the macros suitable both for use
in .S files, and in inline asm in .c files. Headers (bitops.h,
uaccess.h, atomic.h, bug.h) which had their own such compatibility
macros are changed to use asm-compat.h.
ppc_asm.h is now for use in .S files *only*, and a #error enforces
that. As such, we're a lot more careless about namespace pollution
here than in asm-compat.h.
While we're at it, this patch adds a call to the PPC405_ERR77 macro in
futex.h which should have had it already, but didn't.
Built and booted on pSeries, Maple and iSeries (ARCH=powerpc). Built
for 32-bit powermac (ARCH=powerpc) and Walnut (ARCH=ppc).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
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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This adds code to work around some problems with old versions of
Open Firmware, such as on the early powermacs (7500 etc.) and the
"Longtrail" CHRP machine. On these machines we have to claim
the physical and virtual address ranges explicitly when claiming
memory and then set up a V->P mapping.
The Longtrail has more problems: setprop doesn't work, and we have
to set an "allow-reclaim" variable to 0 in order to get claim on
physical memory ranges to fail if the memory is already claimed.
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>
|
|
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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Kumar Gala
Benjamin Herrenschmidt
Arnd Bergmann
Michael Ellerman
Adrian Bunk
Peter Korsgaard
Sylvain Munaut
Otavio Salvador
Eugene Surovegin
Linus Torvalds
Edson Seabra
Al Viro
Johannes Berg
Paul Mackerras
Vitaly Bordug
Paolo Galtieri
Marcelo Tosatti
Olof Johansson
Ivan Kokshaysky
David Gibson
Matt Porter
Andrew Morton
Nick Piggin