Commit graph

253 commits

Author SHA1 Message Date
Ralf Baechle c9c5023d83 [MIPS] Fix buggy use of kmap_coherent.
Assuming the call of kmap_coherent in local_r4k_flush_cache_page doesn't
need fixing this was skipped in fcae549295bcae801ac48fc1c2030ab8cc487020.
Turns out it needed the same change after all.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-06-16 15:14:48 +01:00
Atsushi Nemoto 7bd0fea2c5 [MIPS] Fix the fix for divide by zero error in build_{clear,copy}_page
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-06-16 15:14:47 +01:00
Ralf Baechle 89052bd7b3 [MIPS] Fix build for PNX platforms.
Build error was caused by commit 351336929c.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-06-16 15:14:47 +01:00
Ralf Baechle 497d2adcbf [MIPS] Export empty_zero_page for sake of the ext4 module.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-06-16 15:14:46 +01:00
Yoichi Yuasa cd9da13d6e Fix divide by zero error in build_clear_page() and build_copy_page()
Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-06-05 18:13:16 +01:00
Thomas Bogendoerfer 326e2e1a59 [MIPS] R4700: Fix build_tlb_probe_entry
Treat R4700 like R4600 in build_tlb_probe_entry. Without this fix kernel
will lock up.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-06-05 18:13:14 +01:00
Adrian Bunk a640630460 [MIPS] unexport __kmap_atomic_to_page
This patch removes the no longer used export of __kmap_atomic_to_page.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-05-12 16:46:51 +01:00
Dmitri Vorobiev e698d66b81 [MIPS] unexport copy_from_user_page()
No users for the copy_from_user_page() routine exist outside of the
core kernel code. Therefore, EXPORT_SYMBOL(copy_from_user_page) is
useless, and this patch removes it.

Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-28 17:14:30 +01:00
Dmitri Vorobiev 715243e6c3 [MIPS] unexport copy_to_user_page()
The copy_to_user_page() function is called only in the core kernel
code. Therefore, there is no need to export it. This patch removes
EXPORT_SYMBOL(copy_to_user_page).

Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-28 17:14:30 +01:00
Dmitri Vorobiev 11327ef77f [MIPS] unexport copy_user_highpage()
The copy_user_highpage() routine has no users outside of the
core kernel code, so exporting this symbol is pointless.
This patch removes EXPORT_SYMBOL(copy_user_highpage).

Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-28 17:14:30 +01:00
Johannes Weiner f2ce89f30e [MIPS] remove redundant display of free swap space in show_mem()
Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-28 17:14:27 +01:00
Ralf Baechle 39b8d52542 [MIPS] Add support for MIPS CMP platform.
Signed-off-by: Chris Dearman <chris@mips.com>
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-28 17:14:26 +01:00
Chris Dearman 351336929c [MIPS] Allow setting of the cache attribute at run time.
Slightly tacky, but there is a precedent in the sparc archirecture code.

Signed-off-by: Chris Dearman <chris@mips.com>
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-28 17:14:25 +01:00
Chris Dearman 962f480e0f [MIPS] All MIPS32 processors support64-bit physical addresses.
Still, only the 4K may actually implement it.

Signed-off-by: Chris Dearman <chris@mips.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-28 17:14:25 +01:00
Thiemo Seufer fb2a27e743 [MIPS] Reimplement clear_page/copy_page
Fold the SB-1 specific implementation of clear_page/copy_page in the
generic version, and rewrite that one in tlbex style. The immediate
benefits:
  - It converts the compile-time workaround for SB-1 pass 1 prefetches
    to a more efficient run-time check.
  - It allows adjustment of loop unfolling, which helps to reduce the
    number of redundant cdex cache ops.
  - It fixes some esoteric cornercases (the cache line length calculations
    can go wrong, and support for 64k pages without prefetch instructions
    will overflow the addiu immediate).
  - Somewhat better guesses of "good" prefetch values.

Signed-off-by: Thiemo Seufer <ths@networkno.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-28 17:14:23 +01:00
Ralf Baechle 9c5a3d729c [MIPS] Handle aliases in vmalloc correctly.
flush_cache_vmap / flush_cache_vunmap were calling flush_cache_all which -
having been deprecated - turned into a nop ...

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-07 22:31:04 +01:00
Thomas Bogendoerfer b1ec4c8e48 [MIPS] Add missing 4KEC TLB refill handler
Early 4KEc were MIPS32r1 and therefore need some love to get a TLB
refill handler.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-01 15:46:33 +01:00
Ralf Baechle 234fcd1484 [MIPS] Fix loads of section missmatches
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-03-12 14:14:41 +00:00
Thiemo Seufer a7c2996e41 [MIPS] Fix typo in comment
We support now other page sizes as well.

Signed-off-by: Thiemo Seufer <ths@networkno.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-03-12 14:14:41 +00:00
Thiemo Seufer 345599ab12 [MIPS] SB1: Fix CONFIG_SIBYTE_DMA_PAGEOPS build failure.
Fix type mismatch warnings for 64-bit kernel builds which trigger -Werror.
The problem affects only SB-1 kernels with CONFIG_SIBYTE_DMA_PAGEOPS
enabled.

Signed-off-by: Thiemo Seufer <ths@networkno.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-02-19 17:01:31 +00:00
Ralf Baechle 9a74b3eb22 [MIPS] Fix buggy invocations of kmap_coherent()
kmap_coherent will only work correctly if the page it is called on is
not marked dirty.  If it's dirty the kernel address of the page should
be used instead of a temporary mapping.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-02-19 17:01:31 +00:00
Ralf Baechle 2eaa7ec286 [MIPS] Handle I-cache coherency in flush_cache_range()
So far flush_cache_range() did't consider the I-cache largely because it
did rarely ever matter to real world code.  This was working primarily
because normally code and data are don't share the same pages - with the
exception of MIPS16 code which uses address constants embedded between
the code.   The following sequence of events may break the code:

 o MIPS16 executable being loaded
 o dynamic linker relocates the address constants embedded into the code:
 o   Uses mprotect(2) to make code pages PROT_READ|PROT_WRITE
 o   Performs the actual relocations by writing to the pages which likely
     are COW.  Because no PROT_EXEC is set I-cache coherence will not be
     considered.
 o   Uses mprotect(2) to switch code pages back to PROT_READ|PROT_EXEC.
     This results in a call to flush_cache_range() which also does not
     consider I-caches.
 o => executing the page just having been relocated may now result in the
   I-cache getting refilled with stale data from memory.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-02-19 17:01:31 +00:00
Joe Perches 603e82edf7 arch/mips/: Spelling fixes
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
2008-02-03 16:54:53 +02:00
Thiemo Seufer e30ec4525d [MIPS] Split the micro-assembler from tlbex.c.
This patch moves the micro-assembler in a separate implementation, as
it is useful for further run-time optimizations. The only change in
behaviour is cutting down printk noise at kernel startup time.

Checkpatch complains about macro parameters which aren't protected by
parentheses. I believe this is a flaw in checkpatch, the paste operator
used in those macros won't work with parenthesised parameters.

Signed-off-by: Thiemo Seufer <ths@networkno.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-02-01 14:48:44 +00:00
Manuel Lauss 237cfee1db [MIPS] Alchemy: Au1210/Au1250 CPU support
This patch adds IDs for new Au1200 variants: Au1210 and Au1250.
They are essentially identical to the Au1200 except for the Au1210
which has a different SoC-ID in the PRId register [bits 31:24].
The Au1250 is a "Au1200 V0.2".

Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
Thomas Bogendoerfer c7c6b39050 [MIPS] Use correct dma flushing in dma_cache_sync()
Not cache coherent R10k systems (like IP28) need to do real cache
invalidates in dma_cache_sync().

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:58 +00:00
Thomas Bogendoerfer e9c33572a9 [MIPS] Use real cache invalidate
R10k non coherent machines need a real dma cache invalidate to get rid of
speculative stores in cache.  For other machines this promises a slight
speedup.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:57 +00:00
Franck Bui-Huu 92b1e6a64a [MIPS] tlbex.c: cleanup debug code
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:57 +00:00
Franck Bui-Huu cbdbe07f9d [MIPS] tlbex.c: use __cacheline_aligned instead of __tlb_handler_align
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:57 +00:00
Franck Bui-Huu f49b94d8c1 [MIPS] tlbex.c: cleanup include files
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:56 +00:00
Franck Bui-Huu a9af6041e9 [MIPS] tlbex.c: Cleanup __init usages.
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:56 +00:00
Ralf Baechle 33202349ef [MIPS] Remove useless S-cache flushes.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:56 +00:00
Ralf Baechle 526af35e5d [MIPS] Use pte_present instead of open coded test for _PAGE_PRESENT.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:55 +00:00
Maciej W. Rozycki 619b6e18fc [MIPS] R4000/R4400 daddiu erratum workaround
This complements the generic R4000/R4400 errata workaround code and adds 
bits for the daddiu problem.  In most places it just modifies handwritten 
assembly code so that the assembler is allowed to use a temporary register 
as daddiu may now be treated as a macro that expands to a sequence of li 
and daddu.  It is the AT register or, where AT is unavailable or used 
explicitly for another purpose, an explicitly-named register is selected, 
using the .set at=<reg> feature added recently to gas.  This feature is 
only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the 
workaround remains disabled, the required version of binutils stays 
unchanged.

 Similarly, daddiu instructions put in branch delay slots in noreorder 
fragments are now taken out of them and the assembler is allowed to 
reorder them itself as possible (which it does making the whole idea of 
scheduling them into delay slots manually questionable).

 Also in the very few places where such a simple conversion was not 
possible, a handcoded longer sequence is implemented.

 Other than that there are changes to code responsible for building the 
TLB fault and page clear/copy handlers to avoid daddiu as appropriate.  
These are only effective if the erratum is verified to be present at the 
run time.

 Finally there is a trivial update to __delay(), because it uses daddiu in 
a branch delay slot.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:55 +00:00
Ralf Baechle 161548bf35 [MIPS] tlbex: Cleanup handling of R2 hazards in TLB handlers.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:54 +00:00
Thomas Bogendoerfer 320167182d [MIPS] Wrong CONFIG option prevents setup of DMA zone.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-11 17:05:41 +00:00
Ralf Baechle cce335ae47 [MIPS] 64-bit Sibyte kernels need DMA32.
Sibyte SOCs only have 32-bit PCI.  Due to the sparse use of the address
space only the first 1GB of memory is mapped at physical addresses
below 1GB.  If a system has more than 1GB of memory 32-bit DMA will
not be able to reach all of it.

For now this patch is good enough to keep Sibyte users happy but it seems
eventually something like swiotlb will be needed for Sibyte.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-11-26 17:26:14 +00:00
Ralf Baechle 33b75e5c51 [MIPS] Sibyte: Replace use of removed IO_SPACE_BASE with IOADDR.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-11-15 23:21:49 +00:00
Ralf Baechle a8049c53cd [MIPS] Convert reference to mem_map to pfn_to_page().
This was crashing the combination of highmem and sparsemem.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-11-15 23:21:48 +00:00
Ralf Baechle a754f70886 [MIPS] Sibyte: resurrect old cache hack.
The recent switch of the Sibyte SOCs from the processor specific cache
managment code in c-sb1.c to c-r4k.c lost this old hack

    [MIPS] Hack for SB1 cache issues

    Removing flush_icache_page a while ago broke SB1 which was using an empty
    flush_data_cache_page function.  This glues things well enough so a more
    efficient but also more intrusive solution can be found later.

    Signed-Off-By: Thiemo Seufer <ths@networkno.de>
    Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

in the hope it was no longer needed.  As it turns it still is so resurrect
it until there is a better solution.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-11-15 23:21:48 +00:00
Ralf Baechle a76ab5c10d [MIPS] MT: Fix bug in multithreaded kernels.
When GDB writes a breakpoint into address area of inferior process the
kernel needs to invalidate the modified memory in the inferior which
is done by calling flush_cache_page which in turns calls
r4k_flush_cache_page and local_r4k_flush_cache_page for VSMP or SMTC
kernel via r4k_on_each_cpu().

As the VSMP and SMTC SMP kernels for 34K are running on a single shared
caches it is possible to get away without interprocessor function calls.
This optimization is implemented in r4k_on_each_cpu, so
local_r4k_flush_cache_page is only ever called on the local CPU.

This is where the following code in local_r4k_flush_cache_page() strikes:

        /*
         * If ownes no valid ASID yet, cannot possibly have gotten
         * this page into the cache.
         */
        if (cpu_context(smp_processor_id(), mm) == 0)
                return;

On VSMP and SMTC had a function of cpu_context() for each CPU(TC).

So in case another CPU than the CPU executing local_r4k_cache_flush_page
has not accessed the mm but one of the other CPUs has there may be data
to be flushed in the cache yet local_r4k_cache_flush_page will falsely
return leaving the I-cache inconsistent for the breakpoint.

While the issue was discovered with GDB it also exists in
local_r4k_flush_cache_range() and local_r4k_flush_cache().

Fixed by introducing a new function has_valid_asid which on MT kernels
returns true if a mm is active on any processor in the system.

This is relativly expensive since for memory acccesses in that loop
cache misses have to be assumed but it seems the most viable solution
for 2.6.23 and older -stable kernels.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-29 19:35:37 +00:00
Maciej W. Rozycki 21b2aecaae [MIPS] c-r3k: Implement flush_cache_range()
Contrary to the belief of some, the R3000 and related processors did have
caches, both a data and an instruction cache.  Here is an implementation
of r3k_flush_cache_page(), which is the processor-specific back-end for
flush_cache_range(), done according to the spec in
Documentation/cachetlb.txt.

While at it, remove an unused local function: get_phys_page(), do some
trivial formatting fixes and modernise debugging facilities.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-29 19:35:36 +00:00
Ralf Baechle 6e86b0bf0b [MIPS] Cleanup random difference between the lmo and kernel.org tree.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-29 19:35:33 +00:00
Jens Axboe 4fcc47a053 mips: sg_page() fallout
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-23 12:32:34 +02:00
Jens Axboe 58b053e4ce Update arch/ to use sg helpers
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-22 21:19:59 +02:00
Serge E. Hallyn b460cbc581 pid namespaces: define is_global_init() and is_container_init()
is_init() is an ambiguous name for the pid==1 check.  Split it into
is_global_init() and is_container_init().

A cgroup init has it's tsk->pid == 1.

A global init also has it's tsk->pid == 1 and it's active pid namespace
is the init_pid_ns.  But rather than check the active pid namespace,
compare the task structure with 'init_pid_ns.child_reaper', which is
initialized during boot to the /sbin/init process and never changes.

Changelog:

	2.6.22-rc4-mm2-pidns1:
	- Use 'init_pid_ns.child_reaper' to determine if a given task is the
	  global init (/sbin/init) process. This would improve performance
	  and remove dependence on the task_pid().

	2.6.21-mm2-pidns2:

	- [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc,
	  ppc,avr32}/traps.c for the _exception() call to is_global_init().
	  This way, we kill only the cgroup if the cgroup's init has a
	  bug rather than force a kernel panic.

[akpm@linux-foundation.org: fix comment]
[sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c]
[bunk@stusta.de: kernel/pid.c: remove unused exports]
[sukadev@us.ibm.com: Fix capability.c to work with threaded init]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: Pavel Emelianov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Herbert Poetzel <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:37 -07:00
Ralf Baechle 622a9edd91 Remove dma_cache_(wback|inv|wback_inv) functions
dma_cache_(wback|inv|wback_inv) were the earliest attempt on a generalized
cache managment API for I/O purposes.  Originally it was basically the raw
MIPS low level cache API exported to the entire world.  The API has
suffered from a lack of documentation, was not very widely used unlike it's
more modern brothers and can easily be replaced by dma_cache_sync.  So
remove it rsp.  turn the surviving bits back into an arch private API, as
discussed on linux-arch.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Kyle McMartin <kyle@parisc-linux.org>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:57 -07:00
Linus Torvalds ebc283118e Merge branch 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus:
  [MIPS] Increase cp0 compare clockevent min_delta_ns from 0x30 to 0x300.
  [MIPS] Cache: Provide more information on cache policy on bootup.
  [MIPS] Fix aliasing bug in copy_user_highpage, take 2.
  [MIPS] VPE loader: convert from struct class_ device to struct device
  [MIPS] MIPSsim: Fix booting from NFS root
  [MIPS] Alchemy: Get rid of au1xxx_irq_map_t.
  [MIPS] Alchemy: Get rid of au_ffz().
  [MIPS] Alchemy: Get rid of au_ffs().
  [MIPS] Alchemy: cleanup interrupt code.
  [MIPS] Lasat: Fix build by conversion to irq_cpu.c.
  [MIPS] Lasat: Add #ifndef ... #endif include warpper to lasatint.h.
  [MIPS] IP22: Enable -Werror.
  [MIPS] IP22: Fix warning.
  [MIPS] IP22: Complain if requesting the front panel irq failed.
  [MIPS] vmlinux.lds.S: Handle KPROBES_TEXT.
  [MIPS] vmlinux.lds.S: Fix handling of .notes in final link.
  [MIPS] vmlinux.lds.S: Remove duplicate comment.
  [MIPS] MSP71XX: Add workarounds file.
  [MIPS] IP32: Fix build by conversion to irq_cpu.c.
2007-10-16 10:44:35 -07:00
Ralf Baechle 64bfca5cd8 [MIPS] Cache: Provide more information on cache policy on bootup.
This should help making bug reports for the gadzillion of cores with all
their configuration and synthesis options more useful.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-16 18:23:49 +01:00
Ralf Baechle 985c30ef4d [MIPS] Fix aliasing bug in copy_user_highpage, take 2.
Turns out b868868ae0  wasn't quite right.
When called for a page that isn't marked dirty it would artificially
create an alias instead of doing the obvious thing and access the page
via KSEG0.

The same issue also exists in copy_to_user_page and copy_from_user_page
which was causing the machine to die under rare circumstances for example
when running ps if the BUG_ON() assertion added by the earlier fix was
getting triggered.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-16 18:23:49 +01:00