Commit Graph

262 Commits

Author SHA1 Message Date
Ralf Baechle
af6dc22b03 [MIPS] tlb-r4k: Nuke broken paranoia error test.
Bug originally found and reported by Julia Lawall <julia@diku.dk>.  I
decieded that the whole error check was mostly useless paranoia and should
be discarded.  It would only ever trigger if r3k_have_wired_reg has a wrong
value.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-07-30 21:54:33 +01:00
Johannes Weiner
e66ddf1a45 mips: use generic show_mem()
Remove arch-specific show_mem() in favor of the generic version.

This also removes the following redundant information display:

	- pages in swapcache, printed by show_swap_cache_info()

where show_mem() calls show_free_areas(), which calls
show_swap_cache_info().

And show_mem() does now actually print something on configurations
with multiple nodes.

Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26 12:00:11 -07:00
FUJITA Tomonori
8d8bb39b9e dma-mapping: add the device argument to dma_mapping_error()
Add per-device dma_mapping_ops support for CONFIG_X86_64 as POWER
architecture does:

This enables us to cleanly fix the Calgary IOMMU issue that some devices
are not behind the IOMMU (http://lkml.org/lkml/2008/5/8/423).

I think that per-device dma_mapping_ops support would be also helpful for
KVM people to support PCI passthrough but Andi thinks that this makes it
difficult to support the PCI passthrough (see the above thread).  So I
CC'ed this to KVM camp.  Comments are appreciated.

A pointer to dma_mapping_ops to struct dev_archdata is added.  If the
pointer is non NULL, DMA operations in asm/dma-mapping.h use it.  If it's
NULL, the system-wide dma_ops pointer is used as before.

If it's useful for KVM people, I plan to implement a mechanism to register
a hook called when a new pci (or dma capable) device is created (it works
with hot plugging).  It enables IOMMUs to set up an appropriate
dma_mapping_ops per device.

The major obstacle is that dma_mapping_error doesn't take a pointer to the
device unlike other DMA operations.  So x86 can't have dma_mapping_ops per
device.  Note all the POWER IOMMUs use the same dma_mapping_error function
so this is not a problem for POWER but x86 IOMMUs use different
dma_mapping_error functions.

The first patch adds the device argument to dma_mapping_error.  The patch
is trivial but large since it touches lots of drivers and dma-mapping.h in
all the architecture.

This patch:

dma_mapping_error() doesn't take a pointer to the device unlike other DMA
operations.  So we can't have dma_mapping_ops per device.

Note that POWER already has dma_mapping_ops per device but all the POWER
IOMMUs use the same dma_mapping_error function.  x86 IOMMUs use device
argument.

[akpm@linux-foundation.org: fix sge]
[akpm@linux-foundation.org: fix svc_rdma]
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix bnx2x]
[akpm@linux-foundation.org: fix s2io]
[akpm@linux-foundation.org: fix pasemi_mac]
[akpm@linux-foundation.org: fix sdhci]
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix sparc]
[akpm@linux-foundation.org: fix ibmvscsi]
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26 12:00:03 -07:00
Linus Torvalds
7e2225d860 Merge branch 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus: (54 commits)
  [MIPS] Remove mips_machtype for LASAT machines
  [MIPS] Remove mips_machtype from EMMA2RH machines
  [MIPS] Remove mips_machtype from ARC based machines
  [MIPS] MTX-1 flash partition setup move to platform devices registration
  [MIPS] TXx9: cleanup and fix some sparse warnings
  [MIPS] TXx9: rename asm-mips/mach-jmr3927 to asm-mips/mach-tx39xx
  [MIPS] remove machtype for group Toshiba
  [MIPS] separate rbtx4927_time_init() and rbtx4937_time_init()
  [MIPS] separate rbtx4927_arch_init() and rbtx4937_arch_init()
  [MIPS] txx9_cpu_clock setup move to rbtx4927_time_init()
  [MIPS] txx9_board_vec set directly without mips_machtype
  [MIPS] IP22: Add platform device for Indy volume buttons
  [MIPS] cmbvr4133: Remove support
  [MIPS] remove wrppmc_machine_power_off()
  [MIPS] replace inline assembler to cpu_wait()
  [MIPS] IP22/28: Add platform devices for HAL2
  [MIPS] TXx9: Update and merge defconfigs
  [MIPS] TXx9: Make single kernel can support multiple boards
  [MIPS] TXx9: Update defconfigs
  [MIPS] TXx9: Reorganize PCI code
  ...
2008-07-15 15:01:29 -07:00
Ingo Molnar
1a781a777b Merge branch 'generic-ipi' into generic-ipi-for-linus
Conflicts:

	arch/powerpc/Kconfig
	arch/s390/kernel/time.c
	arch/x86/kernel/apic_32.c
	arch/x86/kernel/cpu/perfctr-watchdog.c
	arch/x86/kernel/i8259_64.c
	arch/x86/kernel/ldt.c
	arch/x86/kernel/nmi_64.c
	arch/x86/kernel/smpboot.c
	arch/x86/xen/smp.c
	include/asm-x86/hw_irq_32.h
	include/asm-x86/hw_irq_64.h
	include/asm-x86/mach-default/irq_vectors.h
	include/asm-x86/mach-voyager/irq_vectors.h
	include/asm-x86/smp.h
	kernel/Makefile

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-15 21:55:59 +02:00
Dmitri Vorobiev
17f61e61b4 [MIPS] Make two functions static
The following routines

uasm_rel_highest()
uasm_rel_higher()

are needlessly defined global. This patch makes them static.

Compile-tested using a customized config for the Malta board. Booting
the same board up to the shell prompt was also successful with this
patch applied.

Spotted by sparse.

Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.fi>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-07-15 18:44:29 +01:00
Thomas Bogendoerfer
14defd90f5 [MIPS] Fix 32bit kernels on R4k with 128 byte cache line size
The generated copy_page for R4k CPU with a 128 byte cache line size used
Create Dirty Exclusive cache line operations even if only part of the
cache line was filled.  This change avoids generating cache operations,
if only part of the cache line size is copied in one loop. It also
increases the maxmimum loop size, because the generated code even fits
into the available space for r4k CPUs with 128 byte cache line size.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-07-08 19:33:46 +01:00
Shane McDonald
b32dfbb9c5 [MIPS] Atlas, decstation: Fix section mismatches triggered by defconfigs
Resolve these mismatches by defining affected functions with the __cpuinit
attribute, rather than __init.

Signed-off-by: Shane McDonald <mcdonald.shane@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-07-08 19:33:46 +01:00
Jens Axboe
8691e5a8f6 smp_call_function: get rid of the unused nonatomic/retry argument
It's never used and the comments refer to nonatomic and retry
interchangably. So get rid of it.

Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-06-26 11:24:35 +02:00
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