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linux/arch/arm/mm
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Nicolas Pitre 7e5a69e83b ARM: 6007/1: fix highmem with VIPT cache and DMA 
The VIVT cache of a highmem page is always flushed before the page
is unmapped.  This cache flush is explicit through flush_cache_kmaps()
in flush_all_zero_pkmaps(), or through __cpuc_flush_dcache_area() in
kunmap_atomic().  There is also an implicit flush of those highmem pages
that were part of a process that just terminated making those pages free
as the whole VIVT cache has to be flushed on every task switch. Hence
unmapped highmem pages need no cache maintenance in that case.

However unmapped pages may still be cached with a VIPT cache because the
cache is tagged with physical addresses.  There is no need for a whole
cache flush during task switching for that reason, and despite the
explicit cache flushes in flush_all_zero_pkmaps() and kunmap_atomic(),
some highmem pages that were mapped in user space end up still cached
even when they become unmapped.

So, we do have to perform cache maintenance on those unmapped highmem
pages in the context of DMA when using a VIPT cache.  Unfortunately,
it is not possible to perform that cache maintenance using physical
addresses as all the L1 cache maintenance coprocessor functions accept
virtual addresses only.  Therefore we have no choice but to set up a
temporary virtual mapping for that purpose.

And of course the explicit cache flushing when unmapping a highmem page
on a system with a VIPT cache now can go, which should increase
performance.

While at it, because the code in __flush_dcache_page() has to be modified
anyway, let's also make sure the mapped highmem pages are pinned with
kmap_high_get() for the duration of the cache maintenance operation.
Because kunmap() does unmap highmem pages lazily, it was reported by
Gary King <GKing@nvidia.com> that those pages ended up being unmapped
during cache maintenance on SMP causing segmentation faults.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-04-14 11:11:27 +01:00
..
abort-ev4.S
abort-ev4t.S
abort-ev5t.S
abort-ev5tj.S
abort-ev6.S Add core support for ARMv6/v7 big-endian 2009-05-30 14:00:18 +01:00
abort-ev7.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
abort-lv4t.S [ARM] nommu: abort handler fixup for !CPU_CP15_MMU cores. 2006-09-28 20:15:46 +01:00
abort-macro.S
abort-nommu.S [ARM] 5227/1: Add the ENDPROC declarations to the .S files 2008-09-01 12:06:34 +01:00
alignment.c Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm 2010-03-01 09:15:15 -08:00
cache-fa.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
cache-feroceon-l2.c [ARM] Kirkwood: small L2 code cleanup 2009-03-28 22:39:30 -04:00
cache-l2x0.c ARM: 5995/1: ARM: Add L2x0 outer_sync() support (3/4) 2010-03-25 21:13:50 +00:00
cache-tauros2.c ARM: Add Tauros2 L2 cache controller support 2009-11-27 15:43:21 -05:00
cache-v3.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
cache-v4.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
cache-v4wb.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
cache-v4wt.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
cache-v6.S ARM: dma-mapping: fix for speculative prefetching 2010-02-15 15:22:25 +00:00
cache-v7.S ARM: dma-mapping: fix for speculative prefetching 2010-02-15 15:22:25 +00:00
cache-xsc3l2.c [ARM] pxa: do not enable L2 after MMU is enabled 2010-01-01 15:50:34 +08:00
context.c ARM: 5905/1: ARM: Global ASID allocation on SMP 2010-02-15 21:39:51 +00:00
copypage-fa.c ARM: Add support for FA526 v2 2009-03-25 13:10:01 +02:00
copypage-feroceon.c ARM: Flush user mapping on VIVT processors when copying a page 2009-10-05 15:42:16 +01:00
copypage-v3.c ARM: Pass VMA to copy_user_highpage() implementations 2009-10-05 15:17:45 +01:00
copypage-v4mc.c ARM: Pass VMA to copy_user_highpage() implementations 2009-10-05 15:17:45 +01:00
copypage-v4wb.c ARM: Flush user mapping on VIVT processors when copying a page 2009-10-05 15:42:16 +01:00
copypage-v4wt.c ARM: Pass VMA to copy_user_highpage() implementations 2009-10-05 15:17:45 +01:00
copypage-v6.c ARM: 6007/1: fix highmem with VIPT cache and DMA 2010-04-14 11:11:27 +01:00
copypage-xsc3.c ARM: Flush user mapping on VIVT processors when copying a page 2009-10-05 15:42:16 +01:00
copypage-xscale.c ARM: Pass VMA to copy_user_highpage() implementations 2009-10-05 15:17:45 +01:00
discontig.c mm: move bootmem descriptors definition to a single place 2008-07-24 10:47:14 -07:00
dma-mapping.c ARM: 6007/1: fix highmem with VIPT cache and DMA 2010-04-14 11:11:27 +01:00
extable.c [ARM] Convert asm/uaccess.h to linux/uaccess.h 2008-09-06 11:35:55 +01:00
fault-armv.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
fault.c ARM: 5900/2: arm: enable support for software perf events 2010-02-12 17:25:53 +00:00
fault.h [ARM] do_bad_area() always takes current and current->active_mm 2006-09-27 16:13:48 +01:00
flush.c ARM: 6007/1: fix highmem with VIPT cache and DMA 2010-04-14 11:11:27 +01:00
highmem.c ARM: 6007/1: fix highmem with VIPT cache and DMA 2010-04-14 11:11:27 +01:00
init.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
iomap.c [ARM] Convert asm/io.h to linux/io.h 2008-09-06 12:10:45 +01:00
ioremap.c ARM: Add caller information to ioremap 2010-02-15 21:39:11 +00:00
Kconfig ARM: 5996/1: ARM: Change the mandatory barriers implementation (4/4) 2010-03-25 21:13:50 +00:00
Makefile ARM: Ensure ARMv6/7 mm files are built using appropriate assembler options 2010-01-12 19:02:05 +00:00
mm.h ARM: Reduce __flush_dcache_page() visibility 2009-12-04 14:58:50 +00:00
mmap.c fix broken aliasing checks for MAP_FIXED on sparc32, mips, arm and sh 2009-12-11 06:44:59 -05:00
mmu.c ARM: Fix ioremap_cached()/ioremap_wc() for SMP platforms 2010-04-09 15:00:11 +01:00
nommu.c ARM: Add caller information to ioremap 2010-02-15 21:39:11 +00:00
pabort-legacy.S ARM: 5727/1: Pass IFSR register to do_PrefetchAbort() 2009-10-02 22:34:32 +01:00
pabort-v6.S ARM: 5727/1: Pass IFSR register to do_PrefetchAbort() 2009-10-02 22:34:32 +01:00
pabort-v7.S ARM: 5727/1: Pass IFSR register to do_PrefetchAbort() 2009-10-02 22:34:32 +01:00
pgd.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
proc-arm6_7.S ARM: Fix wrong register in proc-arm6_7.S data abort handler 2010-02-03 15:48:03 +00:00
proc-arm7tdmi.S ARM: 5727/1: Pass IFSR register to do_PrefetchAbort() 2009-10-02 22:34:32 +01:00
proc-arm9tdmi.S ARM: 5727/1: Pass IFSR register to do_PrefetchAbort() 2009-10-02 22:34:32 +01:00
proc-arm720.S ARM: 5727/1: Pass IFSR register to do_PrefetchAbort() 2009-10-02 22:34:32 +01:00
proc-arm740.S ARM: 5727/1: Pass IFSR register to do_PrefetchAbort() 2009-10-02 22:34:32 +01:00
proc-arm920.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
proc-arm922.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
proc-arm925.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
proc-arm926.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
proc-arm940.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
proc-arm946.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
proc-arm1020.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
proc-arm1020e.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
proc-arm1022.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
proc-arm1026.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
proc-fa526.S ARM: 5727/1: Pass IFSR register to do_PrefetchAbort() 2009-10-02 22:34:32 +01:00
proc-feroceon.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
proc-macros.S Merge branch 'devel-stable' into devel 2009-09-12 12:02:26 +01:00
proc-mohawk.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
proc-sa110.S ARM: 5727/1: Pass IFSR register to do_PrefetchAbort() 2009-10-02 22:34:32 +01:00
proc-sa1100.S ARM: 5727/1: Pass IFSR register to do_PrefetchAbort() 2009-10-02 22:34:32 +01:00
proc-syms.c ARM: add size argument to __cpuc_flush_dcache_page 2009-12-14 14:53:22 +00:00
proc-v6.S ARM: 5888/1: arm: Update comments in cacheflush.h and remove unnecessary V6 and V7 comments 2010-01-19 23:11:56 +00:00
proc-v7.S ARM: 5888/1: arm: Update comments in cacheflush.h and remove unnecessary V6 and V7 comments 2010-01-19 23:11:56 +00:00
proc-xsc3.S Merge branches 'at91', 'cache', 'cup', 'ep93xx', 'ixp4xx', 'nuc', 'pending-dma-streaming', 'u300' and 'umc' into devel 2010-02-25 22:06:43 +00:00
proc-xscale.S ARM: dma-mapping: remove dmac_clean_range and dmac_inv_range 2010-02-15 15:22:23 +00:00
tlb-fa.S ARM: Add support for FA526 v2 2009-03-25 13:10:01 +02:00
tlb-v3.S
tlb-v4.S
tlb-v4wb.S
tlb-v4wbi.S
tlb-v6.S arm: Use __INIT macro instead of .text.init. 2009-04-27 19:51:58 -07:00
tlb-v7.S ARM: 5858/1: Remove unused vma_vm_flags macro from v7wbi_flush_user_tlb_range 2010-01-05 20:52:06 +00:00
vmregion.c ARM: dma-mapping: split out vmregion code from dma coherent mapping code 2009-11-24 17:41:34 +00:00
vmregion.h ARM: dma-mapping: split out vmregion code from dma coherent mapping code 2009-11-24 17:41:34 +00:00