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authorHelge Deller <deller@gmx.de>2014-01-31 21:33:17 +0100
committerHelge Deller <deller@gmx.de>2014-02-02 20:57:16 +0100
commit57737c49dd72c96cfbcd4f66559f3ffc399aeb4f (patch)
tree390ecd631d941babf6f7390bbac4f7c6187f957a /arch/parisc/kernel/cache.c
parent8a10bc9d27ceb084b0d8be621a033a475eb9fdfd (diff)
downloadlinux-57737c49dd72c96cfbcd4f66559f3ffc399aeb4f.tar.bz2
parisc: fix cache-flushing
This commit: f8dae00684d678afa13041ef170cecfd1297ed40: parisc: Ensure full cache coherency for kmap/kunmap caused negative caching side-effects, e.g. hanging processes with expect and too many inequivalent alias messages from flush_dcache_page() on Debian 5 systems. This patch now partly reverts it and has been in production use on our debian buildd makeservers since a week without any major problems. Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: John David Anglin <dave.anglin@bell.net> Cc: stable@vger.kernel.org # v3.9+ Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'arch/parisc/kernel/cache.c')
-rw-r--r--arch/parisc/kernel/cache.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index a72545554a31..ac87a40502e6 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -388,6 +388,20 @@ void flush_kernel_dcache_page_addr(void *addr)
}
EXPORT_SYMBOL(flush_kernel_dcache_page_addr);
+void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
+ struct page *pg)
+{
+ /* Copy using kernel mapping. No coherency is needed (all in
+ kunmap) for the `to' page. However, the `from' page needs to
+ be flushed through a mapping equivalent to the user mapping
+ before it can be accessed through the kernel mapping. */
+ preempt_disable();
+ flush_dcache_page_asm(__pa(vfrom), vaddr);
+ preempt_enable();
+ copy_page_asm(vto, vfrom);
+}
+EXPORT_SYMBOL(copy_user_page);
+
void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
{
unsigned long flags;