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authorJames Bottomley <JBottomley@Parallels.com>2012-05-16 11:10:27 +0100
committerJames Bottomley <JBottomley@Parallels.com>2012-05-16 13:15:21 +0100
commitb3cb8674811d1851bbf1486a73d62b90c119b994 (patch)
treec2158cee689175a1fae57767ab8b4c955d0a237c /arch/parisc
parent207f583d7179f707f402c36a7bda5ca1fd03ad5b (diff)
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[PARISC] fix panic on prefetch(NULL) on PA7300LC
Due to an errata, the PA7300LC generates a TLB miss interruption even on the prefetch instruction. This means that prefetch(NULL), which is supposed to be a nop on linux actually generates a NULL deref fault. Fix this by testing the address of prefetch against NULL before doing the prefetch. Cc: stable@vger.kernel.org Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'arch/parisc')
-rw-r--r--arch/parisc/include/asm/prefetch.h7
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/parisc/include/asm/prefetch.h b/arch/parisc/include/asm/prefetch.h
index c5edc60c059f..1ee7c82672c1 100644
--- a/arch/parisc/include/asm/prefetch.h
+++ b/arch/parisc/include/asm/prefetch.h
@@ -21,7 +21,12 @@
#define ARCH_HAS_PREFETCH
static inline void prefetch(const void *addr)
{
- __asm__("ldw 0(%0), %%r0" : : "r" (addr));
+ __asm__(
+#ifndef CONFIG_PA20
+ /* Need to avoid prefetch of NULL on PA7300LC */
+ " extrw,u,= %0,31,32,%%r0\n"
+#endif
+ " ldw 0(%0), %%r0" : : "r" (addr));
}
/* LDD is a PA2.0 addition. */