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Commit b3cb8674 authored by James Bottomley's avatar James Bottomley
Browse files

[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: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 207f583d

arch/parisc/include/asm/prefetch.h

+6 −1
Original line number Diff line number Diff line
@@ -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. */