Commit b3cb8674811d1851bbf1486a73d62b90c119b994
1 parent
207f583d71
Exists in
smarc-l5.0.0_1.0.0-ga
and in
5 other branches
[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>
Showing 1 changed file with 6 additions and 1 deletions Side-by-side Diff
arch/parisc/include/asm/prefetch.h
| ... | ... | @@ -21,7 +21,12 @@ |
| 21 | 21 | #define ARCH_HAS_PREFETCH |
| 22 | 22 | static inline void prefetch(const void *addr) |
| 23 | 23 | { |
| 24 | - __asm__("ldw 0(%0), %%r0" : : "r" (addr)); | |
| 24 | + __asm__( | |
| 25 | +#ifndef CONFIG_PA20 | |
| 26 | + /* Need to avoid prefetch of NULL on PA7300LC */ | |
| 27 | + " extrw,u,= %0,31,32,%%r0\n" | |
| 28 | +#endif | |
| 29 | + " ldw 0(%0), %%r0" : : "r" (addr)); | |
| 25 | 30 | } |
| 26 | 31 | |
| 27 | 32 | /* LDD is a PA2.0 addition. */ |