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authorsukadev@linux.vnet.ibm.com <sukadev@linux.vnet.ibm.com>2011-12-02 07:26:23 -0500
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-12-07 22:22:52 -0500
commit8a3e3d31d13ece3003e8f750178a7db02c5cd123 (patch)
tree975f02f4077cf9631de20011211fddb5367f937a /arch/powerpc/include
parent11eab297f57bd6168425ae968e56c314e71b024e (diff)
powerpc: Punch a hole in /dev/mem for librtas
With CONFIG_STRICT_DEVMEM=y, user space cannot read any part of /dev/mem. Since this breaks librtas, punch a hole in /dev/mem to allow access to the rmo_buffer that librtas needs. Anton Blanchard reported the problem and helped with the fix. A quick test for this patch: # cat /proc/rtas/rmo_buffer 000000000f190000 10000 # python -c "print 0x000000000f190000 / 0x10000" 3865 # dd if=/dev/mem of=/tmp/foo count=1 bs=64k skip=3865 1+0 records in 1+0 records out 65536 bytes (66 kB) copied, 0.000205235 s, 319 MB/s # dd if=/dev/mem of=/tmp/foo dd: reading `/dev/mem': Operation not permitted 0+0 records in 0+0 records out 0 bytes (0 B) copied, 0.00022519 s, 0.0 kB/s Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/include')
-rw-r--r--arch/powerpc/include/asm/rtas.h12
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index 1646b76bd3d2..01c143bb77ae 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -313,5 +313,17 @@ static inline u32 rtas_config_addr(int busno, int devfn, int reg)
313extern void __cpuinit rtas_give_timebase(void); 313extern void __cpuinit rtas_give_timebase(void);
314extern void __cpuinit rtas_take_timebase(void); 314extern void __cpuinit rtas_take_timebase(void);
315 315
316#ifdef CONFIG_PPC_RTAS
317static inline int page_is_rtas_user_buf(unsigned long pfn)
318{
319 unsigned long paddr = (pfn << PAGE_SHIFT);
320 if (paddr >= rtas_rmo_buf && paddr < (rtas_rmo_buf + RTAS_RMOBUF_MAX))
321 return 1;
322 return 0;
323}
324#else
325static inline int page_is_rtas_user_buf(unsigned long pfn) { return 0;}
326#endif
327
316#endif /* __KERNEL__ */ 328#endif /* __KERNEL__ */
317#endif /* _POWERPC_RTAS_H */ 329#endif /* _POWERPC_RTAS_H */