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authorsukadev@linux.vnet.ibm.com <sukadev@linux.vnet.ibm.com>2011-12-02 12:26:23 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-12-08 14:22:52 +1100
commit8a3e3d31d13ece3003e8f750178a7db02c5cd123 (patch)
tree975f02f4077cf9631de20011211fddb5367f937a /arch/powerpc/mm
parent11eab297f57bd6168425ae968e56c314e71b024e (diff)
downloadlinux-8a3e3d31d13ece3003e8f750178a7db02c5cd123.tar.bz2
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/mm')
-rw-r--r--arch/powerpc/mm/mem.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 83d819f30864..395f42d5f785 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -51,6 +51,7 @@
#include <asm/vdso.h>
#include <asm/fixmap.h>
#include <asm/swiotlb.h>
+#include <asm/rtas.h>
#include "mmu_decl.h"
@@ -600,6 +601,8 @@ int devmem_is_allowed(unsigned long pfn)
return 0;
if (!page_is_ram(pfn))
return 1;
+ if (page_is_rtas_user_buf(pfn))
+ return 1;
return 0;
}
#endif /* CONFIG_STRICT_DEVMEM */