Unverified Commit 3e25d5a4 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Arnd Bergmann
Browse files

asm-generic: add an optional pfn_valid check to page_to_phys 



page_to_pfn is usually implemented by pointer arithmetics on the memory
map, which means that bogus input can lead to even more bogus output.

Powerpc had a pfn_valid check on the intermediate pfn in the page_to_phys
implementation when CONFIG_DEBUG_VIRTUAL is defined, which seems
generally useful, so add that to the generic version.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarThomas Huth <thuth@redhat.com>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
parent c5c3238d

include/asm-generic/memory_model.h

+10 −0
Original line number Diff line number Diff line
@@ -64,7 +64,17 @@ static inline int pfn_valid(unsigned long pfn) 
#define page_to_pfn __page_to_pfn

#define pfn_to_page __pfn_to_page



#ifdef CONFIG_DEBUG_VIRTUAL

#define page_to_phys(page)						\

({									\

	unsigned long __pfn = page_to_pfn(page);			\

									\

	WARN_ON_ONCE(!pfn_valid(__pfn));				\

	PFN_PHYS(__pfn);						\

})

#else

#define page_to_phys(page)	PFN_PHYS(page_to_pfn(page))

#endif /* CONFIG_DEBUG_VIRTUAL */

#define phys_to_page(phys)	pfn_to_page(PHYS_PFN(phys))



#endif /* __ASSEMBLY__ */