Re: [PATCH 2/2] asm-generic: add an optional pfn_valid check to page_to_phys
From: Christophe Leroy <hidden>
Date: 2024-11-05 09:56:45
Also in:
linux-alpha, linux-arch, linux-arm-kernel, linux-m68k, linux-mips, linux-riscv, linux-s390, linux-sh, linux-um, lkml, loongarch, sparclinux
Le 23/10/2024 à 07:36, Christoph Hellwig a écrit :
quoted hunk ↗ jump to hunk
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: Christoph Hellwig <hch@lst.de> --- include/asm-generic/memory_model.h | 10 ++++++++++ 1 file changed, 10 insertions(+)diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h index a73a140cbecd..6d1fb6162ac1 100644 --- a/include/asm-generic/memory_model.h +++ b/include/asm-generic/memory_model.h@@ -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)); \
On powerpc I think it was a WARN_ON(). Will a WARN_ON_ONCE() be enough ?
+ 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__ */