Re: [PATCH 2/2] asm-generic: add an optional pfn_valid check to page_to_phys

2024-11-05 Thread Christophe Leroy 



Le 23/10/2024 à 07:36, Christoph Hellwig a écrit :

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 
---
  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__ */


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Re: [PATCH v7 6/8] x86/module: prepare module loading for ROX allocations of text

2024-11-05 Thread Nathan Chancellor 
On Tue, Nov 05, 2024 at 09:02:26AM +0200, Mike Rapoport wrote:
> There's a silly mistake in cfi_rewrite_endbr() in that commit, the patch
> below should fix it. Can you please test?

Yup, that was it! All my machines boot with this diff applied on top of
next-20241105, so with that fixed, I think we are all good here.

Tested-by: Nathan Chancellor 

> diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
> index 3407efc26528..243843e44e89 100644
> --- a/arch/x86/kernel/alternative.c
> +++ b/arch/x86/kernel/alternative.c
> @@ -1241,7 +1241,7 @@ static void cfi_rewrite_endbr(s32 *start, s32 *end, 
> struct module *mod)
>   void *addr = (void *)s + *s;
>   void *wr_addr = module_writable_address(mod, addr);
>  
> - poison_endbr(addr+16, wr_addr, false);
> + poison_endbr(addr + 16, wr_addr + 16, false);
>   }
>  }

Cheers,
Nathan

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