Messages in this thread | | | Date | Mon, 14 Mar 2016 14:27:34 +0000 | From | Matt Fleming <> | Subject | Re: [PATCH] x86/efi: Always map boot service regions into new EFI page tables |
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On Mon, 14 Mar, at 01:05:02PM, Ingo Molnar wrote: > > There's a number of such occurences that look suspicious: > > triton:~/tip> git grep 'cpa->pfn.*<<.*PAGE_SHIFT' arch/x86/ > arch/x86/mm/pageattr.c: set_pmd(pmd, __pmd(cpa->pfn << PAGE_SHIFT | _PAGE_PSE | > arch/x86/mm/pageattr.c: set_pud(pud, __pud(cpa->pfn << PAGE_SHIFT | _PAGE_PSE | > arch/x86/mm/pageattr.c: unsigned long laddr = (unsigned long)__va(cpa->pfn << PAGE_SHIFT); > arch/x86/mm/pageattr.c: unsigned long temp_cpa_vaddr = (cpa->pfn << PAGE_SHIFT) + > > are you sure none of the code runs on 32-bit?
The following occurrences do not run on 32-bit,
> arch/x86/mm/pageattr.c: set_pmd(pmd, __pmd(cpa->pfn << PAGE_SHIFT | _PAGE_PSE | > arch/x86/mm/pageattr.c: set_pud(pud, __pud(cpa->pfn << PAGE_SHIFT | _PAGE_PSE |
but these might,
> arch/x86/mm/pageattr.c: unsigned long laddr = (unsigned long)__va(cpa->pfn << PAGE_SHIFT); > arch/x86/mm/pageattr.c: unsigned long temp_cpa_vaddr = (cpa->pfn << PAGE_SHIFT) +
> All this got introduced with: > > | commit edc3b9129cecd0f0857112136f5b8b1bc1d45918 > | Author: Matt Fleming <matt@codeblueprint.co.uk> > | Date: Fri Nov 27 21:09:31 2015 +0000 > | > | x86/mm/pat: Ensure cpa->pfn only contains page frame numbers > > AFAICS.
Kinda. The bugs that do not run on 32-bit were introduced with this commit. The ones that will run on 32-bit existed before this.
Running the attached semantic patch across arch/x86/mm yields a few more places where we get the data type wrong for PAE,
* file: arch/x86/mm/mmap.c:43 shifting int '( ( - 1UL ) & STACK_RND_MASK )' by PAGE_SHIFT is truncated to 32-bits * file: arch/x86/mm/pageattr-test.c:57 shifting long 'i' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr-test.c:138 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/gup.c:422 shifting int 'nr' by PAGE_SHIFT is truncated to 32-bits * file: arch/x86/mm/gup.c:303 shifting unsigned long '( unsigned long ) nr_pages' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/gup.c:370 shifting unsigned long '( unsigned long ) nr_pages' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pat.c:751 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr-test.c:57 shifting long 'i' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:947 shifting unsigned 'num_pages' by PAGE_SHIFT is truncated to 32-bits * file: arch/x86/mm/pageattr.c:1995 shifting unsigned 'numpages' by PAGE_SHIFT is truncated to 32-bits * file: arch/x86/mm/pageattr-test.c:138 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:1117 shifting unsigned long 'cpa -> numpages' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:1017 shifting unsigned long 'cpa -> numpages' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:1277 shifting unsigned long 'cpa -> pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:1318 shifting unsigned long 'cpa -> pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:986 shifting unsigned long 'cpa -> pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:1059 shifting unsigned long 'cpa -> pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:197 shifting unsigned long 'end_pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:100 shifting unsigned long 'min_pfn_mapped' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:641 shifting unsigned long 'pagenr' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:111 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:121 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:111 shifting unsigned long __initdata 'pgt_buf_end' by PAGE_SHIFT is truncated to 32-bits * file: arch/x86/mm/init.c:196 shifting unsigned long 'start_pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:91 shifting unsigned long '( unsigned long ) num' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:117 shifting unsigned long '( pfn + i )' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init_32.c:293 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init_32.c:301 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init_32.c:344 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init_32.c:361 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init_32.c:471 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE
The coccinelle script isn't perfect, and there are a number of false positives. For example, the first hit is bogus and looks like a coccinelle bug, but the results do show some things that need to be investigated.
Running it over arch/x86/ turns up 66 potential issues. // A variable declared as a 32-bit data type should not be shifted by // PAGE_SHIFT because the result may not fit in sizeof(T) for large // numbers of pages, or high page frame numbers, e.g. both of these // are potentially bogus: // // unsigned long pfn; // unsigned int numpages; // ... // unsigned long pa = pfn << PAGE_SHIFT; // unsigned long size = numpages << PAGE_SHIFT; // // Options: --no-includes --include-headers
virtual context virtual report virtual org
@inttrunc@ {int, unsigned int, size_t, signed int, long, unsigned long, signed long} i; position p; type tt; tt i1; @@
\(i@p\&i1\) << PAGE_SHIFT
@script:python@ p << inttrunc.p; i << inttrunc.i; tt << inttrunc.tt; @@ pae_types = ["unsigned long", "signed long", "long"]
print "* file: %s:%s shifting %s '%s' by PAGE_SHIFT is truncated to 32-bits%s" % \ (p[0].file, p[0].line, tt, i, \ " for PAE" if tt in pae_types else "")
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