Messages in this thread | | | Subject | Re: [PATCH v4 RESEND 4/11] x86/asm: Fix pud/pmd interfaces to handle large PAT bit | From | Toshi Kani <> | Date | Mon, 09 Nov 2015 14:01:44 -0700 |
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On Mon, 2015-11-09 at 22:10 +0200, Kirill A. Shutemov wrote: > On Mon, Nov 09, 2015 at 12:16:41PM -0700, Toshi Kani wrote: > > On Mon, 2015-11-09 at 13:06 -0500, Boris Ostrovsky wrote: > > > On 09/17/2015 02:24 PM, Toshi Kani wrote: > > > > Now that we have pud/pmd mask interfaces, which handle pfn & flags > > > > mask properly for the large PAT bit. > > > > > > > > Fix pud/pmd pfn & flags interfaces by replacing PTE_PFN_MASK and > > > > PTE_FLAGS_MASK with the pud/pmd mask interfaces. > > > > > > > > Suggested-by: Juergen Gross <jgross@suse.com> > > > > Signed-off-by: Toshi Kani <toshi.kani@hpe.com> > > > > Cc: Juergen Gross <jgross@suse.com> > > > > Cc: Konrad Wilk <konrad.wilk@oracle.com> > > > > Cc: Thomas Gleixner <tglx@linutronix.de> > > > > Cc: H. Peter Anvin <hpa@zytor.com> > > > > Cc: Ingo Molnar <mingo@redhat.com> > > > > Cc: Borislav Petkov <bp@alien8.de> > > > > --- > > > > arch/x86/include/asm/pgtable.h | 14 ++++++++------ > > > > arch/x86/include/asm/pgtable_types.h | 4 ++-- > > > > 2 files changed, 10 insertions(+), 8 deletions(-) > > > > > > > > > > > > > Looks like this commit is causing this splat for 32-bit kernels. I am > > > attaching my config file, just in case. > > > > Thanks for the report! I'd like to reproduce the issue since I am not sure > > how this change caused it... > > > > I tried to build a kernel with the attached config file, and got the > > following error. Not sure what I am missing. > > The problem is that PMD_PAGE_MASK as well as PUD_PAGE_MASK are 'unsigned > long', not 'unsigned long long'. So on 32-bit with PAE enabled your > pmd_pfn_mask()/pud_pfn_mask() will truncate bits 32..43 of pmd/pudval and > you'll never get proper page frame for pages above 4G.
Thanks Kirill! Yes, this explains the issue. Since I did not change these MASKs, and I tested 32-bit kernels on a small system, I was not able to catch this issue... -Toshi
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