Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1342198

Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page table mappings

Show all headers | View raw

On Wed, Feb 24, 2016 at 8:41 AM, Borislav Petkov <bp@alien8.de> wrote:
> On Wed, Feb 24, 2016 at 05:20:02PM +0100, Borislav Petkov wrote:
>> That's mixed mode. I think you mean the FLUSH_TLB_ALL in efi_call.
>> That's EFI on 64-bit but that is mandated by the spec, AFAIR.
>
> Ok, so mfleming set me straight on IRC - that's tip/master I should be
> staring at.
>
> In any case, I think we should do __flush_tlb_all() in efi_call_cirt()
> just in case, for the simple reason that EFI could be installing some
> funky TLB entries which we don't want. I'm not saying it does and it
> probably won't but what's stopping it?
>
> Or am I being overly paranoid?

I think you may be overly paranoid here.  At least no working 32-bit
EFI does this because we run it in compat mode.  Any paging entries it
inserts would be misinterpreted and likely immediately cause a crash.
Also, the EFI code doesn't know a virtual address through which to
reference the paging structures in the first place -- it could read
CR3, but that gives a physical address, and it's not at all clear to
me what even the crazier firmware authors would do with a physical
address that doesn't live in EFI-defined ranges.

--Andy

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page table mappings tip-bot for Sai Praneeth <tipbot@zytor.com>@zytor.com - 2016-02-23 10:20 +0100
  Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-23 18:50 +0100
    Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Linus Torvalds <torvalds@linux-foundation.org> - 2016-02-23 19:10 +0100
      Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Borislav Petkov <bp@alien8.de> - 2016-02-23 19:20 +0100
      Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page table mappings "H. Peter Anvin" <hpa@zytor.com> - 2016-02-24 03:20 +0100
      Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page table mappings "H. Peter Anvin" <hpa@zytor.com> - 2016-02-24 03:20 +0100
      Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Ingo Molnar <mingo@kernel.org> - 2016-02-25 10:00 +0100
    Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> - 2016-02-24 02:00 +0100
      Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-24 03:50 +0100
        Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-24 15:20 +0100
          Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Borislav Petkov <bp@alien8.de> - 2016-02-24 17:30 +0100
            Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-24 17:40 +0100
              Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Linus Torvalds <torvalds@linux-foundation.org> - 2016-02-24 20:00 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-24 20:50 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-24 21:00 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Sylvain Chouleur <sylvain.chouleur@gmail.com> - 2016-02-29 12:00 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-03-02 12:30 +0100
              Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-24 20:40 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-24 21:00 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Ingo Molnar <mingo@kernel.org> - 2016-02-25 10:10 +0100
                Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-25 16:30 +0100
            Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-24 17:50 +0100
            Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Borislav Petkov <bp@alien8.de> - 2016-02-24 17:50 +0100
          Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Andy Lutomirski <luto@amacapital.net> - 2016-02-24 17:50 +0100
            Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page  table mappings Matt Fleming <matt@codeblueprint.co.uk> - 2016-02-25 17:10 +0100

csiph-web