於 三，2013-09-04 於 08:01 -0400，Josh Boyer 提到：
> On Wed, Sep 4, 2013 at 6:51 AM, joeyli <jlee@xxxxxxxx> wrote:
> > 於 五，2013-08-30 於 19:41 -0400，Josh Boyer 提到：
> >> On Fri, Aug 30, 2013 at 01:46:30PM -0700, H. Peter Anvin wrote:
> >> > On 08/29/2013 11:37 AM, Josh Boyer wrote:
> >> > >> setup_efi_pci(boot_params);
> >> > >> diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
> >> > >> index c15ddaf..d35da96 100644
> >> > >> --- a/arch/x86/include/uapi/asm/bootparam.h
> >> > >> +++ b/arch/x86/include/uapi/asm/bootparam.h
> >> > >> @@ -131,7 +131,8 @@ struct boot_params {
> >> > >> __u8 eddbuf_entries; /* 0x1e9 */
> >> > >> __u8 edd_mbr_sig_buf_entries; /* 0x1ea */
> >> > >> __u8 kbd_status; /* 0x1eb */
> >> > >> - __u8 _pad5[3]; /* 0x1ec */
> >> > >> + __u8 secure_boot; /* 0x1ec */
> >> > >> + __u8 _pad5[2]; /* 0x1ec */
> >> > >> /*
> >> > >> * The sentinel is set to a nonzero value (0xff) in header.S.
> >> > >> *
> >> > >
> >> > > You need to include the following chunk of code with this, otherwise the
> >> > > secure_boot variable gets cleared.
> >> > >
> >> >
> >> > Not really.
> >> >
> >> > There are three cases:
> >> >
> >> > 1. Boot stub only. Here we do the right thing with the bootparams.
> >> > 2. Boot loader bypasses the boot stub completely. Here we MUST NOT do
> >> > what you suggest above.
> >> > 3. Boot stub with a boot_params structure passed in. Here we should
> >> > run sanitize_boot_params() (an inline for a reason) in the boot
> >> > stub, before we set the secure_boot field. Once that is done, we
> >> > again don't need that modification.
> >>
> >> OK. If 3 works, then great. All I know is that Fedora has been
> >> carrying the above hunk for months and it was missing in this patch set.
> >> So when I went to test it, the patches didn't do anything because the
> >> secure_boot field was getting cleared.
> >>
> >> I'm more than happy to try option 3, and I'll poke at it next week
> >> unless someone beats me to it.
> >>
> >> josh
> >
> > The secure_boot field cleaned by sanitize_boot_params() when using grub2
> > linuxefi to load efi stub kernel.
> > I printed the boot_params->sentinel value, confirm this value is NOT 0
> > when running grub2 linuxefi path, the entry point is efi_stub_entry.
> >
> > On the other hand,
> > the sentinel value is 0 when direct run efi stub kernel in UEFI shell,
> > the secure_boot field can keep.
> >
> > Does that mean grub2 should clean the sentinel value? or we move the get
> > secure_boot value to efi_init()?
>
> See V3 of this patch that Matthew sent yesterday. It calls
> sanitize_boot_params in efi_main before calling get_secure_boot. I
> tested that yesterday and it worked fine.
>
> josh
Ah!
Thanks for you point out, I missed his v3 patch.
Joey Lee
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