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
--
To unsubscribe from this list: send the line "unsubscribe linux-efi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
