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From: "Jan Beulich" <JBeulich@suse.com>
To: Daniel Kiper <daniel.kiper@oracle.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
	xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH RFC 2/7] xen/x86: Manually build PE header
Date: Tue, 15 May 2018 02:01:40 -0600	[thread overview]
Message-ID: <5AFA93E402000078001C2BF7@prv1-mh.provo.novell.com> (raw)
In-Reply-To: <20180514165201.GO12135@olila.local.net-space.pl>

>>> On 14.05.18 at 18:52, <daniel.kiper@oracle.com> wrote:
> On Mon, May 14, 2018 at 04:40:39AM -0600, Jan Beulich wrote:
>> >>> On 08.05.18 at 14:47, <daniel.kiper@oracle.com> wrote:
>> > On Fri, May 04, 2018 at 09:38:03AM -0600, Jan Beulich wrote:
>> >> >>> On 08.07.17 at 23:53, <daniel.kiper@oracle.com> wrote:
>> >> > +        /*
>> >> > +         * DOS message.
>> >> > +         *
>> >> > +         * It is copied from binutils package, version 2.28,
>> >> > +         * include/coff/pe.h:struct external_PEI_filehdr and
>> >> > +         * bfd/peXXigen.c:_bfd_XXi_only_swap_filehdr_out().
>> >> > +         */
>> >> > +        .long   0x0eba1f0e
>> >> > +        .long   0xcd09b400
>> >> > +        .long   0x4c01b821
>> >> > +        .long   0x685421cd
>> >> > +        .long   0x70207369
>> >> > +        .long   0x72676f72
>> >> > +        .long   0x63206d61
>> >> > +        .long   0x6f6e6e61
>> >> > +        .long   0x65622074
>> >> > +        .long   0x6e757220
>> >> > +        .long   0x206e6920
>> >> > +        .long   0x20534f44
>> >> > +        .long   0x65646f6d
>> >> > +        .long   0x0a0d0d2e
>> >> > +        .long   0x24
>> >> > +        .long   0
>> >>
>> >> Other than what the comment says, this isn't just a message (or else you
>> >> could have used .asciz for the whole thing). I'm not convinced we need
>> >> any of this.
>> >
>> > Potentially we can drop this. However, ld from binutils put this into
>> > EFI binary. And IIRC this is exactly what is embedded by other linkers
>> > into PE/COFF compatible files, e.g. *.efi, *.exe, *.dll, etc. So,
>> > I would leave this just for the sake of compatibility.
>>
>> Having this in .exe files is indeed helpful (or at least was back when DOS still
>> played some sort of a role). In .dll it is already highly questionable, and
>> hence even more so in .efi. Let's not encode and carry cruft that's not
>> needed for anything.
> 
> OK, but I think that we should leave at least one or two instructions here, e.g.
> hlt and jmp back to it or something like that. Or int 0x21 with 0x4c00 in %ax.
> Latter seems better for me.

I certainly don't mind you doing something minimalistic like what you propose.

Jan



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  reply	other threads:[~2018-05-15  8:01 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-08 21:53 [PATCH RFC 0/7] Change xen.efi build and add SHIM_LOCK verification into efi_multiboot2() Daniel Kiper
2017-07-08 21:53 ` [PATCH RFC 1/7] xen: Introduce XEN_COMPILE_POSIX_TIME Daniel Kiper
2018-04-30 15:56   ` Jan Beulich
2018-05-08 12:18     ` Daniel Kiper
2018-05-14 10:30       ` Jan Beulich
2018-05-14 16:25         ` Daniel Kiper
2018-05-15  7:47           ` Jan Beulich
2017-07-08 21:53 ` [PATCH RFC 2/7] xen/x86: Manually build PE header Daniel Kiper
2018-05-04 15:38   ` Jan Beulich
2018-05-08 12:47     ` Daniel Kiper
2018-05-14 10:40       ` Jan Beulich
2018-05-14 16:52         ` Daniel Kiper
2018-05-15  8:01           ` Jan Beulich [this message]
2017-07-08 21:53 ` [PATCH RFC 3/7] xen/x86: Add some addresses to the Multiboot header Daniel Kiper
2018-05-04 15:40   ` Jan Beulich
2018-05-08 13:01     ` Daniel Kiper
2017-07-08 21:53 ` [PATCH RFC 4/7] xen/x86: Add some addresses to the Multiboot2 header Daniel Kiper
2017-07-08 21:53 ` [PATCH RFC 5/7] efi: split out efi_shim_lock() Daniel Kiper
2017-07-08 21:53 ` [PATCH RFC 6/7] xen/x86/efi: Verify dom0 kernel with SHIM_LOCK protocol in efi_multiboot2() Daniel Kiper
2018-05-04 15:46   ` Jan Beulich
2018-05-08 13:09     ` Daniel Kiper
2018-05-14 10:43       ` Jan Beulich
2018-05-14 16:56         ` Daniel Kiper
2018-05-15  8:06           ` Jan Beulich
2017-07-08 21:53 ` [PATCH RFC 7/7] xen/x86: Build xen.mb.efi directly from xen-syms Daniel Kiper

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