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From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
	Andrew Cooper <andrew.cooper3@citrix.com>, Wei Liu <wl@xen.org>
Subject: Re: [PATCH 4/8] x86/EFI: redo .reloc section bounds determination
Date: Wed, 21 Apr 2021 11:46:31 +0200	[thread overview]
Message-ID: <YH/0dzlPxwWF1PA2@Air-de-Roger> (raw)
In-Reply-To: <b886eb2c-cabc-f195-4996-aae1fc3c61d9@suse.com>

On Thu, Apr 01, 2021 at 11:45:38AM +0200, Jan Beulich wrote:
> There's no need to link relocs-dummy.o into the ELF binary. The two
> symbols needed can as well be provided by the linker script. Then our
> mkreloc tool also doesn't need to put them in the generated assembler
> source.

Maybe I'm just dense today, but I think the message needs to be
expanded a bit to mention that while the __base_relocs_{start,end} are
not used when loaded as an EFI application, they are used by the EFI
code in Xen when booted using the multiboot2 protocol for example, as
they are used by efi_arch_relocate_image.

I think relocation is not needed when natively loaded as an EFI
application, as then the load address matches the one expected by
Xen?

I also wonder, at some point there where plans for providing a single
binary that would work as multiboot{1,2} and also be capable of being
loaded as an EFI application (ie: have a PE/COFF header also I assume
together with the ELF one), won't the changes here make it more
difficult to reach that goal or require reverting later on, as I feel
they are adding more differences between the PE binary and the ELF
one.

The code LGTM, but I think at least I would like the commit message to
be expanded.

Thanks, Roger.


  reply	other threads:[~2021-04-21  9:47 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-01  9:43 [PATCH 0/8] x86/EFI: build adjustments Jan Beulich
2021-04-01  9:44 ` [PATCH 1/8] x86/EFI: drop stale section special casing when generating base relocs Jan Beulich
2021-04-01 11:51   ` Andrew Cooper
2021-04-01  9:44 ` [PATCH 2/8] x86/EFI: sections may not live at VA 0 in PE binaries Jan Beulich
2021-04-01 12:01   ` Andrew Cooper
2021-04-01 13:51     ` Jan Beulich
2021-04-21  8:52   ` Roger Pau Monné
2021-04-21 10:32     ` Jan Beulich
2021-04-21 12:57       ` Roger Pau Monné
2021-04-21 13:28         ` Jan Beulich
2021-04-01  9:45 ` [PATCH 3/8] x86/EFI: program headers are an ELF concept Jan Beulich
2021-04-21  9:11   ` Roger Pau Monné
2021-04-21 10:36     ` Jan Beulich
2021-04-21 14:21       ` Roger Pau Monné
2021-04-21 14:30         ` Jan Beulich
2021-04-01  9:45 ` [PATCH 4/8] x86/EFI: redo .reloc section bounds determination Jan Beulich
2021-04-21  9:46   ` Roger Pau Monné [this message]
2021-04-21 10:44     ` Jan Beulich
2021-04-21 14:54       ` Roger Pau Monné
2021-04-01  9:46 ` [PATCH 5/8] x86: drop use of prelink-efi.o Jan Beulich
2021-04-21  9:51   ` Roger Pau Monné
2021-04-01  9:46 ` [PATCH 6/8] x86/EFI: avoid use of GNU ld's --disable-reloc-section when possible Jan Beulich
2021-04-21 10:21   ` Roger Pau Monné
2021-04-21 12:03     ` Jan Beulich
2021-04-21 15:20       ` Roger Pau Monné
2021-04-21 15:34         ` Jan Beulich
2021-04-22  7:22           ` Roger Pau Monné
2021-04-22 10:42             ` Jan Beulich
2021-04-01  9:47 ` [PATCH 7/8] x86/EFI: keep debug info in xen.efi Jan Beulich
2021-04-21 11:15   ` Roger Pau Monné
2021-04-21 13:06     ` Jan Beulich
2021-04-21 15:30       ` Roger Pau Monné
2021-04-21 15:38         ` Jan Beulich
2021-04-22  8:14           ` Roger Pau Monné
2021-04-22 11:03             ` Jan Beulich
2021-04-22 14:56               ` Roger Pau Monné
2021-04-22 15:46                 ` Jan Beulich
2021-04-22 15:53                   ` Roger Pau Monné
2021-04-22 16:01                     ` Jan Beulich
2021-04-23  7:30                       ` Roger Pau Monné
2021-04-23  8:51                         ` Jan Beulich
2021-04-23 10:07                           ` Roger Pau Monné
2021-04-23 10:45                             ` Jan Beulich
2021-04-23 10:58                               ` Roger Pau Monné
2021-04-01  9:47 ` [PATCH 8/8] x86/EFI: don't have an overly large image size Jan Beulich
2021-04-21 11:18   ` Roger Pau Monné
2021-04-21 13:15     ` Jan Beulich
2021-04-15  9:53 ` Ping: [PATCH 0/8] x86/EFI: build adjustments Jan Beulich

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