From: Ard Biesheuvel <ardb@kernel.org> To: Arvind Sankar <nivedita@alum.mit.edu> Cc: linux-efi <linux-efi@vger.kernel.org>, linux-arm-kernel <linux-arm-kernel@lists.infradead.org>, Laszlo Ersek <lersek@redhat.com>, Leif Lindholm <leif@nuviainc.com>, Peter Jones <pjones@redhat.com>, Matthew Garrett <mjg59@google.com>, Alexander Graf <agraf@csgraf.de>, Daniel Kiper <daniel.kiper@oracle.com>, Hans de Goede <hdegoede@redhat.com>, Michael Brown <mbrown@fensystems.co.uk>, Ingo Molnar <mingo@kernel.org> Subject: Re: [RFC PATCH 0/3] efi/x86: add support for generic EFI mixed mode boot Date: Thu, 13 Feb 2020 22:36:14 +0000 [thread overview] Message-ID: <CAKv+Gu9Azn9oGHaTqv+-Foj4=b5Y-JradERq4NC5V9XOaVjSKQ@mail.gmail.com> (raw) In-Reply-To: <20200213184752.GA1424509@rani.riverdale.lan> On Thu, 13 Feb 2020 at 19:47, Arvind Sankar <nivedita@alum.mit.edu> wrote: > > On Thu, Feb 13, 2020 at 05:55:44PM +0000, Ard Biesheuvel wrote: > > On Thu, 13 Feb 2020 at 18:53, Arvind Sankar <nivedita@alum.mit.edu> wrote: > > > As an alternative to the new section, how about having a CONFIG option > > > to emit the 64-bit kernel with a 32-bit PE header instead, which would > > > point to efi32_pe_entry? In that case it could be directly loaded by > > > existing firmware already. You could even have a tool that can mangle an > > > existing bzImage's header from 64-bit to 32-bit, say using the newly > > > added kernel_info structure to record the existence and location of > > > efi32_pe_entry. > > > > > > > That wouldn't work with, say, signed distro kernels. > > No, the idea would be that the distro would distribute two signed > images, one 32-bit and one 64-bit, which are identical except for the > header. At install time, the installer chooses based on the system's > firmware bit-ness. > I guess it would be possible, but then we'd need two different images while today, we can run the same image on both kinds of firmwares. The only thing I am trying to do is remove all the quirky bootparams stuff from the loader so that we can switch to LoadImage > > > > > Also, the PE header can live anywhere inside the image, right? Is there > > > any reason to struggle to shoehorn it into the "boot sector"? > > > > It cannot. It must live outside a region described by the section headers. > > It could still be inserted after .setup, or at the very end of the file, no? The PE/COFF spec mentions that the COFF header needs to follow the signature. Also, the SizeOfHeaders field would become somewhat ambiguous if the header is split up like that.
WARNING: multiple messages have this Message-ID (diff)
From: Ard Biesheuvel <ardb@kernel.org> To: Arvind Sankar <nivedita@alum.mit.edu> Cc: linux-efi <linux-efi@vger.kernel.org>, Alexander Graf <agraf@csgraf.de>, Daniel Kiper <daniel.kiper@oracle.com>, Matthew Garrett <mjg59@google.com>, Michael Brown <mbrown@fensystems.co.uk>, Hans de Goede <hdegoede@redhat.com>, Peter Jones <pjones@redhat.com>, Leif Lindholm <leif@nuviainc.com>, Laszlo Ersek <lersek@redhat.com>, Ingo Molnar <mingo@kernel.org>, linux-arm-kernel <linux-arm-kernel@lists.infradead.org> Subject: Re: [RFC PATCH 0/3] efi/x86: add support for generic EFI mixed mode boot Date: Thu, 13 Feb 2020 22:36:14 +0000 [thread overview] Message-ID: <CAKv+Gu9Azn9oGHaTqv+-Foj4=b5Y-JradERq4NC5V9XOaVjSKQ@mail.gmail.com> (raw) In-Reply-To: <20200213184752.GA1424509@rani.riverdale.lan> On Thu, 13 Feb 2020 at 19:47, Arvind Sankar <nivedita@alum.mit.edu> wrote: > > On Thu, Feb 13, 2020 at 05:55:44PM +0000, Ard Biesheuvel wrote: > > On Thu, 13 Feb 2020 at 18:53, Arvind Sankar <nivedita@alum.mit.edu> wrote: > > > As an alternative to the new section, how about having a CONFIG option > > > to emit the 64-bit kernel with a 32-bit PE header instead, which would > > > point to efi32_pe_entry? In that case it could be directly loaded by > > > existing firmware already. You could even have a tool that can mangle an > > > existing bzImage's header from 64-bit to 32-bit, say using the newly > > > added kernel_info structure to record the existence and location of > > > efi32_pe_entry. > > > > > > > That wouldn't work with, say, signed distro kernels. > > No, the idea would be that the distro would distribute two signed > images, one 32-bit and one 64-bit, which are identical except for the > header. At install time, the installer chooses based on the system's > firmware bit-ness. > I guess it would be possible, but then we'd need two different images while today, we can run the same image on both kinds of firmwares. The only thing I am trying to do is remove all the quirky bootparams stuff from the loader so that we can switch to LoadImage > > > > > Also, the PE header can live anywhere inside the image, right? Is there > > > any reason to struggle to shoehorn it into the "boot sector"? > > > > It cannot. It must live outside a region described by the section headers. > > It could still be inserted after .setup, or at the very end of the file, no? The PE/COFF spec mentions that the COFF header needs to follow the signature. Also, the SizeOfHeaders field would become somewhat ambiguous if the header is split up like that. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-02-13 22:36 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-13 14:59 [RFC PATCH 0/3] efi/x86: add support for generic EFI mixed mode boot Ard Biesheuvel 2020-02-13 14:59 ` Ard Biesheuvel 2020-02-13 14:59 ` [RFC PATCH 1/3] efi/x86: drop redundant .bss section Ard Biesheuvel 2020-02-13 14:59 ` Ard Biesheuvel 2020-02-13 14:59 ` [RFC PATCH 2/3] efi/x86: add true mixed mode entry point into .compat section Ard Biesheuvel 2020-02-13 14:59 ` Ard Biesheuvel 2020-02-13 16:59 ` Arvind Sankar 2020-02-13 16:59 ` Arvind Sankar 2020-02-13 17:13 ` Ard Biesheuvel 2020-02-13 17:13 ` Ard Biesheuvel 2020-02-13 14:59 ` [RFC PATCH 3/3] efi/x86: implement mixed mode boot without the handover protocol Ard Biesheuvel 2020-02-13 14:59 ` Ard Biesheuvel 2020-02-13 17:23 ` Arvind Sankar 2020-02-13 17:23 ` Arvind Sankar 2020-02-13 17:42 ` Ard Biesheuvel 2020-02-13 17:42 ` Ard Biesheuvel 2020-02-13 17:53 ` [RFC PATCH 0/3] efi/x86: add support for generic EFI mixed mode boot Arvind Sankar 2020-02-13 17:53 ` Arvind Sankar 2020-02-13 17:55 ` Ard Biesheuvel 2020-02-13 17:55 ` Ard Biesheuvel 2020-02-13 18:47 ` Arvind Sankar 2020-02-13 18:47 ` Arvind Sankar 2020-02-13 22:36 ` Ard Biesheuvel [this message] 2020-02-13 22:36 ` Ard Biesheuvel 2020-02-14 0:10 ` Arvind Sankar 2020-02-14 0:10 ` Arvind Sankar 2020-02-14 0:12 ` Arvind Sankar 2020-02-14 0:12 ` Arvind Sankar 2020-02-14 0:21 ` Ard Biesheuvel 2020-02-14 0:21 ` Ard Biesheuvel 2020-02-14 0:38 ` Arvind Sankar 2020-02-14 0:38 ` Arvind Sankar
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