From: Lukas Wunner <lukas@wunner.de>
To: Matt Fleming <matt@codeblueprint.co.uk>
Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
Andreas Noever <andreas.noever@gmail.com>,
x86@kernel.org
Subject: Re: [PATCH 0/6] Apple device properties
Date: Mon, 22 Aug 2016 11:58:50 +0200 [thread overview]
Message-ID: <20160822095850.GA22131@wunner.de> (raw)
In-Reply-To: <20160818203433.GP30909@codeblueprint.co.uk>
On Thu, Aug 18, 2016 at 09:34:33PM +0100, Matt Fleming wrote:
> On Mon, 15 Aug, at 06:13:58PM, Lukas Wunner wrote:
> > But I would like to understand the "cannot jump through pointers at
> > runtime" argument because the binary code looks to me like it should
> > work on 32 bit. I guess I must be missing something obvious?
>
> Ah no, I forgot that efi_boot_services_{32,64}_t doesn't contain
> pointers - it contains u32/u64 objects. So yeah, your patch looks
> fine.
>
> It does trigger the following warnings when building for i386 though,
>
> In file included from /dev/shm/mfleming/git/efi/drivers/firmware/efi/libstub/efi-stub-helper.c:14:0:
> /dev/shm/mfleming/git/efi/drivers/firmware/efi/libstub/efi-stub-helper.c: In function ???efi_get_memory_map???:
> /dev/shm/mfleming/git/efi/arch/x86/include/asm/efi.h:205:3: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
> ((efi_boot_services_64_t *)__efi_early()->boot_services)->f : \
> ^
Right, sorry, I didn't compile-test that version on x86_32.
I'm sending out a new version now which compiles cleanly in all three
cases (x86_32, x86_64 with and without mixed-mode), works fine on my
64-bit EFI and the 32-bit code at least *looks* okay when disassembled.
By the way, arch/x86/Kconfig says that "it is not possible to boot a
mixed-mode enabled kernel via the EFI boot stub - a bootloader that
supports the EFI handover protocol must be used".
Is this still correct? With all the mixed-mode support in head_64.S
and eboot.c, I'm wondering what's missing?
Thanks,
Lukas
WARNING: multiple messages have this Message-ID (diff)
From: Lukas Wunner <lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
To: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Andreas Noever
<andreas.noever-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
Subject: Re: [PATCH 0/6] Apple device properties
Date: Mon, 22 Aug 2016 11:58:50 +0200 [thread overview]
Message-ID: <20160822095850.GA22131@wunner.de> (raw)
In-Reply-To: <20160818203433.GP30909-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
On Thu, Aug 18, 2016 at 09:34:33PM +0100, Matt Fleming wrote:
> On Mon, 15 Aug, at 06:13:58PM, Lukas Wunner wrote:
> > But I would like to understand the "cannot jump through pointers at
> > runtime" argument because the binary code looks to me like it should
> > work on 32 bit. I guess I must be missing something obvious?
>
> Ah no, I forgot that efi_boot_services_{32,64}_t doesn't contain
> pointers - it contains u32/u64 objects. So yeah, your patch looks
> fine.
>
> It does trigger the following warnings when building for i386 though,
>
> In file included from /dev/shm/mfleming/git/efi/drivers/firmware/efi/libstub/efi-stub-helper.c:14:0:
> /dev/shm/mfleming/git/efi/drivers/firmware/efi/libstub/efi-stub-helper.c: In function ???efi_get_memory_map???:
> /dev/shm/mfleming/git/efi/arch/x86/include/asm/efi.h:205:3: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
> ((efi_boot_services_64_t *)__efi_early()->boot_services)->f : \
> ^
Right, sorry, I didn't compile-test that version on x86_32.
I'm sending out a new version now which compiles cleanly in all three
cases (x86_32, x86_64 with and without mixed-mode), works fine on my
64-bit EFI and the 32-bit code at least *looks* okay when disassembled.
By the way, arch/x86/Kconfig says that "it is not possible to boot a
mixed-mode enabled kernel via the EFI boot stub - a bootloader that
supports the EFI handover protocol must be used".
Is this still correct? With all the mixed-mode support in head_64.S
and eboot.c, I'm wondering what's missing?
Thanks,
Lukas
next prev parent reply other threads:[~2016-08-22 9:57 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-27 11:20 [PATCH 0/6] Apple device properties Lukas Wunner
2016-07-27 11:20 ` Lukas Wunner
2016-07-27 11:20 ` [PATCH 1/6] efi: Retrieve " Lukas Wunner
2016-07-27 11:20 ` Lukas Wunner
2016-07-30 19:16 ` Andrei Borzenkov
2016-07-30 19:16 ` Andrei Borzenkov
2016-08-04 15:13 ` Matt Fleming
2016-08-04 15:13 ` Matt Fleming
[not found] ` <20160804151345.GM3636-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2016-08-05 11:42 ` Lukas Wunner
2016-08-05 11:42 ` Lukas Wunner
2016-08-05 12:06 ` Matt Fleming
2016-07-27 11:20 ` [PATCH 6/6] thunderbolt: Use Device ROM retrieved from EFI Lukas Wunner
2016-07-27 11:20 ` [PATCH 3/6] efi: Add device path parser Lukas Wunner
2016-07-27 11:20 ` [PATCH 5/6] efi: Assign Apple device properties Lukas Wunner
[not found] ` <a0edd928ab099682c2cb4c4544c599573144d03a.1469616641.git.lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
2016-08-04 15:52 ` Matt Fleming
2016-08-04 15:52 ` Matt Fleming
2016-07-27 11:20 ` [PATCH 2/6] ACPI / bus: Make acpi_get_first_physical_node() public Lukas Wunner
2016-08-17 0:38 ` Rafael J. Wysocki
[not found] ` <1821462.QyPXGhZaWJ-sKB8Sp2ER+y1GS7QM15AGw@public.gmane.org>
2016-09-12 22:03 ` Rafael J. Wysocki
2016-09-12 22:03 ` Rafael J. Wysocki
2016-07-27 11:20 ` [PATCH 4/6] driver core: Don't leak secondary fwnode on device removal Lukas Wunner
2016-07-27 11:20 ` Lukas Wunner
2016-08-17 0:38 ` Rafael J. Wysocki
2016-08-30 9:03 ` Lukas Wunner
2016-09-12 22:03 ` Rafael J. Wysocki
2016-07-27 23:48 ` [PATCH 0/6] Apple device properties Rafael J. Wysocki
2016-07-27 23:48 ` Rafael J. Wysocki
2016-07-28 0:25 ` [PATCH 5/6] efi: Assign " Lukas Wunner
2016-07-28 0:25 ` [PATCH 2/6] ACPI / bus: Make acpi_get_first_physical_node() public Lukas Wunner
2016-07-28 0:25 ` [PATCH 4/6] driver core: Don't leak secondary fwnode on device removal Lukas Wunner
2016-07-28 0:25 ` [PATCH 1/6] efi: Retrieve Apple device properties Lukas Wunner
2016-07-28 0:25 ` [PATCH 6/6] thunderbolt: Use Device ROM retrieved from EFI Lukas Wunner
2016-07-28 0:25 ` [PATCH 3/6] efi: Add device path parser Lukas Wunner
2016-08-04 14:57 ` [PATCH 0/6] Apple device properties Matt Fleming
2016-08-09 13:38 ` Lukas Wunner
2016-08-15 11:54 ` Matt Fleming
2016-08-15 16:13 ` Lukas Wunner
2016-08-18 20:34 ` Matt Fleming
2016-08-22 9:58 ` Lukas Wunner [this message]
2016-08-22 9:58 ` Lukas Wunner
2016-08-24 19:49 ` Matt Fleming
2016-07-28 0:25 Lukas Wunner
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