linux-kernel - Re: [PATCH 0/2] RFC: Move efi bgrt code out of arch/x86

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Date:   Wed, 15 Feb 2017 17:44:28 +0000
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     Bhupesh Sharma <bhsharma@...hat.com>
Cc:     "linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        Nicolai Stange <nicstange@...il.com>,
        Leif Lindholm <leif.lindholm@...aro.org>,
        "Prakhya, Sai Praneeth" <sai.praneeth.prakhya@...el.com>,
        Peter Jones <pjones@...hat.com>,
        Bhupesh SHARMA <bhupesh.linux@...il.com>,
        Ingo Molnar <mingo@...nel.org>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        Dan Williams <dan.j.williams@...el.com>,
        Dave Young <dyoung@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Mark Rutland <mark.rutland@....com>,
        Will Deacon <will.deacon@....com>
Subject: Re: [PATCH 0/2] RFC: Move efi bgrt code out of arch/x86

Hello Bhupesh,

On 15 February 2017 at 13:04, Bhupesh Sharma <bhsharma@...hat.com> wrote:
> This patchset presents a RFC approach to move the ACPI BGRT table
> handling related code out of 'arch/x86' and place it inside
> 'drivers/firmware/efi' so that it can be used to support
> ACPI BGRT table and BGRT logo across x86 and AARCH64 ARCHs.
>
> Note that this patchset is primarily tested on Qemu VMs for x86_64
> and AARCH64 environments, while I try to get my hands on a real
> AARCH64 hardware which supports a graphic card and whose boot firmware
> I can modify to support the ACPI BGRT table to be passed to the kernel.
>
> Here are some details/outputs about/from the test environment:
>
> AARCH64:
> ========
> 1. I used the latest Qemu (master branch) and compiled it for aarch64 with softmmu support.
>    Here is the command line I use to launch the same:
>
> # qemu-system-aarch64 -cpu cortex-a57 -M virt -m 2048 -bios QEMU_EFI.fd -kernel Image -initrd rootfs.cpio -serial stdio --append "acpi=force" -device virtio-gpu-pci
>
> where, QEMU_EFI.fd is the DEBUG build of EDK2 ArmVirtQemu.dsc (master branch)
>        rootfs.cpio is the AARCH64 build of Buildroot (Little Endian AARCH64)
>        -device virtio-gpu-pci provides the Graphical support required to have BGRT logo.
>
>
> 2. Here are some test results once Linux boots up, which show a valid BGRT table/logo being
>    seen by the kernel:
>
> # acpidump
> ...
>
> BGRT @ 0x0000000000000000
>   0000: 42 47 52 54 38 00 00 00 01 B4 49 4E 54 45 4C 20  BGRT8.....INTEL
>   0010: 45 44 4B 32 20 20 20 20 02 00 00 00 20 20 20 20  EDK2    ....
>   0020: 13 00 00 01 01 00 01 00 00 80 B0 BA 00 00 00 00  ................
>   0030: 2F 01 00 00 0F 01 00 00                          /.......
>
> # dmesg | grep -i BGRT
> [    0.000000] ACPI: BGRT 0x00000000B8640000 000038 (v01 INTEL  EDK2     00000002      01000013)
>
>
> # ls -lah /sys/firmware/acpi/bgrt/image
> -r--r--r--    1 root     root       32.9K Feb 15 11:27 /sys/firmware/acpi/bgrt/image
>
> x86:
> ====
> 1. I used the latest Qemu (master branch) and compiled it for x86.
>    Here is the command line I use to launch the same:
>
> # qemu-system-x86_64 -enable-kvm -sdl -m 2048 -vga std -boot c -cpu host -bios OVMF_CODE.fd -kernel bzImage -initrd rootfs.cpio -serial stdio
>
> where, OVMF_CODE.fd is the RELEASE build of EDK2 OvmfPkg (master branch)
>        rootfs.cpio is the x86_64 build of Buildroot
>
> 2. Similar test results are seen as noted for the AARCH64 case above, which show a valid BGRT table/logo being
>    seen by the kernel.
>
> Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
> Cc: Ingo Molnar <mingo@...nel.org>
> Cc: Matt Fleming <matt@...eblueprint.co.uk>
> Cc: Dan Williams <dan.j.williams@...el.com>
> Cc: Dave Young <dyoung@...hat.com>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Mark Rutland <mark.rutland@....com>
> Cc: Will Deacon <will.deacon@....com>
>
> Bhupesh Sharma (2):
>   x86/efi-bgrt: Move efi-bgrt handling out of arch/x86
>   bgrt: Make ACPI BGRT parsing code common for ARCHs
>
>  arch/arm64/kernel/acpi.c                               | 3 +++
>  arch/x86/kernel/acpi/boot.c                            | 6 ------
>  arch/x86/platform/efi/Makefile                         | 1 -
>  drivers/acpi/Kconfig                                   | 2 +-
>  drivers/acpi/bgrt.c                                    | 6 ++++++
>  drivers/firmware/efi/Makefile                          | 1 +
>  {arch/x86/platform => drivers/firmware}/efi/efi-bgrt.c | 0
>  include/linux/efi-bgrt.h                               | 2 ++
>  8 files changed, 13 insertions(+), 8 deletions(-)
>  rename {arch/x86/platform => drivers/firmware}/efi/efi-bgrt.c (100%)
>

These patches look fine to me, and I think we should be able to merge
them without any changes.

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>

You only failed to cc the ACPI maintainers, please add Len and Rafael next time.

Thanks,
Ard.