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

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Date:   Wed, 15 Feb 2017 18:34:50 +0530
From:   Bhupesh Sharma <bhsharma@...hat.com>
To:     linux-efi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, x86@...nel.org,
        linux-acpi@...r.kernel.org
Cc:     nicstange@...il.com, leif.lindholm@...aro.org,
        sai.praneeth.prakhya@...el.com, pjones@...hat.com,
        bhupesh.linux@...il.com, Bhupesh Sharma <bhsharma@...hat.com>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        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: [PATCH 0/2] RFC: Move efi bgrt code out of arch/x86

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%)

-- 
2.7.4