From: Laszlo Ersek <lersek@redhat.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Julien Grall <julien.grall@linaro.org>
Cc: "edk2-devel@lists.01.org" <edk2-devel@lists.01.org>
Subject: Re: [PATCH] ArmVirtPkg: use protocol-based DevicePathLib instance for most DXE modules
Date: Tue, 24 Apr 2018 11:52:00 +0200 [thread overview]
Message-ID: <f3dca5ec-8b5f-f6d7-51b9-fd7c53013aa2@redhat.com> (raw)
In-Reply-To: <CAKv+Gu-JDqP-+g01BokAAbbZ5XJzTS9uhMTwGiGU_6mxNJtGEw@mail.gmail.com>
On 04/24/18 08:16, Ard Biesheuvel wrote:
> On 24 April 2018 at 02:50, Laszlo Ersek <lersek@redhat.com> wrote:
>> Port OvmfPkg commit 5c3481b0b611e to ArmVirtPkg. Some explanation should
>> be in order (because 5c3481b0b611e doesn't offer any):
>>
>> - The UefiDevicePathLibDevicePathProtocol instance uses the Device Path
>> Utilities Protocol, produced by DevicePathDxe, for formatting and
>> parsing the textual device path representation. This allows for a
>> lighter weight lib instance that gets linked into several DXE modules.
>> In comparison, the more standalone UefiDevicePathLib instance includes
>> the formatting and parsing routines in every client module.
>>
>> - The DXE core needs DevicePathLib before it dispatches DevicePathDxe, so
>> it needs to stick with the standalone instance.
>>
>> - DevicePathDxe itself also needs the standalone instance, for
>> implementing the protocol.
>>
>> - The DXE-phase PCD driver, "MdeModulePkg/Universal/PCD/Dxe/Pcd.inf",
>> depends on DevicePathLib via UefiLib and DxeServicesLib at the least; so
>> with this update, it inherits a dependency on the protocol. In reverse,
>> DevicePathDxe depends on the PCD Protocol, via PcdLib. The cycle is
>> broken by using BasePcdLibNull in DevicePathDxe. That restricts it to
>> FixedAtBuild, Patch, and FeatureFlag PCDs, but that's fine.
>>
>> Example space savings (using ArmVirtQemu and the GCC5 toolchain):
>> - NOOPT: 187KB in FVMAIN, 12KB in FVMAIN_COMPACT
>> - DEBUG: 147KB in FVMAIN, 20KB in FVMAIN_COMPACT
>> - RELEASE: 123KB in FVMAIN, 17KB in FVMAIN_COMPACT
>>
>> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> Cc: Julien Grall <julien.grall@linaro.org>
>> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=940
>> Contributed-under: TianoCore Contribution Agreement 1.1
>> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
>
> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Thanks, Ard!
Julien, can you please fetch the patch:
>> Notes:
>> Repo: https://github.com/lersek/edk2.git
>> Branch: armvirt_devpathlib
and regression-test it on Xen? I'd prefer to push the patch with your T-b.
Thanks!
Laszlo
next prev parent reply other threads:[~2018-04-24 9:52 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-24 0:50 [PATCH] ArmVirtPkg: use protocol-based DevicePathLib instance for most DXE modules Laszlo Ersek
2018-04-24 6:16 ` Ard Biesheuvel
2018-04-24 9:52 ` Laszlo Ersek [this message]
2018-04-30 9:25 ` Laszlo Ersek
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