From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heinrich Schuchardt Date: Mon, 9 Nov 2020 14:58:55 +0100 Subject: [PATCH] efi_loader: improve detection of ESP for storing UEFI variables In-Reply-To: <87lffad5on.fsf@cjr.nz> References: <20201108235855.28788-1-pc@cjr.nz> <87lffad5on.fsf@cjr.nz> Message-ID: <0be294e8-cb29-7dbe-2009-e6ec9c210a03@gmx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 09.11.20 14:24, Paulo Alcantara wrote: > Heinrich Schuchardt writes: > >> On 09.11.20 00:58, Paulo Alcantara wrote: >>> The UEFI specification does not restrict on the number and location of >>> ESPs in a system. They are discovered as required by looking at the >>> partition type, but firmware implementations are allowed to support >>> ESPs which do not contain a valid partition type. >> >> I guess you refer to chapter "13.3.3 Number and Location of System >> Partitions" of the UEFI spec saying: "Further, UEFI implementations >> may allow the use of conforming FAT partitions which do not use the >> ESP GUID." > > Yep, sorry. Thanks for pointing it out! > >> Why should U-Boot support FAT partitions that are not of type FAT 0xef >> and GPT partition that do not use the ESP GUID? > > In most UEFI (EDK2-based) systems I used, I could boot my OSes and > diagnostic tools by simply having a supported filesystem (FAT12/16/32) > and /EFI/BOOT/BOOT{ARCH}.EFI file and never cared about setting the > partition type at all. It took me a while for figuring out why I > couldn't get my UEFI variables loaded from my FAT partition that > contained /ubootefi.var and /EFI/BOOT/BOOTAA64.efi files. > > I am not trying to support ESPs that lack the appropriate partition type > everywhere in U-Boot, but at least for the UEFI variables (ubootefi.var) > feature seemed a nice thing to have. > > Perhaps we could make it a separate config option like "Allow searching > for ESPs without partition type" and default it to N, don't know... > In your last mail you wrote you are working for SUSE. Is there a bug in the SUSE installer that makes it create the wrong partition type? Best regards Heinrich