On Dec 22, 2023, at 01:36, Toomas Soome <tso...@me.com> wrote: > > > >> On 22. Dec 2023, at 11:09, Mark Millard <mark...@yahoo.com> wrote: >> >> Tomoaki AOKI <junchoon_at_dec.sakura.ne.jp> wrote on >> Date: Thu, 21 Dec 2023 23:21:00 UTC : >> >>> On Thu, 21 Dec 2023 14:22:14 +0100 >>> Dimitry Andric <d...@freebsd.org> wrote: >>> >>>> Yeah, my procedure is the same as yours: I first copy >>>> /boot/efi/efi/freebsd/loader.efi to /boot/efi/efi/freebsd/loader.old, then >>>> copy the freshly built and installed /boot/loader.efi to >>>> /boot/efi/efi/freebsd/loader.efi. I don't see a technical reason why this >>>> could not be just another step in the installworld procedure. >>>> >>>> That said, I am unsure if the pathname /boot/efi/efi is always the same, >>>> at least for all UEFI systems. It is the default layout when you do a >>>> regular install with recent installer onto a UEFI system, but some users >>>> may use completely different mount points. So you should still have some >>>> way of configuring the default location for loader installation. >>>> >>>> Also, on default installations a fallback entry named >>>> /boot/efi/efi/boot/bootx64.efi is made, essentially another copy of >>>> loader.efi but with a different name. Namely, the default name that UEFI >>>> (on x86_64 at least) searches for, if it doesn't know anything else. I.e. >>>> if it isn't configured via efibootmgr(8), or the EFI variables have been >>>> junked for some reason. It might make sense to also update that file. >>>> >>>> -Dimitry >>> >>> Just an idea. >>> >>> It would be nice if loader.efi (hopefully, boot1.efi,too) could pass >>> "where am I placed?" info, maybe via kenv. >>> >>> Would need boot1.efi to pass something (ideally, "where am I booted >>> from?", but "boot1_used=1" is sufficient). >>> >>> To do so, loader.efi can confirm whether it was loaded via boot1.efi or >>> directly from UEFI firmware. If nothing is passed to it, it can probe >>> "where it is?" using UEFI call and set it, otherwise, it should >>> be /boot/loader.efi, so nothing is needed to do. >> >> To my knowledge aarch64 and armv7 never use the copy in >> /boot/loader.efi during a boot. It has to have been copied >> into the appropriate msdosfs such that it has an >> appropriate path and name there. That is what is found >> and used during the boot. > > > All UEFI systems start from ESP (EFI System Partition). The only good reason > to install boot1.efi there is when you have very small ESP and need to save > that space - and in that case the boot1.esp will search and execute > /boot/loader.efi.
Yep. May be I misinterpreted what the text strongly tied to "it should be /boot/loader.efi" and so ended up not pointing out an actual distinction. > The problem about boot1.efi (or any other UEFI chainload) is that loading > file and executing it will not replace current program in memory, but will > add new one, this may be problem with systems with minimal memory > configurations. And yes, boot1.efi is not really platform specific - it is > just another EFI application - one can build and use it on arm (or any other) > systems Not powerpc (32-bit), powerpc64, or powerpc64le: these are not UEFI systems at all, if I understand right. Of course, if only tier 1 is documented, such would not be covered. But documentation that is limited to tier 1 should say so explicitly --but various examples have historically not done so. > and then it will load and start /boot/loader.efi. > > starting loader directly from ESP has few advantages — you wont waste memory > for boot1.efi, you save a bit of boot time, you can use auxiliary files from > ESP to pass some information to loader.efi (for example to tell where your > rootfs is in case of multiboot setups). > > the boot1.efi could be a bit more appealing if it would be able to load and > start kernel directly, allowing to build very memory limited setups, but then > again, it does sound like very specific corner case. Thanks for the UEFi-context notes that go well beyond anything I referenced. Good stuff. > rgds, > toomas > > >> >>> If no related kenv is set and freebsd-boot partition exists, it should >>> be booted with legacy (BIOS) boot. >> >> If there even is a "legacy (BIOS) boot" is a platform >> specific issue as far as I know. >> >>> The easiest to be set by loader.efi and/or boot1.efi would be raw UEFI >>> device path. So would need analyzing where actually is on booted >>> FreeBBSD environment. >> >> See the earlier point about aarch64 and armv7 not using >> /boot/* files while loading the FreeBSD loader: the >> FreeBSD loader variant used is the first stage able to >> look inside UFS or ZFS file systems. Loading and >> starting the FreeBSD loader happens before that stage >> in those types of contexts. >> >>> . . . >> >> Also, to my knowledge, powerpc (32-bit), powerpc64, and >> powerpc64le do not involve any variant of loader.efi or >> UEFI/ACPI or UEFI/DeviceTriee in their boot sequnces. >> Again: more platform specific rather than generic. >> === Mark Millard marklmi at yahoo.com
