Date: Fri, 22 Dec 2023 11:36:24 +0200 From: Toomas Soome <tsoome@me.com> To: Mark Millard <marklmi@yahoo.com> Cc: Tomoaki AOKI <junchoon@dec.sakura.ne.jp>, Current FreeBSD <freebsd-current@freebsd.org> Subject: Re: symlink to /boot/loader.efi Message-ID: <94C108FE-3D2F-4116-B071-810F64DECEC4@me.com> In-Reply-To: <AF65AD57-5D93-4FC2-84E8-58E1D7C0C3BC@yahoo.com> References: <AF65AD57-5D93-4FC2-84E8-58E1D7C0C3BC.ref@yahoo.com> <AF65AD57-5D93-4FC2-84E8-58E1D7C0C3BC@yahoo.com>
next in thread | previous in thread | raw e-mail | index | archive | help
> On 22. Dec 2023, at 11:09, Mark Millard <marklmi@yahoo.com> wrote: >=20 > Tomoaki AOKI <junchoon_at_dec.sakura.ne.jp> wrote on > Date: Thu, 21 Dec 2023 23:21:00 UTC : >=20 >> On Thu, 21 Dec 2023 14:22:14 +0100 >> Dimitry Andric <dim@FreeBSD.org> wrote: >>=20 >>> 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. >>>=20 >>> 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. >>>=20 >>> 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. >>>=20 >>> -Dimitry >>=20 >> Just an idea. >>=20 >> It would be nice if loader.efi (hopefully, boot1.efi,too) could pass >> "where am I placed?" info, maybe via kenv. >>=20 >> Would need boot1.efi to pass something (ideally, "where am I booted >> from?", but "boot1_used=3D1" is sufficient). >>=20 >> 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. >=20 > 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. 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 and then it will load and start = /boot/loader.efi. starting loader directly from ESP has few advantages =E2=80=94 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. rgds, toomas >=20 >> If no related kenv is set and freebsd-boot partition exists, it = should >> be booted with legacy (BIOS) boot. >=20 > If there even is a "legacy (BIOS) boot" is a platform > specific issue as far as I know. >=20 >> 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. >=20 > 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. >=20 >> . . . >=20 > 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. >=20 > =3D=3D=3D > Mark Millard > marklmi at yahoo.com >=20 >=20
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?94C108FE-3D2F-4116-B071-810F64DECEC4>