Date: Mon, 18 Dec 2017 15:37:30 -0700 From: Warner Losh <imp@bsdimp.com> To: Mark Millard <markmi@dsl-only.net> Cc: FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: UEFI booting survey Message-ID: <CANCZdfo5=5vKZ2cY8k7K3L%2BbfEPQREr9yB=EsVPiMkAStCq_SA@mail.gmail.com> In-Reply-To: <60C20606-853E-43AE-9F90-44C65026A098@dsl-only.net> References: <60C20606-853E-43AE-9F90-44C65026A098@dsl-only.net>
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On Mon, Dec 18, 2017 at 3:12 PM, Mark Millard <markmi@dsl-only.net> wrote: > Warner Losh imp at bsdimp.com wrote on > Mon Dec 18 20:29:45 UTC 2017 : > > > The specific thing we will stop doing is that in the absence of > > instructions to the contrary, we will no longer search for root on a > device > > other than the one the loader.efi came from. > > Warner Losh imp at bsdimp.com wrote on > Sun Dec 17 19:52:07 UTC 2017 : > > > In the coming months, we're looking at dropping boot1.efi and instead > > installing /boot/loader.efi onto the ESP (most likely as > > \efi\freebsd\loader.efi). > > > Combining the two statements would appear to have consequences > not obvious from the separate statements in isolation. Rewording > the first to substitute where loader.efi comes from based on > the second (if I interpret right): > > MISQUOTE > The specific thing we will stop doing is that in the absence of > instructions to the contrary, we will no longer search for root > on other than the device for the ESP used (which will hold > loader.efi). > END MISQUOTE > The specific thing we will stop doing is that in the absence of instructions to the contrary, we will no longer search for root on other than the device for the ESP used (which will hold now loader.efi as boot1.efi will shortly be eliminated). Or the following pseudo-code with all the weird special cases removed for clarity load loader.efi from ESP if BootXXXX uefi variable holds a second path, use that for root/kernel otherwise if an override variable holds a kernel/root path, use that otherwise scan for a usable ZFS pool, use that if it exists otherwise use the same partition loader.efi was booted from for root/kernel if it's usable otherwise use the first UFS partition on the ESP that's usable. A partition is usable if /boot/loader.rc exists on that path. What is being deleted is one final step: "otherwise use the first UFS partition on any drive in a random order that's usable." which used to be at the end of the boot1.efi psuedo code. It's my belief that no such installations actually use this due to the random factor today (plug in a new USB drive and it might take over). If my belief is wrong, it's my belief that efibootmgr will solve it, and failing that, the fallback mechanism (for platforms that use u-boot + EFI where UEFI variables don't work) will allow the two or three people that are doing this today. Warner
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