Can't remount efivarfs as rw

[pattydaone]

I'm currently trying to install Gentoo on an m1 mac mini. At the moment, I'm on the "install bootloader" step, which I have naturally chosen grub.
Upon attempting to run

Code: Select all

grub-install

, I get an error complaining about input/output. No big deal, running

Code: Select all

mount | grep efivars

shows it's mounted as ro.
The problem is, when I try to run the command listed on this page: https://wiki.gentoo.org/wiki/Efibootmgr#Configuration

Code: Select all

mount -o remount,rw -t efivarfs efivarfs /sys/firmware/efi/efivars

it errors out with

Code: Select all

mount: /sys/firmware/efi/efivars: mount point not mounted or bad option.

Because "mount | grep efivars" shows that, indeed, efivarfs is mounted on that path, I supposed it was an option issue. So I did:

Code: Select all

umount /sys/firmware/efi/efivars 
mount -o rw -t efivarfs efivarfs /sys/firmware/efi/efivars

But, even though I set rw as an option, it seemed to have ignored that and mounted it with ro,relatime as the options.
I'm kind of at a loss, and am really not sure what to do. I've never installed gentoo on anything before, though I am not stranger to linux, so I don't think it's unlikely I've missed something earlier on in the install. But generally, I tried to follow the install guide on the wiki up until "kernel configuration" to a t, where I moved to the Project:Asahi guide and started on that.

Any help would be appreciated, let me know if more information is needed.

[alamahant]

Why is efivars mounted ro?
Are you using a live cd?
Try remounting rw first in the livecd and then inside chroot.
Since the chroot bind mounts host /sys.

[pingtoo]

alamahant,

You were right on any general machines, but OP use Mac Mini. And not able to mount read-write is OP's concern.

pattydaone,

I suspect it is because your machine is an Apple machine which tend to protect their own stuff. so maybe necessary UEFI service was not implemented(or it is imcomplete) in the firmware therefor Linux can only mount it read-only.

[Zucca]

Hi and welcome.
I run Gentoo on M2 MacBook Air. I hope I can help.

Have you followed this guide?

What does command

Code: Select all

efibootmgr

... output?

[pattydaone]

Have you followed this guide?

I have. I suspect I've found the problem, though I'm not absolutely certain yet.
The guide tells you to "follow the Gentoo Handbook for amd64, up until the section for kernel installation" but I think this is inaccurate.
One of the things you're directed to do in the handbook is create an EFI partition on disk, but I'm pretty sure you're meant to skip that and use the Asahi EFI partition that you get when you install the UEFI (m1n1 + u-boot) environment all the way at the beginning.
I think this is the case because of the Asahi Gentoo Support Script provided midway through the Project:Asahi guide; if you inspect the script, it has a check for /boot/vendorfw directory, and if it fails, errors out telling you to mount the Asahi ESP to /boot. If it exists, it installs grub to that partition.
I'm not 100% certain this is the problem, my system still doesn't boot (because I haven't fully set it up), but grub installed and configured without error.

May I ask if this is also where you put your bootloader? Or do you have it on a different EFI partition?

[Zucca]

Code: Select all

M2-Air ~ # tree -L 2 /boot/
/boot/
|-- EFI
|   |-- BOOT
|   `-- gentoo
|-- System.map-6.14.2-p1-asahi-dist
|-- System.map-6.14.4-p1-asahi-dist
|-- System.map-6.14.4-p1-asahi-dist.old
|-- System.map-6.15.10-p3-asahi-dist
|-- System.map-6.17.7-p2-asahi-dist
|-- asahi
|   |-- AdminUserRecoveryInfo.plist
|   |-- BuildManifest.plist
|   |-- RestoreVersion.plist
|   |-- SystemVersion.plist
|   |-- all_firmware.tar.gz
|   |-- installer.log
|   |-- kernelcache.release.mac14g
|   `-- stub_info.json
|-- config-6.14.2-p1-asahi-dist
|-- config-6.14.4-p1-asahi-dist
|-- config-6.14.4-p1-asahi-dist.old
|-- config-6.15.10-p3-asahi-dist
|-- config-6.17.7-p2-asahi-dist
|-- dtbs
|   |-- 6.10.5-p1-asahi-dist
|   |-- 6.10.7-p2-asahi-dist
|   `-- 6.10.9-p3-asahi-dist
|-- grub
|   |-- arm64-efi
|   |-- boot.cfg
|   |-- fonts
|   |-- grub.cfg
|   |-- grub.cfg.old
|   |-- grub.cfg~
|   |-- grubenv
|   |-- locale
|   |-- settings.cfg
|   `-- themes
|-- initramfs-6.14.2-p1-asahi-dist.img
|-- initramfs-6.14.4-p1-asahi-dist.img
|-- initramfs-6.14.4-p1-asahi-dist.img.old
|-- initramfs-6.15.10-p3-asahi-dist.img
|-- initramfs-6.17.7-p2-asahi-dist.img
|-- m1n1
|   |-- boot.bin
|   `-- boot.bin.old
|-- vendorfw
|   |-- firmware.cpio
|   |-- firmware.tar
|   |-- manifest.txt
|   `-- u-boot
|-- vmlinuz-6.14.2-p1-asahi-dist
|-- vmlinuz-6.14.4-p1-asahi-dist
|-- vmlinuz-6.14.4-p1-asahi-dist.old
|-- vmlinuz-6.15.10-p3-asahi-dist
`-- vmlinuz-6.17.7-p2-asahi-dist

17 directories, 39 files

I have put kernel, bootloader and all the other things in /boot. So I havent't bothered to make a separate EFI partition (ESP), thus /boot acts as my ESP also.

[pattydaone]

I have put kernel, bootloader and all the other things in /boot. So I havent't bothered to make a separate EFI partition (ESP), thus /boot acts as my ESP also.

I would suppose, then, that that's what you're supposed to do on these machines; I have just finished install and gotten mine to boot properly.

Do you think it would be appropriate to have the aforementioned wiki page updated to reflect this?

[Zucca]

I would suppose, then, that that's what you're supposed to do on these machines

Not really. This is Gentoo, you can setup your system however you like.
I think according to latest FHS*, /efi should be the actual ESP and /boot should contain files related to booting up the specific OS.

*) These seems to be no mentions of /efi in FHS...

[pattydaone]

I'll take your word for it. Though it still doesn't explain why I wasn't able to remount efivarfs as rw, there is a strong possibility that was through some other fault of mine (like I said, it was my first ever gentoo install...)
Nevertheless, I appreciate what assistance you gave.

[pingtoo]

I'll take your word for it. Though it still doesn't explain why I wasn't able to remount efivarfs as rw, there is a strong possibility that was through some other fault of mine (like I said, it was my first ever gentoo install...)
Nevertheless, I appreciate what assistance you gave.

Thanks Zucca that point out for Mac hardware to boot linux it will require u-boot. I didn't know that.

However u-boot is something I know a little bit. u-boot when build to setup enable EFI and at runtime to boot OS with EFI service is usually only provide a read-only environment on EFI variables.

I am not sure how the Asahi build u-boot configuration so I don't want to said one way or the other. However I know it is possible to configure u-boot such that it will emulate a blob file on file system (u-boot internal storage) that allow OS write something to it. However it is not persist on reboot.

So if you experiencing the efivarfs can only be mount read-only is most likely a u-boot thingy, it is nothing wrong with you Gentoo setup.

[Zucca]

To be frank, I don't currently remember which was the order... but I think it's

• m1n1
• u-boot
• efi boot manager

...

I read the Apple silicon boot process explanation once or twice... It's complex... mostly because forced security IIRC.

[CooSee]

https://zakk.au/posts/gentoo-m-series-mac-arm64/

no idea about M1 - maybe the above will help a little.