Re: "Boot this kernel once" functionality? (amd64)

[Reinoud Zandijk <reinoud%NetBSD.org@localhost>]

On Wed, Sep 16, 2020 at 12:09:43PM +0200, Martin Husemann wrote:
> On Wed, Sep 16, 2020 at 12:05:26PM +0200, Anthony Mallet wrote:
> > I was also wondering if it would be possible to pass arguments to the
> > primary or secondary bootloader via reboot(2) and the boothowto
> > flags. But this doesn't seem doable. Right?
> 
> This works fine on e.g. sparc*; I can do: shutdown -b netbsd.t -r now
> 
> and it will pass "netbsd.t" as boot argument to the firmware, which passes
> it on to the bootloader and then it boots /netbsd.t once.

In shutdown(8) I read that the arguments are passed to reboot(8) and that is
mentioned in kloader(4) so I guess its using that mechanism.

As for amd64, it would be great if I could boot a kernel once. It could
simplify testing out a new kernel. Not that a few lines of boot.cfg can't do
that but still.

> I don't know if there is enough of a persistent environment for UEFI boots
> (I would guess there is), and probably no easy way for BIOS boot.

I could imagine some BIOS/UEFI wiping all DRAM on reboot for security reasons.

Reinoud