Re: netbsd-9, boot, EFI and device tree

[tlaronde%polynum.com@localhost]

> On Sun, Apr 25, 2021 at 06:42:19PM +0200, Manuel Bouyer wrote:
> The second issue (but not for this project) is that I need some
> kernel command line parameters (console=xxx, root=yyy for example).
> With u-boot loading netbsd.ub, I can set this in an u-boot variable.
> But I don't know how to do this with the EFI second-stage boot loader.

One more:

From https://github.com/ARM-software/u-boot/blob/master/doc/README.uefi:

	The environment variable 'bootargs' is passed as load options in the
	UEFI system table. The Linux kernel EFI stub uses the load options
	as command line arguments.

So the bootargs environment variable could be used, but the current
EFI second-stage boot loader doesn't handle the load options cf.
files in /usr/src/sys/stand/efiboot/bootarm. It takes care of the fdt
and of loading the kernel but that's all.

From the cache.S, in armv7_exec_kernel, there is a "Setup kernel args",
but what is the specification for r0, r1 and r3 (what is the policy
for the usage of these registers? r2 seems to be for the fdt address)?
Could one of r0, r1 or r3 be the address of command line parameters?
-- 
        Thierry Laronde <tlaronde +AT+ polynum +dot+ com>
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