[systemd-devel] bootloader time on a non-EFI bootloader

[Andrei Borzenkov]

On Fri, Apr 10, 2015 at 12:32 PM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Fri, 10.04.15 10:34, Koen Kooi (koen at dominion.thruhere.net) wrote:
>
>>
>> > Op 9 apr. 2015, om 11:28 heeft Lennart Poettering <lennart at poettering.net> het volgende geschreven:
>> >
>> > On Mon, 16.03.15 11:29, Umut Tezduyar Lindskog (umut at tezduyar.com) wrote:
>> >
>> >> Hi,
>> >>
>> >> I would like to pass the time it was spent in bootloader to systemd.
>> >> Is there a kernel command line to pass this information on non EFI
>> >> bootloader? Or is there an another way?
>> >
>> > I am open to add this, but I really don't want to see tons of
>> > different "drivers" to read this data added to systemd. Hence the way
>> > I think this should work, is adding a generic interface to the kernel
>> > to /sys/firmware/timing or so, where this information can be read
>> > from. We'd then make systemd read that. And wherever the information
>> > comes from would be a kernel internal decision, and could be
>> > implemented in a myriad of different ways for different architectures.
>> >
>> > Also note that ACPI 5.0 exports this timing information in a generic
>> > way anyway. Given that ACPI is fairly standard and apparently is even
>> > what embedded is standardizing on I'd be open to adding native support
>> > for parsing this info from ACPI to systemd, if it's easy enough.
>>
>> My situation is slightly different: UEFI that loads a linux Image
>> directly using the EFI stub, but no ACPI since it’s a devicetree
>> platform. What kind of options to I have to get the boottime info?
>> Long term I’d like to use gummiboot, but I haven’t tried building it
>> for aarch64 yet.
>
> Hmm, I thought EFI implied ACPI?
>

On x86 probably (although even there I failed to find explicit
statement); on ARM UEFI specs several times use "if ACPI is
supported".