Hi Ard,
On 6/3/22 15:20, Huacai Chen wrote:
> Add basic boot, setup and reset routines for LoongArch. Now, LoongArch
> machines use UEFI-based firmware. The firmware passes configuration
> information to the kernel via ACPI and DMI/SMBIOS.
>
> Currently an existing interface between the kernel and the bootloader
> is implemented. Kernel gets 2 values from the bootloader, passed in
> registers a0 and a1; a0 is an "EFI boot flag" distinguishing UEFI and
> non-UEFI firmware, while a1 is a pointer to an FDT with systable,
> memmap, cmdline and initrd information.
>
> The standard UEFI boot protocol (EFISTUB) will be added later.
>
> Cc: [email protected]
> Cc: Ard Biesheuvel <[email protected]>
> Reviewed-by: WANG Xuerui <[email protected]>
> Reviewed-by: Jiaxun Yang <[email protected]>
> Co-developed-by: Yun Liu <[email protected]>
> Signed-off-by: Yun Liu <[email protected]>
> Signed-off-by: Huacai Chen <[email protected]>
Would you please look at this patch, which has all the arch-independent
changes backed out, and Ack if it is fit for mainlining?
I communicated a little with Huacai about the approach for supporting
alternative boot protocols down the road, and we agreed to carry the
respective changes downstream. And if needs truly arise for modifying
common EFI logic, we can do so in a non-rushed manner later.
For the current status of the code, apparently it just accepts the
standard efistub-shape FDT pointer from (whatever booting the image),
and everything onwards are fully using the common code without
modification as you can see from the diffstat. I rebased my BPI support
patch on top of this (basically translating Loongson BPI data structures
into the expected FDT form), and can confirm the boot can progress to
the same point as before -- indeed the SVAM changes etc. are not
necessary for a working system, and the code remains working.
Thanks in advance.
On Fri, Jun 3, 2022 at 11:27 AM WANG Xuerui <[email protected]> wrote:
> On 6/3/22 15:20, Huacai Chen wrote:
> > Add basic boot, setup and reset routines for LoongArch. Now, LoongArch
> > machines use UEFI-based firmware. The firmware passes configuration
> > information to the kernel via ACPI and DMI/SMBIOS.
> >
> > Currently an existing interface between the kernel and the bootloader
> > is implemented. Kernel gets 2 values from the bootloader, passed in
> > registers a0 and a1; a0 is an "EFI boot flag" distinguishing UEFI and
> > non-UEFI firmware, while a1 is a pointer to an FDT with systable,
> > memmap, cmdline and initrd information.
> >
> > The standard UEFI boot protocol (EFISTUB) will be added later.
> >
> > Cc: [email protected]
> > Cc: Ard Biesheuvel <[email protected]>
> > Reviewed-by: WANG Xuerui <[email protected]>
> > Reviewed-by: Jiaxun Yang <[email protected]>
> > Co-developed-by: Yun Liu <[email protected]>
> > Signed-off-by: Yun Liu <[email protected]>
> > Signed-off-by: Huacai Chen <[email protected]>
>
> Would you please look at this patch, which has all the arch-independent
> changes backed out, and Ack if it is fit for mainlining?
>
> I communicated a little with Huacai about the approach for supporting
> alternative boot protocols down the road, and we agreed to carry the
> respective changes downstream. And if needs truly arise for modifying
> common EFI logic, we can do so in a non-rushed manner later.
>
> For the current status of the code, apparently it just accepts the
> standard efistub-shape FDT pointer from (whatever booting the image),
> and everything onwards are fully using the common code without
> modification as you can see from the diffstat. I rebased my BPI support
> patch on top of this (basically translating Loongson BPI data structures
> into the expected FDT form), and can confirm the boot can progress to
> the same point as before -- indeed the SVAM changes etc. are not
> necessary for a working system, and the code remains working.
I'm a bit lost here: Does this mean the v15 version is back to the old
pre-efistub interface and allows booting with existing firmware, or
is it now left out completely? I still see a kernel_entry() function
in head.S, and I see references to loongson_sysconf, but I don't
see if that is what gets passed in from the bootloader.
I really want to make sure that without the EFI stub, there is no
other way to boot the kernel that would have to get maintained
in the long run.
Arnd