Re: [musl] Re: [GIT PULL] asm-generic changes for 5.19

[Huacai Chen]

Hi, Ard,

On Thu, Jun 2, 2022 at 12:44 AM WANG Xuerui <kernel@xxxxxxxxxx> wrote:
>
> Hi Ard,
>
> On 6/2/22 00:01, Ard Biesheuvel wrote:
> > On Wed, 1 Jun 2022 at 09:41, Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
> >> On Wed, Jun 1, 2022 at 7:52 AM WANG Xuerui <kernel@xxxxxxxxxx> wrote:
> >>> On 6/1/22 00:01, Huacai Chen wrote:
> >>>> https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson.git/log/?h=loongarch-next
> >>>> has been updated. Now this branch droped irqchip drivers and pci
> >>>> drivers. But the existing irqchip drivers need some small adjustment
> >>>> to avoid build errors [1], and I hope Marc can give an Acked-by.
> >>>> Thanks.
> >>>>
> >>>> This branch can be built with defconfig and allmodconfig (except
> >>>> drivers/platform/surface/aggregator/controller.c, because it requires
> >>>> 8bit/16bit cmpxchg, which I was told to remove their support).
> >>>>
> >>>> [1] https://lore.kernel.org/lkml/e7cf33a170d0b4e98e53744f60dbf922@xxxxxxxxxx/T/#t
> >>> I see the loongarch-next HEAD has been updated and it's now purely arch
> >>> changes aside from the two trivial irqchip cleanups. Some other changes
> >>> to the v11 patchset [1] are included, but arguably minor enough to not
> >>> invalidate previous Reviewed-by tags.
> >> Very nice! I don't see exactly how the previous build bugs were addressed,
> >> but I can confirm that this version builds. Regarding the two irqchip patches,
> >> 621e7015b529 ("irqchip/loongson-liointc: Fix build error for LoongArch") is
> >> a good way to work around the mips oddity, and I have no problem taking
> >> that through the asm-generic tree. The other one, f54b4a166023 ("irqchip:
> >>   Adjust Kconfig for Loongson"), looks mostly unnecessary, and I think only
> >> the LOONGSON_HTPIC change should be included here, while I would
> >> leave out the COMPILE_TEST changes and instead have the driver
> >> changes take care of making it possible to keep building it on x86, possibly
> >> doing
> >>
> >>          depends on MACH_LOONGSON64 || (COMPILE_TEST && ACPI)
> >>
> >> in the future, after the loongarch64 ACPI support is merged.
> >>
> >>> After some small tweaks:
> >>>
> >>> - adding "#include <asm/irqflags.h>" to arch/loongarch/include/asm/ptrace.h,
> >>> - adding an arch/loongarch/include/uapi/asm/bpf_perf_event.h with the
> >>> same content as arch/arm64's, and
> >>> - adding "depends on ARM64 || X86" to
> >>> drivers/platform/surface/aggregator/Kconfig,
> >>>
> >>> the current loongarch-next HEAD (commit
> >>> 36552a24f70d21b7d63d9ef490561dbdc13798d7) now passes allmodconfig build
> >>> (with CONFIG_WERROR disabled; my Gentoo-flavored gcc-12 seems to emit
> >>> warnings on a few drivers).
> >> The only one of these issues that I see is the surface aggregator one.
> >> I think we can address all three as follow-up fixes after -rc1 if the port
> >> gets merged and these are still required.
> >>
> >>> The majority of userspace ABI has been stable for a few months already,
> >>> after the addition of orig_a0 and removal of newfstatat; the necessary
> >>> changes to switch to statx are already reviewed [2] / merged [3], and
> >>> have been integrated into the LoongArch port of Gentoo for a while. Eric
> >>> looked at the v11 and gave comments, and changes were made according to
> >>> the suggestions, but it'd probably better to get a proper Reviewed-by.
> >> Right.
> >>
> >>> Among the rest of patches, I think maybe the EFI/boot protocol part
> >>> still need approval/ack from the EFI maintainer. However because the
> >>> current port isn't going to be able to run on any real hardware, maybe
> >>> that part could be done later; I'm not sure if the unacknowledged EFI
> >>> bits should be removed as well.
> >> Ard, do you have any last comments on this?
> >>
> > It would be nice if the questions I raised against the previous
> > revision (v11) were addressed (or at least answered) first. In
> > general, I think this is feeling a bit rushed and IMHO we should
> > probably defer this to the next cycle.
>
> Actually I think Huacai did reply to your review on v11:
> https://lore.kernel.org/all/CAAhV-H7KAg8RxN7M=WiOOh0fDhEKTyqrwp6V-SC0cyR0iMrdeg@xxxxxxxxxxxxxx/.
> It's a bit unfortunate that he probably didn't justify some of the
> approaches enough, and it's especially unfortunate that some of the
> points (like maybe the kernel version string in the EFI stub header) are
> result of their internal discussion, which I presume to be especially
> hard to change due to their particularly worrying corporate dynamics...
I'm sorry that you haven't seen my reply, but as Xuerui said, I have
replied to your review. :)
Since you didn't reply to my answers again, I supposed that you
consider "everything is OK". :)
Now I plan to send V13, with the following changes:
1, Remove kernel_version string in efistub;
2, Remove the boardinfo knob in /sys/firmware/efi;
3, Add a reference in the commit message to explain while we need a
magic number [1].
[1] https://lists.gnu.org/archive/html/grub-devel/2021-10/msg00215.html

Huacai

>
> But again, my point is that the userspace ABI in particular is *not*
> rushed -- it has been brewing since v1 of the port which is already
> several months ago, and multiple distro-building efforts are already
> underway. We (LoongArch distro packagers) want to freeze the userspace
> ABI so that many downstream efforts wouldn't be blocked by the merging
> of kernel port.
>
> As the boot protocol is technically not part of the userspace ABI that
> toolchains care about, and we already know it'll be a rather
> standards-compliant UEFI implementation even if this part gets dropped
> for brewing one more cycle, would taking this part out work for you?
>