Re: [PATCH v2 0/7] selftests/nolibc: customize CROSS_COMPILE for all supported architectures

Willy Tarreau
2023-08-14T08:26:45Z

On Mon, Aug 14, 2023 at 03:38:54PM +0800, Zhangjin Wu wrote:
> > On Sun, Aug 13, 2023 at 06:05:03PM +0800, Zhangjin Wu wrote:
> > > > I think that later I'll further extend XARCH with new variants to
> > > > support ARMv5 and Thumb2, because we have different code for this
> > > > and I continue to manually change the CFLAGS to test both.
> > > >
> > >
> > > Ok, what about further add x86_64 as the default variant for x86 (like ppc for
> > > powerpc)? and then it is able to only resereve the variables for x86_64. I have
> > > prepared a patch for this goal in our new tinyconfig patchset, it will further
> > > avoid adding the same nolibc-test-x86.config and nolibc-test-x86_64.config.
> >
> > I'm confused, x86 already defaults to x86_64, it's just that it depends
> > on the .config itself to figure whether to produce a 32- or 64-bit kernel.
> > But for example it starts qemu in 64-bit mode. Am I missing anything ?
> >
>
> In kernel side, it is, but in our nolibc-test, we have added a copy of x86_64
> for x86:
>
> $ grep -E "_x86" tools/testing/selftests/nolibc/Makefile
> IMAGE_x86_64 = arch/x86/boot/bzImage
> IMAGE_x86 = arch/x86/boot/bzImage
> CROSS_COMPILE_x86_64 ?= x86_64-linux- x86_64-linux-gnu-
> CROSS_COMPILE_x86 ?= x86_64-linux- x86_64-linux-gnu-
> DEFCONFIG_x86_64 = defconfig
> DEFCONFIG_x86 = defconfig
> QEMU_ARCH_x86_64 = x86_64
> QEMU_ARCH_x86 = x86_64
> QEMU_ARGS_x86_64 = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
> QEMU_ARGS_x86 = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
>
> With 'XARCH', the "_x86" copy of them can be simply replaced with such a line:
>
> # configure default variants for target kernel supported architectures
> XARCH_powerpc = ppc
> +XARCH_x86 = x86_64
> XARCH = $(or $(XARCH_$(ARCH)),$(ARCH))
>
> And therefore, the future nolibc-test-x86_64.config is also enough for x86.
>
> But I have seen the 'x86' exception in tools/include/nolibc/Makefile, just a
> confirm on if this replacement is ok.

Ah I thought you meant the opposite, i.e. that ppc did map to powerpc
that I was not seeing anywhere else. Yes we can probably do that and
remove the x86-specific lines later.

Willy