Hi, Nathan,
On Tue, Jun 27, 2023 at 12:07 AM Nathan Chancellor <nathan@xxxxxxxxxx> wrote:
>
> On Mon, Jun 26, 2023 at 03:50:47PM +0800, Huacai Chen wrote:
> > After commit 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of
> > cc-ifversion") we get a build error when make modules_install:
> >
> > cc1: error: '-mloongson-mmi' must be used with '-mhard-float'
> >
> > The reason is when make modules_install, 'call cc-option' doesn't work
> > in $(KBUILD_CFLAGS) of 'CHECKFLAGS'. Then there is no -mno-loongson-mmi
> > applied and -march=loongson3a enable MMI instructions.
>
> The first sentence does not make much sense to me, specifically "in
> $(KBUILD_CFLAGS) of 'CHECKFLAGS'". What configuration and build command
> reproduces this? I do not see how '-mno-loongson-mmi' would fail to get
> added to cflags-y after 0e96ea5c3eb5, which should have had no
> functional change... I don't want to hang this change up since there is
> real breakage but I want to make sure we fully understand why
> 0e96ea5c3eb5 broke things and why this patch resolves it.
Please use loongson3_defconfig to build a loongson kernel with
toolchains from here [1]:
'make' will succeed, but there is a build error when 'make
modules_install'. And you should be careful because 'make
modules_install' doesn't stop when the error occurs.
[1] https://mirrors.edge.kernel.org/pub/tools/crosstool/
Huacai
>
> > Fix this by partially reverting to the old logic, use 'call cc-option'
> > to conditionally apply -march=loongson3a and -march=mips64r2.
> >
> > Fixes: 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of cc-ifversion")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
> > Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> > Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> > ---
> > arch/mips/Makefile | 5 +----
> > 1 file changed, 1 insertion(+), 4 deletions(-)
> >
> > diff --git a/arch/mips/Makefile b/arch/mips/Makefile
> > index a7a4ee66a9d3..7fb76d12829e 100644
> > --- a/arch/mips/Makefile
> > +++ b/arch/mips/Makefile
> > @@ -186,11 +186,8 @@ cflags-$(CONFIG_CPU_LOONGSON2F) += -march=loongson2f -Wa,--trap
> > # Some -march= flags enable MMI instructions, and GCC complains about that
> > # support being enabled alongside -msoft-float. Thus explicitly disable MMI.
> > cflags-$(CONFIG_CPU_LOONGSON2EF) += $(call cc-option,-mno-loongson-mmi)
> > -ifdef CONFIG_CPU_LOONGSON64
> > cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap
> > -cflags-$(CONFIG_CC_IS_GCC) += -march=loongson3a
> > -cflags-$(CONFIG_CC_IS_CLANG) += -march=mips64r2
> > -endif
> > +cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-march=loongson3a,-march=mips64r2)
> > cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-mno-loongson-mmi)
> >
> > cflags-$(CONFIG_CPU_R4000_WORKAROUNDS) += $(call cc-option,-mfix-r4000,)
> > --
> > 2.39.3
> >
