Hi, Nathan,
On Tue, Jun 27, 2023 at 12:07 AM Nathan Chancellor nathan@kernel.org 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 $(KBUILD_CFLAGS) of 'CHECKFLAGS'". What configuration and build command reproduces this? I do not see how '-mno-loongson-mmi' would fail to get added to cflags-y after 0e96ea5c3eb5, which should have had no functional change... I don't want to hang this change up since there is real breakage but I want to make sure we fully understand why 0e96ea5c3eb5 broke things and why this patch resolves it.
Please use loongson3_defconfig to build a loongson kernel with toolchains from here [1]: 'make' will succeed, but there is a build error when 'make modules_install'. And you should be careful because 'make modules_install' doesn't stop when the error occurs.
[1] https://mirrors.edge.kernel.org/pub/tools/crosstool/
Huacai
Fix this by partially reverting to the old logic, use 'call cc-option' to conditionally apply -march=loongson3a and -march=mips64r2.
Fixes: 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of cc-ifversion") Cc: stable@vger.kernel.org Cc: Nathan Chancellor nathan@kernel.org Cc: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Huacai Chen chenhuacai@loongson.cn
arch/mips/Makefile | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/mips/Makefile b/arch/mips/Makefile index a7a4ee66a9d3..7fb76d12829e 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -186,11 +186,8 @@ cflags-$(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