> 2023年4月6日 21:09，Nathan Chancellor <nathan@xxxxxxxxxx> 写道：
>
> When building allnoconfig with clang after commit de34007751aa ("MIPS:
> generic: Enable all CPUs supported by virt board in Kconfig"), the
> following error occurs:
>
> error: unknown target CPU 'r4600'
> note: valid target CPU values are: mips1, mips2, mips3, mips4, mips5, mips32, mips32r2, mips32r3, mips32r5, mips32r6, mips64, mips64r2, mips64r3, mips64r5, mips64r6, octeon, octeon+, p5600
>
> Working around that, there are similar errors for 'loongson2e' and
> 'loongson2f'.
>
> These CPUs are not supported in clang/LLVM, so do not select support for
> them in MIPS_GENERIC_KERNEL when building with clang.
>
> Fixes: de34007751aa ("MIPS: generic: Enable all CPUs supported by virt board in Kconfig")
> Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Thanks for the patch.
Actually there is no need for any special support for those CPUs.
We should be able to build those kernels with -march=mips3.
I think something like:
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -150,7 +150,7 @@ cflags-y += $(call cc-option,-Wa$(comma)-mno-fix-loongson3-llsc,)
#
cflags-$(CONFIG_CPU_R3000) += -march=r3000
cflags-$(CONFIG_CPU_R4300) += -march=r4300 -Wa,--trap
-cflags-$(CONFIG_CPU_R4X00) += -march=r4600 -Wa,--trap
+cflags-$(CONFIG_CPU_R4X00) += $(call cc-option,-march=r4600,-march=mips3) -Wa,--trap
cflags-$(CONFIG_CPU_TX49XX) += -march=r4600 -Wa,--trap
cflags-$(CONFIG_CPU_MIPS32_R1) += -march=mips32 -Wa,--trap
cflags-$(CONFIG_CPU_MIPS32_R2) += -march=mips32r2 -Wa,--trap
@@ -181,8 +181,8 @@ endif
cflags-$(CONFIG_CAVIUM_CN63XXP1) += -Wa,-mfix-cn63xxp1
cflags-$(CONFIG_CPU_BMIPS) += -march=mips32 -Wa,-mips32 -Wa,--trap
-cflags-$(CONFIG_CPU_LOONGSON2E) += -march=loongson2e -Wa,--trap
-cflags-$(CONFIG_CPU_LOONGSON2F) += -march=loongson2f -Wa,--trap
+cflags-$(CONFIG_CPU_LOONGSON2E) += $(call cc-option,-march=loongson2e,-march=mips3) -Wa,--trap
+cflags-$(CONFIG_CPU_LOONGSON2F) += $(call cc-option,-march=loongson2f,-march=mips3) -Wa,--trap
# Some -march= flags enable MMI instructions, and GCC complains about that
# support being enabled alongside -msoft-float. Thus explicitly disable MMI.
cflags-$(CONFIG_CPU_LOONGSON2EF) += $(call cc-option,-mno-loongson-mmi)
Will make them build.
Thanks
- Jiaxun
