于 2020年9月21日 GMT+08:00 下午8:15:54, Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> 写到: >On Mon, Sep 21, 2020 at 05:12:27PM +0800, Huacai Chen wrote: >> Loongson-3's COP2 is Multi-Media coprocessor, it is disabled in kernel >> mode by default. However, gslq/gssq (16-bytes load/store instructions) >> overrides the instruction format of lwc2/swc2. If we wan't to use gslq/ >> gssq for optimization in kernel, we should enable COP2 usage in kernel. >> >> Please pay attention that in this patch we only enable COP2 in kernel, >> which means it will lose ST0_CU2 when a process go to user space (try >> to use COP2 in user space will trigger an exception and then grab COP2, >> which is similar to FPU). And as a result, we need to modify the context >> switching code because the new scheduled process doesn't contain ST0_CU2 >> in its THERAD_STATUS probably. >> >> For zboot, we disable gslq/gssq be generated by toolchain. >> >> Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx> >> --- >> V3: Stop using ST0_MM and use ST0_CU2 instead (Thank Thomas and Maciej). >> V4: Adopt Thomas's suggestion to improve coding style. >> V5: Use ST0_KERNEL_CUMASK in all possible places to avoid #ifdefs. >> V6: Modify switch_to() and don't touch r4k_switch.S. >> V7: For zboot, disable gslq/gssq be generated by toolchain. >> >> arch/mips/boot/compressed/Makefile | 5 +++++ >> arch/mips/include/asm/mipsregs.h | 7 +++++++ >> arch/mips/include/asm/stackframe.h | 6 +++--- >> arch/mips/kernel/head.S | 2 +- >> arch/mips/kernel/process.c | 4 ++-- >> arch/mips/kernel/traps.c | 2 +- >> 6 files changed, 19 insertions(+), 7 deletions(-) >> >> diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile >> index 9a9ba77..2c491c1 100644 >> --- a/arch/mips/boot/compressed/Makefile >> +++ b/arch/mips/boot/compressed/Makefile >> @@ -22,6 +22,11 @@ KBUILD_CFLAGS := $(filter-out -pg, $(KBUILD_CFLAGS)) >> >> KBUILD_CFLAGS := $(filter-out -fstack-protector, $(KBUILD_CFLAGS)) >> >> +# Disable lq/sq in zboot >> +ifdef CONFIG_CPU_LOONGSON64 >> +KBUILD_CFLAGS := $(filter-out -march=loongson3a, $(KBUILD_CFLAGS)) -march=mips64r2 >> +endif >> + > >thanks for doing this, I'm going to apply this later. > >This remind of another question, what about loongson2ef ? I'm getting >kbuild failure because of enabled loongson-mmi mails. Are we are missing >something like cflags-y += $(call cc-option,-mno-loongson-mmi) in Platform >file ? Who is taking care of loongson2ef ? I'll send a patch later. Sorry for the inconvenience. I'm taking care of it. Just being a little bit busy recently. Thanks. - Jiaxun > >Thomas. >
