Re: [PATCH v1 2/2] LoongArch: Add ifdefs to fix LSX and LASX related issues

From: maobibo
Date: Wed Aug 21 2024 - 21:10:06 EST




On 2024/8/21 下午6:07, Tiezhu Yang wrote:
On 08/21/2024 09:12 AM, maobibo wrote:


On 2024/8/20 下午8:37, Tiezhu Yang wrote:
There exist some issues when building kernel if CONFIG_CPU_HAS_LBT is set
but CONFIG_CPU_HAS_LSX and CONFIG_CPU_HAS_LASX are not set. In this case,
there are no definitions of _restore_lsx and _restore_lasx and there are
also no definitions of kvm_restore_lsx and kvm_restore_lasx in fpu.S and
switch.S respectively, just add some ifdefs to fix the issues.

...

It is hard to understand to put CONFIG_CPU_HAS_LASX inside
CONFIG_CPU_HAS_LBT, in general option CONFIG_CPU_HAS_LBT has nothing
with CONFIG_CPU_HAS_LASX.

Would you like to add parameter func in macro fpu_restore_csr like this?

--- a/arch/loongarch/include/asm/asmmacro.h
+++ b/arch/loongarch/include/asm/asmmacro.h
@@ -55,10 +55,11 @@
 #endif
        .endm

-       .macro fpu_restore_csr thread tmp0 tmp1
+       .macro fpu_restore_csr thread tmp0 tmp1 func
        ldptr.w         \tmp0, \thread, THREAD_FCSR
        movgr2fcsr      fcsr0, \tmp0
 #ifdef CONFIG_CPU_HAS_LBT
+       STACK_FRAME_NON_STANDARD        \func
        /* TM bit is always 0 if LBT not supported */
        andi            \tmp0, \tmp0, FPU_CSR_TM
        beqz            \tmp0, 2f
@@ -282,10 +283,10 @@
        lsx_save_data           \thread, \tmp0
        .endm

For the record, I modified the related code as you suggested and tested with various configs, it works well.

But as we discussed offline, these current changes are small relatively
and the STACK_FRAME_NON_STANDARD related code may be removed if there
is a proper possible way, so just leave it as is in my opinion.
Just be curious, what is the proper possible way to remove this, is it solved with new gcc/binutil version? Do we plan to drop latest gcc/binutils support in near future only in order to remove these STACK_FRAME_NON_STANDARD code?

Regards
Bibo Mao

Thanks,
Tiezhu