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

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Message-ID: <1d23bbfe-dd36-b2ff-c4b3-cf69396ea53f@loongson.cn>
Date: Wed, 21 Aug 2024 09:12:34 +0800
From: maobibo <maobibo@...ngson.cn>
To: Tiezhu Yang <yangtiezhu@...ngson.cn>, Huacai Chen <chenhuacai@...nel.org>
Cc: Arnd Bergmann <arnd@...db.de>, loongarch@...ts.linux.dev,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 2/2] LoongArch: Add ifdefs to fix LSX and LASX related
 issues



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.
> 
>    AS      arch/loongarch/kernel/fpu.o
> arch/loongarch/kernel/fpu.o: warning: objtool: unexpected relocation symbol type in .rela.discard.func_stack_frame_non_standard: 0
> arch/loongarch/kernel/fpu.o: warning: objtool: unexpected relocation symbol type in .rela.discard.func_stack_frame_non_standard: 0
> 
>    AS [M]  arch/loongarch/kvm/switch.o
> arch/loongarch/kvm/switch.o: warning: objtool: unexpected relocation symbol type in .rela.discard.func_stack_frame_non_standard: 0
> arch/loongarch/kvm/switch.o: warning: objtool: unexpected relocation symbol type in .rela.discard.func_stack_frame_non_standard: 0
> 
>    MODPOST Module.symvers
> ERROR: modpost: "kvm_restore_lsx" [arch/loongarch/kvm/kvm.ko] undefined!
> ERROR: modpost: "kvm_restore_lasx" [arch/loongarch/kvm/kvm.ko] undefined!
> 
> Cc: stable@...r.kernel.org # 6.9+
> Fixes: cb8a2ef0848c ("LoongArch: Add ORC stack unwinder support")
> Reported-by: kernel test robot <lkp@...el.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202408120955.qls5oNQY-lkp@intel.com/
> Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
> ---
>   arch/loongarch/kernel/fpu.S | 4 ++++
>   arch/loongarch/kvm/switch.S | 4 ++++
>   2 files changed, 8 insertions(+)
> 
> diff --git a/arch/loongarch/kernel/fpu.S b/arch/loongarch/kernel/fpu.S
> index 69a85f2479fb..6ab640101457 100644
> --- a/arch/loongarch/kernel/fpu.S
> +++ b/arch/loongarch/kernel/fpu.S
> @@ -530,6 +530,10 @@ SYM_FUNC_END(_restore_lasx_context)
>   
>   #ifdef CONFIG_CPU_HAS_LBT
>   STACK_FRAME_NON_STANDARD _restore_fp
> +#ifdef CONFIG_CPU_HAS_LSX
>   STACK_FRAME_NON_STANDARD _restore_lsx
> +#endif
> +#ifdef CONFIG_CPU_HAS_LASX
>   STACK_FRAME_NON_STANDARD _restore_lasx
>   #endif
> +#endif
> diff --git a/arch/loongarch/kvm/switch.S b/arch/loongarch/kvm/switch.S
> index 80e988985a6a..0c292f818492 100644
> --- a/arch/loongarch/kvm/switch.S
> +++ b/arch/loongarch/kvm/switch.S
> @@ -277,6 +277,10 @@ SYM_DATA(kvm_enter_guest_size, .quad kvm_enter_guest_end - kvm_enter_guest)
>   
>   #ifdef CONFIG_CPU_HAS_LBT
>   STACK_FRAME_NON_STANDARD kvm_restore_fpu
> +#ifdef CONFIG_CPU_HAS_LSX
>   STACK_FRAME_NON_STANDARD kvm_restore_lsx
> +#endif
> +#ifdef CONFIG_CPU_HAS_LASX
>   STACK_FRAME_NON_STANDARD kvm_restore_lasx
>   #endif
> +#endif
> 
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

Regards
Bibo Mao