Re: [PATCH] MIPS: loongson64: use 0b011 instead of 0b101 as xphys cached

Re: [PATCH] MIPS: loongson64: use 0b011 instead of 0b101 as xphys cached

[Jiaxun Yang]

在 2021/2/20 上午11:31, Huang Pei 写道:
> Loongson 3 use *0b011* as Cachable(not 0b101), this only affect
> loongson64 without enough CP0 Kscratch for holding current pgd.
> 3A2000+ use CP0 PWbase holding current (user) pgd
>
> Signed-off-by: Huang Pei <huangpei@loongson.cn>
> ---
>   arch/mips/mm/tlbex.c | 7 +++++++
>   1 file changed, 7 insertions(+)
>
> diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c
> index a7521b8f7658..51effa5dbf9d 100644
> --- a/arch/mips/mm/tlbex.c
> +++ b/arch/mips/mm/tlbex.c
> @@ -848,8 +848,15 @@ void build_get_pmde64(u32 **p, struct uasm_label **l, struct uasm_reloc **r,
>   		/* Clear lower 23 bits of context. */
>   		uasm_i_dins(p, ptr, 0, 0, 23);
>   
> +#ifdef CONFIG_CPU_LOONGSON64
> +		/* 1 0	0 1 1  << 6  xkphys cached */
> +		/* 0x98xx xxxx xxxx xxxx */
> +		uasm_i_ori(p, ptr, ptr, 0x4c0);

Hi Pei,

What about (CAC_BASE >> 53) instead of magic number?

Also there is another similar usage at build_fast_tlb_refill_handler, please
fix it as well.

Thanks.

- Jiaxun

> +#else
>   		/* 1 0	1 0 1  << 6  xkphys cached */
> +		/* 0xa8xx xxxx xxxx xxxx */
>   		uasm_i_ori(p, ptr, ptr, 0x540);
> +#endif
>   		uasm_i_drotr(p, ptr, ptr, 11);
>   #elif defined(CONFIG_SMP)
>   		UASM_i_CPUID_MFC0(p, ptr, SMP_CPUID_REG);