[PATCH] riscv: mm: Enable PMD split page table lock for RV64

[Kefeng Wang]

Hi Palmer, ping ...

On 2021/7/30 21:11, Kefeng Wang wrote:
> After commit 1355c31eeb7e ("asm-generic: pgalloc: provide generic
> pmd_alloc_one() and pmd_free_one()"), it is easy to enable
> ARCH_ENABLE_SPLIT_PMD_PTLOCK for RV64.
>
> Signed-off-by: Kefeng Wang <wangkefeng.wang at huawei.com>
> ---
>   arch/riscv/Kconfig   | 1 +
>   arch/riscv/mm/init.c | 3 ++-
>   2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 8fcceb8eda07..c3e456fc7108 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -12,6 +12,7 @@ config 32BIT
>   
>   config RISCV
>   	def_bool y
> +	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
>   	select ARCH_CLOCKSOURCE_INIT
>   	select ARCH_SUPPORTS_ATOMIC_RMW
>   	select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index e547e53cddd2..ce12905a0224 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -361,7 +361,8 @@ static phys_addr_t __init alloc_pmd_late(uintptr_t va)
>   	unsigned long vaddr;
>   
>   	vaddr = __get_free_page(GFP_KERNEL);
> -	BUG_ON(!vaddr);
> +	BUG_ON(!vaddr || !pgtable_pmd_page_ctor(virt_to_page(vaddr)));
> +
>   	return __pa(vaddr);
>   }
>