[PATCH v2] riscv: mm: Enable PMD split page table lock for RV64

[Kefeng Wang]

Hi Palmer,  ping, it looks this patch is missed...

On 2021/9/27 11:03, Kefeng Wang wrote:
> After commit 1355c31eeb7e ("asm-generic: pgalloc: provide generic
> pmd_alloc_one() and pmd_free_one()"), the main part to support
> PMD split page table lock is in asm-generic/pgalloc.h.
>
> The only change is add pgtable_pmd_page_ctor() into alloc_pmd_late(),
> then we could enable ARCH_ENABLE_SPLIT_PMD_PTLOCK for RV64.
>
> Reviewed-by: Alexandre Ghiti <alex at ghiti.fr>
> Signed-off-by: Kefeng Wang <wangkefeng.wang at huawei.com>
> ---
> v2:
> - rebase to v5.15-rc3, update changelog, and add RB
>
>   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 301a54233c7e..5c4463f30eb0 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -14,6 +14,7 @@ config RISCV
>   	def_bool y
>   	select ARCH_CLOCKSOURCE_INIT
>   	select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
> +	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
>   	select ARCH_HAS_BINFMT_FLAT
>   	select ARCH_HAS_DEBUG_VM_PGTABLE
>   	select ARCH_HAS_DEBUG_VIRTUAL if MMU
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index c0cddf0fc22d..1f21375ba86f 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -367,7 +367,8 @@ 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);
>   }
>