riscv: mm: Enable PMD split page table lock for RV64

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@ghiti.fr>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 821252b..97f7ecd 100644 (file)
--- 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 24b2b80..b7b70fb 100644 (file)
--- 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);
 }