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

[Kefeng Wang]

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);
 }
 
-- 
2.26.2