[PATCH v3] riscv: Add support to allocate gigantic hugepages using CMA

[Kefeng Wang]

Commit 9e953cda5cdf ("riscv: Introduce huge page support for32/64bit
kernel") adds support gigantic hugepage support for RV64.

This patch adds support to allocate gigantic hugepages using CMA by
specifying the hugetlb_cma= kernel parameter on RV64.

Cc: Alexandre Ghiti <alex at ghiti.fr>
Reviewed-by: Alexandre Ghiti <alex at ghiti.fr>
Signed-off-by: Kefeng Wang <wangkefeng.wang at huawei.com>
---
v3: Update changelog and add Reviewed-by.
 arch/riscv/mm/init.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index a14bf3910eec..e547e53cddd2 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -19,6 +19,7 @@
 #include <linux/set_memory.h>
 #include <linux/dma-map-ops.h>
 #include <linux/crash_dump.h>
+#include <linux/hugetlb.h>
 
 #include <asm/fixmap.h>
 #include <asm/tlbflush.h>
@@ -216,6 +217,8 @@ static void __init setup_bootmem(void)
 
 	early_init_fdt_scan_reserved_mem();
 	dma_contiguous_reserve(dma32_phys_limit);
+	if (IS_ENABLED(CONFIG_64BIT))
+		hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);
 	memblock_allow_resize();
 }
 
-- 
2.26.2