[PATCH -next] riscv: Enable HAVE_ARCH_HUGE_VMAP for 64BIT

[Liu Shixin <liushixin2@huawei.com>]

This sets the HAVE_ARCH_HUGE_VMAP option. Enable pmd vmap support and
define the required page table functions(Currently, riscv has only
three-level page tables support for 64BIT).

Signed-off-by: Liu Shixin <liushixin2@huawei.com>
---
 .../features/vm/huge-vmap/arch-support.txt    |  2 +-
 arch/riscv/Kconfig                            |  1 +
 arch/riscv/include/asm/vmalloc.h              | 12 +++++
 arch/riscv/mm/Makefile                        |  1 +
 arch/riscv/mm/pgtable.c                       | 53 +++++++++++++++++++
 5 files changed, 68 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/mm/pgtable.c

diff --git a/Documentation/features/vm/huge-vmap/arch-support.txt b/Documentation/features/vm/huge-vmap/arch-support.txt
index 439fd9069b8b..0ff394acc9cf 100644
--- a/Documentation/features/vm/huge-vmap/arch-support.txt
+++ b/Documentation/features/vm/huge-vmap/arch-support.txt
@@ -22,7 +22,7 @@
     |    openrisc: | TODO |
     |      parisc: | TODO |
     |     powerpc: |  ok  |
-    |       riscv: | TODO |
+    |       riscv: |  ok  |
     |        s390: | TODO |
     |          sh: | TODO |
     |       sparc: | TODO |
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 8fcceb8eda07..94cc2a254773 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -61,6 +61,7 @@ config RISCV
 	select GENERIC_TIME_VSYSCALL if MMU && 64BIT
 	select HANDLE_DOMAIN_IRQ
 	select HAVE_ARCH_AUDITSYSCALL
+	select HAVE_ARCH_HUGE_VMAP if MMU && 64BIT
 	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
 	select HAVE_ARCH_JUMP_LABEL_RELATIVE if !XIP_KERNEL
 	select HAVE_ARCH_KASAN if MMU && 64BIT
diff --git a/arch/riscv/include/asm/vmalloc.h b/arch/riscv/include/asm/vmalloc.h
index ff9abc00d139..8f17f421f80c 100644
--- a/arch/riscv/include/asm/vmalloc.h
+++ b/arch/riscv/include/asm/vmalloc.h
@@ -1,4 +1,16 @@
 #ifndef _ASM_RISCV_VMALLOC_H
 #define _ASM_RISCV_VMALLOC_H
 
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+
+#define IOREMAP_MAX_ORDER (PMD_SHIFT)
+
+#define arch_vmap_pmd_supported	arch_vmap_pmd_supported
+static inline bool __init arch_vmap_pmd_supported(pgprot_t prot)
+{
+	return true;
+}
+
+#endif
+
 #endif /* _ASM_RISCV_VMALLOC_H */
diff --git a/arch/riscv/mm/Makefile b/arch/riscv/mm/Makefile
index 7ebaef10ea1b..f932b4d69946 100644
--- a/arch/riscv/mm/Makefile
+++ b/arch/riscv/mm/Makefile
@@ -13,6 +13,7 @@ obj-y += extable.o
 obj-$(CONFIG_MMU) += fault.o pageattr.o
 obj-y += cacheflush.o
 obj-y += context.o
+obj-y += pgtable.o
 
 ifeq ($(CONFIG_MMU),y)
 obj-$(CONFIG_SMP) += tlbflush.o
diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c
new file mode 100644
index 000000000000..f68dd2b71dce
--- /dev/null
+++ b/arch/riscv/mm/pgtable.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <asm/pgalloc.h>
+#include <linux/gfp.h>
+#include <linux/kernel.h>
+#include <linux/pgtable.h>
+
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+
+int pud_set_huge(pud_t *pud, phys_addr_t phys, pgprot_t prot)
+{
+	return 0;
+}
+
+int pud_clear_huge(pud_t *pud)
+{
+	return 0;
+}
+
+int pud_free_pmd_page(pud_t *pud, unsigned long addr)
+{
+	return 0;
+}
+
+int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
+{
+	pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), prot);
+
+	set_pmd(pmd, new_pmd);
+	return 1;
+}
+
+int pmd_clear_huge(pmd_t *pmd)
+{
+	if (!pmd_leaf(READ_ONCE(*pmd)))
+		return 0;
+	pmd_clear(pmd);
+	return 1;
+}
+
+int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
+{
+	pte_t *pte;
+
+	pte = (pte_t *)pmd_page_vaddr(*pmd);
+	pmd_clear(pmd);
+
+	flush_tlb_kernel_range(addr, addr + PMD_SIZE);
+	pte_free_kernel(NULL, pte);
+	return 1;
+}
+
+#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
-- 
2.18.0.huawei.25