[PATCH -next 2/2] riscv: Enable HAVE_ARCH_HUGE_VMAP for 64BIT

[Liu Shixin]

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 at huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt at google.com>
---
 arch/riscv/Kconfig               |  1 +
 arch/riscv/include/asm/vmalloc.h | 12 ++++++++++
 arch/riscv/mm/Makefile           |  1 +
 arch/riscv/mm/pgtable.c          | 40 ++++++++++++++++++++++++++++++++
 4 files changed, 54 insertions(+)
 create mode 100644 arch/riscv/mm/pgtable.c

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 1cb3280cc498..227033595994 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -60,6 +60,7 @@ 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
 	select HAVE_ARCH_JUMP_LABEL_RELATIVE
 	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..738dc6f3530f
--- /dev/null
+++ b/arch/riscv/mm/pgtable.c
@@ -0,0 +1,40 @@
+// 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
+
+#ifndef __PAGETABLE_PMD_FOLDED
+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;
+}
+#endif
+
+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