[PATCH v6 4/4] riscv: mm: support Svnapot in huge vmap

[panqinglin2020 at iscas.ac.cn]

From: Qinglin Pan <panqinglin2020 at iscas.ac.cn>

The HAVE_ARCH_HUGE_VMAP option can be used to help implement arch
special huge vmap size. This commit selects this option by default and
re-writes the arch_vmap_pte_range_map_size for Svnapot 64KB size.

It can be tested when booting kernel in qemu with pci device, which
will make the kernel to call pci driver using ioremap, and the
re-written function will be called.

Signed-off-by: Qinglin Pan <panqinglin2020 at iscas.ac.cn>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index bc19786f25f5..4b6ca943168f 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -70,6 +70,7 @@ config RISCV
 	select GENERIC_TIME_VSYSCALL if MMU && 64BIT
 	select GENERIC_VDSO_TIME_NS if HAVE_GENERIC_VDSO
 	select HAVE_ARCH_AUDITSYSCALL
+	select HAVE_ARCH_HUGE_VMAP
 	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/pgtable.h b/arch/riscv/include/asm/pgtable.h
index a8cab063fd05..aa7eda57054c 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -749,6 +749,43 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
+static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
+{
+	return 0;
+}
+
+static inline int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
+{
+	return 0;
+}
+
+static inline void p4d_clear_huge(p4d_t *p4d) { }
+
+static inline int pud_clear_huge(pud_t *pud)
+{
+	return 0;
+}
+
+static inline int pmd_clear_huge(pmd_t *pmd)
+{
+	return 0;
+}
+
+static inline int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
+{
+	return 0;
+}
+
+static inline int pud_free_pmd_page(pud_t *pud, unsigned long addr)
+{
+	return 0;
+}
+
+static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
+{
+	return 0;
+}
+
 /*
  * Encode and decode a swap entry
  *
diff --git a/arch/riscv/include/asm/vmalloc.h b/arch/riscv/include/asm/vmalloc.h
index ff9abc00d139..ecd1f784299b 100644
--- a/arch/riscv/include/asm/vmalloc.h
+++ b/arch/riscv/include/asm/vmalloc.h
@@ -1,4 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 #ifndef _ASM_RISCV_VMALLOC_H
 #define _ASM_RISCV_VMALLOC_H
 
+#include <linux/pgtable.h>
+
+#ifdef CONFIG_RISCV_ISA_SVNAPOT
+#define arch_vmap_pte_range_map_size vmap_pte_range_map_size
+static inline unsigned long
+vmap_pte_range_map_size(unsigned long addr, unsigned long end, u64 pfn,
+			unsigned int max_page_shift)
+{
+	if (!has_svnapot())
+		return PAGE_SIZE;
+
+	if (addr & NAPOT_CONT64KB_MASK)
+		return PAGE_SIZE;
+
+	if (pfn & (NAPOT_64KB_PTE_NUM - 1UL))
+		return PAGE_SIZE;
+
+	if ((end - addr) < NAPOT_CONT64KB_SIZE)
+		return PAGE_SIZE;
+
+	if (max_page_shift < NAPOT_CONT64KB_SHIFT)
+		return PAGE_SIZE;
+
+	return NAPOT_CONT64KB_SIZE;
+}
+#endif /*CONFIG_RISCV_ISA_SVNAPOT*/
+
 #endif /* _ASM_RISCV_VMALLOC_H */
-- 
2.35.1