Backport subject "riscv: Memory Hot(Un)Plug support"

arch/riscv/Kconfig

@@ -20,6 +20,8 @@ config RISCV
 	select ACPI_SPCR_TABLE if ACPI
 	select ARCH_DMA_DEFAULT_COHERENT
 	select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
+	select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM_VMEMMAP
+	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
 	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
 	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
 	select ARCH_HAS_BINFMT_FLAT
@@ -38,6 +40,7 @@ config RISCV
 	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 	select ARCH_HAS_PMEM_API
 	select ARCH_HAS_PREPARE_SYNC_CORE_CMD
+	select ARCH_HAS_PTE_DEVMAP if 64BIT && MMU
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SET_DIRECT_MAP if MMU
 	select ARCH_HAS_SET_MEMORY if MMU
@@ -50,6 +53,7 @@ config RISCV
 	select ARCH_HAS_VDSO_DATA
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select ARCH_KEEP_MEMBLOCK if ACPI
+	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE	if 64BIT && MMU
 	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
 	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
 	select ARCH_STACKWALK
@@ -67,6 +71,7 @@ config RISCV
 	select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT
 	select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
 	select ARCH_WANT_LD_ORPHAN_WARN if !XIP_KERNEL
+	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP
 	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
 	select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE
 	select ARCH_WEAK_RELEASE_ACQUIRE if ARCH_USE_QUEUED_SPINLOCKS

arch/riscv/include/asm/kasan.h

@@ -6,8 +6,6 @@
 
 #ifndef __ASSEMBLY__
 
-#ifdef CONFIG_KASAN
-
 /*
  * The following comment was copied from arm64:
  * KASAN_SHADOW_START: beginning of the kernel virtual addresses.
@@ -34,6 +32,8 @@
  */
 #define KASAN_SHADOW_START	((KASAN_SHADOW_END - KASAN_SHADOW_SIZE) & PGDIR_MASK)
 #define KASAN_SHADOW_END	MODULES_LOWEST_VADDR
+
+#ifdef CONFIG_KASAN
 #define KASAN_SHADOW_OFFSET	_AC(CONFIG_KASAN_SHADOW_OFFSET, UL)
 
 void kasan_init(void);

arch/riscv/include/asm/mmu.h

@@ -26,8 +26,8 @@ typedef struct {
 #endif
 } mm_context_t;
 
-void __init create_pgd_mapping(pgd_t *pgdp, uintptr_t va, phys_addr_t pa,
-			       phys_addr_t sz, pgprot_t prot);
+void __meminit create_pgd_mapping(pgd_t *pgdp, uintptr_t va, phys_addr_t pa, phys_addr_t sz,
+				  pgprot_t prot);
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_RISCV_MMU_H */

arch/riscv/include/asm/page.h

@@ -185,6 +185,11 @@ extern phys_addr_t __phys_addr_symbol(unsigned long x);
 
 unsigned long kaslr_offset(void);
 
+static __always_inline void *pfn_to_kaddr(unsigned long pfn)
+{
+	return __va(pfn << PAGE_SHIFT);
+}
+
 #endif /* __ASSEMBLY__ */
 
 #define virt_addr_valid(vaddr)	({						\

arch/riscv/include/asm/pgtable-64.h

@@ -400,4 +400,24 @@ static inline struct page *pgd_page(pgd_t pgd)
 #define p4d_offset p4d_offset
 p4d_t *p4d_offset(pgd_t *pgd, unsigned long address);
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static inline int pte_devmap(pte_t pte);
+static inline pte_t pmd_pte(pmd_t pmd);
+
+static inline int pmd_devmap(pmd_t pmd)
+{
+	return pte_devmap(pmd_pte(pmd));
+}
+
+static inline int pud_devmap(pud_t pud)
+{
+	return 0;
+}
+
+static inline int pgd_devmap(pgd_t pgd)
+{
+	return 0;
+}
+#endif
+
 #endif /* _ASM_RISCV_PGTABLE_64_H */

arch/riscv/include/asm/pgtable-bits.h

@@ -17,6 +17,7 @@
 #define _PAGE_ACCESSED  (1 << 6)    /* Set by hardware on any access */
 #define _PAGE_DIRTY     (1 << 7)    /* Set by hardware on any write */
 #define _PAGE_SOFT      (1 << 8)    /* Reserved for software */
+#define _PAGE_DEVMAP    (1 << 9)    /* RSW, devmap */
 
 #define _PAGE_SPECIAL   _PAGE_SOFT
 #define _PAGE_TABLE     _PAGE_PRESENT

arch/riscv/include/asm/pgtable.h

@@ -182,7 +182,7 @@ struct pt_alloc_ops {
 #endif
 };
 
-extern struct pt_alloc_ops pt_ops __initdata;
+extern struct pt_alloc_ops pt_ops __meminitdata;
 
 #ifdef CONFIG_MMU
 /* Number of PGD entries that a user-mode program can use */
@@ -407,6 +407,13 @@ static inline int pte_special(pte_t pte)
 	return pte_val(pte) & _PAGE_SPECIAL;
 }
 
+#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
+static inline int pte_devmap(pte_t pte)
+{
+	return pte_val(pte) & _PAGE_DEVMAP;
+}
+#endif
+
 /* static inline pte_t pte_rdprotect(pte_t pte) */
 
 static inline pte_t pte_wrprotect(pte_t pte)
@@ -448,6 +455,11 @@ static inline pte_t pte_mkspecial(pte_t pte)
 	return __pte(pte_val(pte) | _PAGE_SPECIAL);
 }
 
+static inline pte_t pte_mkdevmap(pte_t pte)
+{
+	return __pte(pte_val(pte) | _PAGE_DEVMAP);
+}
+
 static inline pte_t pte_mkhuge(pte_t pte)
 {
 	return pte;
@@ -761,6 +773,11 @@ static inline pmd_t pmd_mkdirty(pmd_t pmd)
 	return pte_pmd(pte_mkdirty(pmd_pte(pmd)));
 }
 
+static inline pmd_t pmd_mkdevmap(pmd_t pmd)
+{
+	return pte_pmd(pte_mkdevmap(pmd_pte(pmd)));
+}
+
 static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 				pmd_t *pmdp, pmd_t pmd)
 {