/* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (C) 2012 Regents of the University of California */ #ifndef _ASM_RISCV_PGTABLE_H #define _ASM_RISCV_PGTABLE_H #include #include #include #ifndef CONFIG_MMU #define KERNEL_LINK_ADDR PAGE_OFFSET #else #define ADDRESS_SPACE_END (UL(-1)) #ifdef CONFIG_64BIT /* Leave 2GB for kernel and BPF at the end of the address space */ #define KERNEL_LINK_ADDR (ADDRESS_SPACE_END - SZ_2G + 1) #else #define KERNEL_LINK_ADDR PAGE_OFFSET #endif /* Number of entries in the page global directory */ #define PTRS_PER_PGD (PAGE_SIZE / sizeof(pgd_t)) /* Number of entries in the page table */ #define PTRS_PER_PTE (PAGE_SIZE / sizeof(pte_t)) /* * Half of the kernel address space (half of the entries of the page global * directory) is for the direct mapping. */ #define KERN_VIRT_SIZE ((PTRS_PER_PGD / 2 * PGDIR_SIZE) / 2) #define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1) #define VMALLOC_END PAGE_OFFSET #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE) #define BPF_JIT_REGION_SIZE (SZ_128M) #ifdef CONFIG_64BIT #define BPF_JIT_REGION_START (BPF_JIT_REGION_END - BPF_JIT_REGION_SIZE) #define BPF_JIT_REGION_END (MODULES_END) #else #define BPF_JIT_REGION_START (PAGE_OFFSET - BPF_JIT_REGION_SIZE) #define BPF_JIT_REGION_END (VMALLOC_END) #endif /* Modules always live before the kernel */ #ifdef CONFIG_64BIT /* This is used to define the end of the KASAN shadow region */ #define MODULES_LOWEST_VADDR (KERNEL_LINK_ADDR - SZ_2G) #define MODULES_VADDR (PFN_ALIGN((unsigned long)&_end) - SZ_2G) #define MODULES_END (PFN_ALIGN((unsigned long)&_start)) #endif /* * Roughly size the vmemmap space to be large enough to fit enough * struct pages to map half the virtual address space. Then * position vmemmap directly below the VMALLOC region. */ #ifdef CONFIG_64BIT #define VA_BITS (pgtable_l5_enabled ? \ 57 : (pgtable_l4_enabled ? 48 : 39)) #else #define VA_BITS 32 #endif #define VMEMMAP_SHIFT \ (VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT) #define VMEMMAP_SIZE BIT(VMEMMAP_SHIFT) #define VMEMMAP_END VMALLOC_START #define VMEMMAP_START (VMALLOC_START - VMEMMAP_SIZE) /* * Define vmemmap for pfn_to_page & page_to_pfn calls. Needed if kernel * is configured with CONFIG_SPARSEMEM_VMEMMAP enabled. */ #define vmemmap ((struct page *)VMEMMAP_START) #define PCI_IO_SIZE SZ_16M #define PCI_IO_END VMEMMAP_START #define PCI_IO_START (PCI_IO_END - PCI_IO_SIZE) #define FIXADDR_TOP PCI_IO_START #ifdef CONFIG_64BIT #define FIXADDR_SIZE PMD_SIZE #else #define FIXADDR_SIZE PGDIR_SIZE #endif #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) #endif #ifdef CONFIG_XIP_KERNEL #define XIP_OFFSET SZ_32M #define XIP_OFFSET_MASK (SZ_32M - 1) #else #define XIP_OFFSET 0 #endif #ifndef __ASSEMBLY__ #include #include #include #ifdef CONFIG_64BIT #include #else #include #endif /* CONFIG_64BIT */ #ifdef CONFIG_XIP_KERNEL #define XIP_FIXUP(addr) ({ \ uintptr_t __a = (uintptr_t)(addr); \ (__a >= CONFIG_XIP_PHYS_ADDR && \ __a < CONFIG_XIP_PHYS_ADDR + XIP_OFFSET * 2) ? \ __a - CONFIG_XIP_PHYS_ADDR + CONFIG_PHYS_RAM_BASE - XIP_OFFSET :\ __a; \ }) #else #define XIP_FIXUP(addr) (addr) #endif /* CONFIG_XIP_KERNEL */ struct pt_alloc_ops { pte_t *(*get_pte_virt)(phys_addr_t pa); phys_addr_t (*alloc_pte)(uintptr_t va); #ifndef __PAGETABLE_PMD_FOLDED pmd_t *(*get_pmd_virt)(phys_addr_t pa); phys_addr_t (*alloc_pmd)(uintptr_t va); pud_t *(*get_pud_virt)(phys_addr_t pa); phys_addr_t (*alloc_pud)(uintptr_t va); #endif }; extern struct pt_alloc_ops pt_ops __initdata; #ifdef CONFIG_MMU /* Number of PGD entries that a user-mode program can use */ #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE) /* Page protection bits */ #define _PAGE_BASE (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_USER) #define PAGE_NONE __pgprot(_PAGE_PROT_NONE | _PAGE_READ) #define PAGE_READ __pgprot(_PAGE_BASE | _PAGE_READ) #define PAGE_WRITE __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_WRITE) #define PAGE_EXEC __pgprot(_PAGE_BASE | _PAGE_EXEC) #define PAGE_READ_EXEC __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_EXEC) #define PAGE_WRITE_EXEC __pgprot(_PAGE_BASE | _PAGE_READ | \ _PAGE_EXEC | _PAGE_WRITE) #define PAGE_COPY PAGE_READ #define PAGE_COPY_EXEC PAGE_EXEC #define PAGE_COPY_READ_EXEC PAGE_READ_EXEC #define PAGE_SHARED PAGE_WRITE #define PAGE_SHARED_EXEC PAGE_WRITE_EXEC #define _PAGE_KERNEL (_PAGE_READ \ | _PAGE_WRITE \ | _PAGE_PRESENT \ | _PAGE_ACCESSED \ | _PAGE_DIRTY \ | _PAGE_GLOBAL) #define PAGE_KERNEL __pgprot(_PAGE_KERNEL) #define PAGE_KERNEL_READ __pgprot(_PAGE_KERNEL & ~_PAGE_WRITE) #define PAGE_KERNEL_EXEC __pgprot(_PAGE_KERNEL | _PAGE_EXEC) #define PAGE_KERNEL_READ_EXEC __pgprot((_PAGE_KERNEL & ~_PAGE_WRITE) \ | _PAGE_EXEC) #define PAGE_TABLE __pgprot(_PAGE_TABLE) /* * The RISC-V ISA doesn't yet specify how to query or modify PMAs, so we can't * change the properties of memory regions. */ #define _PAGE_IOREMAP _PAGE_KERNEL extern pgd_t swapper_pg_dir[]; /* MAP_PRIVATE permissions: xwr (copy-on-write) */ #define __P000 PAGE_NONE #define __P001 PAGE_READ #define __P010 PAGE_COPY #define __P011 PAGE_COPY #define __P100 PAGE_EXEC #define __P101 PAGE_READ_EXEC #define __P110 PAGE_COPY_EXEC #define __P111 PAGE_COPY_READ_EXEC /* MAP_SHARED permissions: xwr */ #define __S000 PAGE_NONE #define __S001 PAGE_READ #define __S010 PAGE_SHARED #define __S011 PAGE_SHARED #define __S100 PAGE_EXEC #define __S101 PAGE_READ_EXEC #define __S110 PAGE_SHARED_EXEC #define __S111 PAGE_SHARED_EXEC #ifdef CONFIG_TRANSPARENT_HUGEPAGE static inline int pmd_present(pmd_t pmd) { /* * Checking for _PAGE_LEAF is needed too because: * When splitting a THP, split_huge_page() will temporarily clear * the present bit, in this situation, pmd_present() and * pmd_trans_huge() still needs to return true. */ return (pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROT_NONE | _PAGE_LEAF)); } #else static inline int pmd_present(pmd_t pmd) { return (pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROT_NONE)); } #endif static inline int pmd_none(pmd_t pmd) { return (pmd_val(pmd) == 0); } static inline int pmd_bad(pmd_t pmd) { return !pmd_present(pmd) || (pmd_val(pmd) & _PAGE_LEAF); } #define pmd_leaf pmd_leaf static inline int pmd_leaf(pmd_t pmd) { return pmd_present(pmd) && (pmd_val(pmd) & _PAGE_LEAF); } static inline void set_pmd(pmd_t *pmdp, pmd_t pmd) { *pmdp = pmd; } static inline void pmd_clear(pmd_t *pmdp) { set_pmd(pmdp, __pmd(0)); } static inline pgd_t pfn_pgd(unsigned long pfn, pgprot_t prot) { return __pgd((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot)); } static inline unsigned long _pgd_pfn(pgd_t pgd) { return pgd_val(pgd) >> _PAGE_PFN_SHIFT; } static inline struct page *pmd_page(pmd_t pmd) { return pfn_to_page(pmd_val(pmd) >> _PAGE_PFN_SHIFT); } static inline unsigned long pmd_page_vaddr(pmd_t pmd) { return (unsigned long)pfn_to_virt(pmd_val(pmd) >> _PAGE_PFN_SHIFT); } static inline pte_t pmd_pte(pmd_t pmd) { return __pte(pmd_val(pmd)); } static inline pte_t pud_pte(pud_t pud) { return __pte(pud_val(pud)); } /* Yields the page frame number (PFN) of a page table entry */ static inline unsigned long pte_pfn(pte_t pte) { return (pte_val(pte) >> _PAGE_PFN_SHIFT); } #define pte_page(x) pfn_to_page(pte_pfn(x)) /* Constructs a page table entry */ static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot) { return __pte((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot)); } #define mk_pte(page, prot) pfn_pte(page_to_pfn(page), prot) static inline int pte_present(pte_t pte) { return (pte_val(pte) & (_PAGE_PRESENT | _PAGE_PROT_NONE)); } static inline int pte_none(pte_t pte) { return (pte_val(pte) == 0); } static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_WRITE; } static inline int pte_exec(pte_t pte) { return pte_val(pte) & _PAGE_EXEC; } static inline int pte_huge(pte_t pte) { return pte_present(pte) && (pte_val(pte) & _PAGE_LEAF); } static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; } static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; } static inline int pte_special(pte_t pte) { return pte_val(pte) & _PAGE_SPECIAL; } /* static inline pte_t pte_rdprotect(pte_t pte) */ static inline pte_t pte_wrprotect(pte_t pte) { return __pte(pte_val(pte) & ~(_PAGE_WRITE)); } /* static inline pte_t pte_mkread(pte_t pte) */ static inline pte_t pte_mkwrite(pte_t pte) { return __pte(pte_val(pte) | _PAGE_WRITE); } /* static inline pte_t pte_mkexec(pte_t pte) */ static inline pte_t pte_mkdirty(pte_t pte) { return __pte(pte_val(pte) | _PAGE_DIRTY); } static inline pte_t pte_mkclean(pte_t pte) { return __pte(pte_val(pte) & ~(_PAGE_DIRTY)); } static inline pte_t pte_mkyoung(pte_t pte) { return __pte(pte_val(pte) | _PAGE_ACCESSED); } static inline pte_t pte_mkold(pte_t pte) { return __pte(pte_val(pte) & ~(_PAGE_ACCESSED)); } static inline pte_t pte_mkspecial(pte_t pte) { return __pte(pte_val(pte) | _PAGE_SPECIAL); } static inline pte_t pte_mkhuge(pte_t pte) { return pte; } #ifdef CONFIG_NUMA_BALANCING /* * See the comment in include/asm-generic/pgtable.h */ static inline int pte_protnone(pte_t pte) { return (pte_val(pte) & (_PAGE_PRESENT | _PAGE_PROT_NONE)) == _PAGE_PROT_NONE; } static inline int pmd_protnone(pmd_t pmd) { return pte_protnone(pmd_pte(pmd)); } #endif /* Modify page protection bits */ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) { return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot)); } #define pgd_ERROR(e) \ pr_err("%s:%d: bad pgd " PTE_FMT ".\n", __FILE__, __LINE__, pgd_val(e)) /* Commit new configuration to MMU hardware */ static inline void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) { /* * The kernel assumes that TLBs don't cache invalid entries, but * in RISC-V, SFENCE.VMA specifies an ordering constraint, not a * cache flush; it is necessary even after writing invalid entries. * Relying on flush_tlb_fix_spurious_fault would suffice, but * the extra traps reduce performance. So, eagerly SFENCE.VMA. */ local_flush_tlb_page(address); } static inline void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp) { pte_t *ptep = (pte_t *)pmdp; update_mmu_cache(vma, address, ptep); } #define __HAVE_ARCH_PTE_SAME static inline int pte_same(pte_t pte_a, pte_t pte_b) { return pte_val(pte_a) == pte_val(pte_b); } /* * Certain architectures need to do special things when PTEs within * a page table are directly modified. Thus, the following hook is * made available. */ static inline void set_pte(pte_t *ptep, pte_t pteval) { *ptep = pteval; } void flush_icache_pte(pte_t pte); static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval) { if (pte_present(pteval) && pte_exec(pteval)) flush_icache_pte(pteval); set_pte(ptep, pteval); } static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { set_pte_at(mm, addr, ptep, __pte(0)); } #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS static inline int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address, pte_t *ptep, pte_t entry, int dirty) { if (!pte_same(*ptep, entry)) set_pte_at(vma->vm_mm, address, ptep, entry); /* * update_mmu_cache will unconditionally execute, handling both * the case that the PTE changed and the spurious fault case. */ return true; } #define __HAVE_ARCH_PTEP_GET_AND_CLEAR static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long address, pte_t *ptep) { return __pte(atomic_long_xchg((atomic_long_t *)ptep, 0)); } #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) { if (!pte_young(*ptep)) return 0; return test_and_clear_bit(_PAGE_ACCESSED_OFFSET, &pte_val(*ptep)); } #define __HAVE_ARCH_PTEP_SET_WRPROTECT static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep) { atomic_long_and(~(unsigned long)_PAGE_WRITE, (atomic_long_t *)ptep); } #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH static inline int ptep_clear_flush_young(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) { /* * This comment is borrowed from x86, but applies equally to RISC-V: * * Clearing the accessed bit without a TLB flush * doesn't cause data corruption. [ It could cause incorrect * page aging and the (mistaken) reclaim of hot pages, but the * chance of that should be relatively low. ] * * So as a performance optimization don't flush the TLB when * clearing the accessed bit, it will eventually be flushed by * a context switch or a VM operation anyway. [ In the rare * event of it not getting flushed for a long time the delay * shouldn't really matter because there's no real memory * pressure for swapout to react to. ] */ return ptep_test_and_clear_young(vma, address, ptep); } /* * THP functions */ static inline pmd_t pte_pmd(pte_t pte) { return __pmd(pte_val(pte)); } static inline pmd_t pmd_mkhuge(pmd_t pmd) { return pmd; } static inline pmd_t pmd_mkinvalid(pmd_t pmd) { return __pmd(pmd_val(pmd) & ~(_PAGE_PRESENT|_PAGE_PROT_NONE)); } #define __pmd_to_phys(pmd) (pmd_val(pmd) >> _PAGE_PFN_SHIFT << PAGE_SHIFT) static inline unsigned long pmd_pfn(pmd_t pmd) { return ((__pmd_to_phys(pmd) & PMD_MASK) >> PAGE_SHIFT); } static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) { return pte_pmd(pte_modify(pmd_pte(pmd), newprot)); } #define pmd_write pmd_write static inline int pmd_write(pmd_t pmd) { return pte_write(pmd_pte(pmd)); } static inline int pmd_dirty(pmd_t pmd) { return pte_dirty(pmd_pte(pmd)); } static inline int pmd_young(pmd_t pmd) { return pte_young(pmd_pte(pmd)); } static inline pmd_t pmd_mkold(pmd_t pmd) { return pte_pmd(pte_mkold(pmd_pte(pmd))); } static inline pmd_t pmd_mkyoung(pmd_t pmd) { return pte_pmd(pte_mkyoung(pmd_pte(pmd))); } static inline pmd_t pmd_mkwrite(pmd_t pmd) { return pte_pmd(pte_mkwrite(pmd_pte(pmd))); } static inline pmd_t pmd_wrprotect(pmd_t pmd) { return pte_pmd(pte_wrprotect(pmd_pte(pmd))); } static inline pmd_t pmd_mkclean(pmd_t pmd) { return pte_pmd(pte_mkclean(pmd_pte(pmd))); } static inline pmd_t pmd_mkdirty(pmd_t pmd) { return pte_pmd(pte_mkdirty(pmd_pte(pmd))); } static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp, pmd_t pmd) { return set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd)); } static inline void set_pud_at(struct mm_struct *mm, unsigned long addr, pud_t *pudp, pud_t pud) { return set_pte_at(mm, addr, (pte_t *)pudp, pud_pte(pud)); } #ifdef CONFIG_TRANSPARENT_HUGEPAGE static inline int pmd_trans_huge(pmd_t pmd) { return pmd_leaf(pmd); } #define __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS static inline int pmdp_set_access_flags(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp, pmd_t entry, int dirty) { return ptep_set_access_flags(vma, address, (pte_t *)pmdp, pmd_pte(entry), dirty); } #define __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp) { return ptep_test_and_clear_young(vma, address, (pte_t *)pmdp); } #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, unsigned long address, pmd_t *pmdp) { return pte_pmd(ptep_get_and_clear(mm, address, (pte_t *)pmdp)); } #define __HAVE_ARCH_PMDP_SET_WRPROTECT static inline void pmdp_set_wrprotect(struct mm_struct *mm, unsigned long address, pmd_t *pmdp) { ptep_set_wrprotect(mm, address, (pte_t *)pmdp); } #define pmdp_establish pmdp_establish static inline pmd_t pmdp_establish(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp, pmd_t pmd) { return __pmd(atomic_long_xchg((atomic_long_t *)pmdp, pmd_val(pmd))); } #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ /* * Encode and decode a swap entry * * Format of swap PTE: * bit 0: _PAGE_PRESENT (zero) * bit 1 to 3: _PAGE_LEAF (zero) * bit 5: _PAGE_PROT_NONE (zero) * bits 6 to 10: swap type * bits 10 to XLEN-1: swap offset */ #define __SWP_TYPE_SHIFT 6 #define __SWP_TYPE_BITS 5 #define __SWP_TYPE_MASK ((1UL << __SWP_TYPE_BITS) - 1) #define __SWP_OFFSET_SHIFT (__SWP_TYPE_BITS + __SWP_TYPE_SHIFT) #define MAX_SWAPFILES_CHECK() \ BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS) #define __swp_type(x) (((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK) #define __swp_offset(x) ((x).val >> __SWP_OFFSET_SHIFT) #define __swp_entry(type, offset) ((swp_entry_t) \ { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION #define __pmd_to_swp_entry(pmd) ((swp_entry_t) { pmd_val(pmd) }) #define __swp_entry_to_pmd(swp) __pmd((swp).val) #endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */ /* * In the RV64 Linux scheme, we give the user half of the virtual-address space * and give the kernel the other (upper) half. */ #ifdef CONFIG_64BIT #define KERN_VIRT_START (-(BIT(VA_BITS)) + TASK_SIZE) #else #define KERN_VIRT_START FIXADDR_START #endif /* * Task size is 0x4000000000 for RV64 or 0x9fc00000 for RV32. * Note that PGDIR_SIZE must evenly divide TASK_SIZE. * Task size is: * - 0x9fc00000 (~2.5GB) for RV32. * - 0x4000000000 ( 256GB) for RV64 using SV39 mmu * - 0x800000000000 ( 128TB) for RV64 using SV48 mmu * * Note that PGDIR_SIZE must evenly divide TASK_SIZE since "RISC-V * Instruction Set Manual Volume II: Privileged Architecture" states that * "load and store effective addresses, which are 64bits, must have bits * 63–48 all equal to bit 47, or else a page-fault exception will occur." */ #ifdef CONFIG_64BIT #define TASK_SIZE (PGDIR_SIZE * PTRS_PER_PGD / 2) #define TASK_SIZE_MIN (PGDIR_SIZE_L3 * PTRS_PER_PGD / 2) #else #define TASK_SIZE FIXADDR_START #define TASK_SIZE_MIN TASK_SIZE #endif #else /* CONFIG_MMU */ #define PAGE_SHARED __pgprot(0) #define PAGE_KERNEL __pgprot(0) #define swapper_pg_dir NULL #define TASK_SIZE 0xffffffffUL #define VMALLOC_START 0 #define VMALLOC_END TASK_SIZE #endif /* !CONFIG_MMU */ #define kern_addr_valid(addr) (1) /* FIXME */ extern char _start[]; extern void *_dtb_early_va; extern uintptr_t _dtb_early_pa; #if defined(CONFIG_XIP_KERNEL) && defined(CONFIG_MMU) #define dtb_early_va (*(void **)XIP_FIXUP(&_dtb_early_va)) #define dtb_early_pa (*(uintptr_t *)XIP_FIXUP(&_dtb_early_pa)) #else #define dtb_early_va _dtb_early_va #define dtb_early_pa _dtb_early_pa #endif /* CONFIG_XIP_KERNEL */ extern u64 satp_mode; extern bool pgtable_l4_enabled; void paging_init(void); void misc_mem_init(void); /* * ZERO_PAGE is a global shared page that is always zero, * used for zero-mapped memory areas, etc. */ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) #endif /* !__ASSEMBLY__ */ #endif /* _ASM_RISCV_PGTABLE_H */