nds32: MMU definitions

This patch includes virtual memory layout, PHYS_OFFSET is defined as 0x0. It
also includes the 4KB/8KB page size configurations and pte operations.
Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

arch/nds32/include/asm/fixmap.h

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#ifndef __ASM_NDS32_FIXMAP_H
+#define __ASM_NDS32_FIXMAP_H
+
+#ifdef CONFIG_HIGHMEM
+#include <linux/threads.h>
+#include <asm/kmap_types.h>
+#endif
+
+enum fixed_addresses {
+	FIX_HOLE,
+	FIX_KMAP_RESERVED,
+	FIX_KMAP_BEGIN,
+#ifdef CONFIG_HIGHMEM
+	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS),
+#endif
+	FIX_EARLYCON_MEM_BASE,
+	__end_of_fixed_addresses
+};
+#define FIXADDR_TOP             ((unsigned long) (-(16 * PAGE_SIZE)))
+#define FIXADDR_SIZE		((__end_of_fixed_addresses) << PAGE_SHIFT)
+#define FIXADDR_START		(FIXADDR_TOP - FIXADDR_SIZE)
+#define FIXMAP_PAGE_IO		__pgprot(PAGE_DEVICE)
+void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
+
+#include <asm-generic/fixmap.h>
+#endif /* __ASM_NDS32_FIXMAP_H */

arch/nds32/include/asm/highmem.h

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#ifndef _ASM_HIGHMEM_H
+#define _ASM_HIGHMEM_H
+
+#include <asm/proc-fns.h>
+#include <asm/kmap_types.h>
+#include <asm/fixmap.h>
+#include <asm/pgtable.h>
+
+/*
+ * Right now we initialize only a single pte table. It can be extended
+ * easily, subsequent pte tables have to be allocated in one physical
+ * chunk of RAM.
+ */
+/*
+ * Ordering is (from lower to higher memory addresses):
+ *
+ * high_memory
+ *			Persistent kmap area
+ * PKMAP_BASE
+ *			fixed_addresses
+ * FIXADDR_START
+ * FIXADDR_TOP
+ *			Vmalloc area
+ * VMALLOC_START
+ * VMALLOC_END
+ */
+#define PKMAP_BASE		((FIXADDR_START - PGDIR_SIZE) & (PGDIR_MASK))
+#define LAST_PKMAP		PTRS_PER_PTE
+#define LAST_PKMAP_MASK		(LAST_PKMAP - 1)
+#define PKMAP_NR(virt)		(((virt) - (PKMAP_BASE)) >> PAGE_SHIFT)
+#define PKMAP_ADDR(nr)		(PKMAP_BASE + ((nr) << PAGE_SHIFT))
+#define kmap_prot		PAGE_KERNEL
+
+static inline void flush_cache_kmaps(void)
+{
+	cpu_dcache_wbinval_all();
+}
+
+/* declarations for highmem.c */
+extern unsigned long highstart_pfn, highend_pfn;
+
+extern pte_t *pkmap_page_table;
+
+extern void *kmap_high(struct page *page);
+extern void kunmap_high(struct page *page);
+
+extern void kmap_init(void);
+
+/*
+ * The following functions are already defined by <linux/highmem.h>
+ * when CONFIG_HIGHMEM is not set.
+ */
+#ifdef CONFIG_HIGHMEM
+extern void *kmap(struct page *page);
+extern void kunmap(struct page *page);
+extern void *kmap_atomic(struct page *page);
+extern void __kunmap_atomic(void *kvaddr);
+extern void *kmap_atomic_pfn(unsigned long pfn);
+extern struct page *kmap_atomic_to_page(void *ptr);
+#endif
+
+#endif

arch/nds32/include/asm/memory.h

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#ifndef __ASM_NDS32_MEMORY_H
+#define __ASM_NDS32_MEMORY_H
+
+#include <linux/compiler.h>
+#include <linux/sizes.h>
+
+#ifndef __ASSEMBLY__
+#include <asm/page.h>
+#endif
+
+#ifndef PHYS_OFFSET
+#define PHYS_OFFSET     (0x0)
+#endif
+
+#ifndef __virt_to_bus
+#define __virt_to_bus	__virt_to_phys
+#endif
+
+#ifndef __bus_to_virt
+#define __bus_to_virt	__phys_to_virt
+#endif
+
+/*
+ * TASK_SIZE - the maximum size of a user space task.
+ * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area
+ */
+#define TASK_SIZE		((CONFIG_PAGE_OFFSET) - (SZ_32M))
+#define TASK_UNMAPPED_BASE	ALIGN(TASK_SIZE / 3, SZ_32M)
+#define PAGE_OFFSET		(CONFIG_PAGE_OFFSET)
+
+/*
+ * Physical vs virtual RAM address space conversion.  These are
+ * private definitions which should NOT be used outside memory.h
+ * files.  Use virt_to_phys/phys_to_virt/__pa/__va instead.
+ */
+#ifndef __virt_to_phys
+#define __virt_to_phys(x)	((x) - PAGE_OFFSET + PHYS_OFFSET)
+#define __phys_to_virt(x)	((x) - PHYS_OFFSET + PAGE_OFFSET)
+#endif
+
+/*
+ * The module space lives between the addresses given by TASK_SIZE
+ * and PAGE_OFFSET - it must be within 32MB of the kernel text.
+ */
+#define MODULES_END	(PAGE_OFFSET)
+#define MODULES_VADDR	(MODULES_END - SZ_32M)
+
+#if TASK_SIZE > MODULES_VADDR
+#error Top of user space clashes with start of module space
+#endif
+
+#ifndef __ASSEMBLY__
+
+/*
+ * PFNs are used to describe any physical page; this means
+ * PFN 0 == physical address 0.
+ *
+ * This is the PFN of the first RAM page in the kernel
+ * direct-mapped view.  We assume this is the first page
+ * of RAM in the mem_map as well.
+ */
+#define PHYS_PFN_OFFSET	(PHYS_OFFSET >> PAGE_SHIFT)
+
+/*
+ * Drivers should NOT use these either.
+ */
+#define __pa(x)			__virt_to_phys((unsigned long)(x))
+#define __va(x)			((void *)__phys_to_virt((unsigned long)(x)))
+
+/*
+ * Conversion between a struct page and a physical address.
+ *
+ * Note: when converting an unknown physical address to a
+ * struct page, the resulting pointer must be validated
+ * using VALID_PAGE().  It must return an invalid struct page
+ * for any physical address not corresponding to a system
+ * RAM address.
+ *
+ *  pfn_valid(pfn)	indicates whether a PFN number is valid
+ *
+ *  virt_to_page(k)	convert a _valid_ virtual address to struct page *
+ *  virt_addr_valid(k)	indicates whether a virtual address is valid
+ */
+#ifndef CONFIG_DISCONTIGMEM
+
+#define ARCH_PFN_OFFSET		PHYS_PFN_OFFSET
+#define pfn_valid(pfn)		((pfn) >= PHYS_PFN_OFFSET && (pfn) < (PHYS_PFN_OFFSET + max_mapnr))
+
+#define virt_to_page(kaddr)	(pfn_to_page(__pa(kaddr) >> PAGE_SHIFT))
+#define virt_addr_valid(kaddr)	((unsigned long)(kaddr) >= PAGE_OFFSET && (unsigned long)(kaddr) < (unsigned long)high_memory)
+
+#else /* CONFIG_DISCONTIGMEM */
+#error CONFIG_DISCONTIGMEM is not supported yet.
+#endif /* !CONFIG_DISCONTIGMEM */
+
+#define page_to_phys(page)	(page_to_pfn(page) << PAGE_SHIFT)
+
+#endif
+
+#include <asm-generic/memory_model.h>
+
+#endif

arch/nds32/include/asm/mmu.h

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#ifndef __NDS32_MMU_H
+#define __NDS32_MMU_H
+
+typedef struct {
+	unsigned int id;
+	void *vdso;
+} mm_context_t;
+
+#endif

arch/nds32/include/asm/page.h

+/*
+ * SPDX-License-Identifier: GPL-2.0
+ * Copyright (C) 2005-2017 Andes Technology Corporation
+ */
+
+#ifndef _ASMNDS32_PAGE_H
+#define _ASMNDS32_PAGE_H
+
+#ifdef CONFIG_ANDES_PAGE_SIZE_4KB
+#define PAGE_SHIFT      12
+#endif
+#ifdef CONFIG_ANDES_PAGE_SIZE_8KB
+#define PAGE_SHIFT      13
+#endif
+#include <linux/const.h>
+#define PAGE_SIZE       (_AC(1,UL) << PAGE_SHIFT)
+#define PAGE_MASK       (~(PAGE_SIZE-1))
+
+#ifdef __KERNEL__
+
+#ifndef __ASSEMBLY__
+
+struct page;
+struct vm_area_struct;
+#ifdef CONFIG_CPU_CACHE_ALIASING
+extern void copy_user_highpage(struct page *to, struct page *from,
+			       unsigned long vaddr, struct vm_area_struct *vma);
+extern void clear_user_highpage(struct page *page, unsigned long vaddr);
+
+#define __HAVE_ARCH_COPY_USER_HIGHPAGE
+#define clear_user_highpage	clear_user_highpage
+#else
+#define clear_user_page(page, vaddr, pg)        clear_page(page)
+#define copy_user_page(to, from, vaddr, pg)     copy_page(to, from)
+#endif
+
+void clear_page(void *page);
+void copy_page(void *to, void *from);
+
+typedef unsigned long pte_t;
+typedef unsigned long pmd_t;
+typedef unsigned long pgd_t;
+typedef unsigned long pgprot_t;
+
+#define pte_val(x)      (x)
+#define pmd_val(x)      (x)
+#define pgd_val(x)	(x)
+#define pgprot_val(x)   (x)
+
+#define __pte(x)        (x)
+#define __pmd(x)        (x)
+#define __pgd(x)        (x)
+#define __pgprot(x)     (x)
+
+typedef struct page *pgtable_t;
+
+#include <asm/memory.h>
+#include <asm-generic/getorder.h>
+
+#endif /* !__ASSEMBLY__ */
+
+#define VM_DATA_DEFAULT_FLAGS	(VM_READ | VM_WRITE | VM_EXEC | \
+				 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+
+#endif /* __KERNEL__ */
+
+#endif

arch/nds32/include/asm/pgalloc.h

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#ifndef _ASMNDS32_PGALLOC_H
+#define _ASMNDS32_PGALLOC_H
+
+#include <asm/processor.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <asm/proc-fns.h>
+
+/*
+ * Since we have only two-level page tables, these are trivial
+ */
+#define pmd_alloc_one(mm, addr)		({ BUG(); ((pmd_t *)2); })
+#define pmd_free(mm, pmd)			do { } while (0)
+#define pgd_populate(mm, pmd, pte)	BUG()
+#define pmd_pgtable(pmd) pmd_page(pmd)
+
+extern pgd_t *pgd_alloc(struct mm_struct *mm);
+extern void pgd_free(struct mm_struct *mm, pgd_t * pgd);
+
+#define check_pgt_cache()		do { } while (0)
+
+static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
+					  unsigned long addr)
+{
+	pte_t *pte;
+
+	pte =
+	    (pte_t *) __get_free_page(GFP_KERNEL | __GFP_RETRY_MAYFAIL |
+				      __GFP_ZERO);
+
+	return pte;
+}
+
+static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addr)
+{
+	pgtable_t pte;
+
+	pte = alloc_pages(GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_ZERO, 0);
+	if (pte)
+		cpu_dcache_wb_page((unsigned long)page_address(pte));
+
+	return pte;
+}
+
+/*
+ * Free one PTE table.
+ */
+static inline void pte_free_kernel(struct mm_struct *mm, pte_t * pte)
+{
+	if (pte) {
+		free_page((unsigned long)pte);
+	}
+}
+
+static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
+{
+	__free_page(pte);
+}
+
+/*
+ * Populate the pmdp entry with a pointer to the pte.  This pmd is part
+ * of the mm address space.
+ *
+ * Ensure that we always set both PMD entries.
+ */
+static inline void
+pmd_populate_kernel(struct mm_struct *mm, pmd_t * pmdp, pte_t * ptep)
+{
+	unsigned long pte_ptr = (unsigned long)ptep;
+	unsigned long pmdval;
+
+	BUG_ON(mm != &init_mm);
+
+	/*
+	 * The pmd must be loaded with the physical
+	 * address of the PTE table
+	 */
+	pmdval = __pa(pte_ptr) | _PAGE_KERNEL_TABLE;
+	set_pmd(pmdp, __pmd(pmdval));
+}
+
+static inline void
+pmd_populate(struct mm_struct *mm, pmd_t * pmdp, pgtable_t ptep)
+{
+	unsigned long pmdval;
+
+	BUG_ON(mm == &init_mm);
+
+	pmdval = page_to_pfn(ptep) << PAGE_SHIFT | _PAGE_USER_TABLE;
+	set_pmd(pmdp, __pmd(pmdval));
+}
+
+#endif

arch/nds32/include/asm/shmparam.h

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#ifndef _ASMNDS32_SHMPARAM_H
+#define _ASMNDS32_SHMPARAM_H
+
+/*
+ * This should be the size of the virtually indexed cache/ways,
+ * whichever is greater since the cache aliases every size/ways
+ * bytes.
+ */
+#define	SHMLBA	(4 * SZ_8K)	/* attach addr a multiple of this */
+
+/*
+ * Enforce SHMLBA in shmat
+ */
+#define __ARCH_FORCE_SHMLBA
+
+#endif /* _ASMNDS32_SHMPARAM_H */