nios2: Page table management

/*

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 *

 * Copyright (C) 1994 - 2001, 2003 by Ralf Baechle

 * Copyright (C) 1999, 2000, 2001 Silicon Graphics, Inc.

 */

#ifndef _ASM_NIOS2_PGALLOC_H

#define _ASM_NIOS2_PGALLOC_H

#include <linux/mm.h>

static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,

	pte_t *pte)

{

	set_pmd(pmd, __pmd((unsigned long)pte));

}

static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,

	pgtable_t pte)

{

	set_pmd(pmd, __pmd((unsigned long)page_address(pte)));

}

#define pmd_pgtable(pmd) pmd_page(pmd)

/*

 * Initialize a new pmd table with invalid pointers.

 */

extern void pmd_init(unsigned long page, unsigned long pagetable);

extern pgd_t *pgd_alloc(struct mm_struct *mm);

static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)

{

	free_pages((unsigned long)pgd, PGD_ORDER);

}

static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,

	unsigned long address)

{

	pte_t *pte;

	pte = (pte_t *) __get_free_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO,

					PTE_ORDER);

	return pte;

}

static inline pgtable_t pte_alloc_one(struct mm_struct *mm,

	unsigned long address)

{

	struct page *pte;

	pte = alloc_pages(GFP_KERNEL | __GFP_REPEAT, PTE_ORDER);

	if (pte) {

		if (!pgtable_page_ctor(pte)) {

			__free_page(pte);

			return NULL;

		}

		clear_highpage(pte);

	}

	return pte;

}

static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)

{

	free_pages((unsigned long)pte, PTE_ORDER);

}

static inline void pte_free(struct mm_struct *mm, struct page *pte)

{

	pgtable_page_dtor(pte);

	__free_pages(pte, PTE_ORDER);

}

#define __pte_free_tlb(tlb, pte, addr)				\

	do {							\

		pgtable_page_dtor(pte);				\

		tlb_remove_page((tlb), (pte));			\

	} while (0)

#define check_pgt_cache()	do { } while (0)

#endif /* _ASM_NIOS2_PGALLOC_H */

/*

 * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>

 * Copyright (C) 2009 Wind River Systems Inc

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 */

#ifndef _ASM_NIOS2_PGTABLE_BITS_H

#define _ASM_NIOS2_PGTABLE_BITS_H

/*

 * These are actual hardware defined protection bits in the tlbacc register

 * which looks like this:

 *

 * 31 30 ... 26 25 24 23 22 21 20 19 18 ...  1  0

 * ignored........  C  R  W  X  G PFN............

 */

#define _PAGE_GLOBAL	(1<<20)

#define _PAGE_EXEC	(1<<21)

#define _PAGE_WRITE	(1<<22)

#define _PAGE_READ	(1<<23)

#define _PAGE_CACHED	(1<<24)	/* C: data access cacheable */

/*

 * Software defined bits. They are ignored by the hardware and always read back

 * as zero, but can be written as non-zero.

 */

#define _PAGE_PRESENT	(1<<25)	/* PTE contains a translation */

#define _PAGE_ACCESSED	(1<<26)	/* page referenced */

#define _PAGE_DIRTY	(1<<27)	/* dirty page */

#define _PAGE_FILE	(1<<28)	/* PTE used for file mapping or swap */

#endif /* _ASM_NIOS2_PGTABLE_BITS_H */

/*

 * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>

 * Copyright (C) 2009 Wind River Systems Inc

 *

 * Based on asm/pgtable-32.h from mips which is:

 *

 * Copyright (C) 1994, 95, 96, 97, 98, 99, 2000, 2003 Ralf Baechle

 * Copyright (C) 1999, 2000, 2001 Silicon Graphics, Inc.

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 */

#ifndef _ASM_NIOS2_PGTABLE_H

#define _ASM_NIOS2_PGTABLE_H

#include <linux/io.h>

#include <linux/bug.h>

#include <asm/page.h>

#include <asm/cacheflush.h>

#include <asm/tlbflush.h>

#include <asm/pgtable-bits.h>

#include <asm-generic/pgtable-nopmd.h>

#define FIRST_USER_ADDRESS	0

#define VMALLOC_START		CONFIG_NIOS2_KERNEL_MMU_REGION_BASE

#define VMALLOC_END		(CONFIG_NIOS2_KERNEL_REGION_BASE - 1)

struct mm_struct;

/* Helper macro */

#define MKP(x, w, r) __pgprot(_PAGE_PRESENT | _PAGE_CACHED |		\

				((x) ? _PAGE_EXEC : 0) |		\

				((r) ? _PAGE_READ : 0) |		\

				((w) ? _PAGE_WRITE : 0))

/*

 * These are the macros that generic kernel code needs

 * (to populate protection_map[])

 */

/* Remove W bit on private pages for COW support */

#define __P000	MKP(0, 0, 0)

#define __P001	MKP(0, 0, 1)

#define __P010	MKP(0, 0, 0)	/* COW */

#define __P011	MKP(0, 0, 1)	/* COW */

#define __P100	MKP(1, 0, 0)

#define __P101	MKP(1, 0, 1)

#define __P110	MKP(1, 0, 0)	/* COW */

#define __P111	MKP(1, 0, 1)	/* COW */

/* Shared pages can have exact HW mapping */

#define __S000	MKP(0, 0, 0)

#define __S001	MKP(0, 0, 1)

#define __S010	MKP(0, 1, 0)

#define __S011	MKP(0, 1, 1)

#define __S100	MKP(1, 0, 0)

#define __S101	MKP(1, 0, 1)

#define __S110	MKP(1, 1, 0)

#define __S111	MKP(1, 1, 1)

/* Used all over the kernel */

#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_CACHED | _PAGE_READ | \

			     _PAGE_WRITE | _PAGE_EXEC | _PAGE_GLOBAL)

#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_CACHED | _PAGE_READ | \

			     _PAGE_WRITE | _PAGE_ACCESSED)

#define PAGE_COPY MKP(0, 0, 1)

#define PGD_ORDER	0

#define PTE_ORDER	0

#define PTRS_PER_PGD	((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))

#define PTRS_PER_PTE	((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))

#define USER_PTRS_PER_PGD	\

	(CONFIG_NIOS2_KERNEL_MMU_REGION_BASE / PGDIR_SIZE)

#define PGDIR_SHIFT	22

#define PGDIR_SIZE	(1UL << PGDIR_SHIFT)

#define PGDIR_MASK	(~(PGDIR_SIZE-1))

/*

 * 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))

extern pgd_t swapper_pg_dir[PTRS_PER_PGD];

extern pte_t invalid_pte_table[PAGE_SIZE/sizeof(pte_t)];

/*

 * (pmds are folded into puds so this doesn't get actually called,

 * but the define is needed for a generic inline function.)

 */

static inline void set_pmd(pmd_t *pmdptr, pmd_t pmdval)

{

	pmdptr->pud.pgd.pgd = pmdval.pud.pgd.pgd;

}

/* to find an entry in a page-table-directory */

#define pgd_index(addr)		(((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))

#define pgd_offset(mm, addr)	((mm)->pgd + pgd_index(addr))

static inline int pte_write(pte_t pte)		\

	{ return pte_val(pte) & _PAGE_WRITE; }

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_file(pte_t pte)		\

	{ return pte_val(pte) & _PAGE_FILE; }

static inline int pte_special(pte_t pte)	{ return 0; }

#define pgprot_noncached pgprot_noncached

static inline pgprot_t pgprot_noncached(pgprot_t _prot)

{

	unsigned long prot = pgprot_val(_prot);

	prot &= ~_PAGE_CACHED;

	return __pgprot(prot);

}

static inline int pte_none(pte_t pte)

{

	return !(pte_val(pte) & ~(_PAGE_GLOBAL|0xf));

}

static inline int pte_present(pte_t pte)	\

	{ return pte_val(pte) & _PAGE_PRESENT; }

/*

 * The following only work if pte_present() is true.

 * Undefined behaviour if not..

 */

static inline pte_t pte_wrprotect(pte_t pte)

{

	pte_val(pte) &= ~_PAGE_WRITE;

	return pte;

}

static inline pte_t pte_mkclean(pte_t pte)

{

	pte_val(pte) &= ~_PAGE_DIRTY;

	return pte;

}

static inline pte_t pte_mkold(pte_t pte)

{

	pte_val(pte) &= ~_PAGE_ACCESSED;

	return pte;

}

static inline pte_t pte_mkwrite(pte_t pte)

{

	pte_val(pte) |= _PAGE_WRITE;

	return pte;

}

static inline pte_t pte_mkdirty(pte_t pte)

{

	pte_val(pte) |= _PAGE_DIRTY;

	return pte;

}

static inline pte_t pte_mkspecial(pte_t pte)	{ return pte; }

static inline pte_t pte_mkyoung(pte_t pte)

{

	pte_val(pte) |= _PAGE_ACCESSED;

	return pte;

}

static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)

{

	const unsigned long mask = _PAGE_READ | _PAGE_WRITE | _PAGE_EXEC;

	pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask);

	return pte;

}

static inline int pmd_present(pmd_t pmd)

{

	return (pmd_val(pmd) != (unsigned long) invalid_pte_table)

			&& (pmd_val(pmd) != 0UL);

}

static inline void pmd_clear(pmd_t *pmdp)

{

	pmd_val(*pmdp) = (unsigned long) invalid_pte_table;

}

#define pte_pfn(pte)		(pte_val(pte) & 0xfffff)

#define pfn_pte(pfn, prot)	(__pte(pfn | pgprot_val(prot)))

#define pte_page(pte)		(pfn_to_page(pte_pfn(pte)))

/*

 * Store a linux PTE into the linux page table.

 */

static inline void set_pte(pte_t *ptep, pte_t pteval)

{

	*ptep = pteval;

}

static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,

			      pte_t *ptep, pte_t pteval)

{

	unsigned long paddr = page_to_virt(pte_page(pteval));

	flush_dcache_range(paddr, paddr + PAGE_SIZE);

	set_pte(ptep, pteval);

}

static inline int pmd_none(pmd_t pmd)

{

	return (pmd_val(pmd) ==

		(unsigned long) invalid_pte_table) || (pmd_val(pmd) == 0UL);

}

#define pmd_bad(pmd)	(pmd_val(pmd) & ~PAGE_MASK)

static inline void pte_clear(struct mm_struct *mm,

				unsigned long addr, pte_t *ptep)

{

	pte_t null;

	pte_val(null) = (addr >> PAGE_SHIFT) & 0xf;

	set_pte_at(mm, addr, ptep, null);

	flush_tlb_one(addr);

}

/*

 * Conversion functions: convert a page and protection to a page entry,

 * and a page entry and page directory to the page they refer to.

 */

#define mk_pte(page, prot)	(pfn_pte(page_to_pfn(page), prot))

#define pte_unmap(pte)	do { } while (0)

/*

 * Conversion functions: convert a page and protection to a page entry,

 * and a page entry and page directory to the page they refer to.

 */

#define pmd_phys(pmd)		virt_to_phys((void *)pmd_val(pmd))

#define pmd_page(pmd)		(pfn_to_page(pmd_phys(pmd) >> PAGE_SHIFT))

#define pmd_page_vaddr(pmd)	pmd_val(pmd)

#define pte_offset_map(dir, addr)			\

	((pte_t *) page_address(pmd_page(*dir)) +	\

	 (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)))

/* to find an entry in a kernel page-table-directory */

#define pgd_offset_k(addr)	pgd_offset(&init_mm, addr)

/* Get the address to the PTE for a vaddr in specific directory */

#define pte_offset_kernel(dir, addr)			\

	((pte_t *) pmd_page_vaddr(*(dir)) +		\

	 (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)))

#define pte_ERROR(e) \

	pr_err("%s:%d: bad pte %08lx.\n", \

		__FILE__, __LINE__, pte_val(e))

#define pgd_ERROR(e) \

	pr_err("%s:%d: bad pgd %08lx.\n", \

		__FILE__, __LINE__, pgd_val(e))

/*

 * Encode and decode a swap entry (must be !pte_none(pte) && !pte_present(pte)

 * && !pte_file(pte)):

 *

 * 31 30 29 28 27 26 25 24 23 22 21 20 19 18 ...  1  0

 *  0  0  0  0 type.  0  0  0  0  0  0 offset.........

 *

 * This gives us up to 2**2 = 4 swap files and 2**20 * 4K = 4G per swap file.

 *

 * Note that the offset field is always non-zero, thus !pte_none(pte) is always

 * true.

 */

#define __swp_type(swp)		(((swp).val >> 26) & 0x3)

#define __swp_offset(swp)	((swp).val & 0xfffff)

#define __swp_entry(type, off)	((swp_entry_t) { (((type) & 0x3) << 26) \

						 | ((off) & 0xfffff) })

#define __swp_entry_to_pte(swp)	((pte_t) { (swp).val })

#define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })

/* Encode and decode a nonlinear file mapping entry */

#define PTE_FILE_MAX_BITS	25

#define pte_to_pgoff(pte)	(pte_val(pte) & 0x1ffffff)

#define pgoff_to_pte(off)	__pte(((off) & 0x1ffffff) | _PAGE_FILE)

#define kern_addr_valid(addr)		(1)

#include <asm-generic/pgtable.h>

#define pgtable_cache_init()		do { } while (0)

extern void __init paging_init(void);

extern void __init mmu_init(void);

extern void update_mmu_cache(struct vm_area_struct *vma,

			     unsigned long address, pte_t *pte);

#endif /* _ASM_NIOS2_PGTABLE_H */

/*

 * Copyright (C) 2009 Wind River Systems Inc

 *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 */

#include <linux/mm.h>

#include <linux/sched.h>

#include <asm/pgtable.h>

#include <asm/cpuinfo.h>

/* pteaddr:

 *   ptbase | vpn* | zero

 *   31-22  | 21-2 | 1-0

 *

 *   *vpn is preserved on double fault

 *

 * tlbacc:

 *   IG   |*flags| pfn

 *   31-25|24-20 | 19-0

 *

 *   *crwxg

 *

 * tlbmisc:

 *   resv  |way   |rd | we|pid |dbl|bad|perm|d

 *   31-24 |23-20 |19 | 20|17-4|3  |2  |1   |0

 *

 */

/*

 * Initialize a new pgd / pmd table with invalid pointers.

 */

static void pgd_init(pgd_t *pgd)

{

	unsigned long *p = (unsigned long *) pgd;

	int i;

	for (i = 0; i < USER_PTRS_PER_PGD; i += 8) {

		p[i + 0] = (unsigned long) invalid_pte_table;

		p[i + 1] = (unsigned long) invalid_pte_table;

		p[i + 2] = (unsigned long) invalid_pte_table;

		p[i + 3] = (unsigned long) invalid_pte_table;

		p[i + 4] = (unsigned long) invalid_pte_table;

		p[i + 5] = (unsigned long) invalid_pte_table;

		p[i + 6] = (unsigned long) invalid_pte_table;

		p[i + 7] = (unsigned long) invalid_pte_table;

	}

}

pgd_t *pgd_alloc(struct mm_struct *mm)

{

	pgd_t *ret, *init;

	ret = (pgd_t *) __get_free_pages(GFP_KERNEL, PGD_ORDER);

	if (ret) {

		init = pgd_offset(&init_mm, 0UL);

		pgd_init(ret);

		memcpy(ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,

		       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));

	}

	return ret;

}

void __init pagetable_init(void)

{

	/* Initialize the entire pgd.  */

	pgd_init(swapper_pg_dir);

	pgd_init(swapper_pg_dir + USER_PTRS_PER_PGD);

}