OpenRISC: Memory management

Signed-off-by: Jonas Bonn <jonas@southpole.se>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 463 insertions, 0 deletions

diff --git a/arch/openrisc/include/asm/pgtable.h b/arch/openrisc/include/asm/pgtable.h
new file mode 100644
index 000000000000..043505d7f684
--- /dev/null
+++ b/arch/openrisc/include/asm/pgtable.h
@@ -0,0 +1,463 @@
+/*
+ * OpenRISC Linux
+ *
+ * Linux architectural port borrowing liberally from similar works of
+ * others.  All original copyrights apply as per the original source
+ * declaration.
+ *
+ * OpenRISC implementation:
+ * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
+ * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
+ * et al.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+/* or32 pgtable.h - macros and functions to manipulate page tables
+ *
+ * Based on:
+ * include/asm-cris/pgtable.h
+ */
+
+#ifndef __ASM_OPENRISC_PGTABLE_H
+#define __ASM_OPENRISC_PGTABLE_H
+
+#include <asm-generic/pgtable-nopmd.h>
+
+#ifndef __ASSEMBLY__
+#include <asm/mmu.h>
+#include <asm/fixmap.h>
+
+/*
+ * The Linux memory management assumes a three-level page table setup. On
+ * or32, we use that, but "fold" the mid level into the top-level page
+ * table. Since the MMU TLB is software loaded through an interrupt, it
+ * supports any page table structure, so we could have used a three-level
+ * setup, but for the amounts of memory we normally use, a two-level is
+ * probably more efficient.
+ *
+ * This file contains the functions and defines necessary to modify and use
+ * the or32 page table tree.
+ */
+
+extern void paging_init(void);
+
+/* Certain architectures need to do special things when pte's
+ * within a page table are directly modified.  Thus, the following
+ * hook is made available.
+ */
+#define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
+#define set_pte_at(mm, addr, ptep, pteval) set_pte(ptep, pteval)
+/*
+ * (pmds are folded into pgds so this doesn't get actually called,
+ * but the define is needed for a generic inline function.)
+ */
+#define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
+
+#define PGDIR_SHIFT	(PAGE_SHIFT + (PAGE_SHIFT-2))
+#define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
+#define PGDIR_MASK	(~(PGDIR_SIZE-1))
+
+/*
+ * entries per page directory level: we use a two-level, so
+ * we don't really have any PMD directory physically.
+ * pointers are 4 bytes so we can use the page size and
+ * divide it by 4 (shift by 2).
+ */
+#define PTRS_PER_PTE	(1UL << (PAGE_SHIFT-2))
+
+#define PTRS_PER_PGD	(1UL << (PAGE_SHIFT-2))
+
+/* calculate how many PGD entries a user-level program can use
+ * the first mappable virtual address is 0
+ * (TASK_SIZE is the maximum virtual address space)
+ */
+
+#define USER_PTRS_PER_PGD       (TASK_SIZE/PGDIR_SIZE)
+#define FIRST_USER_ADDRESS      0
+
+/*
+ * Kernels own virtual memory area.
+ */
+
+/*
+ * The size and location of the vmalloc area are chosen so that modules
+ * placed in this area aren't more than a 28-bit signed offset from any
+ * kernel functions that they may need.  This greatly simplifies handling
+ * of the relocations for l.j and l.jal instructions as we don't need to
+ * introduce any trampolines for reaching "distant" code.
+ *
+ * 64 MB of vmalloc area is comparable to what's available on other arches.
+ */
+
+#define VMALLOC_START	(PAGE_OFFSET-0x04000000)
+#define VMALLOC_END	(PAGE_OFFSET)
+#define VMALLOC_VMADDR(x) ((unsigned long)(x))
+
+/* Define some higher level generic page attributes.
+ *
+ * If you change _PAGE_CI definition be sure to change it in
+ * io.h for ioremap_nocache() too.
+ */
+
+/*
+ * An OR32 PTE looks like this:
+ *
+ * |  31 ... 10 |  9  |  8 ... 6  |  5  |  4  |  3  |  2  |  1  |  0  |
+ *  Phys pg.num    L     PP Index    D     A    WOM   WBC   CI    CC
+ *
+ *  L  : link
+ *  PPI: Page protection index
+ *  D  : Dirty
+ *  A  : Accessed
+ *  WOM: Weakly ordered memory
+ *  WBC: Write-back cache
+ *  CI : Cache inhibit
+ *  CC : Cache coherent
+ *
+ * The protection bits below should correspond to the layout of the actual
+ * PTE as per above
+ */
+
+#define _PAGE_CC       0x001 /* software: pte contains a translation */
+#define _PAGE_CI       0x002 /* cache inhibit          */
+#define _PAGE_WBC      0x004 /* write back cache       */
+#define _PAGE_FILE     0x004 /* set: pagecache, unset: swap (when !PRESENT) */
+#define _PAGE_WOM      0x008 /* weakly ordered memory  */
+
+#define _PAGE_A        0x010 /* accessed               */
+#define _PAGE_D        0x020 /* dirty                  */
+#define _PAGE_URE      0x040 /* user read enable       */
+#define _PAGE_UWE      0x080 /* user write enable      */
+
+#define _PAGE_SRE      0x100 /* superuser read enable  */
+#define _PAGE_SWE      0x200 /* superuser write enable */
+#define _PAGE_EXEC     0x400 /* software: page is executable */
+#define _PAGE_U_SHARED 0x800 /* software: page is shared in user space */
+
+/* 0x001 is cache coherency bit, which should always be set to
+ *       1 - for SMP (when we support it)
+ *       0 - otherwise
+ *
+ * we just reuse this bit in software for _PAGE_PRESENT and
+ * force it to 0 when loading it into TLB.
+ */
+#define _PAGE_PRESENT  _PAGE_CC
+#define _PAGE_USER     _PAGE_URE
+#define _PAGE_WRITE    (_PAGE_UWE | _PAGE_SWE)
+#define _PAGE_DIRTY    _PAGE_D
+#define _PAGE_ACCESSED _PAGE_A
+#define _PAGE_NO_CACHE _PAGE_CI
+#define _PAGE_SHARED   _PAGE_U_SHARED
+#define _PAGE_READ     (_PAGE_URE | _PAGE_SRE)
+
+#define _PAGE_CHG_MASK	(PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
+#define _PAGE_BASE     (_PAGE_PRESENT | _PAGE_ACCESSED)
+#define _PAGE_ALL      (_PAGE_PRESENT | _PAGE_ACCESSED)
+#define _KERNPG_TABLE \
+	(_PAGE_BASE | _PAGE_SRE | _PAGE_SWE | _PAGE_ACCESSED | _PAGE_DIRTY)
+
+#define PAGE_NONE       __pgprot(_PAGE_ALL)
+#define PAGE_READONLY   __pgprot(_PAGE_ALL | _PAGE_URE | _PAGE_SRE)
+#define PAGE_READONLY_X __pgprot(_PAGE_ALL | _PAGE_URE | _PAGE_SRE | _PAGE_EXEC)
+#define PAGE_SHARED \
+	__pgprot(_PAGE_ALL | _PAGE_URE | _PAGE_SRE | _PAGE_UWE | _PAGE_SWE \
+		 | _PAGE_SHARED)
+#define PAGE_SHARED_X \
+	__pgprot(_PAGE_ALL | _PAGE_URE | _PAGE_SRE | _PAGE_UWE | _PAGE_SWE \
+		 | _PAGE_SHARED | _PAGE_EXEC)
+#define PAGE_COPY       __pgprot(_PAGE_ALL | _PAGE_URE | _PAGE_SRE)
+#define PAGE_COPY_X     __pgprot(_PAGE_ALL | _PAGE_URE | _PAGE_SRE | _PAGE_EXEC)
+
+#define PAGE_KERNEL \
+	__pgprot(_PAGE_ALL | _PAGE_SRE | _PAGE_SWE \
+		 | _PAGE_SHARED | _PAGE_DIRTY | _PAGE_EXEC)
+#define PAGE_KERNEL_RO \
+	__pgprot(_PAGE_ALL | _PAGE_SRE \
+		 | _PAGE_SHARED | _PAGE_DIRTY | _PAGE_EXEC)
+#define PAGE_KERNEL_NOCACHE \
+	__pgprot(_PAGE_ALL | _PAGE_SRE | _PAGE_SWE \
+		 | _PAGE_SHARED | _PAGE_DIRTY | _PAGE_EXEC | _PAGE_CI)
+
+#define __P000	PAGE_NONE
+#define __P001	PAGE_READONLY_X
+#define __P010	PAGE_COPY
+#define __P011	PAGE_COPY_X
+#define __P100	PAGE_READONLY
+#define __P101	PAGE_READONLY_X
+#define __P110	PAGE_COPY
+#define __P111	PAGE_COPY_X
+
+#define __S000	PAGE_NONE
+#define __S001	PAGE_READONLY_X
+#define __S010	PAGE_SHARED
+#define __S011	PAGE_SHARED_X
+#define __S100	PAGE_READONLY
+#define __S101	PAGE_READONLY_X
+#define __S110	PAGE_SHARED
+#define __S111	PAGE_SHARED_X
+
+/* zero page used for uninitialized stuff */
+extern unsigned long empty_zero_page[2048];
+#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
+
+/* number of bits that fit into a memory pointer */
+#define BITS_PER_PTR			(8*sizeof(unsigned long))
+
+/* to align the pointer to a pointer address */
+#define PTR_MASK			(~(sizeof(void *)-1))
+
+/* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
+/* 64-bit machines, beware!  SRB. */
+#define SIZEOF_PTR_LOG2			2
+
+/* to find an entry in a page-table */
+#define PAGE_PTR(address) \
+((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
+
+/* to set the page-dir */
+#define SET_PAGE_DIR(tsk, pgdir)
+
+#define pte_none(x)	(!pte_val(x))
+#define pte_present(x)	(pte_val(x) & _PAGE_PRESENT)
+#define pte_clear(mm, addr, xp)	do { pte_val(*(xp)) = 0; } while (0)
+
+#define pmd_none(x)	(!pmd_val(x))
+#define	pmd_bad(x)	((pmd_val(x) & (~PAGE_MASK)) != _KERNPG_TABLE)
+#define pmd_present(x)	(pmd_val(x) & _PAGE_PRESENT)
+#define pmd_clear(xp)	do { pmd_val(*(xp)) = 0; } while (0)
+
+/*
+ * The following only work if pte_present() is true.
+ * Undefined behaviour if not..
+ */
+
+static inline int pte_read(pte_t pte)  { return pte_val(pte) & _PAGE_READ; }
+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_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; }
+static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
+
+static inline pte_t pte_wrprotect(pte_t pte)
+{
+	pte_val(pte) &= ~(_PAGE_WRITE);
+	return pte;
+}
+
+static inline pte_t pte_rdprotect(pte_t pte)
+{
+	pte_val(pte) &= ~(_PAGE_READ);
+	return pte;
+}
+
+static inline pte_t pte_exprotect(pte_t pte)
+{
+	pte_val(pte) &= ~(_PAGE_EXEC);
+	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_mkread(pte_t pte)
+{
+	pte_val(pte) |= _PAGE_READ;
+	return pte;
+}
+
+static inline pte_t pte_mkexec(pte_t pte)
+{
+	pte_val(pte) |= _PAGE_EXEC;
+	return pte;
+}
+
+static inline pte_t pte_mkdirty(pte_t pte)
+{
+	pte_val(pte) |= _PAGE_DIRTY;
+	return pte;
+}
+
+static inline pte_t pte_mkyoung(pte_t pte)
+{
+	pte_val(pte) |= _PAGE_ACCESSED;
+	return pte;
+}
+
+/*
+ * Conversion functions: convert a page and protection to a page entry,
+ * and a page entry and page directory to the page they refer to.
+ */
+
+/* What actually goes as arguments to the various functions is less than
+ * obvious, but a rule of thumb is that struct page's goes as struct page *,
+ * really physical DRAM addresses are unsigned long's, and DRAM "virtual"
+ * addresses (the 0xc0xxxxxx's) goes as void *'s.
+ */
+
+static inline pte_t __mk_pte(void *page, pgprot_t pgprot)
+{
+	pte_t pte;
+	/* the PTE needs a physical address */
+	pte_val(pte) = __pa(page) | pgprot_val(pgprot);
+	return pte;
+}
+
+#define mk_pte(page, pgprot) __mk_pte(page_address(page), (pgprot))
+
+#define mk_pte_phys(physpage, pgprot) \
+({                                                                      \
+	pte_t __pte;                                                    \
+									\
+	pte_val(__pte) = (physpage) + pgprot_val(pgprot);               \
+	__pte;                                                          \
+})
+
+static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
+{
+	pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot);
+	return pte;
+}
+
+
+/*
+ * pte_val refers to a page in the 0x0xxxxxxx physical DRAM interval
+ * __pte_page(pte_val) refers to the "virtual" DRAM interval
+ * pte_pagenr refers to the page-number counted starting from the virtual
+ * DRAM start
+ */
+
+static inline unsigned long __pte_page(pte_t pte)
+{
+	/* the PTE contains a physical address */
+	return (unsigned long)__va(pte_val(pte) & PAGE_MASK);
+}
+
+#define pte_pagenr(pte)         ((__pte_page(pte) - PAGE_OFFSET) >> PAGE_SHIFT)
+
+/* permanent address of a page */
+
+#define __page_address(page) (PAGE_OFFSET + (((page) - mem_map) << PAGE_SHIFT))
+#define pte_page(pte)		(mem_map+pte_pagenr(pte))
+
+/*
+ * only the pte's themselves need to point to physical DRAM (see above)
+ * the pagetable links are purely handled within the kernel SW and thus
+ * don't need the __pa and __va transformations.
+ */
+static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
+{
+	pmd_val(*pmdp) = _KERNPG_TABLE | (unsigned long) ptep;
+}
+
+#define pmd_page(pmd)		(pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
+#define pmd_page_kernel(pmd)    ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
+
+/* to find an entry in a page-table-directory. */
+#define pgd_index(address)      ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
+
+#define __pgd_offset(address)   pgd_index(address)
+
+#define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
+
+/* to find an entry in a kernel page-table-directory */
+#define pgd_offset_k(address) pgd_offset(&init_mm, address)
+
+#define __pmd_offset(address) \
+	(((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
+
+/*
+ * the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
+ *
+ * this macro returns the index of the entry in the pte page which would
+ * control the given virtual address
+ */
+#define __pte_offset(address)                   \
+	(((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
+#define pte_offset_kernel(dir, address)         \
+	((pte_t *) pmd_page_kernel(*(dir)) +  __pte_offset(address))
+#define pte_offset_map(dir, address)	        \
+	((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
+#define pte_offset_map_nested(dir, address)     \
+	pte_offset_map(dir, address)
+
+#define pte_unmap(pte)          do { } while (0)
+#define pte_unmap_nested(pte)   do { } while (0)
+#define pte_pfn(x)		((unsigned long)(((x).pte)) >> PAGE_SHIFT)
+#define pfn_pte(pfn, prot)  __pte((((pfn) << PAGE_SHIFT)) | pgprot_val(prot))
+
+#define pte_ERROR(e) \
+	printk(KERN_ERR "%s:%d: bad pte %p(%08lx).\n", \
+	       __FILE__, __LINE__, &(e), pte_val(e))
+#define pgd_ERROR(e) \
+	printk(KERN_ERR "%s:%d: bad pgd %p(%08lx).\n", \
+	       __FILE__, __LINE__, &(e), pgd_val(e))
+
+extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; /* defined in head.S */
+
+/*
+ * or32 doesn't have any external MMU info: the kernel page
+ * tables contain all the necessary information.
+ *
+ * Actually I am not sure on what this could be used for.
+ */
+static inline void update_mmu_cache(struct vm_area_struct *vma,
+	unsigned long address, pte_t *pte)
+{
+}
+
+/* __PHX__ FIXME, SWAP, this probably doesn't work */
+
+/* Encode and de-code a swap entry (must be !pte_none(e) && !pte_present(e)) */
+/* Since the PAGE_PRESENT bit is bit 4, we can use the bits above */
+
+#define __swp_type(x)			(((x).val >> 5) & 0x7f)
+#define __swp_offset(x)			((x).val >> 12)
+#define __swp_entry(type, offset) \
+	((swp_entry_t) { ((type) << 5) | ((offset) << 12) })
+#define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
+#define __swp_entry_to_pte(x)		((pte_t) { (x).val })
+
+/* Encode and decode a nonlinear file mapping entry */
+
+#define PTE_FILE_MAX_BITS               26
+#define pte_to_pgoff(x)	                (pte_val(x) >> 6)
+#define pgoff_to_pte(x)	                __pte(((x) << 6) | _PAGE_FILE)
+
+#define kern_addr_valid(addr)           (1)
+
+#define io_remap_pfn_range(vma, vaddr, pfn, size, prot)         \
+	remap_pfn_range(vma, vaddr, pfn, size, prot)
+
+#include <asm-generic/pgtable.h>
+
+/*
+ * No page table caches to initialise
+ */
+#define pgtable_cache_init()		do { } while (0)
+#define io_remap_page_range		remap_page_range
+
+typedef pte_t *pte_addr_t;
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_OPENRISC_PGTABLE_H */