diff options
Diffstat (limited to 'arch/arm/include/asm/pgtable.h')
| -rw-r--r-- | arch/arm/include/asm/pgtable.h | 401 |
1 files changed, 401 insertions, 0 deletions
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h new file mode 100644 index 000000000000..8e21ef15bd74 --- /dev/null +++ b/arch/arm/include/asm/pgtable.h @@ -0,0 +1,401 @@ +/* + * arch/arm/include/asm/pgtable.h + * + * Copyright (C) 1995-2002 Russell King + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#ifndef _ASMARM_PGTABLE_H +#define _ASMARM_PGTABLE_H + +#include <asm-generic/4level-fixup.h> +#include <asm/proc-fns.h> + +#ifndef CONFIG_MMU + +#include "pgtable-nommu.h" + +#else + +#include <asm/memory.h> +#include <mach/vmalloc.h> +#include <asm/pgtable-hwdef.h> + +/* + * Just any arbitrary offset to the start of the vmalloc VM area: the + * current 8MB value just means that there will be a 8MB "hole" after the + * physical memory until the kernel virtual memory starts. That means that + * any out-of-bounds memory accesses will hopefully be caught. + * The vmalloc() routines leaves a hole of 4kB between each vmalloced + * area for the same reason. ;) + * + * Note that platforms may override VMALLOC_START, but they must provide + * VMALLOC_END. VMALLOC_END defines the (exclusive) limit of this space, + * which may not overlap IO space. + */ +#ifndef VMALLOC_START +#define VMALLOC_OFFSET (8*1024*1024) +#define VMALLOC_START (((unsigned long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)) +#endif + +/* + * Hardware-wise, we have a two level page table structure, where the first + * level has 4096 entries, and the second level has 256 entries. Each entry + * is one 32-bit word. Most of the bits in the second level entry are used + * by hardware, and there aren't any "accessed" and "dirty" bits. + * + * Linux on the other hand has a three level page table structure, which can + * be wrapped to fit a two level page table structure easily - using the PGD + * and PTE only. However, Linux also expects one "PTE" table per page, and + * at least a "dirty" bit. + * + * Therefore, we tweak the implementation slightly - we tell Linux that we + * have 2048 entries in the first level, each of which is 8 bytes (iow, two + * hardware pointers to the second level.) The second level contains two + * hardware PTE tables arranged contiguously, followed by Linux versions + * which contain the state information Linux needs. We, therefore, end up + * with 512 entries in the "PTE" level. + * + * This leads to the page tables having the following layout: + * + * pgd pte + * | | + * +--------+ +0 + * | |-----> +------------+ +0 + * +- - - - + +4 | h/w pt 0 | + * | |-----> +------------+ +1024 + * +--------+ +8 | h/w pt 1 | + * | | +------------+ +2048 + * +- - - - + | Linux pt 0 | + * | | +------------+ +3072 + * +--------+ | Linux pt 1 | + * | | +------------+ +4096 + * + * See L_PTE_xxx below for definitions of bits in the "Linux pt", and + * PTE_xxx for definitions of bits appearing in the "h/w pt". + * + * PMD_xxx definitions refer to bits in the first level page table. + * + * The "dirty" bit is emulated by only granting hardware write permission + * iff the page is marked "writable" and "dirty" in the Linux PTE. This + * means that a write to a clean page will cause a permission fault, and + * the Linux MM layer will mark the page dirty via handle_pte_fault(). + * For the hardware to notice the permission change, the TLB entry must + * be flushed, and ptep_set_access_flags() does that for us. + * + * The "accessed" or "young" bit is emulated by a similar method; we only + * allow accesses to the page if the "young" bit is set. Accesses to the + * page will cause a fault, and handle_pte_fault() will set the young bit + * for us as long as the page is marked present in the corresponding Linux + * PTE entry. Again, ptep_set_access_flags() will ensure that the TLB is + * up to date. + * + * However, when the "young" bit is cleared, we deny access to the page + * by clearing the hardware PTE. Currently Linux does not flush the TLB + * for us in this case, which means the TLB will retain the transation + * until either the TLB entry is evicted under pressure, or a context + * switch which changes the user space mapping occurs. + */ +#define PTRS_PER_PTE 512 +#define PTRS_PER_PMD 1 +#define PTRS_PER_PGD 2048 + +/* + * PMD_SHIFT determines the size of the area a second-level page table can map + * PGDIR_SHIFT determines what a third-level page table entry can map + */ +#define PMD_SHIFT 21 +#define PGDIR_SHIFT 21 + +#define LIBRARY_TEXT_START 0x0c000000 + +#ifndef __ASSEMBLY__ +extern void __pte_error(const char *file, int line, unsigned long val); +extern void __pmd_error(const char *file, int line, unsigned long val); +extern void __pgd_error(const char *file, int line, unsigned long val); + +#define pte_ERROR(pte) __pte_error(__FILE__, __LINE__, pte_val(pte)) +#define pmd_ERROR(pmd) __pmd_error(__FILE__, __LINE__, pmd_val(pmd)) +#define pgd_ERROR(pgd) __pgd_error(__FILE__, __LINE__, pgd_val(pgd)) +#endif /* !__ASSEMBLY__ */ + +#define PMD_SIZE (1UL << PMD_SHIFT) +#define PMD_MASK (~(PMD_SIZE-1)) +#define PGDIR_SIZE (1UL << PGDIR_SHIFT) +#define PGDIR_MASK (~(PGDIR_SIZE-1)) + +/* + * This is the lowest virtual address we can permit any user space + * mapping to be mapped at. This is particularly important for + * non-high vector CPUs. + */ +#define FIRST_USER_ADDRESS PAGE_SIZE + +#define FIRST_USER_PGD_NR 1 +#define USER_PTRS_PER_PGD ((TASK_SIZE/PGDIR_SIZE) - FIRST_USER_PGD_NR) + +/* + * section address mask and size definitions. + */ +#define SECTION_SHIFT 20 +#define SECTION_SIZE (1UL << SECTION_SHIFT) +#define SECTION_MASK (~(SECTION_SIZE-1)) + +/* + * ARMv6 supersection address mask and size definitions. + */ +#define SUPERSECTION_SHIFT 24 +#define SUPERSECTION_SIZE (1UL << SUPERSECTION_SHIFT) +#define SUPERSECTION_MASK (~(SUPERSECTION_SIZE-1)) + +/* + * "Linux" PTE definitions. + * + * We keep two sets of PTEs - the hardware and the linux version. + * This allows greater flexibility in the way we map the Linux bits + * onto the hardware tables, and allows us to have YOUNG and DIRTY + * bits. + * + * The PTE table pointer refers to the hardware entries; the "Linux" + * entries are stored 1024 bytes below. + */ +#define L_PTE_PRESENT (1 << 0) +#define L_PTE_FILE (1 << 1) /* only when !PRESENT */ +#define L_PTE_YOUNG (1 << 1) +#define L_PTE_BUFFERABLE (1 << 2) /* matches PTE */ +#define L_PTE_CACHEABLE (1 << 3) /* matches PTE */ +#define L_PTE_USER (1 << 4) +#define L_PTE_WRITE (1 << 5) +#define L_PTE_EXEC (1 << 6) +#define L_PTE_DIRTY (1 << 7) +#define L_PTE_SHARED (1 << 10) /* shared(v6), coherent(xsc3) */ + +#ifndef __ASSEMBLY__ + +/* + * The pgprot_* and protection_map entries will be fixed up in runtime + * to include the cachable and bufferable bits based on memory policy, + * as well as any architecture dependent bits like global/ASID and SMP + * shared mapping bits. + */ +#define _L_PTE_DEFAULT L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_CACHEABLE | L_PTE_BUFFERABLE +#define _L_PTE_READ L_PTE_USER | L_PTE_EXEC + +extern pgprot_t pgprot_user; +extern pgprot_t pgprot_kernel; + +#define PAGE_NONE pgprot_user +#define PAGE_COPY __pgprot(pgprot_val(pgprot_user) | _L_PTE_READ) +#define PAGE_SHARED __pgprot(pgprot_val(pgprot_user) | _L_PTE_READ | \ + L_PTE_WRITE) +#define PAGE_READONLY __pgprot(pgprot_val(pgprot_user) | _L_PTE_READ) +#define PAGE_KERNEL pgprot_kernel + +#define __PAGE_NONE __pgprot(_L_PTE_DEFAULT) +#define __PAGE_COPY __pgprot(_L_PTE_DEFAULT | _L_PTE_READ) +#define __PAGE_SHARED __pgprot(_L_PTE_DEFAULT | _L_PTE_READ | L_PTE_WRITE) +#define __PAGE_READONLY __pgprot(_L_PTE_DEFAULT | _L_PTE_READ) + +#endif /* __ASSEMBLY__ */ + +/* + * The table below defines the page protection levels that we insert into our + * Linux page table version. These get translated into the best that the + * architecture can perform. Note that on most ARM hardware: + * 1) We cannot do execute protection + * 2) If we could do execute protection, then read is implied + * 3) write implies read permissions + */ +#define __P000 __PAGE_NONE +#define __P001 __PAGE_READONLY +#define __P010 __PAGE_COPY +#define __P011 __PAGE_COPY +#define __P100 __PAGE_READONLY +#define __P101 __PAGE_READONLY +#define __P110 __PAGE_COPY +#define __P111 __PAGE_COPY + +#define __S000 __PAGE_NONE +#define __S001 __PAGE_READONLY +#define __S010 __PAGE_SHARED +#define __S011 __PAGE_SHARED +#define __S100 __PAGE_READONLY +#define __S101 __PAGE_READONLY +#define __S110 __PAGE_SHARED +#define __S111 __PAGE_SHARED + +#ifndef __ASSEMBLY__ +/* + * ZERO_PAGE is a global shared page that is always zero: used + * for zero-mapped memory areas etc.. + */ +extern struct page *empty_zero_page; +#define ZERO_PAGE(vaddr) (empty_zero_page) + +#define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT) +#define pfn_pte(pfn,prot) (__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))) + +#define pte_none(pte) (!pte_val(pte)) +#define pte_clear(mm,addr,ptep) set_pte_ext(ptep, __pte(0), 0) +#define pte_page(pte) (pfn_to_page(pte_pfn(pte))) +#define pte_offset_kernel(dir,addr) (pmd_page_vaddr(*(dir)) + __pte_index(addr)) +#define pte_offset_map(dir,addr) (pmd_page_vaddr(*(dir)) + __pte_index(addr)) +#define pte_offset_map_nested(dir,addr) (pmd_page_vaddr(*(dir)) + __pte_index(addr)) +#define pte_unmap(pte) do { } while (0) +#define pte_unmap_nested(pte) do { } while (0) + +#define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,pte,ext) + +#define set_pte_at(mm,addr,ptep,pteval) do { \ + set_pte_ext(ptep, pteval, (addr) >= TASK_SIZE ? 0 : PTE_EXT_NG); \ + } while (0) + +/* + * The following only work if pte_present() is true. + * Undefined behaviour if not.. + */ +#define pte_present(pte) (pte_val(pte) & L_PTE_PRESENT) +#define pte_write(pte) (pte_val(pte) & L_PTE_WRITE) +#define pte_dirty(pte) (pte_val(pte) & L_PTE_DIRTY) +#define pte_young(pte) (pte_val(pte) & L_PTE_YOUNG) +#define pte_special(pte) (0) + +/* + * The following only works if pte_present() is not true. + */ +#define pte_file(pte) (pte_val(pte) & L_PTE_FILE) +#define pte_to_pgoff(x) (pte_val(x) >> 2) +#define pgoff_to_pte(x) __pte(((x) << 2) | L_PTE_FILE) + +#define PTE_FILE_MAX_BITS 30 + +#define PTE_BIT_FUNC(fn,op) \ +static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; } + +PTE_BIT_FUNC(wrprotect, &= ~L_PTE_WRITE); +PTE_BIT_FUNC(mkwrite, |= L_PTE_WRITE); +PTE_BIT_FUNC(mkclean, &= ~L_PTE_DIRTY); +PTE_BIT_FUNC(mkdirty, |= L_PTE_DIRTY); +PTE_BIT_FUNC(mkold, &= ~L_PTE_YOUNG); +PTE_BIT_FUNC(mkyoung, |= L_PTE_YOUNG); + +static inline pte_t pte_mkspecial(pte_t pte) { return pte; } + +/* + * Mark the prot value as uncacheable and unbufferable. + */ +#define pgprot_noncached(prot) __pgprot(pgprot_val(prot) & ~(L_PTE_CACHEABLE | L_PTE_BUFFERABLE)) +#define pgprot_writecombine(prot) __pgprot(pgprot_val(prot) & ~L_PTE_CACHEABLE) + +#define pmd_none(pmd) (!pmd_val(pmd)) +#define pmd_present(pmd) (pmd_val(pmd)) +#define pmd_bad(pmd) (pmd_val(pmd) & 2) + +#define copy_pmd(pmdpd,pmdps) \ + do { \ + pmdpd[0] = pmdps[0]; \ + pmdpd[1] = pmdps[1]; \ + flush_pmd_entry(pmdpd); \ + } while (0) + +#define pmd_clear(pmdp) \ + do { \ + pmdp[0] = __pmd(0); \ + pmdp[1] = __pmd(0); \ + clean_pmd_entry(pmdp); \ + } while (0) + +static inline pte_t *pmd_page_vaddr(pmd_t pmd) +{ + unsigned long ptr; + + ptr = pmd_val(pmd) & ~(PTRS_PER_PTE * sizeof(void *) - 1); + ptr += PTRS_PER_PTE * sizeof(void *); + + return __va(ptr); +} + +#define pmd_page(pmd) virt_to_page(__va(pmd_val(pmd))) + +/* + * Permanent address of a page. We never have highmem, so this is trivial. + */ +#define pages_to_mb(x) ((x) >> (20 - PAGE_SHIFT)) + +/* + * 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) + +/* + * The "pgd_xxx()" functions here are trivial for a folded two-level + * setup: the pgd is never bad, and a pmd always exists (as it's folded + * into the pgd entry) + */ +#define pgd_none(pgd) (0) +#define pgd_bad(pgd) (0) +#define pgd_present(pgd) (1) +#define pgd_clear(pgdp) do { } while (0) +#define set_pgd(pgd,pgdp) do { } while (0) + +/* to find an entry in a page-table-directory */ +#define pgd_index(addr) ((addr) >> PGDIR_SHIFT) + +#define pgd_offset(mm, addr) ((mm)->pgd+pgd_index(addr)) + +/* to find an entry in a kernel page-table-directory */ +#define pgd_offset_k(addr) pgd_offset(&init_mm, addr) + +/* Find an entry in the second-level page table.. */ +#define pmd_offset(dir, addr) ((pmd_t *)(dir)) + +/* Find an entry in the third-level page table.. */ +#define __pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) + +static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) +{ + const unsigned long mask = L_PTE_EXEC | L_PTE_WRITE | L_PTE_USER; + pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask); + return pte; +} + +extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; + +/* Encode and decode a swap entry. + * + * We support up to 32GB of swap on 4k machines + */ +#define __swp_type(x) (((x).val >> 2) & 0x7f) +#define __swp_offset(x) ((x).val >> 9) +#define __swp_entry(type,offset) ((swp_entry_t) { ((type) << 2) | ((offset) << 9) }) +#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) +#define __swp_entry_to_pte(swp) ((pte_t) { (swp).val }) + +/* Needs to be defined here and not in linux/mm.h, as it is arch dependent */ +/* FIXME: this is not correct */ +#define kern_addr_valid(addr) (1) + +#include <asm-generic/pgtable.h> + +/* + * We provide our own arch_get_unmapped_area to cope with VIPT caches. + */ +#define HAVE_ARCH_UNMAPPED_AREA + +/* + * remap a physical page `pfn' of size `size' with page protection `prot' + * into virtual address `from' + */ +#define io_remap_pfn_range(vma,from,pfn,size,prot) \ + remap_pfn_range(vma, from, pfn, size, prot) + +#define pgtable_cache_init() do { } while (0) + +#endif /* !__ASSEMBLY__ */ + +#endif /* CONFIG_MMU */ + +#endif /* _ASMARM_PGTABLE_H */ |