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Diffstat (limited to 'arch/arm/include/asm/pgtable.h')
| -rw-r--r-- | arch/arm/include/asm/pgtable.h | 487 |
1 files changed, 487 insertions, 0 deletions
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h new file mode 100644 index 00000000..6682ab93 --- /dev/null +++ b/arch/arm/include/asm/pgtable.h @@ -0,0 +1,487 @@ +/* + * 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 <linux/const.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, preceded 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 + * +- - - - + | Linux pt 0 | + * | | +------------+ +1024 + * +--------+ +0 | Linux pt 1 | + * | |-----> +------------+ +2048 + * +- - - - + +4 | h/w pt 0 | + * | |-----> +------------+ +3072 + * +--------+ +8 | h/w 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 + +#define PTE_HWTABLE_PTRS (PTRS_PER_PTE) +#define PTE_HWTABLE_OFF (PTE_HWTABLE_PTRS * sizeof(pte_t)) +#define PTE_HWTABLE_SIZE (PTRS_PER_PTE * sizeof(u32)) + +/* + * 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, pte_t); +extern void __pmd_error(const char *file, int line, pmd_t); +extern void __pgd_error(const char *file, int line, pgd_t); + +#define pte_ERROR(pte) __pte_error(__FILE__, __LINE__, pte) +#define pmd_ERROR(pmd) __pmd_error(__FILE__, __LINE__, pmd) +#define pgd_ERROR(pgd) __pgd_error(__FILE__, __LINE__, 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 USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE) + +/* + * 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 (_AT(pteval_t, 1) << 0) +#define L_PTE_YOUNG (_AT(pteval_t, 1) << 1) +#define L_PTE_FILE (_AT(pteval_t, 1) << 2) /* only when !PRESENT */ +#define L_PTE_DIRTY (_AT(pteval_t, 1) << 6) +#define L_PTE_RDONLY (_AT(pteval_t, 1) << 7) +#define L_PTE_USER (_AT(pteval_t, 1) << 8) +#define L_PTE_XN (_AT(pteval_t, 1) << 9) +#define L_PTE_SHARED (_AT(pteval_t, 1) << 10) /* shared(v6), coherent(xsc3) */ + +/* + * These are the memory types, defined to be compatible with + * pre-ARMv6 CPUs cacheable and bufferable bits: XXCB + */ +#define L_PTE_MT_UNCACHED (_AT(pteval_t, 0x00) << 2) /* 0000 */ +#define L_PTE_MT_BUFFERABLE (_AT(pteval_t, 0x01) << 2) /* 0001 */ +#define L_PTE_MT_WRITETHROUGH (_AT(pteval_t, 0x02) << 2) /* 0010 */ +#define L_PTE_MT_WRITEBACK (_AT(pteval_t, 0x03) << 2) /* 0011 */ +#define L_PTE_MT_MINICACHE (_AT(pteval_t, 0x06) << 2) /* 0110 (sa1100, xscale) */ +#define L_PTE_MT_WRITEALLOC (_AT(pteval_t, 0x07) << 2) /* 0111 */ +#define L_PTE_MT_DEV_SHARED (_AT(pteval_t, 0x04) << 2) /* 0100 */ +#define L_PTE_MT_DEV_NONSHARED (_AT(pteval_t, 0x0c) << 2) /* 1100 */ +#define L_PTE_MT_DEV_WC (_AT(pteval_t, 0x09) << 2) /* 1001 */ +#define L_PTE_MT_DEV_CACHED (_AT(pteval_t, 0x0b) << 2) /* 1011 */ +#define L_PTE_MT_MASK (_AT(pteval_t, 0x0f) << 2) + +#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 + +extern pgprot_t pgprot_user; +extern pgprot_t pgprot_kernel; + +#define _MOD_PROT(p, b) __pgprot(pgprot_val(p) | (b)) + +#define PAGE_NONE _MOD_PROT(pgprot_user, L_PTE_XN | L_PTE_RDONLY) +#define PAGE_SHARED _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_XN) +#define PAGE_SHARED_EXEC _MOD_PROT(pgprot_user, L_PTE_USER) +#define PAGE_COPY _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY | L_PTE_XN) +#define PAGE_COPY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY) +#define PAGE_READONLY _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY | L_PTE_XN) +#define PAGE_READONLY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY) +#define PAGE_KERNEL _MOD_PROT(pgprot_kernel, L_PTE_XN) +#define PAGE_KERNEL_EXEC pgprot_kernel + +#define __PAGE_NONE __pgprot(_L_PTE_DEFAULT | L_PTE_RDONLY | L_PTE_XN) +#define __PAGE_SHARED __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_XN) +#define __PAGE_SHARED_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER) +#define __PAGE_COPY __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY | L_PTE_XN) +#define __PAGE_COPY_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY) +#define __PAGE_READONLY __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY | L_PTE_XN) +#define __PAGE_READONLY_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY) + +#define __pgprot_modify(prot,mask,bits) \ + __pgprot((pgprot_val(prot) & ~(mask)) | (bits)) + +#define pgprot_noncached(prot) \ + __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_UNCACHED) + +#define pgprot_writecombine(prot) \ + __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_BUFFERABLE) + +#define pgprot_writethrough(prot) \ + __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_WRITETHROUGH) + +#ifdef CONFIG_ARM_DMA_MEM_BUFFERABLE +#define pgprot_dmacoherent(prot) \ + __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_BUFFERABLE | L_PTE_XN) +#define __HAVE_PHYS_MEM_ACCESS_PROT +struct file; +extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, + unsigned long size, pgprot_t vma_prot); +#else +#define pgprot_dmacoherent(prot) \ + __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_UNCACHED | L_PTE_XN) +#endif + +#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_EXEC +#define __P101 __PAGE_READONLY_EXEC +#define __P110 __PAGE_COPY_EXEC +#define __P111 __PAGE_COPY_EXEC + +#define __S000 __PAGE_NONE +#define __S001 __PAGE_READONLY +#define __S010 __PAGE_SHARED +#define __S011 __PAGE_SHARED +#define __S100 __PAGE_READONLY_EXEC +#define __S101 __PAGE_READONLY_EXEC +#define __S110 __PAGE_SHARED_EXEC +#define __S111 __PAGE_SHARED_EXEC + +#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) + + +extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; + +/* 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) + +/* + * 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) +#define set_pud(pud,pudp) do { } while (0) + + +/* Find an entry in the second-level page table.. */ +#define pmd_offset(dir, addr) ((pmd_t *)(dir)) + +#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) +{ + return __va(pmd_val(pmd) & PAGE_MASK); +} + +#define pmd_page(pmd) pfn_to_page(__phys_to_pfn(pmd_val(pmd))) + +/* we don't need complex calculations here as the pmd is folded into the pgd */ +#define pmd_addr_end(addr,end) (end) + + +#ifndef CONFIG_HIGHPTE +#define __pte_map(pmd) pmd_page_vaddr(*(pmd)) +#define __pte_unmap(pte) do { } while (0) +#else +#define __pte_map(pmd) (pte_t *)kmap_atomic(pmd_page(*(pmd))) +#define __pte_unmap(pte) kunmap_atomic(pte) +#endif + +#define pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) + +#define pte_offset_kernel(pmd,addr) (pmd_page_vaddr(*(pmd)) + pte_index(addr)) + +#define pte_offset_map(pmd,addr) (__pte_map(pmd) + pte_index(addr)) +#define pte_unmap(pte) __pte_unmap(pte) + +#define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT) +#define pfn_pte(pfn,prot) __pte(__pfn_to_phys(pfn) | pgprot_val(prot)) + +#define pte_page(pte) pfn_to_page(pte_pfn(pte)) +#define mk_pte(page,prot) pfn_pte(page_to_pfn(page), prot) + +#define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,pte,ext) +#define pte_clear(mm,addr,ptep) set_pte_ext(ptep, __pte(0), 0) + +#if __LINUX_ARM_ARCH__ < 6 +static inline void __sync_icache_dcache(pte_t pteval) +{ +} +#else +extern void __sync_icache_dcache(pte_t pteval); +#endif + +static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pteval) +{ + if (addr >= TASK_SIZE) + set_pte_ext(ptep, pteval, 0); + else { + __sync_icache_dcache(pteval); + set_pte_ext(ptep, pteval, PTE_EXT_NG); + } +} + +#define pte_none(pte) (!pte_val(pte)) +#define pte_present(pte) (pte_val(pte) & L_PTE_PRESENT) +#define pte_write(pte) (!(pte_val(pte) & L_PTE_RDONLY)) +#define pte_dirty(pte) (pte_val(pte) & L_PTE_DIRTY) +#define pte_young(pte) (pte_val(pte) & L_PTE_YOUNG) +#define pte_exec(pte) (!(pte_val(pte) & L_PTE_XN)) +#define pte_special(pte) (0) + +#define pte_present_user(pte) \ + ((pte_val(pte) & (L_PTE_PRESENT | L_PTE_USER)) == \ + (L_PTE_PRESENT | L_PTE_USER)) + +#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_RDONLY); +PTE_BIT_FUNC(mkwrite, &= ~L_PTE_RDONLY); +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; } + +static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) +{ + const pteval_t mask = L_PTE_XN | L_PTE_RDONLY | L_PTE_USER; + pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask); + return pte; +} + +/* + * Encode and decode a swap entry. Swap entries are stored in the Linux + * page tables as follows: + * + * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 + * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 + * <--------------- offset --------------------> <- type --> 0 0 0 + * + * This gives us up to 63 swap files and 32GB per swap file. Note that + * the offset field is always non-zero. + */ +#define __SWP_TYPE_SHIFT 3 +#define __SWP_TYPE_BITS 6 +#define __SWP_TYPE_MASK ((1 << __SWP_TYPE_BITS) - 1) +#define __SWP_OFFSET_SHIFT (__SWP_TYPE_BITS + __SWP_TYPE_SHIFT) + +#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(swp) ((pte_t) { (swp).val }) + +/* + * It is an error for the kernel to have more swap files than we can + * encode in the PTEs. This ensures that we know when MAX_SWAPFILES + * is increased beyond what we presently support. + */ +#define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS) + +/* + * Encode and decode a file entry. File entries are stored in the Linux + * page tables as follows: + * + * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 + * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 + * <----------------------- offset ------------------------> 1 0 0 + */ +#define pte_file(pte) (pte_val(pte) & L_PTE_FILE) +#define pte_to_pgoff(x) (pte_val(x) >> 3) +#define pgoff_to_pte(x) __pte(((x) << 3) | L_PTE_FILE) + +#define PTE_FILE_MAX_BITS 29 + +/* 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) + +void identity_mapping_add(pgd_t *, unsigned long, unsigned long); +void identity_mapping_del(pgd_t *, unsigned long, unsigned long); + +#endif /* !__ASSEMBLY__ */ + +#endif /* CONFIG_MMU */ + +#endif /* _ASMARM_PGTABLE_H */ |