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Diffstat (limited to 'include/asm-xtensa/pgtable.h')
| -rw-r--r-- | include/asm-xtensa/pgtable.h | 468 |
1 files changed, 468 insertions, 0 deletions
diff --git a/include/asm-xtensa/pgtable.h b/include/asm-xtensa/pgtable.h new file mode 100644 index 0000000..0bb6416 --- /dev/null +++ b/include/asm-xtensa/pgtable.h @@ -0,0 +1,468 @@ +/* + * linux/include/asm-xtensa/page.h + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version2 as + * published by the Free Software Foundation. + * + * Copyright (C) 2001 - 2005 Tensilica Inc. + */ + +#ifndef _XTENSA_PGTABLE_H +#define _XTENSA_PGTABLE_H + +#include <asm-generic/pgtable-nopmd.h> +#include <asm/page.h> + +/* Assertions. */ + +#ifdef CONFIG_MMU + + +#if (XCHAL_MMU_RINGS < 2) +# error Linux build assumes at least 2 ring levels. +#endif + +#if (XCHAL_MMU_CA_BITS != 4) +# error We assume exactly four bits for CA. +#endif + +#if (XCHAL_MMU_SR_BITS != 0) +# error We have no room for SR bits. +#endif + +/* + * Use the first min-wired way for mapping page-table pages. + * Page coloring requires a second min-wired way. + */ + +#if (XCHAL_DTLB_MINWIRED_SETS == 0) +# error Need a min-wired way for mapping page-table pages +#endif + +#define DTLB_WAY_PGTABLE XCHAL_DTLB_SET(XCHAL_DTLB_MINWIRED_SET0, WAY) + +#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK +# if XCHAL_DTLB_SET(XCHAL_DTLB_MINWIRED_SET0, WAYS) >= 2 +# define DTLB_WAY_DCACHE_ALIAS0 (DTLB_WAY_PGTABLE + 1) +# define DTLB_WAY_DCACHE_ALIAS1 (DTLB_WAY_PGTABLE + 2) +# else +# error Page coloring requires its own wired dtlb way! +# endif +#endif + +#endif /* CONFIG_MMU */ + +/* + * We only use two ring levels, user and kernel space. + */ + +#define USER_RING 1 /* user ring level */ +#define KERNEL_RING 0 /* kernel ring level */ + +/* + * The Xtensa architecture port of Linux has a two-level page table system, + * i.e. the logical three-level Linux page table layout are folded. + * Each task has the following memory page tables: + * + * PGD table (page directory), ie. 3rd-level page table: + * One page (4 kB) of 1024 (PTRS_PER_PGD) pointers to PTE tables + * (Architectures that don't have the PMD folded point to the PMD tables) + * + * The pointer to the PGD table for a given task can be retrieved from + * the task structure (struct task_struct*) t, e.g. current(): + * (t->mm ? t->mm : t->active_mm)->pgd + * + * PMD tables (page middle-directory), ie. 2nd-level page tables: + * Absent for the Xtensa architecture (folded, PTRS_PER_PMD == 1). + * + * PTE tables (page table entry), ie. 1st-level page tables: + * One page (4 kB) of 1024 (PTRS_PER_PTE) PTEs with a special PTE + * invalid_pte_table for absent mappings. + * + * The individual pages are 4 kB big with special pages for the empty_zero_page. + */ +#define PGDIR_SHIFT 22 +#define PGDIR_SIZE (1UL << PGDIR_SHIFT) +#define PGDIR_MASK (~(PGDIR_SIZE-1)) + +/* + * Entries per page directory level: we use two-level, so + * we don't really have any PMD directory physically. + */ +#define PTRS_PER_PTE 1024 +#define PTRS_PER_PTE_SHIFT 10 +#define PTRS_PER_PMD 1 +#define PTRS_PER_PGD 1024 +#define PGD_ORDER 0 +#define PMD_ORDER 0 +#define USER_PTRS_PER_PGD (TASK_SIZE/PGDIR_SIZE) +#define FIRST_USER_ADDRESS XCHAL_SEG_MAPPABLE_VADDR +#define FIRST_USER_PGD_NR (FIRST_USER_ADDRESS >> PGDIR_SHIFT) + +/* virtual memory area. We keep a distance to other memory regions to be + * on the safe side. We also use this area for cache aliasing. + */ + +// FIXME: virtual memory area must be configuration-dependent + +#define VMALLOC_START 0xC0000000 +#define VMALLOC_END 0xC7FF0000 + +/* Xtensa Linux config PTE layout (when present): + * 31-12: PPN + * 11-6: Software + * 5-4: RING + * 3-0: CA + * + * Similar to the Alpha and MIPS ports, we need to keep track of the ref + * and mod bits in software. We have a software "you can read + * from this page" bit, and a hardware one which actually lets the + * process read from the page. On the same token we have a software + * writable bit and the real hardware one which actually lets the + * process write to the page. + * + * See further below for PTE layout for swapped-out pages. + */ + +#define _PAGE_VALID (1<<0) /* hardware: page is accessible */ +#define _PAGE_WRENABLE (1<<1) /* hardware: page is writable */ + +/* None of these cache modes include MP coherency: */ +#define _PAGE_NO_CACHE (0<<2) /* bypass, non-speculative */ +#if XCHAL_DCACHE_IS_WRITEBACK +# define _PAGE_WRITEBACK (1<<2) /* write back */ +# define _PAGE_WRITETHRU (2<<2) /* write through */ +#else +# define _PAGE_WRITEBACK (1<<2) /* assume write through */ +# define _PAGE_WRITETHRU (1<<2) +#endif +#define _PAGE_NOALLOC (3<<2) /* don't allocate cache,if not cached */ +#define _CACHE_MASK (3<<2) + +#define _PAGE_USER (1<<4) /* user access (ring=1) */ +#define _PAGE_KERNEL (0<<4) /* kernel access (ring=0) */ + +/* Software */ +#define _PAGE_RW (1<<6) /* software: page writable */ +#define _PAGE_DIRTY (1<<7) /* software: page dirty */ +#define _PAGE_ACCESSED (1<<8) /* software: page accessed (read) */ +#define _PAGE_FILE (1<<9) /* nonlinear file mapping*/ + +#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _CACHE_MASK | _PAGE_DIRTY) +#define _PAGE_PRESENT ( _PAGE_VALID | _PAGE_WRITEBACK | _PAGE_ACCESSED) + +#ifdef CONFIG_MMU + +# define PAGE_NONE __pgprot(_PAGE_PRESENT) +# define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_RW) +# define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_USER) +# define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_USER) +# define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_KERNEL | _PAGE_WRENABLE) +# define PAGE_INVALID __pgprot(_PAGE_USER) + +# if (DCACHE_WAY_SIZE > PAGE_SIZE) +# define PAGE_DIRECTORY __pgprot(_PAGE_VALID | _PAGE_ACCESSED | _PAGE_KERNEL) +# else +# define PAGE_DIRECTORY __pgprot(_PAGE_PRESENT | _PAGE_KERNEL) +# endif + +#else /* no mmu */ + +# define PAGE_NONE __pgprot(0) +# define PAGE_SHARED __pgprot(0) +# define PAGE_COPY __pgprot(0) +# define PAGE_READONLY __pgprot(0) +# define PAGE_KERNEL __pgprot(0) + +#endif + +/* + * On certain configurations of Xtensa MMUs (eg. the initial Linux config), + * the MMU can't do page protection for execute, and considers that the same as + * read. Also, write permissions may imply read permissions. + * What follows is the closest we can get by reasonable means.. + * See linux/mm/mmap.c for protection_map[] array that uses these definitions. + */ +#define __P000 PAGE_NONE /* private --- */ +#define __P001 PAGE_READONLY /* private --r */ +#define __P010 PAGE_COPY /* private -w- */ +#define __P011 PAGE_COPY /* private -wr */ +#define __P100 PAGE_READONLY /* private x-- */ +#define __P101 PAGE_READONLY /* private x-r */ +#define __P110 PAGE_COPY /* private xw- */ +#define __P111 PAGE_COPY /* private xwr */ + +#define __S000 PAGE_NONE /* shared --- */ +#define __S001 PAGE_READONLY /* shared --r */ +#define __S010 PAGE_SHARED /* shared -w- */ +#define __S011 PAGE_SHARED /* shared -wr */ +#define __S100 PAGE_READONLY /* shared x-- */ +#define __S101 PAGE_READONLY /* shared x-r */ +#define __S110 PAGE_SHARED /* shared xw- */ +#define __S111 PAGE_SHARED /* shared xwr */ + +#ifndef __ASSEMBLY__ + +#define pte_ERROR(e) \ + printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e)) +#define pgd_ERROR(e) \ + printk("%s:%d: bad pgd entry %08lx.\n", __FILE__, __LINE__, pgd_val(e)) + +extern unsigned long empty_zero_page[1024]; + +#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) + +extern pgd_t swapper_pg_dir[PAGE_SIZE/sizeof(pgd_t)]; + +/* + * The pmd contains the kernel virtual address of the pte page. + */ +#define pmd_page_kernel(pmd) ((unsigned long)(pmd_val(pmd) & PAGE_MASK)) +#define pmd_page(pmd) virt_to_page(pmd_val(pmd)) + +/* + * The following only work if pte_present() is true. + */ +#define pte_none(pte) (!(pte_val(pte) ^ _PAGE_USER)) +#define pte_present(pte) (pte_val(pte) & _PAGE_VALID) +#define pte_clear(mm,addr,ptep) \ + do { update_pte(ptep, __pte(_PAGE_USER)); } while(0) + +#define pmd_none(pmd) (!pmd_val(pmd)) +#define pmd_present(pmd) (pmd_val(pmd) & PAGE_MASK) +#define pmd_clear(pmdp) do { set_pmd(pmdp, __pmd(0)); } while (0) +#define pmd_bad(pmd) (pmd_val(pmd) & ~PAGE_MASK) + +/* Note: We use the _PAGE_USER bit to indicate write-protect kernel memory */ + +static inline int pte_read(pte_t pte) { return pte_val(pte) & _PAGE_USER; } +static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_RW; } +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 pte_t pte_wrprotect(pte_t pte) { pte_val(pte) &= ~(_PAGE_RW | _PAGE_WRENABLE); return pte; } +static inline pte_t pte_rdprotect(pte_t pte) { pte_val(pte) &= ~_PAGE_USER; 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_mkread(pte_t pte) { pte_val(pte) |= _PAGE_USER; 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; } +static inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) |= _PAGE_RW; 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. + */ +#define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT) +#define pte_same(a,b) (pte_val(a) == pte_val(b)) +#define pte_page(x) pfn_to_page(pte_pfn(x)) +#define pfn_pte(pfn, prot) __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot)) +#define mk_pte(page, prot) pfn_pte(page_to_pfn(page), prot) + +extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot) +{ + return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot)); +} + +/* + * Certain architectures need to do special things when pte's + * within a page table are directly modified. Thus, the following + * hook is made available. + */ +static inline void update_pte(pte_t *ptep, pte_t pteval) +{ + *ptep = pteval; +#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK + __asm__ __volatile__ ("memw; dhwb %0, 0; dsync" :: "a" (ptep)); +#endif +} + +extern inline void +set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval) +{ + update_pte(ptep, pteval); +} + + +extern inline void +set_pmd(pmd_t *pmdp, pmd_t pmdval) +{ + *pmdp = pmdval; +#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK + __asm__ __volatile__ ("memw; dhwb %0, 0; dsync" :: "a" (pmdp)); +#endif +} + + +static inline int +ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, + pte_t *ptep) +{ + pte_t pte = *ptep; + if (!pte_young(pte)) + return 0; + update_pte(ptep, pte_mkold(pte)); + return 1; +} + +static inline int +ptep_test_and_clear_dirty(struct vm_area_struct *vma, unsigned long addr, + pte_t *ptep) +{ + pte_t pte = *ptep; + if (!pte_dirty(pte)) + return 0; + update_pte(ptep, pte_mkclean(pte)); + return 1; +} + +static inline pte_t +ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) +{ + pte_t pte = *ptep; + pte_clear(mm, addr, ptep); + return pte; +} + +static inline void +ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep) +{ + pte_t pte = *ptep; + update_pte(ptep, pte_wrprotect(pte)); +} + +/* to find an entry in a kernel page-table-directory */ +#define pgd_offset_k(address) pgd_offset(&init_mm, address) + +/* to find an entry in a page-table-directory */ +#define pgd_offset(mm,address) ((mm)->pgd + pgd_index(address)) + +#define pgd_index(address) ((address) >> PGDIR_SHIFT) + +/* Find an entry in the second-level page table.. */ +#define pmd_offset(dir,address) ((pmd_t*)(dir)) + +/* Find an entry in the third-level page table.. */ +#define pte_index(address) (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) +#define pte_offset_kernel(dir,addr) \ + ((pte_t*) pmd_page_kernel(*(dir)) + pte_index(addr)) +#define pte_offset_map(dir,addr) pte_offset_kernel((dir),(addr)) +#define pte_offset_map_nested(dir,addr) pte_offset_kernel((dir),(addr)) + +#define pte_unmap(pte) do { } while (0) +#define pte_unmap_nested(pte) do { } while (0) + + +/* + * Encode and decode a swap entry. + * Each PTE in a process VM's page table is either: + * "present" -- valid and not swapped out, protection bits are meaningful; + * "not present" -- which further subdivides in these two cases: + * "none" -- no mapping at all; identified by pte_none(), set by pte_clear( + * "swapped out" -- the page is swapped out, and the SWP macros below + * are used to store swap file info in the PTE itself. + * + * In the Xtensa processor MMU, any PTE entries in user space (or anywhere + * in virtual memory that can map differently across address spaces) + * must have a correct ring value that represents the RASID field that + * is changed when switching address spaces. Eg. such PTE entries cannot + * be set to ring zero, because that can cause a (global) kernel ASID + * entry to be created in the TLBs (even with invalid cache attribute), + * potentially causing a multihit exception when going back to another + * address space that mapped the same virtual address at another ring. + * + * SO: we avoid using ring bits (_PAGE_RING_MASK) in "not present" PTEs. + * We also avoid using the _PAGE_VALID bit which must be zero for non-present + * pages. + * + * We end up with the following available bits: 1..3 and 7..31. + * We don't bother with 1..3 for now (we can use them later if needed), + * and chose to allocate 6 bits for SWP_TYPE and the remaining 19 bits + * for SWP_OFFSET. At least 5 bits are needed for SWP_TYPE, because it + * is currently implemented as an index into swap_info[MAX_SWAPFILES] + * and MAX_SWAPFILES is currently defined as 32 in <linux/swap.h>. + * However, for some reason all other architectures in the 2.4 kernel + * reserve either 6, 7, or 8 bits so I'll not detract from that for now. :) + * SWP_OFFSET is an offset into the swap file in page-size units, so + * with 4 kB pages, 19 bits supports a maximum swap file size of 2 GB. + * + * FIXME: 2 GB isn't very big. Other bits can be used to allow + * larger swap sizes. In the meantime, it appears relatively easy to get + * around the 2 GB limitation by simply using multiple swap files. + */ + +#define __swp_type(entry) (((entry).val >> 7) & 0x3f) +#define __swp_offset(entry) ((entry).val >> 13) +#define __swp_entry(type,offs) ((swp_entry_t) {((type) << 7) | ((offs) << 13)}) +#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) +#define __swp_entry_to_pte(x) ((pte_t) { (x).val }) + +#define PTE_FILE_MAX_BITS 29 +#define pte_to_pgoff(pte) (pte_val(pte) >> 3) +#define pgoff_to_pte(off) ((pte_t) { ((off) << 3) | _PAGE_FILE }) + + +#endif /* !defined (__ASSEMBLY__) */ + + +#ifdef __ASSEMBLY__ + +/* Assembly macro _PGD_INDEX is the same as C pgd_index(unsigned long), + * _PGD_OFFSET as C pgd_offset(struct mm_struct*, unsigned long), + * _PMD_OFFSET as C pmd_offset(pgd_t*, unsigned long) + * _PTE_OFFSET as C pte_offset(pmd_t*, unsigned long) + * + * Note: We require an additional temporary register which can be the same as + * the register that holds the address. + * + * ((pte_t*) ((unsigned long)(pmd_val(*pmd) & PAGE_MASK)) + pte_index(addr)) + * + */ +#define _PGD_INDEX(rt,rs) extui rt, rs, PGDIR_SHIFT, 32-PGDIR_SHIFT +#define _PTE_INDEX(rt,rs) extui rt, rs, PAGE_SHIFT, PTRS_PER_PTE_SHIFT + +#define _PGD_OFFSET(mm,adr,tmp) l32i mm, mm, MM_PGD; \ + _PGD_INDEX(tmp, adr); \ + addx4 mm, tmp, mm + +#define _PTE_OFFSET(pmd,adr,tmp) _PTE_INDEX(tmp, adr); \ + srli pmd, pmd, PAGE_SHIFT; \ + slli pmd, pmd, PAGE_SHIFT; \ + addx4 pmd, tmp, pmd + +#else + +extern void paging_init(void); + +#define kern_addr_valid(addr) (1) + +extern void update_mmu_cache(struct vm_area_struct * vma, + unsigned long address, pte_t pte); + +/* + * remap a physical address `phys' of size `size' with page protection `prot' + * into virtual address `from' + */ +#define io_remap_page_range(vma,from,phys,size,prot) \ + remap_pfn_range(vma, from, (phys) >> PAGE_SHIFT, size, prot) + + +/* No page table caches to init */ + +#define pgtable_cache_init() do { } while (0) + +typedef pte_t *pte_addr_t; + +#endif /* !defined (__ASSEMBLY__) */ + +#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG +#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY +#define __HAVE_ARCH_PTEP_GET_AND_CLEAR +#define __HAVE_ARCH_PTEP_SET_WRPROTECT +#define __HAVE_ARCH_PTEP_MKDIRTY +#define __HAVE_ARCH_PTE_SAME + +#include <asm-generic/pgtable.h> + +#endif /* _XTENSA_PGTABLE_H */ |
