- 根目录:
- arch
- xtensa
- include
- asm
- pgtable.h
/*
* include/asm-xtensa/pgtable.h
*
* 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.
*
* Copyright (C) 2001 - 2013 Tensilica Inc.
*/
#ifndef _XTENSA_PGTABLE_H
#define _XTENSA_PGTABLE_H
#include <asm-generic/pgtable-nopmd.h>
#include <asm/page.h>
/*
* 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 is 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_PGD 1024
#define PGD_ORDER 0
#define USER_PTRS_PER_PGD (TASK_SIZE/PGDIR_SIZE)
#define FIRST_USER_ADDRESS 0UL
#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.
*/
#define VMALLOC_START 0xC0000000
#define VMALLOC_END 0xC7FEFFFF
#define TLBTEMP_BASE_1 0xC7FF0000
#define TLBTEMP_BASE_2 (TLBTEMP_BASE_1 + DCACHE_WAY_SIZE)
#if 2 * DCACHE_WAY_SIZE > ICACHE_WAY_SIZE
#define TLBTEMP_SIZE (2 * DCACHE_WAY_SIZE)
#else
#define TLBTEMP_SIZE ICACHE_WAY_SIZE
#endif
/*
* For the Xtensa architecture, the PTE layout is as follows:
*
* 31------12 11 10-9 8-6 5-4 3-2 1-0
* +-----------------------------------------+
* | | Software | HARDWARE |
* | PPN | ADW | RI |Attribute|
* +-----------------------------------------+
* pte_none | MBZ | 01 | 11 | 00 |
* +-----------------------------------------+
* present | PPN | 0 | 00 | ADW | RI | CA | wx |
* +- - - - - - - - - - - - - - - - - - - - -+
* (PAGE_NONE)| PPN | 0 | 00 | ADW | 01 | 11 | 11 |
* +-----------------------------------------+
* swap | index | type | 01 | 11 | 00 |
* +-----------------------------------------+
*
* For T1050 hardware and earlier the layout differs for present and (PAGE_NONE)
* +-----------------------------------------+
* present | PPN | 0 | 00 | ADW | RI | CA | w1 |
* +-----------------------------------------+
* (PAGE_NONE)| PPN | 0 | 00 | ADW | 01 | 01 | 00 |
* +-----------------------------------------+
*
* Legend:
* PPN Physical Page Number
* ADW software: accessed (young) / dirty / writable
* RI ring (0=privileged, 1=user, 2 and 3 are unused)
* CA cache attribute: 00 bypass, 01 writeback, 10 writethrough
* (11 is invalid and used to mark pages that are not present)
* w page is writable (hw)
* x page is executable (hw)
* index swap offset / PAGE_SIZE (bit 11-31: 21 bits -> 8 GB)
* (note that the index is always non-zero)
* type swap type (5 bits -> 32 types)
*
* Notes:
* - (PROT_NONE) is a special case of 'present' but causes an exception for
* any access (read, write, and execute).
* - 'multihit-exception' has the highest priority of all MMU exceptions,
* so the ring must be set to 'RING_USER' even for 'non-present' pages.
* - on older hardware, the exectuable flag was not supported and
* used as a 'valid' flag, so it needs to be always set.
* - we need to keep track of certain flags in software (dirty and young)
* to do this, we use write exceptions and have a separate software w-flag.
* - attribute value 1101 (and 1111 on T1050 and earlier) is reserved
*/
#define _PAGE_ATTRIB_MASK 0xf
#define _PAGE_HW_EXEC (1<<0) /* hardware: page is executable */
#define _PAGE_HW_WRITE (1<<1) /* hardware: page is writable */
#define _PAGE_CA_BYPASS (0<<2) /* bypass, non-speculative */
#define _PAGE_CA_WB (1<<2) /* write-back */
#define _PAGE_CA_WT (2<<2) /* write-through */
#define _PAGE_CA_MASK (3<<2)
#define _PAGE_CA_INVALID (3<<2)
/* We use invalid attribute values to distinguish special pte entries */
#if XCHAL_HW_VERSION_MAJOR < 2000
#define _PAGE_HW_VALID 0x01 /* older HW needed this bit set */
#define _PAGE_NONE 0x04
#else
#define _PAGE_HW_VALID 0x00
#define _PAGE_NONE 0x0f
#endif
#define _PAGE_USER (1<<4) /* user access (ring=1) */
/* Software */
#define _PAGE_WRITABLE_BIT 6
#define _PAGE_WRITABLE (1<<6) /* software: page writable */
#define _PAGE_DIRTY (1<<7) /* software: page dirty */
#define _PAGE_ACCESSED (1<<8) /* software: page accessed (read) */
#ifdef CONFIG_MMU
#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
#define _PAGE_PRESENT (_PAGE_HW_VALID | _PAGE_CA_WB | _PAGE_ACCESSED)
#define PAGE_NONE __pgprot(_PAGE_NONE | _PAGE_USER)
#define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_USER)
#define PAGE_COPY_EXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_HW_EXEC)
#define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_USER)
#define PAGE_READONLY_EXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_HW_EXEC)
#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE)
#define PAGE_SHARED_EXEC \
__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE | _PAGE_HW_EXEC)
#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_HW_WRITE)
#define PAGE_KERNEL_EXEC __pgprot(_PAGE_PRESENT|_PAGE_HW_WRITE|_PAGE_HW_EXEC)
#if (DCACHE_WAY_SIZE > PAGE_SIZE)
# define _PAGE_DIRECTORY (_PAGE_HW_VALID | _PAGE_ACCESSED | _PAGE_CA_BYPASS)
#else
# define _PAGE_DIRECTORY (_PAGE_HW_VALID | _PAGE_ACCESSED | _PAGE_CA_WB)
#endif
#else /* no mmu */
# define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
# 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_EXEC /* private x-- */
#define __P101 PAGE_READONLY_EXEC /* private x-r */
#define __P110 PAGE_COPY_EXEC /* private xw- */
#define __P111 PAGE_COPY_EXEC /* 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_EXEC /* shared x-- */
#define __S101 PAGE_READONLY_EXEC /* shared x-r */
#define __S110 PAGE_SHARED_EXEC /* shared xw- */
#define __S111 PAGE_SHARED_EXEC /* 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))
#ifdef CONFIG_MMU
extern pgd_t swapper_pg_dir[PAGE_SIZE/sizeof(pgd_t)];
extern void paging_init(void);
#else
# define swapper_pg_dir NULL
static inline void paging_init(void) { }
#endif
static inline void pgtable_cache_init(void) { }
/*
* The pmd contains the kernel virtual address of the pte page.
*/
#define pmd_page_vaddr(pmd) ((unsigned long)(pmd_val(pmd) & PAGE_MASK))
#define pmd_page(pmd) virt_to_page(pmd_val(pmd))
/*
* pte status.
*/
# define pte_none(pte) (pte_val(pte) == (_PAGE_CA_INVALID | _PAGE_USER))
#if XCHAL_HW_VERSION_MAJOR < 2000
# define pte_present(pte) ((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_CA_INVALID)
#else
# define pte_present(pte) \
(((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_CA_INVALID) \
|| ((pte_val(pte) & _PAGE_ATTRIB_MASK) == _PAGE_NONE))
#endif
#define pte_clear(mm,addr,ptep) \
do { update_pte(ptep, __pte(_PAGE_CA_INVALID | _PAGE_USER)); } while (0)
#define pmd_none(pmd) (!pmd_val(pmd))
#define pmd_present(pmd) (pmd_val(pmd) & PAGE_MASK)
#define pmd_bad(pmd) (pmd_val(pmd) & ~PAGE_MASK)
#define pmd_clear(pmdp) do { set_pmd(pmdp, __pmd(0)); } while (0)
static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_WRITABLE; }
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_special(pte_t pte) { return 0; }
static inline pte_t pte_wrprotect(pte_t pte)
{ pte_val(pte) &= ~(_PAGE_WRITABLE | _PAGE_HW_WRITE); return pte; }
static inline pte_t pte_mkclean(pte_t pte)
{ pte_val(pte) &= ~(_PAGE_DIRTY | _PAGE_HW_WRITE); return pte; }
static inline pte_t pte_mkold(pte_t pte)
{ pte_val(pte) &= ~_PAGE_ACCESSED; 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_WRITABLE; return pte; }
static inline pte_t pte_mkspecial(pte_t pte)
{ return pte; }
#define pgprot_noncached(prot) (__pgprot(pgprot_val(prot) & ~_PAGE_CA_MASK))
/*
* 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)
static 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__ ("dhwb %0, 0" :: "a" (ptep));
#endif
}
struct mm_struct;
static inline void
set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval)
{
update_pte(ptep, pteval);
}
static inline void set_pte(pte_t *ptep, pte_t pteval)
{
update_pte(ptep, pteval);
}
static inline void
set_pmd(pmd_t *pmdp, pmd_t pmdval)
{
*pmdp = pmdval;
}
struct vm_area_struct;
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 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_vaddr(*(dir)) + pte_index(addr))
#define pte_offset_map(dir,addr) pte_offset_kernel((dir),(addr))
#define pte_unmap(pte) do { } while (0)
/*
* Encode and decode a swap and file entry.
*/
#define SWP_TYPE_BITS 5
#define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS)
#define __swp_type(entry) (((entry).val >> 6) & 0x1f)
#define __swp_offset(entry) ((entry).val >> 11)
#define __swp_entry(type,offs) \
((swp_entry_t){((type) << 6) | ((offs) << 11) | \
_PAGE_CA_INVALID | _PAGE_USER})
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
#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
#define kern_addr_valid(addr) (1)
extern void update_mmu_cache(struct vm_area_struct * vma,
unsigned long address, pte_t *ptep);
typedef pte_t *pte_addr_t;
#endif /* !defined (__ASSEMBLY__) */
#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
#define __HAVE_ARCH_PTEP_SET_WRPROTECT
#define __HAVE_ARCH_PTEP_MKDIRTY
#define __HAVE_ARCH_PTE_SAME
/* We provide our own get_unmapped_area to cope with
* SHM area cache aliasing for userland.
*/
#define HAVE_ARCH_UNMAPPED_AREA
#include <asm-generic/pgtable.h>
#endif /* _XTENSA_PGTABLE_H */