- 根目录:
- arch
- hexagon
- include
- asm
- pgtable.h
/*
* Page table support for the Hexagon architecture
*
* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#ifndef _ASM_PGTABLE_H
#define _ASM_PGTABLE_H
/*
* Page table definitions for Qualcomm Hexagon processor.
*/
#include <linux/swap.h>
#include <asm/page.h>
#include <asm-generic/pgtable-nopmd.h>
/* A handy thing to have if one has the RAM. Declared in head.S */
extern unsigned long empty_zero_page;
extern unsigned long zero_page_mask;
/*
* The PTE model described here is that of the Hexagon Virtual Machine,
* which autonomously walks 2-level page tables. At a lower level, we
* also describe the RISCish software-loaded TLB entry structure of
* the underlying Hexagon processor. A kernel built to run on the
* virtual machine has no need to know about the underlying hardware.
*/
#include <asm/vm_mmu.h>
/*
* To maximize the comfort level for the PTE manipulation macros,
* define the "well known" architecture-specific bits.
*/
#define _PAGE_READ __HVM_PTE_R
#define _PAGE_WRITE __HVM_PTE_W
#define _PAGE_EXECUTE __HVM_PTE_X
#define _PAGE_USER __HVM_PTE_U
/*
* We have a total of 4 "soft" bits available in the abstract PTE.
* The two mandatory software bits are Dirty and Accessed.
* To make nonlinear swap work according to the more recent
* model, we want a low order "Present" bit to indicate whether
* the PTE describes MMU programming or swap space.
*/
#define _PAGE_PRESENT (1<<0)
#define _PAGE_DIRTY (1<<1)
#define _PAGE_ACCESSED (1<<2)
/*
* For now, let's say that Valid and Present are the same thing.
* Alternatively, we could say that it's the "or" of R, W, and X
* permissions.
*/
#define _PAGE_VALID _PAGE_PRESENT
/*
* We're not defining _PAGE_GLOBAL here, since there's no concept
* of global pages or ASIDs exposed to the Hexagon Virtual Machine,
* and we want to use the same page table structures and macros in
* the native kernel as we do in the virtual machine kernel.
* So we'll put up with a bit of inefficiency for now...
*/
/*
* Top "FOURTH" level (pgd), which for the Hexagon VM is really
* only the second from the bottom, pgd and pud both being collapsed.
* Each entry represents 4MB of virtual address space, 4K of table
* thus maps the full 4GB.
*/
#define PGDIR_SHIFT 22
#define PTRS_PER_PGD 1024
#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
#define PGDIR_MASK (~(PGDIR_SIZE-1))
#ifdef CONFIG_PAGE_SIZE_4KB
#define PTRS_PER_PTE 1024
#endif
#ifdef CONFIG_PAGE_SIZE_16KB
#define PTRS_PER_PTE 256
#endif
#ifdef CONFIG_PAGE_SIZE_64KB
#define PTRS_PER_PTE 64
#endif
#ifdef CONFIG_PAGE_SIZE_256KB
#define PTRS_PER_PTE 16
#endif
#ifdef CONFIG_PAGE_SIZE_1MB
#define PTRS_PER_PTE 4
#endif
/* Any bigger and the PTE disappears. */
#define pgd_ERROR(e) \
printk(KERN_ERR "%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__,\
pgd_val(e))
/*
* Page Protection Constants. Includes (in this variant) cache attributes.
*/
extern unsigned long _dflt_cache_att;
#define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_USER | \
_dflt_cache_att)
#define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_USER | \
_PAGE_READ | _PAGE_EXECUTE | _dflt_cache_att)
#define PAGE_COPY PAGE_READONLY
#define PAGE_EXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | \
_PAGE_READ | _PAGE_EXECUTE | _dflt_cache_att)
#define PAGE_COPY_EXEC PAGE_EXEC
#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | \
_PAGE_EXECUTE | _PAGE_WRITE | _dflt_cache_att)
#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_READ | \
_PAGE_WRITE | _PAGE_EXECUTE | _dflt_cache_att)
/*
* Aliases for mapping mmap() protection bits to page protections.
* These get used for static initialization, so using the _dflt_cache_att
* variable for the default cache attribute isn't workable. If the
* default gets changed at boot time, the boot option code has to
* update data structures like the protaction_map[] array.
*/
#define CACHEDEF (CACHE_DEFAULT << 6)
/* Private (copy-on-write) page protections. */
#define __P000 __pgprot(_PAGE_PRESENT | _PAGE_USER | CACHEDEF)
#define __P001 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | CACHEDEF)
#define __P010 __P000 /* Write-only copy-on-write */
#define __P011 __P001 /* Read/Write copy-on-write */
#define __P100 __pgprot(_PAGE_PRESENT | _PAGE_USER | \
_PAGE_EXECUTE | CACHEDEF)
#define __P101 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_EXECUTE | \
_PAGE_READ | CACHEDEF)
#define __P110 __P100 /* Write/execute copy-on-write */
#define __P111 __P101 /* Read/Write/Execute, copy-on-write */
/* Shared page protections. */
#define __S000 __P000
#define __S001 __P001
#define __S010 __pgprot(_PAGE_PRESENT | _PAGE_USER | \
_PAGE_WRITE | CACHEDEF)
#define __S011 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | \
_PAGE_WRITE | CACHEDEF)
#define __S100 __pgprot(_PAGE_PRESENT | _PAGE_USER | \
_PAGE_EXECUTE | CACHEDEF)
#define __S101 __P101
#define __S110 __pgprot(_PAGE_PRESENT | _PAGE_USER | \
_PAGE_EXECUTE | _PAGE_WRITE | CACHEDEF)
#define __S111 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | \
_PAGE_EXECUTE | _PAGE_WRITE | CACHEDEF)
extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; /* located in head.S */
/* Seems to be zero even in architectures where the zero page is firewalled? */
#define FIRST_USER_ADDRESS 0UL
#define pte_special(pte) 0
#define pte_mkspecial(pte) (pte)
/* HUGETLB not working currently */
#ifdef CONFIG_HUGETLB_PAGE
#define pte_mkhuge(pte) __pte((pte_val(pte) & ~0x3) | HVM_HUGEPAGE_SIZE)
#endif
/*
* For now, assume that higher-level code will do TLB/MMU invalidations
* and don't insert that overhead into this low-level function.
*/
extern void sync_icache_dcache(pte_t pte);
#define pte_present_exec_user(pte) \
((pte_val(pte) & (_PAGE_EXECUTE | _PAGE_USER)) == \
(_PAGE_EXECUTE | _PAGE_USER))
static inline void set_pte(pte_t *ptep, pte_t pteval)
{
/* should really be using pte_exec, if it weren't declared later. */
if (pte_present_exec_user(pteval))
sync_icache_dcache(pteval);
*ptep = pteval;
}
/*
* For the Hexagon Virtual Machine MMU (or its emulation), a null/invalid
* L1 PTE (PMD/PGD) has 7 in the least significant bits. For the L2 PTE
* (Linux PTE), the key is to have bits 11..9 all zero. We'd use 0x7
* as a universal null entry, but some of those least significant bits
* are interpreted by software.
*/
#define _NULL_PMD 0x7
#define _NULL_PTE 0x0
static inline void pmd_clear(pmd_t *pmd_entry_ptr)
{
pmd_val(*pmd_entry_ptr) = _NULL_PMD;
}
/*
* Conveniently, a null PTE value is invalid.
*/
static inline void pte_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
pte_val(*ptep) = _NULL_PTE;
}
#ifdef NEED_PMD_INDEX_DESPITE_BEING_2_LEVEL
/**
* pmd_index - returns the index of the entry in the PMD page
* which would control the given virtual address
*/
#define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
#endif
/**
* pgd_index - returns the index of the entry in the PGD page
* which would control the given virtual address
*
* This returns the *index* for the address in the pgd_t
*/
#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
/*
* pgd_offset - find an offset in a page-table-directory
*/
#define pgd_offset(mm, addr) ((mm)->pgd + pgd_index(addr))
/*
* pgd_offset_k - get kernel (init_mm) pgd entry pointer for addr
*/
#define pgd_offset_k(address) pgd_offset(&init_mm, address)
/**
* pmd_none - check if pmd_entry is mapped
* @pmd_entry: pmd entry
*
* MIPS checks it against that "invalid pte table" thing.
*/
static inline int pmd_none(pmd_t pmd)
{
return pmd_val(pmd) == _NULL_PMD;
}
/**
* pmd_present - is there a page table behind this?
* Essentially the inverse of pmd_none. We maybe
* save an inline instruction by defining it this
* way, instead of simply "!pmd_none".
*/
static inline int pmd_present(pmd_t pmd)
{
return pmd_val(pmd) != (unsigned long)_NULL_PMD;
}
/**
* pmd_bad - check if a PMD entry is "bad". That might mean swapped out.
* As we have no known cause of badness, it's null, as it is for many
* architectures.
*/
static inline int pmd_bad(pmd_t pmd)
{
return 0;
}
/*
* pmd_page - converts a PMD entry to a page pointer
*/
#define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
#define pmd_pgtable(pmd) pmd_page(pmd)
/**
* pte_none - check if pte is mapped
* @pte: pte_t entry
*/
static inline int pte_none(pte_t pte)
{
return pte_val(pte) == _NULL_PTE;
};
/*
* pte_present - check if page is present
*/
static inline int pte_present(pte_t pte)
{
return pte_val(pte) & _PAGE_PRESENT;
}
/* mk_pte - make a PTE out of a page pointer and protection bits */
#define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot))
/* pte_page - returns a page (frame pointer/descriptor?) based on a PTE */
#define pte_page(x) pfn_to_page(pte_pfn(x))
/* pte_mkold - mark PTE as not recently accessed */
static inline pte_t pte_mkold(pte_t pte)
{
pte_val(pte) &= ~_PAGE_ACCESSED;
return pte;
}
/* pte_mkyoung - mark PTE as recently accessed */
static inline pte_t pte_mkyoung(pte_t pte)
{
pte_val(pte) |= _PAGE_ACCESSED;
return pte;
}
/* pte_mkclean - mark page as in sync with backing store */
static inline pte_t pte_mkclean(pte_t pte)
{
pte_val(pte) &= ~_PAGE_DIRTY;
return pte;
}
/* pte_mkdirty - mark page as modified */
static inline pte_t pte_mkdirty(pte_t pte)
{
pte_val(pte) |= _PAGE_DIRTY;
return pte;
}
/* pte_young - "is PTE marked as accessed"? */
static inline int pte_young(pte_t pte)
{
return pte_val(pte) & _PAGE_ACCESSED;
}
/* pte_dirty - "is PTE dirty?" */
static inline int pte_dirty(pte_t pte)
{
return pte_val(pte) & _PAGE_DIRTY;
}
/* pte_modify - set protection bits on PTE */
static inline pte_t pte_modify(pte_t pte, pgprot_t prot)
{
pte_val(pte) &= PAGE_MASK;
pte_val(pte) |= pgprot_val(prot);
return pte;
}
/* pte_wrprotect - mark page as not writable */
static inline pte_t pte_wrprotect(pte_t pte)
{
pte_val(pte) &= ~_PAGE_WRITE;
return pte;
}
/* pte_mkwrite - mark page as writable */
static inline pte_t pte_mkwrite(pte_t pte)
{
pte_val(pte) |= _PAGE_WRITE;
return pte;
}
/* pte_mkexec - mark PTE as executable */
static inline pte_t pte_mkexec(pte_t pte)
{
pte_val(pte) |= _PAGE_EXECUTE;
return pte;
}
/* pte_read - "is PTE marked as readable?" */
static inline int pte_read(pte_t pte)
{
return pte_val(pte) & _PAGE_READ;
}
/* pte_write - "is PTE marked as writable?" */
static inline int pte_write(pte_t pte)
{
return pte_val(pte) & _PAGE_WRITE;
}
/* pte_exec - "is PTE marked as executable?" */
static inline int pte_exec(pte_t pte)
{
return pte_val(pte) & _PAGE_EXECUTE;
}
/* __pte_to_swp_entry - extract swap entry from PTE */
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
/* __swp_entry_to_pte - extract PTE from swap entry */
#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
/* pfn_pte - convert page number and protection value to page table entry */
#define pfn_pte(pfn, pgprot) __pte((pfn << PAGE_SHIFT) | pgprot_val(pgprot))
/* pte_pfn - convert pte to page frame number */
#define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT)
#define set_pmd(pmdptr, pmdval) (*(pmdptr) = (pmdval))
/*
* set_pte_at - update page table and do whatever magic may be
* necessary to make the underlying hardware/firmware take note.
*
* VM may require a virtual instruction to alert the MMU.
*/
#define set_pte_at(mm, addr, ptep, pte) set_pte(ptep, pte)
/*
* May need to invoke the virtual machine as well...
*/
#define pte_unmap(pte) do { } while (0)
#define pte_unmap_nested(pte) do { } while (0)
/*
* pte_offset_map - returns the linear address of the page table entry
* corresponding to an address
*/
#define pte_offset_map(dir, address) \
((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
#define pte_offset_map_nested(pmd, addr) pte_offset_map(pmd, addr)
/* pte_offset_kernel - kernel version of pte_offset */
#define pte_offset_kernel(dir, address) \
((pte_t *) (unsigned long) __va(pmd_val(*dir) & PAGE_MASK) \
+ __pte_offset(address))
/* ZERO_PAGE - returns the globally shared zero page */
#define ZERO_PAGE(vaddr) (virt_to_page(&empty_zero_page))
#define __pte_offset(address) (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
/* I think this is in case we have page table caches; needed by init/main.c */
#define pgtable_cache_init() do { } while (0)
/*
* Swap/file PTE definitions. If _PAGE_PRESENT is zero, the rest of the PTE is
* interpreted as swap information. The remaining free bits are interpreted as
* swap type/offset tuple. Rather than have the TLB fill handler test
* _PAGE_PRESENT, we're going to reserve the permissions bits and set them to
* all zeros for swap entries, which speeds up the miss handler at the cost of
* 3 bits of offset. That trade-off can be revisited if necessary, but Hexagon
* processor architecture and target applications suggest a lot of TLB misses
* and not much swap space.
*
* Format of swap PTE:
* bit 0: Present (zero)
* bits 1-5: swap type (arch independent layer uses 5 bits max)
* bits 6-9: bits 3:0 of offset
* bits 10-12: effectively _PAGE_PROTNONE (all zero)
* bits 13-31: bits 22:4 of swap offset
*
* The split offset makes some of the following macros a little gnarly,
* but there's plenty of precedent for this sort of thing.
*/
/* Used for swap PTEs */
#define __swp_type(swp_pte) (((swp_pte).val >> 1) & 0x1f)
#define __swp_offset(swp_pte) \
((((swp_pte).val >> 6) & 0xf) | (((swp_pte).val >> 9) & 0x7ffff0))
#define __swp_entry(type, offset) \
((swp_entry_t) { \
((type << 1) | \
((offset & 0x7ffff0) << 9) | ((offset & 0xf) << 6)) })
/* Oh boy. There are a lot of possible arch overrides found in this file. */
#include <asm-generic/pgtable.h>
#endif