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linux/arch/xtensa/include/asm/pgtable.h
Russell King 4b3073e1c5 MM: Pass a PTE pointer to update_mmu_cache() rather than the PTE itself 
On VIVT ARM, when we have multiple shared mappings of the same file
in the same MM, we need to ensure that we have coherency across all
copies.  We do this via make_coherent() by making the pages
uncacheable.

This used to work fine, until we allowed highmem with highpte - we
now have a page table which is mapped as required, and is not available
for modification via update_mmu_cache().

Ralf Beache suggested getting rid of the PTE value passed to
update_mmu_cache():

  On MIPS update_mmu_cache() calls __update_tlb() which walks pagetables
  to construct a pointer to the pte again.  Passing a pte_t * is much
  more elegant.  Maybe we might even replace the pte argument with the
  pte_t?

Ben Herrenschmidt would also like the pte pointer for PowerPC:

  Passing the ptep in there is exactly what I want.  I want that
  -instead- of the PTE value, because I have issue on some ppc cases,
  for I$/D$ coherency, where set_pte_at() may decide to mask out the
  _PAGE_EXEC.

So, pass in the mapped page table pointer into update_mmu_cache(), and
remove the PTE value, updating all implementations and call sites to
suit.

Includes a fix from Stephen Rothwell:

  sparc: fix fallout from update_mmu_cache API change

  Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-02-20 16:41:46 +00:00

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/*
* 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 - 2007 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 0
#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 0xC7FF8000
/*
* 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_HW_EXEC (1<<0) /* hardware: page is executable */
#define _PAGE_HW_WRITE (1<<1) /* hardware: page is writable */
#define _PAGE_FILE (1<<1) /* non-linear mapping, if !present */
#define _PAGE_PROTNONE (3<<0) /* special case for VM_PROT_NONE */
/* None of these cache modes include MP coherency: */
#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_INVALID (3<<2)
#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) */
/* On older HW revisions, we always have to set bit 0 */
#if XCHAL_HW_VERSION_MAJOR < 2000
# define _PAGE_VALID (1<<0)
#else
# define _PAGE_VALID 0
#endif
#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
#define _PAGE_PRESENT (_PAGE_VALID | _PAGE_CA_WB | _PAGE_ACCESSED)
#ifdef CONFIG_MMU
#define PAGE_NONE __pgprot(_PAGE_INVALID | _PAGE_USER | _PAGE_PROTNONE)
#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_VALID | _PAGE_ACCESSED)
#else
# define _PAGE_DIRECTORY (_PAGE_VALID | _PAGE_ACCESSED | _PAGE_CA_WB)
#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_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);
extern void pgtable_cache_init(void);
#else
# define swapper_pg_dir NULL
static inline void paging_init(void) { }
static inline void pgtable_cache_init(void) { }
#endif
/*
* 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_INVALID)
#define pte_present(pte) \
(((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_INVALID) \
|| ((pte_val(pte) & _PAGE_PROTNONE) == _PAGE_PROTNONE))
#define pte_clear(mm,addr,ptep) \
do { update_pte(ptep, __pte(_PAGE_INVALID)); } 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_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE; }
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; }
/*
* 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_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_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.
*
* Format of swap pte:
* bit 0 MBZ
* bit 1 page-file (must be zero)
* bits 2 - 3 page hw access mode (must be 11: _PAGE_INVALID)
* bits 4 - 5 ring protection (must be 01: _PAGE_USER)
* bits 6 - 10 swap type (5 bits -> 32 types)
* bits 11 - 31 swap offset / PAGE_SIZE (21 bits -> 8GB)
* Format of file pte:
* bit 0 MBZ
* bit 1 page-file (must be one: _PAGE_FILE)
* bits 2 - 3 page hw access mode (must be 11: _PAGE_INVALID)
* bits 4 - 5 ring protection (must be 01: _PAGE_USER)
* bits 6 - 31 file offset / PAGE_SIZE
*/
#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_INVALID})
#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 28
#define pte_to_pgoff(pte) (pte_val(pte) >> 4)
#define pgoff_to_pte(off) \
((pte_t) { ((off) << 4) | _PAGE_INVALID | _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
#define kern_addr_valid(addr) (1)
extern void update_mmu_cache(struct vm_area_struct * vma,
unsigned long address, pte_t *ptep);
/*
* 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)
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
#include <asm-generic/pgtable.h>
#endif /* _XTENSA_PGTABLE_H */
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