Skomentowany plik pgtable.h
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#ifndef _I386_PGTABLE_H
#define _I386_PGTABLE_H
#include <linux/config.h>
/*
* Define USE_PENTIUM_MM if you want the 4MB page table optimizations.
* This works only on a intel Pentium.
*/
#define USE_PENTIUM_MM 1
/*
* The Linux memory management assumes a three-level page table setup. On
* the i386, we use that, but "fold" the mid level into the top-level page
* table, so that we physically have the same two-level page table as the
* i386 mmu expects.
*
* This file contains the functions and defines necessary to modify and use
* the i386 page table tree.
*/
//============================================================================
//
//Plik zawiera ustawienia wartości i definicje funkcji zależnych od archiektury procesora.
//
//============================================================================
/* Caches aren't brain-dead on the intel. */
//===========================================================================
// Te operacje bierze na siebie procesor intela,więc tu są zdefiniowane jako
// puste.
//===========================================================================
#define flush_cache_all() do { } while (0)
#define flush_cache_mm(mm) do { } while (0)
#define flush_cache_range(mm, start, end) do { } while (0)
#define flush_cache_page(vma, vmaddr) do { } while (0)
#define flush_page_to_ram(page) do { } while (0)
/*
* TLB flushing:
*
* - flush_tlb() flushes the current mm struct TLBs
* - flush_tlb_all() flushes all processes TLBs
* - flush_tlb_mm(mm) flushes the specified mm context TLB's
* - flush_tlb_page(vma, vmaddr) flushes one page
* - flush_tlb_range(mm, start, end) flushes a range of pages
*
* ..but the i386 has somewhat limited tlb flushing capabilities,
* and page-granular flushes are available only on i486 and up.
*/
#define __flush_tlb() \
do { unsigned long tmpreg; __asm__ __volatile__("movl %%cr3,%0\n\tmovl %0,%%cr3":"=r" (tmpreg) : :"memory"); } while (0)
#ifdef CONFIG_M386
#define __flush_tlb_one(addr) flush_tlb()
#else
#define __flush_tlb_one(addr) \
__asm__ __volatile__("invlpg %0": :"m" (*(char *) addr))
#endif
#ifndef __SMP__
#define flush_tlb() __flush_tlb()
#define flush_tlb_all() __flush_tlb()
#define local_flush_tlb() __flush_tlb()
static inline void flush_tlb_mm(struct mm_struct *mm)
{
if (mm == current->mm)
__flush_tlb();
}
static inline void flush_tlb_page(struct vm_area_struct *vma,
unsigned long addr)
{
if (vma->vm_mm == current->mm)
__flush_tlb_one(addr);
}
static inline void flush_tlb_range(struct mm_struct *mm,
unsigned long start, unsigned long end)
{
if (mm == current->mm)
__flush_tlb();
}
#else
/*
* We aren't very clever about this yet - SMP could certainly
* avoid some global flushes..
*/
#include <asm/smp.h>
#define local_flush_tlb() \
__flush_tlb()
#define CLEVER_SMP_INVALIDATE
#ifdef CLEVER_SMP_INVALIDATE
/*
* Smarter SMP flushing macros.
* c/o Linus Torvalds.
*
* These mean you can really definitely utterly forget about
* writing to user space from interrupts. (Its not allowed anyway).
*/
static inline void flush_tlb_current_task(void)
{
if (current->mm->count == 1) /* just one copy of this mm */
local_flush_tlb(); /* and that's us, so.. */
else
smp_flush_tlb();
}
#define flush_tlb() flush_tlb_current_task()
#define flush_tlb_all() smp_flush_tlb()
static inline void flush_tlb_mm(struct mm_struct * mm)
{
if (mm == current->mm && mm->count == 1)
local_flush_tlb();
else
smp_flush_tlb();
}
static inline void flush_tlb_page(struct vm_area_struct * vma,
unsigned long va)
{
if (vma->vm_mm == current->mm && current->mm->count == 1)
__flush_tlb_one(va);
else
smp_flush_tlb();
}
static inline void flush_tlb_range(struct mm_struct * mm,
unsigned long start, unsigned long end)
{
flush_tlb_mm(mm);
}
#else
#define flush_tlb() \
smp_flush_tlb()
#define flush_tlb_all() flush_tlb()
static inline void flush_tlb_mm(struct mm_struct *mm)
{
flush_tlb();
}
static inline void flush_tlb_page(struct vm_area_struct *vma,
unsigned long addr)
{
flush_tlb();
}
static inline void flush_tlb_range(struct mm_struct *mm,
unsigned long start, unsigned long end)
{
flush_tlb();
}
#endif
#endif
/* Certain architectures need to do special things when pte's
* within a page table are directly modified. Thus, the following
* hook is made available.
*/
#define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
/* PMD_SHIFT determines the size of the area a second-level page table can map */
//================================================================================
//
// Określenie rozmiaru tablicy stron - drugiego poziomu struktury pamięci.
// Jak łatwo obliczyć tablica stron ma pojemność 2^22 czyli 4MB
//
//================================================================================
#define PMD_SHIFT 22
#define PMD_SIZE (1UL << PMD_SHIFT)
#define PMD_MASK (~(PMD_SIZE-1))
/* PGDIR_SHIFT determines what a third-level page table entry can map */
//=============================================================================
//
// Określenie rozmiaru katalogu tablicy stron - trzeciego poziomu struktury
// pamięci. Jest to również 4MB.
//
//=============================================================================
#define PGDIR_SHIFT 22
#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
#define PGDIR_MASK (~(PGDIR_SIZE-1))
/*
* entries per page directory level: the i386 is two-level, so
* we don't really have any PMD directory physically.
*
//===========================================================================
// Tutaj właśnie widać, ze struktura pamięci w Linuxie jest tak naprawdę
// dwupoziomowa
//===========================================================================
#define PTRS_PER_PTE 1024
#define PTRS_PER_PMD 1
#define PTRS_PER_PGD 1024
/* 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. ;)
*/
#define VMALLOC_OFFSET (8*1024*1024)
#define VMALLOC_START ((high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
#define VMALLOC_VMADDR(x) (TASK_SIZE + (unsigned long)(x))
/*
* The 4MB page is guessing.. Detailed in the infamous "Chapter H"
* of the Pentium details, but assuming intel did the straightforward
* thing, this bit set in the page directory entry just means that
* the page directory entry points directly to a 4MB-aligned block of
* memory.
*/
//=============================================================================
//
// Istnieją pogłoski mówiące, że konstruktorzy Pentium dali mozliwość
// tworzenia 4MB ramek ( tak, cztery megabajty). Nie zostało to jednak
// opisane w oficjalnej dokumentacji procesora, więc są to tylko domysły.
//
//=============================================================================
#define _PAGE_PRESENT 0x001
#define _PAGE_RW 0x002
#define _PAGE_USER 0x004
#define _PAGE_PCD 0x010
#define _PAGE_ACCESSED 0x020
#define _PAGE_DIRTY 0x040
#define _PAGE_4M 0x080 /* 4 MB page, Pentium+.. */
//=============================================================================
// Definicje stałych określających właściwości strony
// Dokładny opis znaczenia poszczególnych bitów w pliku mem_map_t
//=============================================================================
#define _PAGE_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)
#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
#define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED)
#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED)
#define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
#define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
/*
* The i386 can't do page protection for execute, and considers that the same are read.
* Also, write permissions imply read permissions. This is the closest we can get..
*/
#define __P000 PAGE_NONE
#define __P001 PAGE_READONLY
#define __P010 PAGE_COPY
#define __P011 PAGE_COPY
#define __P100 PAGE_READONLY
#define __P101 PAGE_READONLY
#define __P110 PAGE_COPY
#define __P111 PAGE_COPY
#define __S000 PAGE_NONE
#define __S001 PAGE_READONLY
#define __S010 PAGE_SHARED
#define __S011 PAGE_SHARED
#define __S100 PAGE_READONLY
#define __S101 PAGE_READONLY
#define __S110 PAGE_SHARED
#define __S111 PAGE_SHARED
/*
* Define this if things work differently on a i386 and a i486:
* it will (on a i486) warn about kernel memory accesses that are
* done without a 'verify_area(VERIFY_WRITE,..)'
*/
#undef TEST_VERIFY_AREA
/* page table for 0-4MB for everybody */
extern unsigned long pg0[1024];
/* zero page used for uninitialized stuff */
extern unsigned long empty_zero_page[1024];
/*
* BAD_PAGETABLE is used when we need a bogus page-table, while
* BAD_PAGE is used for a bogus page.
*
* ZERO_PAGE is a global shared page that is always zero: used
* for zero-mapped memory areas etc..
*/
extern pte_t __bad_page(void);
extern pte_t * __bad_pagetable(void);
#define BAD_PAGETABLE __bad_pagetable()
#define BAD_PAGE __bad_page()
#define ZERO_PAGE ((unsigned long) empty_zero_page)
/* number of bits that fit into a memory pointer */
#define BITS_PER_PTR (8*sizeof(unsigned long))
/* to align the pointer to a pointer address */
#define PTR_MASK (~(sizeof(void*)-1))
/* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
/* 64-bit machines, beware! SRB. */
#define SIZEOF_PTR_LOG2 2
/* to find an entry in a page-table */
#define PAGE_PTR(address) \
((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
/* to set the page-dir */
#define SET_PAGE_DIR(tsk,pgdir) \
do { \
(tsk)->tss.cr3 = (unsigned long) (pgdir); \
if ((tsk) == current) \
__asm__ __volatile__("movl %0,%%cr3": :"r" (pgdir)); \
} while (0)
//=====================================================================================
// Funkcje zwracające informacje o statusie ramek i stron.
//=====================================================================================
#define pte_none(x) (!pte_val(x))
#define pte_present(x) (pte_val(x) & _PAGE_PRESENT)
#define pte_clear(xp) do { pte_val(*(xp)) = 0; } while (0)
#define pmd_none(x) (!pmd_val(x))
#define pmd_bad(x) ((pmd_val(x) & ~PAGE_MASK) != _PAGE_TABLE)
#define pmd_present(x) (pmd_val(x) & _PAGE_PRESENT)
#define pmd_clear(xp) do { pmd_val(*(xp)) = 0; } while (0)
/*
* 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)
*/
extern inline int pgd_none(pgd_t pgd) { return 0; }
extern inline int pgd_bad(pgd_t pgd) { return 0; }
extern inline int pgd_present(pgd_t pgd) { return 1; }
extern inline void pgd_clear(pgd_t * pgdp) { }
/*
* The following only work if pte_present() is true.
* Undefined behaviour if not..
*/
//=====================================================================================
// Funkcje zwracające informacje o statusie ramki.
// Definicja struktury pte_t w pliku page.h.
// Opis struktury page
//=====================================================================================
extern inline int pte_read(pte_t pte) { return pte_val(pte) & _PAGE_USER; }
extern inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_RW; }
extern inline int pte_exec(pte_t pte) { return pte_val(pte) & _PAGE_USER; }
extern inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
extern inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
extern inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) &= ~_PAGE_RW; return pte; }
extern inline pte_t pte_rdprotect(pte_t pte) { pte_val(pte) &= ~_PAGE_USER; return pte; }
extern inline pte_t pte_exprotect(pte_t pte) { pte_val(pte) &= ~_PAGE_USER; return pte; }
extern inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~_PAGE_DIRTY; return pte; }
extern inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
extern inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) |= _PAGE_RW; return pte; }
extern inline pte_t pte_mkread(pte_t pte) { pte_val(pte) |= _PAGE_USER; return pte; }
extern inline pte_t pte_mkexec(pte_t pte) { pte_val(pte) |= _PAGE_USER; return pte; }
extern inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= _PAGE_DIRTY; return pte; }
extern inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= _PAGE_ACCESSED; return pte; }
/*
* Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directetory to the page they refer to.
*/
//==============================================================================
//
// Funkcje do wykonywania najprostszych operacji na ramkach
//
//==============================================================================
// Tworzenie nowej ramki o zadanym parametrze ochrony
extern inline pte_t mk_pte(unsigned long page, pgprot_t pgprot)
{ pte_t pte; pte_val(pte) = page | pgprot_val(pgprot); return pte; }
// Zmiana praw dostępu do ramki
extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{ pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
extern inline unsigned long pte_page(pte_t pte)
{ return pte_val(pte) & PAGE_MASK; }
extern inline unsigned long pmd_page(pmd_t pmd)
{ return pmd_val(pmd) & PAGE_MASK; }
/* to find an entry in a page-table-directory */
extern inline pgd_t * pgd_offset(struct mm_struct * mm, unsigned long address)
{
return mm->pgd + (address >> PGDIR_SHIFT);
}
/* Find an entry in the second-level page table.. */
extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
{
return (pmd_t *) dir;
}
/* Find an entry in the third-level page table.. */
extern inline pte_t * pte_offset(pmd_t * dir, unsigned long address)
{
return (pte_t *) pmd_page(*dir) + ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1));
}
/*
* Allocate and free page tables. The xxx_kernel() versions are
* used to allocate a kernel page table - this turns on ASN bits
* if any.
*/
extern inline void pte_free_kernel(pte_t * pte)
{
free_page((unsigned long) pte);
}
extern const char bad_pmd_string[];
extern inline pte_t * pte_alloc_kernel(pmd_t * pmd, unsigned long address)
{
address = (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
if (pmd_none(*pmd)) {
pte_t * page = (pte_t *) get_free_page(GFP_KERNEL);
if (pmd_none(*pmd)) {
if (page) {
pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) page;
return page + address;
}
pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;
return NULL;
}
free_page((unsigned long) page);
}
if (pmd_bad(*pmd)) {
printk(bad_pmd_string, pmd_val(*pmd));
pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;
return NULL;
}
return (pte_t *) pmd_page(*pmd) + address;
}
/*
* allocating and freeing a pmd is trivial: the 1-entry pmd is
* inside the pgd, so has no extra memory associated with it.
*/
extern inline void pmd_free_kernel(pmd_t * pmd)
{
pmd_val(*pmd) = 0;
}
extern inline pmd_t * pmd_alloc_kernel(pgd_t * pgd, unsigned long address)
{
return (pmd_t *) pgd;
}
extern inline void pte_free(pte_t * pte)
{
free_page((unsigned long) pte);
}
extern inline pte_t * pte_alloc(pmd_t * pmd, unsigned long address)
{
address = (address >> (PAGE_SHIFT-2)) & 4*(PTRS_PER_PTE - 1);
repeat:
if (pmd_none(*pmd))
goto getnew;
if (pmd_bad(*pmd))
goto fix;
return (pte_t *) (pmd_page(*pmd) + address);
getnew:
{
unsigned long page = __get_free_page(GFP_KERNEL);
if (!pmd_none(*pmd))
goto freenew;
if (!page)
goto oom;
memset((void *) page, 0, PAGE_SIZE);
pmd_val(*pmd) = _PAGE_TABLE | page;
return (pte_t *) (page + address);
freenew:
free_page(page);
goto repeat;
}
fix:
printk(bad_pmd_string, pmd_val(*pmd));
oom:
pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;
return NULL;
}
/*
* allocating and freeing a pmd is trivial: the 1-entry pmd is
* inside the pgd, so has no extra memory associated with it.
*/
extern inline void pmd_free(pmd_t * pmd)
{
pmd_val(*pmd) = 0;
}
extern inline pmd_t * pmd_alloc(pgd_t * pgd, unsigned long address)
{
return (pmd_t *) pgd;
}
extern inline void pgd_free(pgd_t * pgd)
{
free_page((unsigned long) pgd);
}
extern inline pgd_t * pgd_alloc(void)
{
return (pgd_t *) get_free_page(GFP_KERNEL);
}
extern pgd_t swapper_pg_dir[1024];
/*
* The i386 doesn't have any external MMU info: the kernel page
* tables contain all the necessary information.
*/
extern inline void update_mmu_cache(struct vm_area_struct * vma,
unsigned long address, pte_t pte)
{
}
#define SWP_TYPE(entry) (((entry) >> 1) & 0x7f)
#define SWP_OFFSET(entry) ((entry) >> 8)
#define SWP_ENTRY(type,offset) (((type) << 1) | ((offset) << 8))
#endif /* _I386_PAGE_H */