pgtable.h

讲述linux的初始化过程

({ pte_t __pte; pte_val(__pte) = physpage + pgprot_val(pgprot); __pte; })

#define pte_modify(_pte, newprot) \
	(__pte((pte_val(_pte) & _PAGE_CHG_MASK) | pgprot_val(newprot)))

#define page_pte_prot(page,prot)	mk_pte(page, prot)
#define page_pte(page)			page_pte_prot(page, __pgprot(0))

#define pte_none(pte) 			(!pte_val(pte))
#define pte_present(pte)		(pte_val(pte) & (_PAGE_P | _PAGE_PROTNONE))
#define pte_clear(pte)			(pte_val(*(pte)) = 0UL)
/* pte_page() returns the "struct page *" corresponding to the PTE: */
#define pte_page(pte)			(mem_map + (unsigned long) ((pte_val(pte) & _PFN_MASK) >> PAGE_SHIFT))

#define pmd_set(pmdp, ptep) 		(pmd_val(*(pmdp)) = __pa(ptep))
#define pmd_none(pmd)			(!pmd_val(pmd))
#define pmd_bad(pmd)			(!ia64_phys_addr_valid(pmd_val(pmd)))
#define pmd_present(pmd)		(pmd_val(pmd) != 0UL)
#define pmd_clear(pmdp)			(pmd_val(*(pmdp)) = 0UL)
#define pmd_page(pmd)			((unsigned long) __va(pmd_val(pmd) & _PFN_MASK))

#define pgd_set(pgdp, pmdp)		(pgd_val(*(pgdp)) = __pa(pmdp))
#define pgd_none(pgd)			(!pgd_val(pgd))
#define pgd_bad(pgd)			(!ia64_phys_addr_valid(pgd_val(pgd)))
#define pgd_present(pgd)		(pgd_val(pgd) != 0UL)
#define pgd_clear(pgdp)			(pgd_val(*(pgdp)) = 0UL)
#define pgd_page(pgd)			((unsigned long) __va(pgd_val(pgd) & _PFN_MASK))

/*
 * The following have defined behavior only work if pte_present() is true.
 */
#define pte_read(pte)		(((pte_val(pte) & _PAGE_AR_MASK) >> _PAGE_AR_SHIFT) < 6)
#define pte_write(pte)	((unsigned) (((pte_val(pte) & _PAGE_AR_MASK) >> _PAGE_AR_SHIFT) - 2) <= 4)
#define pte_exec(pte)		((pte_val(pte) & _PAGE_AR_RX) != 0)
#define pte_dirty(pte)		((pte_val(pte) & _PAGE_D) != 0)
#define pte_young(pte)		((pte_val(pte) & _PAGE_A) != 0)
/*
 * Note: we convert AR_RWX to AR_RX and AR_RW to AR_R by clearing the 2nd bit in the
 * access rights:
 */
#define pte_wrprotect(pte)	(__pte(pte_val(pte) & ~_PAGE_AR_RW))
#define pte_mkwrite(pte)	(__pte(pte_val(pte) | _PAGE_AR_RW))
#define pte_mkexec(pte)		(__pte(pte_val(pte) | _PAGE_AR_RX))
#define pte_mkold(pte)		(__pte(pte_val(pte) & ~_PAGE_A))
#define pte_mkyoung(pte)	(__pte(pte_val(pte) | _PAGE_A))
#define pte_mkclean(pte)	(__pte(pte_val(pte) & ~_PAGE_D))
#define pte_mkdirty(pte)	(__pte(pte_val(pte) | _PAGE_D))

/*
 * Macro to make mark a page protection value as "uncacheable".  Note
 * that "protection" is really a misnomer here as the protection value
 * contains the memory attribute bits, dirty bits, and various other
 * bits as well.
 */
#define pgprot_noncached(prot)		__pgprot((pgprot_val(prot) & ~_PAGE_MA_MASK) | _PAGE_MA_UC)

/*
 * Macro to make mark a page protection value as "write-combining".
 * Note that "protection" is really a misnomer here as the protection
 * value contains the memory attribute bits, dirty bits, and various
 * other bits as well.  Accesses through a write-combining translation
 * works bypasses the caches, but does allow for consecutive writes to
 * be combined into single (but larger) write transactions.
 */
#define pgprot_writecombine(prot)	__pgprot((pgprot_val(prot) & ~_PAGE_MA_MASK) | _PAGE_MA_WC)

/*
 * Return the region index for virtual address ADDRESS.
 */
static inline unsigned long
rgn_index (unsigned long address)
{
	ia64_va a;

	a.l = address;
	return a.f.reg;
}

/*
 * Return the region offset for virtual address ADDRESS.
 */
static inline unsigned long
rgn_offset (unsigned long address)
{
	ia64_va a;

	a.l = address;
	return a.f.off;
}

static inline unsigned long
pgd_index (unsigned long address)
{
	unsigned long region = address >> 61;
	unsigned long l1index = (address >> PGDIR_SHIFT) & ((PTRS_PER_PGD >> 3) - 1);

	return (region << (PAGE_SHIFT - 6)) | l1index;
}

/* The offset in the 1-level directory is given by the 3 region bits
   (61..63) and the seven level-1 bits (33-39).  */
static inline pgd_t*
pgd_offset (struct mm_struct *mm, unsigned long address)
{
	return mm->pgd + pgd_index(address);
}

/* In the kernel's mapped region we have a full 43 bit space available and completely
   ignore the region number (since we know its in region number 5). */
#define pgd_offset_k(addr) \
	(init_mm.pgd + (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1)))

/* Find an entry in the second-level page table.. */
#define pmd_offset(dir,addr) \
	((pmd_t *) pgd_page(*(dir)) + (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1)))

/* Find an entry in the third-level page table.. */
#define pte_offset(dir,addr) \
	((pte_t *) pmd_page(*(dir)) + (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)))

/* atomic versions of the some PTE manipulations: */

static inline int
ptep_test_and_clear_young (pte_t *ptep)
{
#ifdef CONFIG_SMP
	return test_and_clear_bit(_PAGE_A_BIT, ptep);
#else
	pte_t pte = *ptep;
	if (!pte_young(pte))
		return 0;
	set_pte(ptep, pte_mkold(pte));
	return 1;
#endif
}

static inline int
ptep_test_and_clear_dirty (pte_t *ptep)
{
#ifdef CONFIG_SMP
	return test_and_clear_bit(_PAGE_D_BIT, ptep);
#else
	pte_t pte = *ptep;
	if (!pte_dirty(pte))
		return 0;
	set_pte(ptep, pte_mkclean(pte));
	return 1;
#endif
}

static inline pte_t
ptep_get_and_clear (pte_t *ptep)
{
#ifdef CONFIG_SMP
	return __pte(xchg((long *) ptep, 0));
#else
	pte_t pte = *ptep;
	pte_clear(ptep);
	return pte;
#endif
}

static inline void
ptep_set_wrprotect (pte_t *ptep)
{
#ifdef CONFIG_SMP
	unsigned long new, old;

	do {
		old = pte_val(*ptep);
		new = pte_val(pte_wrprotect(__pte (old)));
	} while (cmpxchg((unsigned long *) ptep, old, new) != old);
#else
	pte_t old_pte = *ptep;
	set_pte(ptep, pte_wrprotect(old_pte));
#endif
}

static inline void
ptep_mkdirty (pte_t *ptep)
{
#ifdef CONFIG_SMP
	set_bit(_PAGE_D_BIT, ptep);
#else
	pte_t old_pte = *ptep;
	set_pte(ptep, pte_mkdirty(old_pte));
#endif
}

static inline int
pte_same (pte_t a, pte_t b)
{
	return pte_val(a) == pte_val(b);
}

/*
 * Macros to check the type of access that triggered a page fault.
 */

static inline int
is_write_access (int access_type)
{
	return (access_type & 0x2);
}

static inline int
is_exec_access (int access_type)
{
	return (access_type & 0x4);
}

extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
extern void paging_init (void);

#define SWP_TYPE(entry)			(((entry).val >> 1) & 0xff)
#define SWP_OFFSET(entry)		(((entry).val << 1) >> 10)
#define SWP_ENTRY(type,offset)		((swp_entry_t) { ((type) << 1) | ((offset) << 9) })
#define pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
#define swp_entry_to_pte(x)		((pte_t) { (x).val })

/* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
#define PageSkip(page)		(0)

#define io_remap_page_range remap_page_range	/* XXX is this right? */

/*
 * ZERO_PAGE is a global shared page that is always zero: used
 * for zero-mapped memory areas etc..
 */
extern unsigned long empty_zero_page[PAGE_SIZE/sizeof(unsigned long)];
#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))

/* We provide our own get_unmapped_area to cope with VA holes for userland */
#define HAVE_ARCH_UNMAPPED_AREA

# endif /* !__ASSEMBLY__ */

#endif /* _ASM_IA64_PGTABLE_H */