1. 根目录:
2. arch
3. powerpc
4. include
5. asm
6. pte-common.h

/* Included from asm/pgtable-*.h only ! */

/*
 * Some bits are only used on some cpu families... Make sure that all
 * the undefined gets a sensible default
 */
#ifndef _PAGE_HASHPTE
#define _PAGE_HASHPTE	0
#endif
#ifndef _PAGE_SHARED
#define _PAGE_SHARED	0
#endif
#ifndef _PAGE_HWWRITE
#define _PAGE_HWWRITE	0
#endif
#ifndef _PAGE_EXEC
#define _PAGE_EXEC	0
#endif
#ifndef _PAGE_ENDIAN
#define _PAGE_ENDIAN	0
#endif
#ifndef _PAGE_COHERENT
#define _PAGE_COHERENT	0
#endif
#ifndef _PAGE_WRITETHRU
#define _PAGE_WRITETHRU	0
#endif
#ifndef _PAGE_4K_PFN
#define _PAGE_4K_PFN		0
#endif
#ifndef _PAGE_SAO
#define _PAGE_SAO	0
#endif
#ifndef _PAGE_PSIZE
#define _PAGE_PSIZE		0
#endif
#ifndef _PMD_PRESENT_MASK
#define _PMD_PRESENT_MASK	_PMD_PRESENT
#endif
#ifndef _PMD_SIZE
#define _PMD_SIZE	0
#define PMD_PAGE_SIZE(pmd)	bad_call_to_PMD_PAGE_SIZE()
#endif
#ifndef _PAGE_KERNEL_RO
#define _PAGE_KERNEL_RO		0
#endif
#ifndef _PAGE_KERNEL_ROX
#define _PAGE_KERNEL_ROX	(_PAGE_EXEC)
#endif
#ifndef _PAGE_KERNEL_RW
#define _PAGE_KERNEL_RW		(_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE)
#endif
#ifndef _PAGE_KERNEL_RWX
#define _PAGE_KERNEL_RWX	(_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE | _PAGE_EXEC)
#endif
#ifndef _PAGE_HPTEFLAGS
#define _PAGE_HPTEFLAGS _PAGE_HASHPTE
#endif
#ifndef _PTE_NONE_MASK
#define _PTE_NONE_MASK	_PAGE_HPTEFLAGS
#endif

/* Make sure we get a link error if PMD_PAGE_SIZE is ever called on a
 * kernel without large page PMD support
 */
#ifndef __ASSEMBLY__
extern unsigned long bad_call_to_PMD_PAGE_SIZE(void);
#endif /* __ASSEMBLY__ */

/* Location of the PFN in the PTE. Most 32-bit platforms use the same
 * as _PAGE_SHIFT here (ie, naturally aligned).
 * Platform who don't just pre-define the value so we don't override it here
 */
#ifndef PTE_RPN_SHIFT
#define PTE_RPN_SHIFT	(PAGE_SHIFT)
#endif

/* The mask convered by the RPN must be a ULL on 32-bit platforms with
 * 64-bit PTEs
 */
#if defined(CONFIG_PPC32) && defined(CONFIG_PTE_64BIT)
#define PTE_RPN_MAX	(1ULL << (64 - PTE_RPN_SHIFT))
#define PTE_RPN_MASK	(~((1ULL<<PTE_RPN_SHIFT)-1))
#else
#define PTE_RPN_MAX	(1UL << (32 - PTE_RPN_SHIFT))
#define PTE_RPN_MASK	(~((1UL<<PTE_RPN_SHIFT)-1))
#endif

/* _PAGE_CHG_MASK masks of bits that are to be preserved across
 * pgprot changes
 */
#define _PAGE_CHG_MASK	(PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \
                         _PAGE_ACCESSED | _PAGE_SPECIAL)

/* Mask of bits returned by pte_pgprot() */
#define PAGE_PROT_BITS	(_PAGE_GUARDED | _PAGE_COHERENT | _PAGE_NO_CACHE | \
			 _PAGE_WRITETHRU | _PAGE_ENDIAN | _PAGE_4K_PFN | \
			 _PAGE_USER | _PAGE_ACCESSED | \
			 _PAGE_RW | _PAGE_HWWRITE | _PAGE_DIRTY | _PAGE_EXEC)

/*
 * We define 2 sets of base prot bits, one for basic pages (ie,
 * cacheable kernel and user pages) and one for non cacheable
 * pages. We always set _PAGE_COHERENT when SMP is enabled or
 * the processor might need it for DMA coherency.
 */
#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_PSIZE)
#if defined(CONFIG_SMP) || defined(CONFIG_PPC_STD_MMU)
#define _PAGE_BASE	(_PAGE_BASE_NC | _PAGE_COHERENT)
#else
#define _PAGE_BASE	(_PAGE_BASE_NC)
#endif

/* Permission masks used to generate the __P and __S table,
 *
 * Note:__pgprot is defined in arch/powerpc/include/asm/page.h
 *
 * Write permissions imply read permissions for now (we could make write-only
 * pages on BookE but we don't bother for now). Execute permission control is
 * possible on platforms that define _PAGE_EXEC
 *
 * Note due to the way vm flags are laid out, the bits are XWR
 */
#define PAGE_NONE	__pgprot(_PAGE_BASE)
#define PAGE_SHARED	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW)
#define PAGE_SHARED_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC)
#define PAGE_COPY	__pgprot(_PAGE_BASE | _PAGE_USER)
#define PAGE_COPY_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
#define PAGE_READONLY	__pgprot(_PAGE_BASE | _PAGE_USER)
#define PAGE_READONLY_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)

#define __P000	PAGE_NONE
#define __P001	PAGE_READONLY
#define __P010	PAGE_COPY
#define __P011	PAGE_COPY
#define __P100	PAGE_READONLY_X
#define __P101	PAGE_READONLY_X
#define __P110	PAGE_COPY_X
#define __P111	PAGE_COPY_X

#define __S000	PAGE_NONE
#define __S001	PAGE_READONLY
#define __S010	PAGE_SHARED
#define __S011	PAGE_SHARED
#define __S100	PAGE_READONLY_X
#define __S101	PAGE_READONLY_X
#define __S110	PAGE_SHARED_X
#define __S111	PAGE_SHARED_X

/* Permission masks used for kernel mappings */
#define PAGE_KERNEL	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RW)
#define PAGE_KERNEL_NC	__pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | \
				 _PAGE_NO_CACHE)
#define PAGE_KERNEL_NCG	__pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | \
				 _PAGE_NO_CACHE | _PAGE_GUARDED)
#define PAGE_KERNEL_X	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RWX)
#define PAGE_KERNEL_RO	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RO)
#define PAGE_KERNEL_ROX	__pgprot(_PAGE_BASE | _PAGE_KERNEL_ROX)

/* Protection used for kernel text. We want the debuggers to be able to
 * set breakpoints anywhere, so don't write protect the kernel text
 * on platforms where such control is possible.
 */
#if defined(CONFIG_KGDB) || defined(CONFIG_XMON) || defined(CONFIG_BDI_SWITCH) ||\
	defined(CONFIG_KPROBES) || defined(CONFIG_DYNAMIC_FTRACE)
#define PAGE_KERNEL_TEXT	PAGE_KERNEL_X
#else
#define PAGE_KERNEL_TEXT	PAGE_KERNEL_ROX
#endif

/* Make modules code happy. We don't set RO yet */
#define PAGE_KERNEL_EXEC	PAGE_KERNEL_X

/*
 * Don't just check for any non zero bits in __PAGE_USER, since for book3e
 * and PTE_64BIT, PAGE_KERNEL_X contains _PAGE_BAP_SR which is also in
 * _PAGE_USER.  Need to explicitly match _PAGE_BAP_UR bit in that case too.
 */
#define pte_user(val)		((val & _PAGE_USER) == _PAGE_USER)

/* Advertise special mapping type for AGP */
#define PAGE_AGP		(PAGE_KERNEL_NC)
#define HAVE_PAGE_AGP

/* Advertise support for _PAGE_SPECIAL */
#define __HAVE_ARCH_PTE_SPECIAL