alistair23-linux/arch/powerpc/include/asm/pgtable.h

#ifndef _ASM_POWERPC_PGTABLE_H
#define _ASM_POWERPC_PGTABLE_H
#ifdef __KERNEL__

#ifndef __ASSEMBLY__
#include <asm/processor.h>		/* For TASK_SIZE */
#include <asm/mmu.h>
#include <asm/page.h>

struct mm_struct;

#ifdef CONFIG_DEBUG_VM
extern void assert_pte_locked(struct mm_struct *mm, unsigned long addr);
#else /* CONFIG_DEBUG_VM */
static inline void assert_pte_locked(struct mm_struct *mm, unsigned long addr)
{
}
#endif /* !CONFIG_DEBUG_VM */

#endif /* !__ASSEMBLY__ */

#if defined(CONFIG_PPC64)
#  include <asm/pgtable-ppc64.h>
#else
#  include <asm/pgtable-ppc32.h>
#endif

/* Special mapping for AGP */
#define PAGE_AGP	(PAGE_KERNEL_NC)
#define HAVE_PAGE_AGP

#ifndef __ASSEMBLY__

/* Insert a PTE, top-level function is out of line. It uses an inline
 * low level function in the respective pgtable-* files
 */
extern void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
		       pte_t pte);

/* This low level function performs the actual PTE insertion
 * Setting the PTE depends on the MMU type and other factors. It's
 * an horrible mess that I'm not going to try to clean up now but
 * I'm keeping it in one place rather than spread around
 */
static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
				pte_t *ptep, pte_t pte, int percpu)
{
#if defined(CONFIG_PPC_STD_MMU_32) && defined(CONFIG_SMP) && !defined(CONFIG_PTE_64BIT)
	/* First case is 32-bit Hash MMU in SMP mode with 32-bit PTEs. We use the
	 * helper pte_update() which does an atomic update. We need to do that
	 * because a concurrent invalidation can clear _PAGE_HASHPTE. If it's a
	 * per-CPU PTE such as a kmap_atomic, we do a simple update preserving
	 * the hash bits instead (ie, same as the non-SMP case)
	 */
	if (percpu)
		*ptep = __pte((pte_val(*ptep) & _PAGE_HASHPTE)
			      | (pte_val(pte) & ~_PAGE_HASHPTE));
	else
		pte_update(ptep, ~_PAGE_HASHPTE, pte_val(pte));

#elif defined(CONFIG_PPC32) && defined(CONFIG_PTE_64BIT) && defined(CONFIG_SMP)
	/* Second case is 32-bit with 64-bit PTE in SMP mode. In this case, we
	 * can just store as long as we do the two halves in the right order
	 * with a barrier in between. This is possible because we take care,
	 * in the hash code, to pre-invalidate if the PTE was already hashed,
	 * which synchronizes us with any concurrent invalidation.
	 * In the percpu case, we also fallback to the simple update preserving
	 * the hash bits
	 */
	if (percpu) {
		*ptep = __pte((pte_val(*ptep) & _PAGE_HASHPTE)
			      | (pte_val(pte) & ~_PAGE_HASHPTE));
		return;
	}
#if _PAGE_HASHPTE != 0
	if (pte_val(*ptep) & _PAGE_HASHPTE)
		flush_hash_entry(mm, ptep, addr);
#endif
	__asm__ __volatile__("\
		stw%U0%X0 %2,%0\n\
		eieio\n\
		stw%U0%X0 %L2,%1"
	: "=m" (*ptep), "=m" (*((unsigned char *)ptep+4))
	: "r" (pte) : "memory");

#elif defined(CONFIG_PPC_STD_MMU_32)
	/* Third case is 32-bit hash table in UP mode, we need to preserve
	 * the _PAGE_HASHPTE bit since we may not have invalidated the previous
	 * translation in the hash yet (done in a subsequent flush_tlb_xxx())
	 * and see we need to keep track that this PTE needs invalidating
	 */
	*ptep = __pte((pte_val(*ptep) & _PAGE_HASHPTE)
		      | (pte_val(pte) & ~_PAGE_HASHPTE));

#else
	/* Anything else just stores the PTE normally. That covers all 64-bit
	 * cases, and 32-bit non-hash with 64-bit PTEs in UP mode
	 */
	*ptep = pte;
#endif
}


#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
extern int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address,
				 pte_t *ptep, pte_t entry, int dirty);

/*
 * Macro to mark a page protection value as "uncacheable".
 */

#define _PAGE_CACHE_CTL	(_PAGE_COHERENT | _PAGE_GUARDED | _PAGE_NO_CACHE | \
			 _PAGE_WRITETHRU)

#define pgprot_noncached(prot)	  (__pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) | \
				            _PAGE_NO_CACHE | _PAGE_GUARDED))

#define pgprot_noncached_wc(prot) (__pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) | \
				            _PAGE_NO_CACHE))

#define pgprot_cached(prot)       (__pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) | \
				            _PAGE_COHERENT))

#define pgprot_cached_wthru(prot) (__pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) | \
				            _PAGE_COHERENT | _PAGE_WRITETHRU))


struct file;
extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
				     unsigned long size, pgprot_t vma_prot);
#define __HAVE_PHYS_MEM_ACCESS_PROT

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

extern pgd_t swapper_pg_dir[];

extern void paging_init(void);

/*
 * kern_addr_valid is intended to indicate whether an address is a valid
 * kernel address.  Most 32-bit archs define it as always true (like this)
 * but most 64-bit archs actually perform a test.  What should we do here?
 */
#define kern_addr_valid(addr)	(1)

#define io_remap_pfn_range(vma, vaddr, pfn, size, prot)		\
		remap_pfn_range(vma, vaddr, pfn, size, prot)

#include <asm-generic/pgtable.h>


/*
 * This gets called at the end of handling a page fault, when
 * the kernel has put a new PTE into the page table for the process.
 * We use it to ensure coherency between the i-cache and d-cache
 * for the page which has just been mapped in.
 * On machines which use an MMU hash table, we use this to put a
 * corresponding HPTE into the hash table ahead of time, instead of
 * waiting for the inevitable extra hash-table miss exception.
 */
extern void update_mmu_cache(struct vm_area_struct *, unsigned long, pte_t);

#endif /* __ASSEMBLY__ */

#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_PGTABLE_H */