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linux-2.6/include/asm-sh/pgtable_32.h
Nick Piggin 7e675137a8 mm: introduce pte_special pte bit 
s390 for one, cannot implement VM_MIXEDMAP with pfn_valid, due to their memory
model (which is more dynamic than most).  Instead, they had proposed to
implement it with an additional path through vm_normal_page(), using a bit in
the pte to determine whether or not the page should be refcounted:

vm_normal_page()
{
	...
        if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
                if (vma->vm_flags & VM_MIXEDMAP) {
#ifdef s390
			if (!mixedmap_refcount_pte(pte))
				return NULL;
#else
                        if (!pfn_valid(pfn))
                                return NULL;
#endif
                        goto out;
                }
	...
}

This is fine, however if we are allowed to use a bit in the pte to determine
refcountedness, we can use that to _completely_ replace all the vma based
schemes.  So instead of adding more cases to the already complex vma-based
scheme, we can have a clearly seperate and simple pte-based scheme (and get
slightly better code generation in the process):

vm_normal_page()
{
#ifdef s390
	if (!mixedmap_refcount_pte(pte))
		return NULL;
	return pte_page(pte);
#else
	...
#endif
}

And finally, we may rather make this concept usable by any architecture rather
than making it s390 only, so implement a new type of pte state for this.
Unfortunately the old vma based code must stay, because some architectures may
not be able to spare pte bits.  This makes vm_normal_page a little bit more
ugly than we would like, but the 2 cases are clearly seperate.

So introduce a pte_special pte state, and use it in mm/memory.c.  It is
currently a noop for all architectures, so this doesn't actually result in any
compiled code changes to mm/memory.o.

BTW:
I haven't put vm_normal_page() into arch code as-per an earlier suggestion.
The reason is that, regardless of where vm_normal_page is actually
implemented, the *abstraction* is still exactly the same. Also, while it
depends on whether the architecture has pte_special or not, that is the
only two possible cases, and it really isn't an arch specific function --
the role of the arch code should be to provide primitive functions and
accessors with which to build the core code; pte_special does that. We do
not want architectures to know or care about vm_normal_page itself, and
we definitely don't want them being able to invent something new there
out of sight of mm/ code. If we made vm_normal_page an arch function, then
we have to make vm_insert_mixed (next patch) an arch function too. So I
don't think moving it to arch code fundamentally improves any abstractions,
while it does practically make the code more difficult to follow, for both
mm and arch developers, and easier to misuse.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Carsten Otte <cotte@de.ibm.com>
Cc: Jared Hulbert <jaredeh@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:23 -07:00

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#ifndef __ASM_SH_PGTABLE_32_H
#define __ASM_SH_PGTABLE_32_H
/*
* Linux PTEL encoding.
*
* Hardware and software bit definitions for the PTEL value (see below for
* notes on SH-X2 MMUs and 64-bit PTEs):
*
* - Bits 0 and 7 are reserved on SH-3 (_PAGE_WT and _PAGE_SZ1 on SH-4).
*
* - Bit 1 is the SH-bit, but is unused on SH-3 due to an MMU bug (the
* hardware PTEL value can't have the SH-bit set when MMUCR.IX is set,
* which is the default in cpu-sh3/mmu_context.h:MMU_CONTROL_INIT).
*
* In order to keep this relatively clean, do not use these for defining
* SH-3 specific flags until all of the other unused bits have been
* exhausted.
*
* - Bit 9 is reserved by everyone and used by _PAGE_PROTNONE.
*
* - Bits 10 and 11 are low bits of the PPN that are reserved on >= 4K pages.
* Bit 10 is used for _PAGE_ACCESSED, bit 11 remains unused.
*
* - On 29 bit platforms, bits 31 to 29 are used for the space attributes
* and timing control which (together with bit 0) are moved into the
* old-style PTEA on the parts that support it.
*
* XXX: Leave the _PAGE_FILE and _PAGE_WT overhaul for a rainy day.
*
* SH-X2 MMUs and extended PTEs
*
* SH-X2 supports an extended mode TLB with split data arrays due to the
* number of bits needed for PR and SZ (now EPR and ESZ) encodings. The PR and
* SZ bit placeholders still exist in data array 1, but are implemented as
* reserved bits, with the real logic existing in data array 2.
*
* The downside to this is that we can no longer fit everything in to a 32-bit
* PTE encoding, so a 64-bit pte_t is necessary for these parts. On the plus
* side, this gives us quite a few spare bits to play with for future usage.
*/
/* Legacy and compat mode bits */
#define _PAGE_WT 0x001 /* WT-bit on SH-4, 0 on SH-3 */
#define _PAGE_HW_SHARED 0x002 /* SH-bit : shared among processes */
#define _PAGE_DIRTY 0x004 /* D-bit : page changed */
#define _PAGE_CACHABLE 0x008 /* C-bit : cachable */
#define _PAGE_SZ0 0x010 /* SZ0-bit : Size of page */
#define _PAGE_RW 0x020 /* PR0-bit : write access allowed */
#define _PAGE_USER 0x040 /* PR1-bit : user space access allowed*/
#define _PAGE_SZ1 0x080 /* SZ1-bit : Size of page (on SH-4) */
#define _PAGE_PRESENT 0x100 /* V-bit : page is valid */
#define _PAGE_PROTNONE 0x200 /* software: if not present */
#define _PAGE_ACCESSED 0x400 /* software: page referenced */
#define _PAGE_FILE _PAGE_WT /* software: pagecache or swap? */
#define _PAGE_SZ_MASK (_PAGE_SZ0 | _PAGE_SZ1)
#define _PAGE_PR_MASK (_PAGE_RW | _PAGE_USER)
/* Extended mode bits */
#define _PAGE_EXT_ESZ0 0x0010 /* ESZ0-bit: Size of page */
#define _PAGE_EXT_ESZ1 0x0020 /* ESZ1-bit: Size of page */
#define _PAGE_EXT_ESZ2 0x0040 /* ESZ2-bit: Size of page */
#define _PAGE_EXT_ESZ3 0x0080 /* ESZ3-bit: Size of page */
#define _PAGE_EXT_USER_EXEC 0x0100 /* EPR0-bit: User space executable */
#define _PAGE_EXT_USER_WRITE 0x0200 /* EPR1-bit: User space writable */
#define _PAGE_EXT_USER_READ 0x0400 /* EPR2-bit: User space readable */
#define _PAGE_EXT_KERN_EXEC 0x0800 /* EPR3-bit: Kernel space executable */
#define _PAGE_EXT_KERN_WRITE 0x1000 /* EPR4-bit: Kernel space writable */
#define _PAGE_EXT_KERN_READ 0x2000 /* EPR5-bit: Kernel space readable */
/* Wrapper for extended mode pgprot twiddling */
#define _PAGE_EXT(x) ((unsigned long long)(x) << 32)
/* software: moves to PTEA.TC (Timing Control) */
#define _PAGE_PCC_AREA5 0x00000000 /* use BSC registers for area5 */
#define _PAGE_PCC_AREA6 0x80000000 /* use BSC registers for area6 */
/* software: moves to PTEA.SA[2:0] (Space Attributes) */
#define _PAGE_PCC_IODYN 0x00000001 /* IO space, dynamically sized bus */
#define _PAGE_PCC_IO8 0x20000000 /* IO space, 8 bit bus */
#define _PAGE_PCC_IO16 0x20000001 /* IO space, 16 bit bus */
#define _PAGE_PCC_COM8 0x40000000 /* Common Memory space, 8 bit bus */
#define _PAGE_PCC_COM16 0x40000001 /* Common Memory space, 16 bit bus */
#define _PAGE_PCC_ATR8 0x60000000 /* Attribute Memory space, 8 bit bus */
#define _PAGE_PCC_ATR16 0x60000001 /* Attribute Memory space, 6 bit bus */
/* Mask which drops unused bits from the PTEL value */
#if defined(CONFIG_CPU_SH3)
#define _PAGE_CLEAR_FLAGS (_PAGE_PROTNONE | _PAGE_ACCESSED| \
_PAGE_FILE | _PAGE_SZ1 | \
_PAGE_HW_SHARED)
#elif defined(CONFIG_X2TLB)
/* Get rid of the legacy PR/SZ bits when using extended mode */
#define _PAGE_CLEAR_FLAGS (_PAGE_PROTNONE | _PAGE_ACCESSED | \
_PAGE_FILE | _PAGE_PR_MASK | _PAGE_SZ_MASK)
#else
#define _PAGE_CLEAR_FLAGS (_PAGE_PROTNONE | _PAGE_ACCESSED | _PAGE_FILE)
#endif
#define _PAGE_FLAGS_HARDWARE_MASK (PHYS_ADDR_MASK & ~(_PAGE_CLEAR_FLAGS))
/* Hardware flags, page size encoding */
#if defined(CONFIG_X2TLB)
# if defined(CONFIG_PAGE_SIZE_4KB)
# define _PAGE_FLAGS_HARD _PAGE_EXT(_PAGE_EXT_ESZ0)
# elif defined(CONFIG_PAGE_SIZE_8KB)
# define _PAGE_FLAGS_HARD _PAGE_EXT(_PAGE_EXT_ESZ1)
# elif defined(CONFIG_PAGE_SIZE_64KB)
# define _PAGE_FLAGS_HARD _PAGE_EXT(_PAGE_EXT_ESZ2)
# endif
#else
# if defined(CONFIG_PAGE_SIZE_4KB)
# define _PAGE_FLAGS_HARD _PAGE_SZ0
# elif defined(CONFIG_PAGE_SIZE_64KB)
# define _PAGE_FLAGS_HARD _PAGE_SZ1
# endif
#endif
#if defined(CONFIG_X2TLB)
# if defined(CONFIG_HUGETLB_PAGE_SIZE_64K)
# define _PAGE_SZHUGE (_PAGE_EXT_ESZ2)
# elif defined(CONFIG_HUGETLB_PAGE_SIZE_256K)
# define _PAGE_SZHUGE (_PAGE_EXT_ESZ0 | _PAGE_EXT_ESZ2)
# elif defined(CONFIG_HUGETLB_PAGE_SIZE_1MB)
# define _PAGE_SZHUGE (_PAGE_EXT_ESZ0 | _PAGE_EXT_ESZ1 | _PAGE_EXT_ESZ2)
# elif defined(CONFIG_HUGETLB_PAGE_SIZE_4MB)
# define _PAGE_SZHUGE (_PAGE_EXT_ESZ3)
# elif defined(CONFIG_HUGETLB_PAGE_SIZE_64MB)
# define _PAGE_SZHUGE (_PAGE_EXT_ESZ2 | _PAGE_EXT_ESZ3)
# endif
#else
# if defined(CONFIG_HUGETLB_PAGE_SIZE_64K)
# define _PAGE_SZHUGE (_PAGE_SZ1)
# elif defined(CONFIG_HUGETLB_PAGE_SIZE_1MB)
# define _PAGE_SZHUGE (_PAGE_SZ0 | _PAGE_SZ1)
# endif
#endif
/*
* Stub out _PAGE_SZHUGE if we don't have a good definition for it,
* to make pte_mkhuge() happy.
*/
#ifndef _PAGE_SZHUGE
# define _PAGE_SZHUGE (_PAGE_FLAGS_HARD)
#endif
#define _PAGE_CHG_MASK \
(PTE_MASK | _PAGE_ACCESSED | _PAGE_CACHABLE | _PAGE_DIRTY)
#ifndef __ASSEMBLY__
#if defined(CONFIG_X2TLB) /* SH-X2 TLB */
#define PAGE_NONE __pgprot(_PAGE_PROTNONE | _PAGE_CACHABLE | \
_PAGE_ACCESSED | _PAGE_FLAGS_HARD)
#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
_PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
_PAGE_EXT(_PAGE_EXT_KERN_READ | \
_PAGE_EXT_KERN_WRITE | \
_PAGE_EXT_USER_READ | \
_PAGE_EXT_USER_WRITE))
#define PAGE_EXECREAD __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
_PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
_PAGE_EXT(_PAGE_EXT_KERN_EXEC | \
_PAGE_EXT_KERN_READ | \
_PAGE_EXT_USER_EXEC | \
_PAGE_EXT_USER_READ))
#define PAGE_COPY PAGE_EXECREAD
#define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
_PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
_PAGE_EXT(_PAGE_EXT_KERN_READ | \
_PAGE_EXT_USER_READ))
#define PAGE_WRITEONLY __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
_PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
_PAGE_EXT(_PAGE_EXT_KERN_WRITE | \
_PAGE_EXT_USER_WRITE))
#define PAGE_RWX __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
_PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
_PAGE_EXT(_PAGE_EXT_KERN_WRITE | \
_PAGE_EXT_KERN_READ | \
_PAGE_EXT_KERN_EXEC | \
_PAGE_EXT_USER_WRITE | \
_PAGE_EXT_USER_READ | \
_PAGE_EXT_USER_EXEC))
#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_CACHABLE | \
_PAGE_DIRTY | _PAGE_ACCESSED | \
_PAGE_HW_SHARED | _PAGE_FLAGS_HARD | \
_PAGE_EXT(_PAGE_EXT_KERN_READ | \
_PAGE_EXT_KERN_WRITE | \
_PAGE_EXT_KERN_EXEC))
#define PAGE_KERNEL_NOCACHE \
__pgprot(_PAGE_PRESENT | _PAGE_DIRTY | \
_PAGE_ACCESSED | _PAGE_HW_SHARED | \
_PAGE_FLAGS_HARD | \
_PAGE_EXT(_PAGE_EXT_KERN_READ | \
_PAGE_EXT_KERN_WRITE | \
_PAGE_EXT_KERN_EXEC))
#define PAGE_KERNEL_RO __pgprot(_PAGE_PRESENT | _PAGE_CACHABLE | \
_PAGE_DIRTY | _PAGE_ACCESSED | \
_PAGE_HW_SHARED | _PAGE_FLAGS_HARD | \
_PAGE_EXT(_PAGE_EXT_KERN_READ | \
_PAGE_EXT_KERN_EXEC))
#define PAGE_KERNEL_PCC(slot, type) \
__pgprot(_PAGE_PRESENT | _PAGE_DIRTY | \
_PAGE_ACCESSED | _PAGE_FLAGS_HARD | \
_PAGE_EXT(_PAGE_EXT_KERN_READ | \
_PAGE_EXT_KERN_WRITE | \
_PAGE_EXT_KERN_EXEC) \
(slot ? _PAGE_PCC_AREA5 : _PAGE_PCC_AREA6) | \
(type))
#elif defined(CONFIG_MMU) /* SH-X TLB */
#define PAGE_NONE __pgprot(_PAGE_PROTNONE | _PAGE_CACHABLE | \
_PAGE_ACCESSED | _PAGE_FLAGS_HARD)
#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \
_PAGE_CACHABLE | _PAGE_ACCESSED | \
_PAGE_FLAGS_HARD)
#define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_CACHABLE | \
_PAGE_ACCESSED | _PAGE_FLAGS_HARD)
#define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_CACHABLE | \
_PAGE_ACCESSED | _PAGE_FLAGS_HARD)
#define PAGE_EXECREAD PAGE_READONLY
#define PAGE_RWX PAGE_SHARED
#define PAGE_WRITEONLY PAGE_SHARED
#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_CACHABLE | \
_PAGE_DIRTY | _PAGE_ACCESSED | \
_PAGE_HW_SHARED | _PAGE_FLAGS_HARD)
#define PAGE_KERNEL_NOCACHE \
__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | \
_PAGE_ACCESSED | _PAGE_HW_SHARED | \
_PAGE_FLAGS_HARD)
#define PAGE_KERNEL_RO __pgprot(_PAGE_PRESENT | _PAGE_CACHABLE | \
_PAGE_DIRTY | _PAGE_ACCESSED | \
_PAGE_HW_SHARED | _PAGE_FLAGS_HARD)
#define PAGE_KERNEL_PCC(slot, type) \
__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | \
_PAGE_ACCESSED | _PAGE_FLAGS_HARD | \
(slot ? _PAGE_PCC_AREA5 : _PAGE_PCC_AREA6) | \
(type))
#else /* no mmu */
#define PAGE_NONE __pgprot(0)
#define PAGE_SHARED __pgprot(0)
#define PAGE_COPY __pgprot(0)
#define PAGE_EXECREAD __pgprot(0)
#define PAGE_RWX __pgprot(0)
#define PAGE_READONLY __pgprot(0)
#define PAGE_WRITEONLY __pgprot(0)
#define PAGE_KERNEL __pgprot(0)
#define PAGE_KERNEL_NOCACHE __pgprot(0)
#define PAGE_KERNEL_RO __pgprot(0)
#define PAGE_KERNEL_PCC(slot, type) \
__pgprot(0)
#endif
#endif /* __ASSEMBLY__ */
#ifndef __ASSEMBLY__
/*
* Certain architectures need to do special things when PTEs
* within a page table are directly modified. Thus, the following
* hook is made available.
*/
#ifdef CONFIG_X2TLB
static inline void set_pte(pte_t *ptep, pte_t pte)
{
ptep->pte_high = pte.pte_high;
smp_wmb();
ptep->pte_low = pte.pte_low;
}
#else
#define set_pte(pteptr, pteval) (*(pteptr) = pteval)
#endif
#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
/*
* (pmds are folded into pgds so this doesn't get actually called,
* but the define is needed for a generic inline function.)
*/
#define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
#define pfn_pte(pfn, prot) \
__pte(((unsigned long long)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
#define pfn_pmd(pfn, prot) \
__pmd(((unsigned long long)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
#define pte_none(x) (!pte_val(x))
#define pte_present(x) ((x).pte_low & (_PAGE_PRESENT | _PAGE_PROTNONE))
#define pte_clear(mm,addr,xp) do { set_pte_at(mm, addr, xp, __pte(0)); } while (0)
#define pmd_none(x) (!pmd_val(x))
#define pmd_present(x) (pmd_val(x))
#define pmd_clear(xp) do { set_pmd(xp, __pmd(0)); } while (0)
#define pmd_bad(x) (pmd_val(x) & ~PAGE_MASK)
#define pages_to_mb(x) ((x) >> (20-PAGE_SHIFT))
#define pte_page(x) pfn_to_page(pte_pfn(x))
/*
* The following only work if pte_present() is true.
* Undefined behaviour if not..
*/
#define pte_not_present(pte) (!((pte).pte_low & _PAGE_PRESENT))
#define pte_dirty(pte) ((pte).pte_low & _PAGE_DIRTY)
#define pte_young(pte) ((pte).pte_low & _PAGE_ACCESSED)
#define pte_file(pte) ((pte).pte_low & _PAGE_FILE)
#define pte_special(pte) (0)
#ifdef CONFIG_X2TLB
#define pte_write(pte) ((pte).pte_high & _PAGE_EXT_USER_WRITE)
#else
#define pte_write(pte) ((pte).pte_low & _PAGE_RW)
#endif
#define PTE_BIT_FUNC(h,fn,op) \
static inline pte_t pte_##fn(pte_t pte) { pte.pte_##h op; return pte; }
#ifdef CONFIG_X2TLB
/*
* We cheat a bit in the SH-X2 TLB case. As the permission bits are
* individually toggled (and user permissions are entirely decoupled from
* kernel permissions), we attempt to couple them a bit more sanely here.
*/
PTE_BIT_FUNC(high, wrprotect, &= ~_PAGE_EXT_USER_WRITE);
PTE_BIT_FUNC(high, mkwrite, |= _PAGE_EXT_USER_WRITE | _PAGE_EXT_KERN_WRITE);
PTE_BIT_FUNC(high, mkhuge, |= _PAGE_SZHUGE);
#else
PTE_BIT_FUNC(low, wrprotect, &= ~_PAGE_RW);
PTE_BIT_FUNC(low, mkwrite, |= _PAGE_RW);
PTE_BIT_FUNC(low, mkhuge, |= _PAGE_SZHUGE);
#endif
PTE_BIT_FUNC(low, mkclean, &= ~_PAGE_DIRTY);
PTE_BIT_FUNC(low, mkdirty, |= _PAGE_DIRTY);
PTE_BIT_FUNC(low, mkold, &= ~_PAGE_ACCESSED);
PTE_BIT_FUNC(low, mkyoung, |= _PAGE_ACCESSED);
static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
/*
* Macro and implementation to make a page protection as uncachable.
*/
#define pgprot_writecombine(prot) \
__pgprot(pgprot_val(prot) & ~_PAGE_CACHABLE)
#define pgprot_noncached pgprot_writecombine
/*
* Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directory to the page they refer to.
*
* extern pte_t mk_pte(struct page *page, pgprot_t pgprot)
*/
#define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot))
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
pte.pte_low &= _PAGE_CHG_MASK;
pte.pte_low |= pgprot_val(newprot);
#ifdef CONFIG_X2TLB
pte.pte_high |= pgprot_val(newprot) >> 32;
#endif
return pte;
}
#define pmd_page_vaddr(pmd) ((unsigned long)pmd_val(pmd))
#define pmd_page(pmd) (virt_to_page(pmd_val(pmd)))
/* to find an entry in a page-table-directory. */
#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
#define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
/* to find an entry in a kernel page-table-directory */
#define pgd_offset_k(address) pgd_offset(&init_mm, address)
/* 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, address) \
((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(address))
#define pte_offset_map(dir, address) pte_offset_kernel(dir, address)
#define pte_offset_map_nested(dir, address) pte_offset_kernel(dir, address)
#define pte_unmap(pte) do { } while (0)
#define pte_unmap_nested(pte) do { } while (0)
#ifdef CONFIG_X2TLB
#define pte_ERROR(e) \
printk("%s:%d: bad pte %p(%08lx%08lx).\n", __FILE__, __LINE__, \
&(e), (e).pte_high, (e).pte_low)
#define pgd_ERROR(e) \
printk("%s:%d: bad pgd %016llx.\n", __FILE__, __LINE__, pgd_val(e))
#else
#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 %08lx.\n", __FILE__, __LINE__, pgd_val(e))
#endif
/*
* Encode and de-code a swap entry
*
* Constraints:
* _PAGE_FILE at bit 0
* _PAGE_PRESENT at bit 8
* _PAGE_PROTNONE at bit 9
*
* For the normal case, we encode the swap type into bits 0:7 and the
* swap offset into bits 10:30. For the 64-bit PTE case, we keep the
* preserved bits in the low 32-bits and use the upper 32 as the swap
* offset (along with a 5-bit type), following the same approach as x86
* PAE. This keeps the logic quite simple, and allows for a full 32
* PTE_FILE_MAX_BITS, as opposed to the 29-bits we're constrained with
* in the pte_low case.
*
* As is evident by the Alpha code, if we ever get a 64-bit unsigned
* long (swp_entry_t) to match up with the 64-bit PTEs, this all becomes
* much cleaner..
*
* NOTE: We should set ZEROs at the position of _PAGE_PRESENT
* and _PAGE_PROTNONE bits
*/
#ifdef CONFIG_X2TLB
#define __swp_type(x) ((x).val & 0x1f)
#define __swp_offset(x) ((x).val >> 5)
#define __swp_entry(type, offset) ((swp_entry_t){ (type) | (offset) << 5})
#define __pte_to_swp_entry(pte) ((swp_entry_t){ (pte).pte_high })
#define __swp_entry_to_pte(x) ((pte_t){ 0, (x).val })
/*
* Encode and decode a nonlinear file mapping entry
*/
#define pte_to_pgoff(pte) ((pte).pte_high)
#define pgoff_to_pte(off) ((pte_t) { _PAGE_FILE, (off) })
#define PTE_FILE_MAX_BITS 32
#else
#define __swp_type(x) ((x).val & 0xff)
#define __swp_offset(x) ((x).val >> 10)
#define __swp_entry(type, offset) ((swp_entry_t){(type) | (offset) <<10})
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) >> 1 })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val << 1 })
/*
* Encode and decode a nonlinear file mapping entry
*/
#define PTE_FILE_MAX_BITS 29
#define pte_to_pgoff(pte) (pte_val(pte) >> 1)
#define pgoff_to_pte(off) ((pte_t) { ((off) << 1) | _PAGE_FILE })
#endif
#endif /* __ASSEMBLY__ */
#endif /* __ASM_SH_PGTABLE_32_H */
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