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linux/include/asm-sparc/pgtable.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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/* $Id: pgtable.h,v 1.110 2001/12/21 04:56:17 davem Exp $ */
#ifndef _SPARC_PGTABLE_H
#define _SPARC_PGTABLE_H
/* asm-sparc/pgtable.h: Defines and functions used to work
* with Sparc page tables.
*
* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
*/
#include <asm-generic/4level-fixup.h>
#include <linux/spinlock.h>
#include <linux/swap.h>
#include <asm/types.h>
#ifdef CONFIG_SUN4
#include <asm/pgtsun4.h>
#else
#include <asm/pgtsun4c.h>
#endif
#include <asm/pgtsrmmu.h>
#include <asm/vac-ops.h>
#include <asm/oplib.h>
#include <asm/btfixup.h>
#include <asm/system.h>
#ifndef __ASSEMBLY__
struct vm_area_struct;
struct page;
extern void load_mmu(void);
extern unsigned long calc_highpages(void);
BTFIXUPDEF_SIMM13(pgdir_shift)
BTFIXUPDEF_SETHI(pgdir_size)
BTFIXUPDEF_SETHI(pgdir_mask)
BTFIXUPDEF_SIMM13(ptrs_per_pmd)
BTFIXUPDEF_SIMM13(ptrs_per_pgd)
BTFIXUPDEF_SIMM13(user_ptrs_per_pgd)
#define pte_ERROR(e) __builtin_trap()
#define pmd_ERROR(e) __builtin_trap()
#define pgd_ERROR(e) __builtin_trap()
BTFIXUPDEF_INT(page_none)
BTFIXUPDEF_INT(page_copy)
BTFIXUPDEF_INT(page_readonly)
BTFIXUPDEF_INT(page_kernel)
#define PMD_SHIFT SUN4C_PMD_SHIFT
#define PMD_SIZE (1UL << PMD_SHIFT)
#define PMD_MASK (~(PMD_SIZE-1))
#define PMD_ALIGN(__addr) (((__addr) + ~PMD_MASK) & PMD_MASK)
#define PGDIR_SHIFT BTFIXUP_SIMM13(pgdir_shift)
#define PGDIR_SIZE BTFIXUP_SETHI(pgdir_size)
#define PGDIR_MASK BTFIXUP_SETHI(pgdir_mask)
#define PTRS_PER_PTE 1024
#define PTRS_PER_PMD BTFIXUP_SIMM13(ptrs_per_pmd)
#define PTRS_PER_PGD BTFIXUP_SIMM13(ptrs_per_pgd)
#define USER_PTRS_PER_PGD BTFIXUP_SIMM13(user_ptrs_per_pgd)
#define FIRST_USER_ADDRESS 0
#define PTE_SIZE (PTRS_PER_PTE*4)
#define PAGE_NONE __pgprot(BTFIXUP_INT(page_none))
extern pgprot_t PAGE_SHARED;
#define PAGE_COPY __pgprot(BTFIXUP_INT(page_copy))
#define PAGE_READONLY __pgprot(BTFIXUP_INT(page_readonly))
extern unsigned long page_kernel;
#ifdef MODULE
#define PAGE_KERNEL page_kernel
#else
#define PAGE_KERNEL __pgprot(BTFIXUP_INT(page_kernel))
#endif
/* Top-level page directory */
extern pgd_t swapper_pg_dir[1024];
extern void paging_init(void);
/* Page table for 0-4MB for everybody, on the Sparc this
* holds the same as on the i386.
*/
extern pte_t pg0[1024];
extern pte_t pg1[1024];
extern pte_t pg2[1024];
extern pte_t pg3[1024];
extern unsigned long ptr_in_current_pgd;
/* Here is a trick, since mmap.c need the initializer elements for
* protection_map[] to be constant at compile time, I set the following
* to all zeros. I set it to the real values after I link in the
* appropriate MMU page table routines at boot time.
*/
#define __P000 __pgprot(0)
#define __P001 __pgprot(0)
#define __P010 __pgprot(0)
#define __P011 __pgprot(0)
#define __P100 __pgprot(0)
#define __P101 __pgprot(0)
#define __P110 __pgprot(0)
#define __P111 __pgprot(0)
#define __S000 __pgprot(0)
#define __S001 __pgprot(0)
#define __S010 __pgprot(0)
#define __S011 __pgprot(0)
#define __S100 __pgprot(0)
#define __S101 __pgprot(0)
#define __S110 __pgprot(0)
#define __S111 __pgprot(0)
extern int num_contexts;
/* First physical page can be anywhere, the following is needed so that
* va-->pa and vice versa conversions work properly without performance
* hit for all __pa()/__va() operations.
*/
extern unsigned long phys_base;
extern unsigned long pfn_base;
/*
* 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_pagetable(void);
extern pte_t __bad_page(void);
extern unsigned long empty_zero_page;
#define BAD_PAGETABLE __bad_pagetable()
#define BAD_PAGE __bad_page()
#define ZERO_PAGE(vaddr) (virt_to_page(&empty_zero_page))
/*
*/
BTFIXUPDEF_CALL_CONST(struct page *, pmd_page, pmd_t)
BTFIXUPDEF_CALL_CONST(unsigned long, pgd_page_vaddr, pgd_t)
#define pmd_page(pmd) BTFIXUP_CALL(pmd_page)(pmd)
#define pgd_page_vaddr(pgd) BTFIXUP_CALL(pgd_page_vaddr)(pgd)
BTFIXUPDEF_SETHI(none_mask)
BTFIXUPDEF_CALL_CONST(int, pte_present, pte_t)
BTFIXUPDEF_CALL(void, pte_clear, pte_t *)
static inline int pte_none(pte_t pte)
{
return !(pte_val(pte) & ~BTFIXUP_SETHI(none_mask));
}
#define pte_present(pte) BTFIXUP_CALL(pte_present)(pte)
#define pte_clear(mm,addr,pte) BTFIXUP_CALL(pte_clear)(pte)
BTFIXUPDEF_CALL_CONST(int, pmd_bad, pmd_t)
BTFIXUPDEF_CALL_CONST(int, pmd_present, pmd_t)
BTFIXUPDEF_CALL(void, pmd_clear, pmd_t *)
static inline int pmd_none(pmd_t pmd)
{
return !(pmd_val(pmd) & ~BTFIXUP_SETHI(none_mask));
}
#define pmd_bad(pmd) BTFIXUP_CALL(pmd_bad)(pmd)
#define pmd_present(pmd) BTFIXUP_CALL(pmd_present)(pmd)
#define pmd_clear(pmd) BTFIXUP_CALL(pmd_clear)(pmd)
BTFIXUPDEF_CALL_CONST(int, pgd_none, pgd_t)
BTFIXUPDEF_CALL_CONST(int, pgd_bad, pgd_t)
BTFIXUPDEF_CALL_CONST(int, pgd_present, pgd_t)
BTFIXUPDEF_CALL(void, pgd_clear, pgd_t *)
#define pgd_none(pgd) BTFIXUP_CALL(pgd_none)(pgd)
#define pgd_bad(pgd) BTFIXUP_CALL(pgd_bad)(pgd)
#define pgd_present(pgd) BTFIXUP_CALL(pgd_present)(pgd)
#define pgd_clear(pgd) BTFIXUP_CALL(pgd_clear)(pgd)
/*
* The following only work if pte_present() is true.
* Undefined behaviour if not..
*/
BTFIXUPDEF_HALF(pte_writei)
BTFIXUPDEF_HALF(pte_dirtyi)
BTFIXUPDEF_HALF(pte_youngi)
static int pte_write(pte_t pte) __attribute_const__;
static inline int pte_write(pte_t pte)
{
return pte_val(pte) & BTFIXUP_HALF(pte_writei);
}
static int pte_dirty(pte_t pte) __attribute_const__;
static inline int pte_dirty(pte_t pte)
{
return pte_val(pte) & BTFIXUP_HALF(pte_dirtyi);
}
static int pte_young(pte_t pte) __attribute_const__;
static inline int pte_young(pte_t pte)
{
return pte_val(pte) & BTFIXUP_HALF(pte_youngi);
}
/*
* The following only work if pte_present() is not true.
*/
BTFIXUPDEF_HALF(pte_filei)
static int pte_file(pte_t pte) __attribute_const__;
static inline int pte_file(pte_t pte)
{
return pte_val(pte) & BTFIXUP_HALF(pte_filei);
}
static inline int pte_special(pte_t pte)
{
return 0;
}
/*
*/
BTFIXUPDEF_HALF(pte_wrprotecti)
BTFIXUPDEF_HALF(pte_mkcleani)
BTFIXUPDEF_HALF(pte_mkoldi)
static pte_t pte_wrprotect(pte_t pte) __attribute_const__;
static inline pte_t pte_wrprotect(pte_t pte)
{
return __pte(pte_val(pte) & ~BTFIXUP_HALF(pte_wrprotecti));
}
static pte_t pte_mkclean(pte_t pte) __attribute_const__;
static inline pte_t pte_mkclean(pte_t pte)
{
return __pte(pte_val(pte) & ~BTFIXUP_HALF(pte_mkcleani));
}
static pte_t pte_mkold(pte_t pte) __attribute_const__;
static inline pte_t pte_mkold(pte_t pte)
{
return __pte(pte_val(pte) & ~BTFIXUP_HALF(pte_mkoldi));
}
BTFIXUPDEF_CALL_CONST(pte_t, pte_mkwrite, pte_t)
BTFIXUPDEF_CALL_CONST(pte_t, pte_mkdirty, pte_t)
BTFIXUPDEF_CALL_CONST(pte_t, pte_mkyoung, pte_t)
#define pte_mkwrite(pte) BTFIXUP_CALL(pte_mkwrite)(pte)
#define pte_mkdirty(pte) BTFIXUP_CALL(pte_mkdirty)(pte)
#define pte_mkyoung(pte) BTFIXUP_CALL(pte_mkyoung)(pte)
#define pte_mkspecial(pte) (pte)
#define pfn_pte(pfn, prot) mk_pte(pfn_to_page(pfn), prot)
BTFIXUPDEF_CALL(unsigned long, pte_pfn, pte_t)
#define pte_pfn(pte) BTFIXUP_CALL(pte_pfn)(pte)
#define pte_page(pte) pfn_to_page(pte_pfn(pte))
/*
* Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directory to the page they refer to.
*/
BTFIXUPDEF_CALL_CONST(pte_t, mk_pte, struct page *, pgprot_t)
BTFIXUPDEF_CALL_CONST(pte_t, mk_pte_phys, unsigned long, pgprot_t)
BTFIXUPDEF_CALL_CONST(pte_t, mk_pte_io, unsigned long, pgprot_t, int)
BTFIXUPDEF_CALL_CONST(pgprot_t, pgprot_noncached, pgprot_t)
#define mk_pte(page,pgprot) BTFIXUP_CALL(mk_pte)(page,pgprot)
#define mk_pte_phys(page,pgprot) BTFIXUP_CALL(mk_pte_phys)(page,pgprot)
#define mk_pte_io(page,pgprot,space) BTFIXUP_CALL(mk_pte_io)(page,pgprot,space)
#define pgprot_noncached(pgprot) BTFIXUP_CALL(pgprot_noncached)(pgprot)
BTFIXUPDEF_INT(pte_modify_mask)
static pte_t pte_modify(pte_t pte, pgprot_t newprot) __attribute_const__;
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
return __pte((pte_val(pte) & BTFIXUP_INT(pte_modify_mask)) |
pgprot_val(newprot));
}
#define pgd_index(address) ((address) >> PGDIR_SHIFT)
/* to find an entry in a page-table-directory */
#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 second-level page table.. */
BTFIXUPDEF_CALL(pmd_t *, pmd_offset, pgd_t *, unsigned long)
#define pmd_offset(dir,addr) BTFIXUP_CALL(pmd_offset)(dir,addr)
/* Find an entry in the third-level page table.. */
BTFIXUPDEF_CALL(pte_t *, pte_offset_kernel, pmd_t *, unsigned long)
#define pte_offset_kernel(dir,addr) BTFIXUP_CALL(pte_offset_kernel)(dir,addr)
/*
* This shortcut works on sun4m (and sun4d) because the nocache area is static,
* and sun4c is guaranteed to have no highmem anyway.
*/
#define pte_offset_map(d, a) pte_offset_kernel(d,a)
#define pte_offset_map_nested(d, a) pte_offset_kernel(d,a)
#define pte_unmap(pte) do{}while(0)
#define pte_unmap_nested(pte) do{}while(0)
/* Certain architectures need to do special things when pte's
* within a page table are directly modified. Thus, the following
* hook is made available.
*/
BTFIXUPDEF_CALL(void, set_pte, pte_t *, pte_t)
#define set_pte(ptep,pteval) BTFIXUP_CALL(set_pte)(ptep,pteval)
#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
struct seq_file;
BTFIXUPDEF_CALL(void, mmu_info, struct seq_file *)
#define mmu_info(p) BTFIXUP_CALL(mmu_info)(p)
/* Fault handler stuff... */
#define FAULT_CODE_PROT 0x1
#define FAULT_CODE_WRITE 0x2
#define FAULT_CODE_USER 0x4
BTFIXUPDEF_CALL(void, update_mmu_cache, struct vm_area_struct *, unsigned long, pte_t)
#define update_mmu_cache(vma,addr,pte) BTFIXUP_CALL(update_mmu_cache)(vma,addr,pte)
BTFIXUPDEF_CALL(void, sparc_mapiorange, unsigned int, unsigned long,
unsigned long, unsigned int)
BTFIXUPDEF_CALL(void, sparc_unmapiorange, unsigned long, unsigned int)
#define sparc_mapiorange(bus,pa,va,len) BTFIXUP_CALL(sparc_mapiorange)(bus,pa,va,len)
#define sparc_unmapiorange(va,len) BTFIXUP_CALL(sparc_unmapiorange)(va,len)
extern int invalid_segment;
/* Encode and de-code a swap entry */
BTFIXUPDEF_CALL(unsigned long, __swp_type, swp_entry_t)
BTFIXUPDEF_CALL(unsigned long, __swp_offset, swp_entry_t)
BTFIXUPDEF_CALL(swp_entry_t, __swp_entry, unsigned long, unsigned long)
#define __swp_type(__x) BTFIXUP_CALL(__swp_type)(__x)
#define __swp_offset(__x) BTFIXUP_CALL(__swp_offset)(__x)
#define __swp_entry(__type,__off) BTFIXUP_CALL(__swp_entry)(__type,__off)
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
/* file-offset-in-pte helpers */
BTFIXUPDEF_CALL(unsigned long, pte_to_pgoff, pte_t pte);
BTFIXUPDEF_CALL(pte_t, pgoff_to_pte, unsigned long pgoff);
#define pte_to_pgoff(pte) BTFIXUP_CALL(pte_to_pgoff)(pte)
#define pgoff_to_pte(off) BTFIXUP_CALL(pgoff_to_pte)(off)
/*
* This is made a constant because mm/fremap.c required a constant.
* Note that layout of these bits is different between sun4c.c and srmmu.c.
*/
#define PTE_FILE_MAX_BITS 24
/*
*/
struct ctx_list {
struct ctx_list *next;
struct ctx_list *prev;
unsigned int ctx_number;
struct mm_struct *ctx_mm;
};
extern struct ctx_list *ctx_list_pool; /* Dynamically allocated */
extern struct ctx_list ctx_free; /* Head of free list */
extern struct ctx_list ctx_used; /* Head of used contexts list */
#define NO_CONTEXT -1
static inline void remove_from_ctx_list(struct ctx_list *entry)
{
entry->next->prev = entry->prev;
entry->prev->next = entry->next;
}
static inline void add_to_ctx_list(struct ctx_list *head, struct ctx_list *entry)
{
entry->next = head;
(entry->prev = head->prev)->next = entry;
head->prev = entry;
}
#define add_to_free_ctxlist(entry) add_to_ctx_list(&ctx_free, entry)
#define add_to_used_ctxlist(entry) add_to_ctx_list(&ctx_used, entry)
static inline unsigned long
__get_phys (unsigned long addr)
{
switch (sparc_cpu_model){
case sun4:
case sun4c:
return sun4c_get_pte (addr) << PAGE_SHIFT;
case sun4m:
case sun4d:
return ((srmmu_get_pte (addr) & 0xffffff00) << 4);
default:
return 0;
}
}
static inline int
__get_iospace (unsigned long addr)
{
switch (sparc_cpu_model){
case sun4:
case sun4c:
return -1; /* Don't check iospace on sun4c */
case sun4m:
case sun4d:
return (srmmu_get_pte (addr) >> 28);
default:
return -1;
}
}
extern unsigned long *sparc_valid_addr_bitmap;
/* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
#define kern_addr_valid(addr) \
(test_bit(__pa((unsigned long)(addr))>>20, sparc_valid_addr_bitmap))
extern int io_remap_pfn_range(struct vm_area_struct *vma,
unsigned long from, unsigned long pfn,
unsigned long size, pgprot_t prot);
/*
* For sparc32&64, the pfn in io_remap_pfn_range() carries <iospace> in
* its high 4 bits. These macros/functions put it there or get it from there.
*/
#define MK_IOSPACE_PFN(space, pfn) (pfn | (space << (BITS_PER_LONG - 4)))
#define GET_IOSPACE(pfn) (pfn >> (BITS_PER_LONG - 4))
#define GET_PFN(pfn) (pfn & 0x0fffffffUL)
#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
#define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
({ \
int __changed = !pte_same(*(__ptep), __entry); \
if (__changed) { \
set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry); \
flush_tlb_page(__vma, __address); \
} \
(sparc_cpu_model == sun4c) || __changed; \
})
#include <asm-generic/pgtable.h>
#endif /* !(__ASSEMBLY__) */
/* We provide our own get_unmapped_area to cope with VA holes for userland */
#define HAVE_ARCH_UNMAPPED_AREA
/*
* No page table caches to initialise
*/
#define pgtable_cache_init() do { } while (0)
#endif /* !(_SPARC_PGTABLE_H) */
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