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/* * Last edited: Nov  7 23:44 1995 (cort) */

#ifndef _PPC_PGTABLE_H

#define _PPC_PGTABLE_H

#include <asm/page.h>

#include <asm/mmu.h>

/*

 * Memory management on the PowerPC is a software emulation of the i386

 * MMU folded onto the PowerPC hardware MMU.  The emulated version looks

 * and behaves like the two-level i386 MMU.  Entries from these tables

 * are merged into the PowerPC hashed MMU tables, on demand, treating the

 * hashed tables like a special cache.

 *

 * Since the PowerPC does not have separate kernel and user address spaces,

 * the user virtual address space must be a [proper] subset of the kernel

 * space.  Thus, all tasks will have a specific virtual mapping for the

 * user virtual space and a common mapping for the kernel space.  The

 * simplest way to split this was literally in half.  Also, life is so

 * much simpler for the kernel if the machine hardware resources are

 * always mapped in.  Thus, some additional space is given up to the

 * kernel space to accommodate this.

 *

 * CAUTION! Some of the trade-offs make sense for the PreP platform on

 * which this code was originally developed.  When it migrates to other

 * PowerPC environments, some of the assumptions may fail and the whole

 * setup may need to be reevaluated.

 *

 * On the PowerPC, page translations are kept in a hashed table.  There

 * is exactly one of these tables [although the architecture supports

 * an arbitrary number].  Page table entries move in/out of this hashed

 * structure on demand, with the kernel filling in entries as they are

 * needed.  Just where a page table entry hits in the hashed table is a

 * function of the hashing which is in turn based on the upper 4 bits

 * of the logical address.  These 4 bits address a "virtual segment id"

 * which is unique per task/page combination for user addresses and

 * fixed for the kernel addresses.  Thus, the kernel space can be simply

 * shared [indeed at low overhead] among all tasks.

 *

 * The basic virtual address space is thus:

 *

 * 0x0XXXXXX  --+

 * 0x1XXXXXX    |

 * 0x2XXXXXX    |  User address space.

 * 0x3XXXXXX    |

 * 0x4XXXXXX    |

 * 0x5XXXXXX    |

 * 0x6XXXXXX    |

 * 0x7XXXXXX  --+

 * 0x8XXXXXX       PCI/ISA I/O space

 * 0x9XXXXXX  --+

 * 0xAXXXXXX    |  Kernel virtual memory

 * 0xBXXXXXX  --+

 * 0xCXXXXXX       PCI/ISA Memory space

 * 0xDXXXXXX

 * 0xEXXXXXX

 * 0xFXXXXXX       Board I/O space

 *

 * CAUTION!  One of the real problems here is keeping the software

 * managed tables coherent with the hardware hashed tables.  When

 * the software decides to update the table, it's normally easy to

 * update the hardware table.  But when the hardware tables need

 * changed, e.g. as the result of a page fault, it's more difficult

 * to reflect those changes back into the software entries.  Currently,

 * this process is quite crude, with updates causing the entire set

 * of tables to become invalidated.  Some performance could certainly

 * be regained by improving this.

 *

 * The Linux memory management assumes a three-level page table setup. On

 * the i386, we use that, but "fold" the mid level into the top-level page

 * table, so that we physically have the same two-level page table as the

 * i386 mmu expects.

 *

 * This file contains the functions and defines necessary to modify and use

 * the i386 page table tree.

 */

/* PMD_SHIFT determines the size of the area a second-level page table can map */

#define PMD_SHIFT       22

#define PMD_SIZE        (1UL << PMD_SHIFT)

#define PMD_MASK        (~(PMD_SIZE-1))

/* PGDIR_SHIFT determines what a third-level page table entry can map */

#define PGDIR_SHIFT     22

#define PGDIR_SIZE      (1UL << PGDIR_SHIFT)

#define PGDIR_MASK      (~(PGDIR_SIZE-1))

/*

 * entries per page directory level: the i386 is two-level, so

 * we don't really have any PMD directory physically.

 */

#define PTRS_PER_PTE    1024

#define PTRS_PER_PMD    1

#define PTRS_PER_PGD    1024

/* Just any arbitrary offset to the start of the vmalloc VM area: the

 * current 8MB value just means that there will be a 8MB "hole" after the

 * physical memory until the kernel virtual memory starts.  That means that

 * any out-of-bounds memory accesses will hopefully be caught.

 * The vmalloc() routines leaves a hole of 4kB between each vmalloced

 * area for the same reason. ;)

 */

#define VMALLOC_OFFSET  (8*1024*1024)

#define VMALLOC_START ((high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))

#define VMALLOC_VMADDR(x) ((unsigned long)(x))

#define _PAGE_PRESENT   0x001

#define _PAGE_RW        0x002

#define _PAGE_USER      0x004

#define _PAGE_PCD       0x010

#define _PAGE_ACCESSED  0x020

#define _PAGE_DIRTY     0x040

#define _PAGE_COW       0x200   /* implemented in software (one of the AVL bits) */

#define _PAGE_NO_CACHE  0x400

#define _PAGE_TABLE     (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)

#define _PAGE_CHG_MASK  (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)

#define PAGE_NONE       __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED)

#define PAGE_SHARED     __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED)

#define PAGE_COPY       __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED | _PAGE_COW)

#define PAGE_READONLY   __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)

#define PAGE_KERNEL     __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)

#define PAGE_KERNEL_NO_CACHE    __pgprot(_PAGE_NO_CACHE | _PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)

/*

 * The i386 can't do page protection for execute, and considers that the same are read.

 * Also, write permissions imply read permissions. This is the closest we can get..

 */

#define __P000  PAGE_NONE

#define __P001  PAGE_READONLY

#define __P010  PAGE_COPY

#define __P011  PAGE_COPY

#define __P100  PAGE_READONLY

#define __P101  PAGE_READONLY

#define __P110  PAGE_COPY

#define __P111  PAGE_COPY

#define __S000  PAGE_NONE

#define __S001  PAGE_READONLY

#define __S010  PAGE_SHARED

#define __S011  PAGE_SHARED

#define __S100  PAGE_READONLY

#define __S101  PAGE_READONLY

#define __S110  PAGE_SHARED

#define __S111  PAGE_SHARED

/*

 * TLB invalidation:

 *

 *  - invalidate() invalidates the current mm struct TLBs

 *  - invalidate_all() invalidates all processes TLBs

 *  - invalidate_mm(mm) invalidates the specified mm context TLB's

 *  - invalidate_page(mm, vmaddr) invalidates one page

 *  - invalidate_range(mm, start, end) invalidates a range of pages

 *

 * FIXME: This could be done much better!

 */

#define invalidate_all() printk("invalidate_all()\n");invalidate()

#if 0

#define invalidate_mm(mm_struct) \

do { if ((mm_struct) == current->mm) invalidate(); else printk("Can't invalidate_mm(%x)\n", mm_struct);} while (0)

#define invalidate_page(mm_struct,addr) \

do { if ((mm_struct) == current->mm) invalidate(); else printk("Can't invalidate_page(%x,%x)\n", mm_struct, addr);} while (0)

#define invalidate_range(mm_struct,start,end) \

do { if ((mm_struct) == current->mm) invalidate(); else printk("Can't invalidate_range(%x,%x,%x)\n", mm_struct, start, end);} while (0)

#endif

/*

 * Define this if things work differently on a i386 and a i486:

 * it will (on a i486) warn about kernel memory accesses that are

 * done without a 'verify_area(VERIFY_WRITE,..)'

 */

#undef CONFIG_TEST_VERIFY_AREA

/* page table for 0-4MB for everybody */

extern unsigned long pg0[1024];

/*

 * 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_page(void);

extern pte_t * __bad_pagetable(void);

extern unsigned long __zero_page(void);

#define BAD_PAGETABLE __bad_pagetable()

#define BAD_PAGE __bad_page()

#define ZERO_PAGE __zero_page()

/* number of bits that fit into a memory pointer */

#define BITS_PER_PTR                    (8*sizeof(unsigned long))

/* to align the pointer to a pointer address */

#define PTR_MASK                        (~(sizeof(void*)-1))

/* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */

/* 64-bit machines, beware!  SRB. */

#define SIZEOF_PTR_LOG2                 2

/* to find an entry in a page-table */

#define PAGE_PTR(address) \

((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)

/* to set the page-dir */

/* tsk is a task_struct and pgdir is a pte_t */

#define SET_PAGE_DIR(tsk,pgdir) \

do { \

        (tsk)->tss.pg_tables = (unsigned long *)(pgdir); \

        if ((tsk) == current) \

        { \

/*_printk("Change page tables = %x\n", pgdir);*/ \

        } \

} while (0)

extern unsigned long high_memory;

extern inline int pte_none(pte_t pte)           { return !pte_val(pte); }

extern inline int pte_present(pte_t pte)        { return pte_val(pte) & _PAGE_PRESENT; }

#if 0

extern inline int pte_inuse(pte_t *ptep)        { return mem_map[MAP_NR(ptep)].reserved; }

/*extern inline int pte_inuse(pte_t *ptep)      { return mem_map[MAP_NR(ptep)] != 1; }*/

#endif

extern inline void pte_clear(pte_t *ptep)       { pte_val(*ptep) = 0; }

#if 0

extern inline void pte_reuse(pte_t * ptep)

{

        if (!mem_map[MAP_NR(ptep)].reserved)

                mem_map[MAP_NR(ptep)].count++;

}

#endif

/*

   extern inline void pte_reuse(pte_t * ptep)

{

        if (!(mem_map[MAP_NR(ptep)] & MAP_PAGE_RESERVED))

                mem_map[MAP_NR(ptep)]++;

}

*/

extern inline int pmd_none(pmd_t pmd)           { return !pmd_val(pmd); }

extern inline int pmd_bad(pmd_t pmd)            { return (pmd_val(pmd) & ~PAGE_MASK) != _PAGE_TABLE; }

extern inline int pmd_present(pmd_t pmd)        { return pmd_val(pmd) & _PAGE_PRESENT; }

extern inline int pmd_inuse(pmd_t *pmdp)        { return 0; }

extern inline void pmd_clear(pmd_t * pmdp)      { pmd_val(*pmdp) = 0; }

extern inline void pmd_reuse(pmd_t * pmdp)      { }

/*

 * The "pgd_xxx()" functions here are trivial for a folded two-level

 * setup: the pgd is never bad, and a pmd always exists (as it's folded

 * into the pgd entry)

 */

extern inline int pgd_none(pgd_t pgd)           { return 0; }

extern inline int pgd_bad(pgd_t pgd)            { return 0; }

extern inline int pgd_present(pgd_t pgd)        { return 1; }

#if 0

/*extern inline int pgd_inuse(pgd_t * pgdp)     { return mem_map[MAP_NR(pgdp)] != 1; }*/

extern inline int pgd_inuse(pgd_t *pgdp)        { return mem_map[MAP_NR(pgdp)].reserved;  }

#endif

extern inline void pgd_clear(pgd_t * pgdp)      { }

/*

extern inline void pgd_reuse(pgd_t * pgdp)

{

        if (!mem_map[MAP_NR(pgdp)].reserved)

                mem_map[MAP_NR(pgdp)].count++;

}

*/

/*

 * The following only work if pte_present() is true.

 * Undefined behaviour if not..

 */

extern inline int pte_read(pte_t pte)           { return pte_val(pte) & _PAGE_USER; }

extern inline int pte_write(pte_t pte)          { return pte_val(pte) & _PAGE_RW; }

extern inline int pte_exec(pte_t pte)           { return pte_val(pte) & _PAGE_USER; }

extern inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_DIRTY; }

extern inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }

extern inline int pte_cow(pte_t pte)            { return pte_val(pte) & _PAGE_COW; }

extern inline pte_t pte_wrprotect(pte_t pte)    { pte_val(pte) &= ~_PAGE_RW; return pte; }

extern inline pte_t pte_rdprotect(pte_t pte)    { pte_val(pte) &= ~_PAGE_USER; return pte; }

extern inline pte_t pte_exprotect(pte_t pte)    { pte_val(pte) &= ~_PAGE_USER; return pte; }

extern inline pte_t pte_mkclean(pte_t pte)      { pte_val(pte) &= ~_PAGE_DIRTY; return pte; }

extern inline pte_t pte_mkold(pte_t pte)        { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }

extern inline pte_t pte_uncow(pte_t pte)        { pte_val(pte) &= ~_PAGE_COW; return pte; }

extern inline pte_t pte_mkwrite(pte_t pte)      { pte_val(pte) |= _PAGE_RW; return pte; }

extern inline pte_t pte_mkread(pte_t pte)       { pte_val(pte) |= _PAGE_USER; return pte; }

extern inline pte_t pte_mkexec(pte_t pte)       { pte_val(pte) |= _PAGE_USER; return pte; }

extern inline pte_t pte_mkdirty(pte_t pte)      { pte_val(pte) |= _PAGE_DIRTY; return pte; }

extern inline pte_t pte_mkyoung(pte_t pte)      { pte_val(pte) |= _PAGE_ACCESSED; return pte; }

extern inline pte_t pte_mkcow(pte_t pte)        { pte_val(pte) |= _PAGE_COW; return 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.

 */

extern inline pte_t mk_pte(unsigned long page, pgprot_t pgprot)

{ pte_t pte; pte_val(pte) = page | pgprot_val(pgprot); return pte; }

extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)

{ pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }

/*extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)

{ pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }

*/

extern inline unsigned long pte_page(pte_t pte)

{ return pte_val(pte) & PAGE_MASK; }

extern inline unsigned long pmd_page(pmd_t pmd)

{ return pmd_val(pmd) & PAGE_MASK; }

/* to find an entry in a page-table-directory */

extern inline pgd_t * pgd_offset(struct mm_struct * mm, unsigned long address)

{

        return mm->pgd + (address >> PGDIR_SHIFT);

}

/* Find an entry in the second-level page table.. */

extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)

{

        return (pmd_t *) dir;

}

/* Find an entry in the third-level page table.. */

extern inline pte_t * pte_offset(pmd_t * dir, unsigned long address)

{

        return (pte_t *) pmd_page(*dir) + ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1));

}

/*

 * Allocate and free page tables. The xxx_kernel() versions are

 * used to allocate a kernel page table - this turns on ASN bits

 * if any, and marks the page tables reserved.

 */

extern inline void pte_free_kernel(pte_t * pte)

{

        free_page((unsigned long) pte);

}

/*extern inline void pte_free_kernel(pte_t * pte)

{

        mem_map[MAP_NR(pte)] = 1;

        free_page((unsigned long) pte);

}

*/

/*

extern inline pte_t * pte_alloc_kernel(pmd_t * pmd, unsigned long address)

{

        address = (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);

        if (pmd_none(*pmd)) {

                pte_t * page = (pte_t *) get_free_page(GFP_KERNEL);

                if (pmd_none(*pmd)) {

                        if (page) {

                                pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) page;

                                mem_map[MAP_NR(page)] = MAP_PAGE_RESERVED;

                                return page + address;

                        }

                        pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;

                        return NULL;

                }

                free_page((unsigned long) page);

        }

        if (pmd_bad(*pmd)) {

                printk("Bad pmd in pte_alloc: %08lx\n", pmd_val(*pmd));

                pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;

                return NULL;

        }

        return (pte_t *) pmd_page(*pmd) + address;

}*/

/*

extern inline pte_t * pte_alloc_kernel(pmd_t *pmd, unsigned long address)

{

printk("pte_alloc_kernel pmd = %08X, address = %08X\n", pmd, address);

        address = (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);

printk("address now = %08X\n", address);

        if (pmd_none(*pmd)) {

                pte_t *page;

printk("pmd_none(*pmd) true\n");

                page = (pte_t *) get_free_page(GFP_KERNEL);

printk("page = %08X after get_free_page(%08X)\n",page,GFP_KERNEL);

                if (pmd_none(*pmd)) {

printk("pmd_none(*pmd=%08X) still\n",*pmd);

                        if (page) {

printk("page true = %08X\n",page);

                                pmd_set(pmd, page);

printk("pmd_set(%08X,%08X)\n",pmd,page);

                                mem_map[MAP_NR(page)].reserved = 1;

printk("did mem_map\n",pmd,page);

                                return page + address;

                        }

printk("did pmd_set(%08X, %08X\n",pmd,BAD_PAGETABLE);

                        pmd_set(pmd, (pte_t *) BAD_PAGETABLE);

                        return NULL;

                }

printk("did free_page(%08X)\n",page);

                free_page((unsigned long) page);

        }

        if (pmd_bad(*pmd)) {

                printk("Bad pmd in pte_alloc: %08lx\n", pmd_val(*pmd));

                pmd_set(pmd, (pte_t *) BAD_PAGETABLE);

                return NULL;

        }

printk("returning pmd_page(%08X) + %08X\n",pmd_page(*pmd) , address);

        return (pte_t *) pmd_page(*pmd) + address;

}

*/

extern inline pte_t * pte_alloc_kernel(pmd_t * pmd, unsigned long address)

{

        address = (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);

        if (pmd_none(*pmd)) {

                pte_t * page = (pte_t *) get_free_page(GFP_KERNEL);

                if (pmd_none(*pmd)) {

                        if (page) {

/*                                pmd_set(pmd,page);*/

                        pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) page;

                                return page + address;

                        }

/*                      pmd_set(pmd, BAD_PAGETABLE);*/

                        pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;

                        return NULL;

                }

                free_page((unsigned long) page);

        }

        if (pmd_bad(*pmd)) {

                printk("Bad pmd in pte_alloc: %08lx\n", pmd_val(*pmd));

/*              pmd_set(pmd, (pte_t *) BAD_PAGETABLE);          */

                pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;

                return NULL;

        }

        return (pte_t *) pmd_page(*pmd) + address;

}

/*

 * allocating and freeing a pmd is trivial: the 1-entry pmd is

 * inside the pgd, so has no extra memory associated with it.

 */

extern inline void pmd_free_kernel(pmd_t * pmd)

{

}

extern inline pmd_t * pmd_alloc_kernel(pgd_t * pgd, unsigned long address)

{

        return (pmd_t *) pgd;

}

extern inline void pte_free(pte_t * pte)

{

        free_page((unsigned long) pte);

}

extern inline pte_t * pte_alloc(pmd_t * pmd, unsigned long address)

{

        address = (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);

        if (pmd_none(*pmd)) {

                pte_t * page = (pte_t *) get_free_page(GFP_KERNEL);

                if (pmd_none(*pmd)) {

                        if (page) {

                                pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) page;

                                return page + address;

                        }

                        pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;

                        return NULL;

                }

                free_page((unsigned long) page);

        }

        if (pmd_bad(*pmd)) {

                printk("Bad pmd in pte_alloc: %08lx\n", pmd_val(*pmd));

                pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;

                return NULL;

        }

        return (pte_t *) pmd_page(*pmd) + address;

}

/*

 * allocating and freeing a pmd is trivial: the 1-entry pmd is

 * inside the pgd, so has no extra memory associated with it.

 */

extern inline void pmd_free(pmd_t * pmd)

{

}

extern inline pmd_t * pmd_alloc(pgd_t * pgd, unsigned long address)

{

        return (pmd_t *) pgd;

}

extern inline void pgd_free(pgd_t * pgd)

{

        free_page((unsigned long) pgd);

}

extern inline pgd_t * pgd_alloc(void)

{

        return (pgd_t *) get_free_page(GFP_KERNEL);

}

extern pgd_t swapper_pg_dir[1024*8];

/*extern pgd_t *swapper_pg_dir;*/

/*

 * Software maintained MMU tables may have changed -- update the

 * hardware [aka cache]

 */

extern inline void update_mmu_cache(struct vm_area_struct * vma,

        unsigned long address, pte_t _pte)

{

#if 0

        printk("Update MMU cache - VMA: %x, Addr: %x, PTE: %x\n", vma, address, *(long *)&_pte);

        _printk("Update MMU cache - VMA: %x, Addr: %x, PTE: %x\n", vma, address, *(long *)&_pte);

/*      MMU_hash_page(&(vma->vm_task)->tss, address & PAGE_MASK, (pte *)&_pte);*/

#endif  

        MMU_hash_page(&(current)->tss, address & PAGE_MASK, (pte *)&_pte);

}

#ifdef _SCHED_INIT_

#define INIT_MMAP { &init_task, 0, 0x40000000, PAGE_SHARED, VM_READ | VM_WRITE | VM_EXEC }

#endif  

#define SWP_TYPE(entry) (((entry) >> 1) & 0x7f)

#define SWP_OFFSET(entry) ((entry) >> 8)

#define SWP_ENTRY(type,offset) (((type) << 1) | ((offset) << 8))

#endif /* _PPC_PAGE_H */