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pgtable_32.c

/*
 * This file contains the routines setting up the linux page tables.
 *  -- paulus
 *
 *  Derived from arch/ppc/mm/init.c:
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
 *    Copyright (C) 1996 Paul Mackerras
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/highmem.h>

#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/fixmap.h>
#include <asm/io.h>

#include "mmu_decl.h"

unsigned long ioremap_base;
unsigned long ioremap_bot;
EXPORT_SYMBOL(ioremap_bot);   /* aka VMALLOC_END */

#if defined(CONFIG_6xx) || defined(CONFIG_POWER3)
#define HAVE_BATS 1
#endif

#if defined(CONFIG_FSL_BOOKE)
#define HAVE_TLBCAM     1
#endif

extern char etext[], _stext[];

#ifdef CONFIG_SMP
extern void hash_page_sync(void);
#endif

#ifdef HAVE_BATS
extern phys_addr_t v_mapped_by_bats(unsigned long va);
extern unsigned long p_mapped_by_bats(phys_addr_t pa);
void setbat(int index, unsigned long virt, phys_addr_t phys,
          unsigned int size, int flags);

#else /* !HAVE_BATS */
#define v_mapped_by_bats(x)   (0UL)
#define p_mapped_by_bats(x)   (0UL)
#endif /* HAVE_BATS */

#ifdef HAVE_TLBCAM
extern unsigned int tlbcam_index;
extern phys_addr_t v_mapped_by_tlbcam(unsigned long va);
extern unsigned long p_mapped_by_tlbcam(phys_addr_t pa);
#else /* !HAVE_TLBCAM */
#define v_mapped_by_tlbcam(x) (0UL)
#define p_mapped_by_tlbcam(x) (0UL)
#endif /* HAVE_TLBCAM */

#ifdef CONFIG_PTE_64BIT
/* Some processors use an 8kB pgdir because they have 8-byte Linux PTEs. */
#define PGDIR_ORDER     1
#else
#define PGDIR_ORDER     0
#endif

pgd_t *pgd_alloc(struct mm_struct *mm)
{
      pgd_t *ret;

      ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, PGDIR_ORDER);
      return ret;
}

void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
      free_pages((unsigned long)pgd, PGDIR_ORDER);
}

__init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
      pte_t *pte;
      extern int mem_init_done;
      extern void *early_get_page(void);

      if (mem_init_done) {
            pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
      } else {
            pte = (pte_t *)early_get_page();
            if (pte)
                  clear_page(pte);
      }
      return pte;
}

pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
      struct page *ptepage;

#ifdef CONFIG_HIGHPTE
      gfp_t flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT | __GFP_ZERO;
#else
      gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
#endif

      ptepage = alloc_pages(flags, 0);
      if (!ptepage)
            return NULL;
      pgtable_page_ctor(ptepage);
      return ptepage;
}

void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
#ifdef CONFIG_SMP
      hash_page_sync();
#endif
      free_page((unsigned long)pte);
}

void pte_free(struct mm_struct *mm, pgtable_t ptepage)
{
#ifdef CONFIG_SMP
      hash_page_sync();
#endif
      pgtable_page_dtor(ptepage);
      __free_page(ptepage);
}

void __iomem *
ioremap(phys_addr_t addr, unsigned long size)
{
      return __ioremap(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED);
}
EXPORT_SYMBOL(ioremap);

void __iomem *
ioremap_flags(phys_addr_t addr, unsigned long size, unsigned long flags)
{
      /* writeable implies dirty for kernel addresses */
      if (flags & _PAGE_RW)
            flags |= _PAGE_DIRTY | _PAGE_HWWRITE;

      /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
      flags &= ~(_PAGE_USER | _PAGE_EXEC | _PAGE_HWEXEC);

      return __ioremap(addr, size, flags);
}
EXPORT_SYMBOL(ioremap_flags);

void __iomem *
__ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
{
      unsigned long v, i;
      phys_addr_t p;
      int err;

      /* Make sure we have the base flags */
      if ((flags & _PAGE_PRESENT) == 0)
            flags |= _PAGE_KERNEL;

      /* Non-cacheable page cannot be coherent */
      if (flags & _PAGE_NO_CACHE)
            flags &= ~_PAGE_COHERENT;

      /*
       * Choose an address to map it to.
       * Once the vmalloc system is running, we use it.
       * Before then, we use space going down from ioremap_base
       * (ioremap_bot records where we're up to).
       */
      p = addr & PAGE_MASK;
      size = PAGE_ALIGN(addr + size) - p;

      /*
       * If the address lies within the first 16 MB, assume it's in ISA
       * memory space
       */
      if (p < 16*1024*1024)
            p += _ISA_MEM_BASE;

      /*
       * Don't allow anybody to remap normal RAM that we're using.
       * mem_init() sets high_memory so only do the check after that.
       */
      if (mem_init_done && (p < virt_to_phys(high_memory))) {
            printk("__ioremap(): phys addr 0x%llx is RAM lr %p\n",
                   (unsigned long long)p, __builtin_return_address(0));
            return NULL;
      }

      if (size == 0)
            return NULL;

      /*
       * Is it already mapped?  Perhaps overlapped by a previous
       * BAT mapping.  If the whole area is mapped then we're done,
       * otherwise remap it since we want to keep the virt addrs for
       * each request contiguous.
       *
       * We make the assumption here that if the bottom and top
       * of the range we want are mapped then it's mapped to the
       * same virt address (and this is contiguous).
       *  -- Cort
       */
      if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
            goto out;

      if ((v = p_mapped_by_tlbcam(p)))
            goto out;

      if (mem_init_done) {
            struct vm_struct *area;
            area = get_vm_area(size, VM_IOREMAP);
            if (area == 0)
                  return NULL;
            v = (unsigned long) area->addr;
      } else {
            v = (ioremap_bot -= size);
      }

      /*
       * Should check if it is a candidate for a BAT mapping
       */

      err = 0;
      for (i = 0; i < size && err == 0; i += PAGE_SIZE)
            err = map_page(v+i, p+i, flags);
      if (err) {
            if (mem_init_done)
                  vunmap((void *)v);
            return NULL;
      }

out:
      return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
}
EXPORT_SYMBOL(__ioremap);

void iounmap(volatile void __iomem *addr)
{
      /*
       * If mapped by BATs then there is nothing to do.
       * Calling vfree() generates a benign warning.
       */
      if (v_mapped_by_bats((unsigned long)addr)) return;

      if (addr > high_memory && (unsigned long) addr < ioremap_bot)
            vunmap((void *) (PAGE_MASK & (unsigned long)addr));
}
EXPORT_SYMBOL(iounmap);

int map_page(unsigned long va, phys_addr_t pa, int flags)
{
      pmd_t *pd;
      pte_t *pg;
      int err = -ENOMEM;

      /* Use upper 10 bits of VA to index the first level map */
      pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
      /* Use middle 10 bits of VA to index the second-level map */
      pg = pte_alloc_kernel(pd, va);
      if (pg != 0) {
            err = 0;
            /* The PTE should never be already set nor present in the
             * hash table
             */
            BUG_ON(pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE));
            set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
                                         __pgprot(flags)));
      }
      return err;
}

/*
 * Map in a big chunk of physical memory starting at KERNELBASE.
 */
void __init mapin_ram(void)
{
      unsigned long v, s, f;
      phys_addr_t p;
      int ktext;

      s = mmu_mapin_ram();
      v = KERNELBASE + s;
      p = memstart_addr + s;
      for (; s < total_lowmem; s += PAGE_SIZE) {
            ktext = ((char *) v >= _stext && (char *) v < etext);
            f = ktext ?_PAGE_RAM_TEXT : _PAGE_RAM;
            map_page(v, p, f);
#ifdef CONFIG_PPC_STD_MMU_32
            if (ktext)
                  hash_preload(&init_mm, v, 0, 0x300);
#endif
            v += PAGE_SIZE;
            p += PAGE_SIZE;
      }
}

/* Scan the real Linux page tables and return a PTE pointer for
 * a virtual address in a context.
 * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 * the PTE pointer is unmodified if PTE is not found.
 */
int
get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
{
        pgd_t     *pgd;
      pud_t *pud;
        pmd_t     *pmd;
        pte_t     *pte;
        int     retval = 0;

        pgd = pgd_offset(mm, addr & PAGE_MASK);
        if (pgd) {
            pud = pud_offset(pgd, addr & PAGE_MASK);
            if (pud && pud_present(*pud)) {
                  pmd = pmd_offset(pud, addr & PAGE_MASK);
                  if (pmd_present(*pmd)) {
                        pte = pte_offset_map(pmd, addr & PAGE_MASK);
                        if (pte) {
                              retval = 1;
                              *ptep = pte;
                              if (pmdp)
                                    *pmdp = pmd;
                              /* XXX caller needs to do pte_unmap, yuck */
                        }
                  }
            }
        }
        return(retval);
}

#ifdef CONFIG_DEBUG_PAGEALLOC

static int __change_page_attr(struct page *page, pgprot_t prot)
{
      pte_t *kpte;
      pmd_t *kpmd;
      unsigned long address;

      BUG_ON(PageHighMem(page));
      address = (unsigned long)page_address(page);

      if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
            return 0;
      if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
            return -EINVAL;
      set_pte_at(&init_mm, address, kpte, mk_pte(page, prot));
      wmb();
      flush_HPTE(0, address, pmd_val(*kpmd));
      pte_unmap(kpte);

      return 0;
}

/*
 * Change the page attributes of an page in the linear mapping.
 *
 * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
 */
static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
{
      int i, err = 0;
      unsigned long flags;

      local_irq_save(flags);
      for (i = 0; i < numpages; i++, page++) {
            err = __change_page_attr(page, prot);
            if (err)
                  break;
      }
      local_irq_restore(flags);
      return err;
}


void kernel_map_pages(struct page *page, int numpages, int enable)
{
      if (PageHighMem(page))
            return;

      change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
}
#endif /* CONFIG_DEBUG_PAGEALLOC */

static int fixmaps;
unsigned long FIXADDR_TOP = 0xfffff000;
EXPORT_SYMBOL(FIXADDR_TOP);

void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
{
      unsigned long address = __fix_to_virt(idx);

      if (idx >= __end_of_fixed_addresses) {
            BUG();
            return;
      }

      map_page(address, phys, pgprot_val(flags));
      fixmaps++;
}

void __this_fixmap_does_not_exist(void)
{
      WARN_ON(1);
}

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