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init.c

/*
 *  PowerPC version
 *    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
 *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
 *  PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
 *
 *  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/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/initrd.h>
#include <linux/pagemap.h>

#include <asm/pgalloc.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/btext.h>
#include <asm/tlb.h>
#include <asm/bootinfo.h>

#include "mem_pieces.h"
#include "mmu_decl.h"

#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
/* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
#if (CONFIG_LOWMEM_SIZE > (0xF0000000 - KERNELBASE))
#error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL"
#endif
#endif
#define MAX_LOW_MEM     CONFIG_LOWMEM_SIZE

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

unsigned long total_memory;
unsigned long total_lowmem;

unsigned long ppc_memstart;
unsigned long ppc_memoffset = PAGE_OFFSET;

int mem_init_done;
int init_bootmem_done;
int boot_mapsize;

extern char _end[];
extern char etext[], _stext[];
extern char __init_begin, __init_end;

#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
pgprot_t kmap_prot;

EXPORT_SYMBOL(kmap_prot);
EXPORT_SYMBOL(kmap_pte);
#endif

void MMU_init(void);
void set_phys_avail(unsigned long total_ram);

/* XXX should be in current.h  -- paulus */
extern struct task_struct *current_set[NR_CPUS];

char *klimit = _end;
struct mem_pieces phys_avail;

/*
 * this tells the system to map all of ram with the segregs
 * (i.e. page tables) instead of the bats.
 * -- Cort
 */
int __map_without_bats;
int __map_without_ltlbs;

/* max amount of RAM to use */
unsigned long __max_memory;
/* max amount of low RAM to map in */
unsigned long __max_low_memory = MAX_LOW_MEM;

void show_mem(void)
{
      int i,free = 0,total = 0,reserved = 0;
      int shared = 0, cached = 0;
      int highmem = 0;

      printk("Mem-info:\n");
      show_free_areas();
      printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
      i = max_mapnr;
      while (i-- > 0) {
            total++;
            if (PageHighMem(mem_map+i))
                  highmem++;
            if (PageReserved(mem_map+i))
                  reserved++;
            else if (PageSwapCache(mem_map+i))
                  cached++;
            else if (!page_count(mem_map+i))
                  free++;
            else
                  shared += page_count(mem_map+i) - 1;
      }
      printk("%d pages of RAM\n",total);
      printk("%d pages of HIGHMEM\n", highmem);
      printk("%d free pages\n",free);
      printk("%d reserved pages\n",reserved);
      printk("%d pages shared\n",shared);
      printk("%d pages swap cached\n",cached);
}

/* Free up now-unused memory */
static void free_sec(unsigned long start, unsigned long end, const char *name)
{
      unsigned long cnt = 0;

      while (start < end) {
            ClearPageReserved(virt_to_page(start));
            init_page_count(virt_to_page(start));
            free_page(start);
            cnt++;
            start += PAGE_SIZE;
      }
      if (cnt) {
            printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
            totalram_pages += cnt;
      }
}

void free_initmem(void)
{
#define FREESEC(TYPE) \
      free_sec((unsigned long)(&__ ## TYPE ## _begin), \
             (unsigned long)(&__ ## TYPE ## _end), \
             #TYPE);

      printk ("Freeing unused kernel memory:");
      FREESEC(init);
      printk("\n");
      ppc_md.progress = NULL;
#undef FREESEC
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
      printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);

      for (; start < end; start += PAGE_SIZE) {
            ClearPageReserved(virt_to_page(start));
            init_page_count(virt_to_page(start));
            free_page(start);
            totalram_pages++;
      }
}
#endif

/*
 * Check for command-line options that affect what MMU_init will do.
 */
void MMU_setup(void)
{
      /* Check for nobats option (used in mapin_ram). */
      if (strstr(cmd_line, "nobats")) {
            __map_without_bats = 1;
      }

      if (strstr(cmd_line, "noltlbs")) {
            __map_without_ltlbs = 1;
      }

      /* Look for mem= option on command line */
      if (strstr(cmd_line, "mem=")) {
            char *p, *q;
            unsigned long maxmem = 0;

            for (q = cmd_line; (p = strstr(q, "mem=")) != 0; ) {
                  q = p + 4;
                  if (p > cmd_line && p[-1] != ' ')
                        continue;
                  maxmem = simple_strtoul(q, &q, 0);
                  if (*q == 'k' || *q == 'K') {
                        maxmem <<= 10;
                        ++q;
                  } else if (*q == 'm' || *q == 'M') {
                        maxmem <<= 20;
                        ++q;
                  }
            }
            __max_memory = maxmem;
      }
}

/*
 * MMU_init sets up the basic memory mappings for the kernel,
 * including both RAM and possibly some I/O regions,
 * and sets up the page tables and the MMU hardware ready to go.
 */
void __init MMU_init(void)
{
      if (ppc_md.progress)
            ppc_md.progress("MMU:enter", 0x111);

      /* parse args from command line */
      MMU_setup();

      /*
       * Figure out how much memory we have, how much
       * is lowmem, and how much is highmem.  If we were
       * passed the total memory size from the bootloader,
       * just use it.
       */
      if (boot_mem_size)
            total_memory = boot_mem_size;
      else
            total_memory = ppc_md.find_end_of_memory();

      if (__max_memory && total_memory > __max_memory)
            total_memory = __max_memory;
      total_lowmem = total_memory;
#ifdef CONFIG_FSL_BOOKE
      /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
       * entries, so we need to adjust lowmem to match the amount we can map
       * in the fixed entries */
      adjust_total_lowmem();
#endif /* CONFIG_FSL_BOOKE */
      if (total_lowmem > __max_low_memory) {
            total_lowmem = __max_low_memory;
#ifndef CONFIG_HIGHMEM
            total_memory = total_lowmem;
#endif /* CONFIG_HIGHMEM */
      }
      set_phys_avail(total_lowmem);

      /* Initialize the MMU hardware */
      if (ppc_md.progress)
            ppc_md.progress("MMU:hw init", 0x300);
      MMU_init_hw();

      /* Map in all of RAM starting at KERNELBASE */
      if (ppc_md.progress)
            ppc_md.progress("MMU:mapin", 0x301);
      mapin_ram();

#ifdef CONFIG_HIGHMEM
      ioremap_base = PKMAP_BASE;
#else
      ioremap_base = 0xfe000000UL;  /* for now, could be 0xfffff000 */
#endif /* CONFIG_HIGHMEM */
      ioremap_bot = ioremap_base;

      /* Map in I/O resources */
      if (ppc_md.progress)
            ppc_md.progress("MMU:setio", 0x302);
      if (ppc_md.setup_io_mappings)
            ppc_md.setup_io_mappings();

      /* Initialize the context management stuff */
      mmu_context_init();

      if (ppc_md.progress)
            ppc_md.progress("MMU:exit", 0x211);

#ifdef CONFIG_BOOTX_TEXT
      /* By default, we are no longer mapped */
            boot_text_mapped = 0;
      /* Must be done last, or ppc_md.progress will die. */
      map_boot_text();
#endif
}

/* This is only called until mem_init is done. */
void __init *early_get_page(void)
{
      void *p;

      if (init_bootmem_done) {
            p = alloc_bootmem_pages(PAGE_SIZE);
      } else {
            p = mem_pieces_find(PAGE_SIZE, PAGE_SIZE);
      }
      return p;
}

/*
 * Initialize the bootmem system and give it all the memory we
 * have available.
 */
void __init do_init_bootmem(void)
{
      unsigned long start, size;
      int i;

      /*
       * Find an area to use for the bootmem bitmap.
       * We look for the first area which is at least
       * 128kB in length (128kB is enough for a bitmap
       * for 4GB of memory, using 4kB pages), plus 1 page
       * (in case the address isn't page-aligned).
       */
      start = 0;
      size = 0;
      for (i = 0; i < phys_avail.n_regions; ++i) {
            unsigned long a = phys_avail.regions[i].address;
            unsigned long s = phys_avail.regions[i].size;
            if (s <= size)
                  continue;
            start = a;
            size = s;
            if (s >= 33 * PAGE_SIZE)
                  break;
      }
      start = PAGE_ALIGN(start);

      min_low_pfn = start >> PAGE_SHIFT;
      max_low_pfn = (PPC_MEMSTART + total_lowmem) >> PAGE_SHIFT;
      max_pfn = (PPC_MEMSTART + total_memory) >> PAGE_SHIFT;
      boot_mapsize = init_bootmem_node(&contig_page_data, min_low_pfn,
                               PPC_MEMSTART >> PAGE_SHIFT,
                               max_low_pfn);

      /* remove the bootmem bitmap from the available memory */
      mem_pieces_remove(&phys_avail, start, boot_mapsize, 1);

      /* add everything in phys_avail into the bootmem map */
      for (i = 0; i < phys_avail.n_regions; ++i)
            free_bootmem(phys_avail.regions[i].address,
                       phys_avail.regions[i].size);

      init_bootmem_done = 1;
}

/*
 * paging_init() sets up the page tables - in fact we've already done this.
 */
void __init paging_init(void)
{
      unsigned long start_pfn, end_pfn;
      unsigned long max_zone_pfns[MAX_NR_ZONES];
#ifdef CONFIG_HIGHMEM
      map_page(PKMAP_BASE, 0, 0);   /* XXX gross */
      pkmap_page_table = pte_offset_kernel(pmd_offset(pgd_offset_k
                  (PKMAP_BASE), PKMAP_BASE), PKMAP_BASE);
      map_page(KMAP_FIX_BEGIN, 0, 0);     /* XXX gross */
      kmap_pte = pte_offset_kernel(pmd_offset(pgd_offset_k
                  (KMAP_FIX_BEGIN), KMAP_FIX_BEGIN), KMAP_FIX_BEGIN);
      kmap_prot = PAGE_KERNEL;
#endif /* CONFIG_HIGHMEM */
      /* All pages are DMA-able so we put them all in the DMA zone. */
      start_pfn = __pa(PAGE_OFFSET) >> PAGE_SHIFT;
      end_pfn = start_pfn + (total_memory >> PAGE_SHIFT);
      add_active_range(0, start_pfn, end_pfn);

      memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
#ifdef CONFIG_HIGHMEM
      max_zone_pfns[ZONE_DMA] = total_lowmem >> PAGE_SHIFT;
      max_zone_pfns[ZONE_HIGHMEM] = total_memory >> PAGE_SHIFT;
#else
      max_zone_pfns[ZONE_DMA] = total_memory >> PAGE_SHIFT;
#endif /* CONFIG_HIGHMEM */
      free_area_init_nodes(max_zone_pfns);
}

void __init mem_init(void)
{
      unsigned long addr;
      int codepages = 0;
      int datapages = 0;
      int initpages = 0;
#ifdef CONFIG_HIGHMEM
      unsigned long highmem_mapnr;

      highmem_mapnr = total_lowmem >> PAGE_SHIFT;
#endif /* CONFIG_HIGHMEM */
      max_mapnr = total_memory >> PAGE_SHIFT;

      high_memory = (void *) __va(PPC_MEMSTART + total_lowmem);
      num_physpages = max_mapnr;    /* RAM is assumed contiguous */

      totalram_pages += free_all_bootmem();

#ifdef CONFIG_BLK_DEV_INITRD
      /* if we are booted from BootX with an initial ramdisk,
         make sure the ramdisk pages aren't reserved. */
      if (initrd_start) {
            for (addr = initrd_start; addr < initrd_end; addr += PAGE_SIZE)
                  ClearPageReserved(virt_to_page(addr));
      }
#endif /* CONFIG_BLK_DEV_INITRD */

      for (addr = PAGE_OFFSET; addr < (unsigned long)high_memory;
           addr += PAGE_SIZE) {
            if (!PageReserved(virt_to_page(addr)))
                  continue;
            if (addr < (ulong) etext)
                  codepages++;
            else if (addr >= (unsigned long)&__init_begin
                   && addr < (unsigned long)&__init_end)
                  initpages++;
            else if (addr < (ulong) klimit)
                  datapages++;
      }

#ifdef CONFIG_HIGHMEM
      {
            unsigned long pfn;

            for (pfn = highmem_mapnr; pfn < max_mapnr; ++pfn) {
                  struct page *page = mem_map + pfn;

                  ClearPageReserved(page);
                  init_page_count(page);
                  __free_page(page);
                  totalhigh_pages++;
            }
            totalram_pages += totalhigh_pages;
      }
#endif /* CONFIG_HIGHMEM */

        printk("Memory: %luk available (%dk kernel code, %dk data, %dk init, %ldk highmem)\n",
             (unsigned long)nr_free_pages()<< (PAGE_SHIFT-10),
             codepages<< (PAGE_SHIFT-10), datapages<< (PAGE_SHIFT-10),
             initpages<< (PAGE_SHIFT-10),
             (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10)));

      mem_init_done = 1;
}

/*
 * Set phys_avail to the amount of physical memory,
 * less the kernel text/data/bss.
 */
void __init
set_phys_avail(unsigned long total_memory)
{
      unsigned long kstart, ksize;

      /*
       * Initially, available physical memory is equivalent to all
       * physical memory.
       */

      phys_avail.regions[0].address = PPC_MEMSTART;
      phys_avail.regions[0].size = total_memory;
      phys_avail.n_regions = 1;

      /*
       * Map out the kernel text/data/bss from the available physical
       * memory.
       */

      kstart = __pa(_stext);  /* should be 0 */
      ksize = PAGE_ALIGN(klimit - _stext);

      mem_pieces_remove(&phys_avail, kstart, ksize, 0);
      mem_pieces_remove(&phys_avail, 0, 0x4000, 0);

#if defined(CONFIG_BLK_DEV_INITRD)
      /* Remove the init RAM disk from the available memory. */
      if (initrd_start) {
            mem_pieces_remove(&phys_avail, __pa(initrd_start),
                          initrd_end - initrd_start, 1);
      }
#endif /* CONFIG_BLK_DEV_INITRD */
}

/* Mark some memory as reserved by removing it from phys_avail. */
void __init reserve_phys_mem(unsigned long start, unsigned long size)
{
      mem_pieces_remove(&phys_avail, start, size, 1);
}

/*
 * This is called when a page has been modified by the kernel.
 * It just marks the page as not i-cache clean.  We do the i-cache
 * flush later when the page is given to a user process, if necessary.
 */
void flush_dcache_page(struct page *page)
{
      clear_bit(PG_arch_1, &page->flags);
}

void flush_dcache_icache_page(struct page *page)
{
#ifdef CONFIG_BOOKE
      void *start = kmap_atomic(page, KM_PPC_SYNC_ICACHE);
      __flush_dcache_icache(start);
      kunmap_atomic(start, KM_PPC_SYNC_ICACHE);
#elif defined(CONFIG_8xx)
      /* On 8xx there is no need to kmap since highmem is not supported */
      __flush_dcache_icache(page_address(page)); 
#else
      __flush_dcache_icache_phys(page_to_pfn(page) << PAGE_SHIFT);
#endif

}
void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
{
      clear_page(page);
      clear_bit(PG_arch_1, &pg->flags);
}

void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
                struct page *pg)
{
      copy_page(vto, vfrom);
      clear_bit(PG_arch_1, &pg->flags);
}

void flush_icache_user_range(struct vm_area_struct *vma, struct page *page,
                       unsigned long addr, int len)
{
      unsigned long maddr;

      maddr = (unsigned long) kmap(page) + (addr & ~PAGE_MASK);
      flush_icache_range(maddr, maddr + len);
      kunmap(page);
}

/*
 * This is called at the end of handling a user page fault, when the
 * fault has been handled by updating a PTE in the linux page tables.
 * We use it to preload an HPTE into the hash table corresponding to
 * the updated linux PTE.
 */
void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
                  pte_t pte)
{
      /* handle i-cache coherency */
      unsigned long pfn = pte_pfn(pte);

      if (pfn_valid(pfn)) {
            struct page *page = pfn_to_page(pfn);
#ifdef CONFIG_8xx
            /* On 8xx, the TLB handlers work in 2 stages:
             * First, a zeroed entry is loaded by TLBMiss handler,
             * which causes the TLBError handler to be triggered.
             * That means the zeroed TLB has to be invalidated
             * whenever a page miss occurs.
             */
            _tlbie(address, 0 /* 8xx doesn't care about PID */);
#endif
            if (!PageReserved(page)
                && !test_bit(PG_arch_1, &page->flags)) {
                  if (vma->vm_mm == current->active_mm)
                        __flush_dcache_icache((void *) address);
                  else
                        flush_dcache_icache_page(page);
                  set_bit(PG_arch_1, &page->flags);
            }
      }

#ifdef CONFIG_PPC_STD_MMU
      /* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
      if (Hash != 0 && pte_young(pte)) {
            struct mm_struct *mm;
            pmd_t *pmd;

            mm = (address < TASK_SIZE)? vma->vm_mm: &init_mm;
            pmd = pmd_offset(pgd_offset(mm, address), address);
            if (!pmd_none(*pmd))
                  add_hash_page(mm->context.id, address, pmd_val(*pmd));
      }
#endif
}

/*
 * This is called by /dev/mem to know if a given address has to
 * be mapped non-cacheable or not
 */
int page_is_ram(unsigned long pfn)
{
      return pfn < max_pfn;
}

pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
                        unsigned long size, pgprot_t vma_prot)
{
      if (ppc_md.phys_mem_access_prot)
            return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot);

      if (!page_is_ram(pfn))
            vma_prot = __pgprot(pgprot_val(vma_prot)
                            | _PAGE_GUARDED | _PAGE_NO_CACHE);
      return vma_prot;
}
EXPORT_SYMBOL(phys_mem_access_prot);

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