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init_32.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
 *  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/lmb.h>
#include <asm/sections.h>

#include "mmu_decl.h"

#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
/* The ammount 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 boot_mapsize;
#ifdef CONFIG_PPC_PMAC
unsigned long agp_special_page;
EXPORT_SYMBOL(agp_special_page);
#endif

#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
pgprot_t kmap_prot;

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

void MMU_init(void);

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

extern int init_bootmem_done;

/*
 * 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 low RAM to map in */
unsigned long __max_low_memory = MAX_LOW_MEM;

/*
 * limit of what is accessible with initial MMU setup -
 * 256MB usually, but only 16MB on 601.
 */
unsigned long __initial_memory_limit = 0x10000000;

/*
 * 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;
      }
#ifdef CONFIG_DEBUG_PAGEALLOC
      __map_without_bats = 1;
      __map_without_ltlbs = 1;
#endif
}

/*
 * 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);

      /* 601 can only access 16MB at the moment */
      if (PVR_VER(mfspr(SPRN_PVR)) == 1)
            __initial_memory_limit = 0x01000000;
      /* 8xx can only access 8MB at the moment */
      if (PVR_VER(mfspr(SPRN_PVR)) == 0x50)
            __initial_memory_limit = 0x00800000;

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

      if (lmb.memory.cnt > 1) {
            lmb.memory.cnt = 1;
            lmb_analyze();
            printk(KERN_WARNING "Only using first contiguous memory region");
      }

      total_memory = lmb_end_of_DRAM();
      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;
            lmb_enforce_memory_limit(total_lowmem);
            lmb_analyze();
#endif /* CONFIG_HIGHMEM */
      }

      /* 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);

      /* From now on, btext is no longer BAT mapped if it was at all */
#ifdef CONFIG_BOOTX_TEXT
      btext_unmap();
#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 = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE,
                              __initial_memory_limit));
      }
      return p;
}

/* 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)
{
      if (start < 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

#ifdef CONFIG_PROC_KCORE
static struct kcore_list kcore_vmem;

static int __init setup_kcore(void)
{
      int i;

      for (i = 0; i < lmb.memory.cnt; i++) {
            unsigned long base;
            unsigned long size;
            struct kcore_list *kcore_mem;

            base = lmb.memory.region[i].base;
            size = lmb.memory.region[i].size;

            kcore_mem = kmalloc(sizeof(struct kcore_list), GFP_ATOMIC);
            if (!kcore_mem)
                  panic("%s: kmalloc failed\n", __FUNCTION__);

            /* must stay under 32 bits */
            if ( 0xfffffffful - (unsigned long)__va(base) < size) {
                  size = 0xfffffffful - (unsigned long)(__va(base));
                  printk(KERN_DEBUG "setup_kcore: restrict size=%lx\n",
                                    size);
            }

            kclist_add(kcore_mem, __va(base), size);
      }

      kclist_add(&kcore_vmem, (void *)VMALLOC_START,
            VMALLOC_END-VMALLOC_START);

      return 0;
}
module_init(setup_kcore);
#endif

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