init.c

linux-2.6.15.6

/*
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas ([e-mail])
 *
 *  Modifications by Paul Mackerras (PowerMac) ([e-mail])
 *  and Cort Dougan (PReP) ([e-mail])
 *    Copyright (C) 1996 Paul Mackerras
 *  Amiga/APUS changes by Jesper Skov ([e-mail]).
 *  PPC44x/36-bit changes by Matt Porter ([e-mail])
 *
 *  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/config.h>
#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 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 mem_init_done;
int init_bootmem_done;
int boot_mapsize;
#ifdef CONFIG_PPC_PMAC
unsigned long agp_special_page;
EXPORT_SYMBOL(agp_special_page);
#endif

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));
		set_page_count(virt_to_page(start), 1);
		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));
		set_page_count(virt_to_page(start), 1);
		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).