init.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

/*  $Id: init.c,v 1.207 2001/11/30 06:55:39 davem Exp $
 *  arch/sparc64/mm/init.c
 *
 *  Copyright (C) 1996-1999 David S. Miller ([e-mail])
 *  Copyright (C) 1997-1999 Jakub Jelinek ([e-mail])
 */
 
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/blk.h>
#include <linux/swap.h>
#include <linux/swapctl.h>
#include <linux/pagemap.h>
#include <linux/fs.h>
#include <linux/seq_file.h>

#include <asm/head.h>
#include <asm/system.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/oplib.h>
#include <asm/iommu.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/dma.h>
#include <asm/starfire.h>
#include <asm/tlb.h>
#include <asm/spitfire.h>

mmu_gather_t mmu_gathers[NR_CPUS];

extern void device_scan(void);

struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS];

unsigned long *sparc64_valid_addr_bitmap;

/* Ugly, but necessary... -DaveM */
unsigned long phys_base;

enum ultra_tlb_layout tlb_type = spitfire;

/* get_new_mmu_context() uses "cache + 1".  */
spinlock_t ctx_alloc_lock = SPIN_LOCK_UNLOCKED;
unsigned long tlb_context_cache = CTX_FIRST_VERSION - 1;
#define CTX_BMAP_SLOTS (1UL << (CTX_VERSION_SHIFT - 6))
unsigned long mmu_context_bmap[CTX_BMAP_SLOTS];

/* References to section boundaries */
extern char __init_begin, __init_end, _start, _end, etext, edata;

/* Initial ramdisk setup */
extern unsigned int sparc_ramdisk_image;
extern unsigned int sparc_ramdisk_size;

struct page *mem_map_zero;

int bigkernel = 0;

int do_check_pgt_cache(int low, int high)
{
        int freed = 0;

	if (pgtable_cache_size > high) {
		do {
#ifdef CONFIG_SMP
			if (pgd_quicklist)
				free_pgd_slow(get_pgd_fast()), freed++;
#endif
			if (pte_quicklist[0])
				free_pte_slow(pte_alloc_one_fast(NULL, 0)), freed++;
			if (pte_quicklist[1])
				free_pte_slow(pte_alloc_one_fast(NULL, 1 << (PAGE_SHIFT + 10))), freed++;
		} while (pgtable_cache_size > low);
	}
#ifndef CONFIG_SMP 
        if (pgd_cache_size > high / 4) {
		struct page *page, *page2;
                for (page2 = NULL, page = (struct page *)pgd_quicklist; page;) {
                        if ((unsigned long)page->pprev_hash == 3) {
                                if (page2)
                                        page2->next_hash = page->next_hash;
                                else
                                        (struct page *)pgd_quicklist = page->next_hash;
                                page->next_hash = NULL;
                                page->pprev_hash = NULL;
                                pgd_cache_size -= 2;
                                __free_page(page);
                                freed++;
                                if (page2)
                                        page = page2->next_hash;
                                else
                                        page = (struct page *)pgd_quicklist;
                                if (pgd_cache_size <= low / 4)
                                        break;
                                continue;
                        }
                        page2 = page;
                        page = page->next_hash;
                }
        }
#endif
        return freed;
}

extern void __update_mmu_cache(struct vm_area_struct *, unsigned long, pte_t);

#ifdef CONFIG_DEBUG_DCFLUSH
atomic_t dcpage_flushes = ATOMIC_INIT(0);
#ifdef CONFIG_SMP
atomic_t dcpage_flushes_xcall = ATOMIC_INIT(0);
#endif
#endif

__inline__ void flush_dcache_page_impl(struct page *page)
{
#ifdef CONFIG_DEBUG_DCFLUSH
	atomic_inc(&dcpage_flushes);
#endif

#if (L1DCACHE_SIZE > PAGE_SIZE)
	__flush_dcache_page(page->virtual,
			    ((tlb_type == spitfire) &&
			     page->mapping != NULL));
#else
	if (page->mapping != NULL &&
	    tlb_type == spitfire)
		__flush_icache_page(__pa(page->virtual));
#endif
}

#define PG_dcache_dirty		PG_arch_1

#define dcache_dirty_cpu(page) \
	(((page)->flags >> 24) & (NR_CPUS - 1UL))

static __inline__ void set_dcache_dirty(struct page *page)
{
	unsigned long mask = smp_processor_id();
	unsigned long non_cpu_bits = (1UL << 24UL) - 1UL;
	mask = (mask << 24) | (1UL << PG_dcache_dirty);
	__asm__ __volatile__("1:\n\t"
			     "ldx	[%2], %%g7\n\t"
			     "and	%%g7, %1, %%g5\n\t"
			     "or	%%g5, %0, %%g5\n\t"
			     "casx	[%2], %%g7, %%g5\n\t"
			     "cmp	%%g7, %%g5\n\t"
			     "bne,pn	%%xcc, 1b\n\t"
			     " membar	#StoreLoad | #StoreStore"
			     : /* no outputs */
			     : "r" (mask), "r" (non_cpu_bits), "r" (&page->flags)
			     : "g5", "g7");
}

static __inline__ void clear_dcache_dirty_cpu(struct page *page, unsigned long cpu)
{
	unsigned long mask = (1UL << PG_dcache_dirty);

	__asm__ __volatile__("! test_and_clear_dcache_dirty\n"
			     "1:\n\t"
			     "ldx	[%2], %%g7\n\t"
			     "srlx	%%g7, 24, %%g5\n\t"
			     "cmp	%%g5, %0\n\t"
			     "bne,pn	%%icc, 2f\n\t"
			     " andn	%%g7, %1, %%g5\n\t"
			     "casx	[%2], %%g7, %%g5\n\t"
			     "cmp	%%g7, %%g5\n\t"
			     "bne,pn	%%xcc, 1b\n\t"
			     " membar	#StoreLoad | #StoreStore\n"
			     "2:"
			     : /* no outputs */
			     : "r" (cpu), "r" (mask), "r" (&page->flags)
			     : "g5", "g7");
}

void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t pte)
{
	struct page *page = pte_page(pte);
	unsigned long pg_flags;

	if (VALID_PAGE(page) &&
	    page->mapping &&
	    ((pg_flags = page->flags) & (1UL << PG_dcache_dirty))) {
		int cpu = (pg_flags >> 24);

		/* This is just to optimize away some function calls
		 * in the SMP case.
		 */
		if (cpu == smp_processor_id())
			flush_dcache_page_impl(page);
		else
			smp_flush_dcache_page_impl(page, cpu);

		clear_dcache_dirty_cpu(page, cpu);
	}
	__update_mmu_cache(vma, address, pte);
}

void flush_dcache_page(struct page *page)
{
	int dirty = test_bit(PG_dcache_dirty, &page->flags);
	int dirty_cpu = dcache_dirty_cpu(page);

	if (page->mapping &&
	    page->mapping->i_mmap == NULL &&
	    page->mapping->i_mmap_shared == NULL) {
		if (dirty) {
			if (dirty_cpu == smp_processor_id())
				return;
			smp_flush_dcache_page_impl(page, dirty_cpu);
		}
		set_dcache_dirty(page);
	} else {
		/* We could delay the flush for the !page->mapping
		 * case too.  But that case is for exec env/arg
		 * pages and those are %99 certainly going to get
		 * faulted into the tlb (and thus flushed) anyways.
		 */
		flush_dcache_page_impl(page);
	}
}

void flush_icache_range(unsigned long start, unsigned long end)
{
	/* Cheetah has coherent I-cache. */
	if (tlb_type == spitfire) {
		unsigned long kaddr;

		for (kaddr = start; kaddr < end; kaddr += PAGE_SIZE)
			__flush_icache_page(__get_phys(kaddr));
	}
}

void show_mem(void)
{
	printk("Mem-info:\n");
	show_free_areas();
	printk("Free swap:       %6dkB\n",
	       nr_swap_pages << (PAGE_SHIFT-10));
	printk("%ld pages of RAM\n", num_physpages);
	printk("%d free pages\n", nr_free_pages());
	printk("%d pages in page table cache\n",pgtable_cache_size);
#ifndef CONFIG_SMP
	printk("%d entries in page dir cache\n",pgd_cache_size);
#endif	
	show_buffers();
}

void mmu_info(struct seq_file *m)
{
	if (tlb_type == cheetah)
		seq_printf(m, "MMU Type\t: Cheetah\n");
	else if (tlb_type == cheetah_plus)
		seq_printf(m, "MMU Type\t: Cheetah+\n");
	else if (tlb_type == spitfire)
		seq_printf(m, "MMU Type\t: Spitfire\n");
	else
		seq_printf(m, "MMU Type\t: ???\n");

#ifdef CONFIG_DEBUG_DCFLUSH
	seq_printf(m, "DCPageFlushes\t: %d\n",
		   atomic_read(&dcpage_flushes));
#ifdef CONFIG_SMP
	seq_printf(m, "DCPageFlushesXC\t: %d\n",
		   atomic_read(&dcpage_flushes_xcall));
#endif /* CONFIG_SMP */
#endif /* CONFIG_DEBUG_DCFLUSH */
}

struct linux_prom_translation {
	unsigned long virt;
	unsigned long size;
	unsigned long data;
};

extern unsigned long prom_boot_page;
extern void prom_remap(unsigned long physpage, unsigned long virtpage, int mmu_ihandle);
extern int prom_get_mmu_ihandle(void);
extern void register_prom_callbacks(void);

/* Exported for SMP bootup purposes. */
unsigned long kern_locked_tte_data;

void __init early_pgtable_allocfail(char *type)
{
	prom_printf("inherit_prom_mappings: Cannot alloc kernel %s.\n", type);
	prom_halt();
}

#define BASE_PAGE_SIZE 8192
static pmd_t *prompmd;

/* When shared+writable mmaps of files go away, we lose all dirty
 * page state, so we have to deal with D-cache aliasing here.
 *
 * This code relies on the fact that flush_cache_range() is always
 * called for an area composed by a single VMA.  It also assumes that
 * the MM's page_table_lock is held.
 */
static inline void flush_cache_pte_range(struct mm_struct *mm, pmd_t *pmd, unsigned long address, unsigned long size)
{
	unsigned long offset;
	pte_t *ptep;

	if (pmd_none(*pmd))
		return;
	ptep = pte_offset(pmd, address);
	offset = address & ~PMD_MASK;
	if (offset + size > PMD_SIZE)
		size = PMD_SIZE - offset;
	size &= PAGE_MASK;
	for (offset = 0; offset < size; ptep++, offset += PAGE_SIZE) {
		pte_t pte = *ptep;

		if (pte_none(pte))
			continue;

		if (pte_present(pte) && pte_dirty(pte)) {
			struct page *page = pte_page(pte);
			unsigned long pgaddr, uaddr;

			if (!VALID_PAGE(page) || PageReserved(page) || !page->mapping)
				continue;
			pgaddr = (unsigned long) page_address(page);
			uaddr = address + offset;
			if ((pgaddr ^ uaddr) & (1 << 13))
				flush_dcache_page_all(mm, page);
		}
	}
}

static inline void flush_cache_pmd_range(struct mm_struct *mm, pgd_t *dir, unsigned long address, unsigned long size)
{
	pmd_t *pmd;
	unsigned long end;

	if (pgd_none(*dir))
		return;
	pmd = pmd_offset(dir, address);
	end = address + size;
	if (end > ((address + PGDIR_SIZE) & PGDIR_MASK))
		end = ((address + PGDIR_SIZE) & PGDIR_MASK);
	do {
		flush_cache_pte_range(mm, pmd, address, end - address);
		address = (address + PMD_SIZE) & PMD_MASK;
		pmd++;
	} while (address < end);
}

void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
	struct mm_struct *mm = vma->vm_mm;
	pgd_t *dir = pgd_offset(mm, start);

	if (mm == current->mm)
		flushw_user();

	if (vma->vm_file == NULL ||
	    ((vma->vm_flags & (VM_SHARED|VM_WRITE)) != (VM_SHARED|VM_WRITE)))
		return;

	do {
		flush_cache_pmd_range(mm, dir, start, end - start);
		start = (start + PGDIR_SIZE) & PGDIR_MASK;
		dir++;
	} while (start && (start < end));
}

/*
 * Translate PROM's mapping we capture at boot time into physical address.
 * The second parameter is only set from prom_callback() invocations.
 */
unsigned long prom_virt_to_phys(unsigned long promva, int *error)
{
	pmd_t *pmdp = prompmd + ((promva >> 23) & 0x7ff);
	pte_t *ptep;
	unsigned long base;

	if (pmd_none(*pmdp)) {
		if (error)
			*error = 1;
		return(0);
	}
	ptep = (pte_t *)pmd_page(*pmdp) + ((promva >> 13) & 0x3ff);
	if (!pte_present(*ptep)) {
		if (error)
			*error = 1;
		return(0);
	}
	if (error) {
		*error = 0;
		return(pte_val(*ptep));
	}
	base = pte_val(*ptep) & _PAGE_PADDR;
	return(base + (promva & (BASE_PAGE_SIZE - 1)));
}

static void inherit_prom_mappings(void)
{
	struct linux_prom_translation *trans;
	unsigned long phys_page, tte_vaddr, tte_data;
	void (*remap_func)(unsigned long, unsigned long, int);
	pmd_t *pmdp;
	pte_t *ptep;
	int node, n, i, tsz;
	extern unsigned int obp_iaddr_patch[2], obp_daddr_patch[2];

	node = prom_finddevice("/virtual-memory");
	n = prom_getproplen(node, "translations");
	if (n == 0 || n == -1) {
		prom_printf("Couldn't get translation property\n");
		prom_halt();
	}
	n += 5 * sizeof(struct linux_prom_translation);
	for (tsz = 1; tsz < n; tsz <<= 1)
		/* empty */;
	trans = __alloc_bootmem(tsz, SMP_CACHE_BYTES, 0UL);
	if (trans == NULL) {
		prom_printf("inherit_prom_mappings: Cannot alloc translations.\n");
		prom_halt();
	}
	memset(trans, 0, tsz);

	if ((n = prom_getproperty(node, "translations", (char *)trans, tsz)) == -1) {
		prom_printf("Couldn't get translation property\n");
		prom_halt();
	}
	n = n / sizeof(*trans);

	/*
	 * The obp translations are saved based on 8k pagesize, since obp can use
	 * a mixture of pagesizes. Misses to the 0xf0000000 - 0x100000000, ie obp 
	 * range, are handled in entry.S and do not use the vpte scheme (see rant
	 * in inherit_locked_prom_mappings()).
	 */
#define OBP_PMD_SIZE 2048
	prompmd = __alloc_bootmem(OBP_PMD_SIZE, OBP_PMD_SIZE, 0UL);
	if (prompmd == NULL)
		early_pgtable_allocfail("pmd");
	memset(prompmd, 0, OBP_PMD_SIZE);
	for (i = 0; i < n; i++) {
		unsigned long vaddr;

		if (trans[i].virt >= LOW_OBP_ADDRESS && trans[i].virt < HI_OBP_ADDRESS) {
			for (vaddr = trans[i].virt;