mm-armv.c

优龙2410linux2.6.8内核源代码

{
	struct cachepolicy *cp;
	unsigned int cr = get_cr();
	int cpu_arch = cpu_architecture();
	int i;

#if defined(CONFIG_CPU_DCACHE_DISABLE)
	if (cachepolicy > CPOLICY_BUFFERED)
		cachepolicy = CPOLICY_BUFFERED;
#elif defined(CONFIG_CPU_DCACHE_WRITETHROUGH)
	if (cachepolicy > CPOLICY_WRITETHROUGH)
		cachepolicy = CPOLICY_WRITETHROUGH;
#endif
	if (cpu_arch < CPU_ARCH_ARMv5) {
		if (cachepolicy >= CPOLICY_WRITEALLOC)
			cachepolicy = CPOLICY_WRITEBACK;
		ecc_mask = 0;
	}

	if (cpu_arch <= CPU_ARCH_ARMv5) {
		mem_types[MT_DEVICE].prot_l1       |= PMD_BIT4;
		mem_types[MT_DEVICE].prot_sect     |= PMD_BIT4;
		mem_types[MT_CACHECLEAN].prot_sect |= PMD_BIT4;
		mem_types[MT_MINICLEAN].prot_sect  |= PMD_BIT4;
		mem_types[MT_VECTORS].prot_l1      |= PMD_BIT4;
		mem_types[MT_MEMORY].prot_sect     |= PMD_BIT4;
	}

	/*
	 * ARMv6 and above have extended page tables.
	 */
	if (cpu_arch >= CPU_ARCH_ARMv6 && (cr & CR_XP)) {
		/*
		 * bit 4 becomes XN which we must clear for the
		 * kernel memory mapping.
		 */
		mem_types[MT_MEMORY].prot_sect &= ~PMD_BIT4;
		/*
		 * Mark cache clean areas read only from SVC mode
		 * and no access from userspace.
		 */
		mem_types[MT_MINICLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
		mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
	}

	cp = &cache_policies[cachepolicy];

	if (cpu_arch >= CPU_ARCH_ARMv5) {
		mem_types[MT_VECTORS].prot_pte |= cp->pte & PTE_CACHEABLE;
	} else {
		mem_types[MT_VECTORS].prot_pte |= cp->pte;
		mem_types[MT_MINICLEAN].prot_sect &= ~PMD_SECT_TEX(1);
	}

	mem_types[MT_VECTORS].prot_l1 |= ecc_mask;
	mem_types[MT_MEMORY].prot_sect |= ecc_mask | cp->pmd;

	for (i = 0; i < 16; i++) {
		unsigned long v = pgprot_val(protection_map[i]);
		v &= (~(PTE_BUFFERABLE|PTE_CACHEABLE)) | cp->pte;
		protection_map[i] = __pgprot(v);
	}

	pgprot_kernel = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG |
				 L_PTE_DIRTY | L_PTE_WRITE |
				 L_PTE_EXEC | cp->pte);

	switch (cp->pmd) {
	case PMD_SECT_WT:
		mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WT;
		break;
	case PMD_SECT_WB:
	case PMD_SECT_WBWA:
		mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WB;
		break;
	}
	printk("Memory policy: ECC %sabled, Data cache %s\n",
		ecc_mask ? "en" : "dis", cp->policy);
}

/*
 * Create the page directory entries and any necessary
 * page tables for the mapping specified by `md'.  We
 * are able to cope here with varying sizes and address
 * offsets, and we take full advantage of sections.
 */
static void __init create_mapping(struct map_desc *md)
{
	unsigned long virt, length;
	int prot_sect, prot_l1, domain;
	pgprot_t prot_pte;
	long off;

	if (md->virtual != vectors_base() && md->virtual < PAGE_OFFSET) {
		printk(KERN_WARNING "BUG: not creating mapping for "
		       "0x%08lx at 0x%08lx in user region\n",
		       md->physical, md->virtual);
		return;
	}

	if (md->type == MT_DEVICE &&
	    md->virtual >= PAGE_OFFSET && md->virtual < VMALLOC_END) {
		printk(KERN_WARNING "BUG: mapping for 0x%08lx at 0x%08lx "
		       "overlaps vmalloc space\n",
		       md->physical, md->virtual);
	}

	domain	  = mem_types[md->type].domain;
	prot_pte  = __pgprot(mem_types[md->type].prot_pte);
	prot_l1   = mem_types[md->type].prot_l1 | PMD_DOMAIN(domain);
	prot_sect = mem_types[md->type].prot_sect | PMD_DOMAIN(domain);

	virt   = md->virtual;
	off    = md->physical - virt;
	length = md->length;

	if (mem_types[md->type].prot_l1 == 0 &&
	    (virt & 0xfffff || (virt + off) & 0xfffff || (virt + length) & 0xfffff)) {
		printk(KERN_WARNING "BUG: map for 0x%08lx at 0x%08lx can not "
		       "be mapped using pages, ignoring.\n",
		       md->physical, md->virtual);
		return;
	}

	while ((virt & 0xfffff || (virt + off) & 0xfffff) && length >= PAGE_SIZE) {
		alloc_init_page(virt, virt + off, prot_l1, prot_pte);

		virt   += PAGE_SIZE;
		length -= PAGE_SIZE;
	}

	while (length >= (PGDIR_SIZE / 2)) {
		alloc_init_section(virt, virt + off, prot_sect);

		virt   += (PGDIR_SIZE / 2);
		length -= (PGDIR_SIZE / 2);
	}

	while (length >= PAGE_SIZE) {
		alloc_init_page(virt, virt + off, prot_l1, prot_pte);

		virt   += PAGE_SIZE;
		length -= PAGE_SIZE;
	}
}

/*
 * In order to soft-boot, we need to insert a 1:1 mapping in place of
 * the user-mode pages.  This will then ensure that we have predictable
 * results when turning the mmu off
 */
void setup_mm_for_reboot(char mode)
{
	unsigned long pmdval;
	pgd_t *pgd;
	pmd_t *pmd;
	int i;
	int cpu_arch = cpu_architecture();

	if (current->mm && current->mm->pgd)
		pgd = current->mm->pgd;
	else
		pgd = init_mm.pgd;

	for (i = 0; i < FIRST_USER_PGD_NR + USER_PTRS_PER_PGD; i++) {
		pmdval = (i << PGDIR_SHIFT) |
			 PMD_SECT_AP_WRITE | PMD_SECT_AP_READ |
			 PMD_TYPE_SECT;
		if (cpu_arch <= CPU_ARCH_ARMv5)
			pmdval |= PMD_BIT4;
		pmd = pmd_offset(pgd + i, i << PGDIR_SHIFT);
		set_pmd(pmd, __pmd(pmdval));
	}
}

/*
 * Setup initial mappings.  We use the page we allocated for zero page to hold
 * the mappings, which will get overwritten by the vectors in traps_init().
 * The mappings must be in virtual address order.
 */
void __init memtable_init(struct meminfo *mi)
{
	struct map_desc *init_maps, *p, *q;
	unsigned long address = 0;
	int i;

	build_mem_type_table();

	init_maps = p = alloc_bootmem_low_pages(PAGE_SIZE);

	for (i = 0; i < mi->nr_banks; i++) {
		if (mi->bank[i].size == 0)
			continue;

		p->physical   = mi->bank[i].start;
		p->virtual    = __phys_to_virt(p->physical);
		p->length     = mi->bank[i].size;
		p->type       = MT_MEMORY;
		p ++;
	}

#ifdef FLUSH_BASE
	p->physical   = FLUSH_BASE_PHYS;
	p->virtual    = FLUSH_BASE;
	p->length     = PGDIR_SIZE;
	p->type       = MT_CACHECLEAN;
	p ++;
#endif

#ifdef FLUSH_BASE_MINICACHE
	p->physical   = FLUSH_BASE_PHYS + PGDIR_SIZE;
	p->virtual    = FLUSH_BASE_MINICACHE;
	p->length     = PGDIR_SIZE;
	p->type       = MT_MINICLEAN;
	p ++;
#endif

	/*
	 * Go through the initial mappings, but clear out any
	 * pgdir entries that are not in the description.
	 */
	q = init_maps;
	do {
		if (address < q->virtual || q == p) {
			clear_mapping(address);
			address += PGDIR_SIZE;
		} else {
			create_mapping(q);

			address = q->virtual + q->length;
			address = (address + PGDIR_SIZE - 1) & PGDIR_MASK;

			q ++;
		}
	} while (address != 0);

	/*
	 * Create a mapping for the machine vectors at virtual address 0
	 * or 0xffff0000.  We should always try the high mapping.
	 */
	init_maps->physical   = virt_to_phys(init_maps);
	init_maps->virtual    = vectors_base();
	init_maps->length     = PAGE_SIZE;
	init_maps->type       = MT_VECTORS;

	create_mapping(init_maps);

	flush_cache_all();
	flush_tlb_all();
}

/*
 * Create the architecture specific mappings
 */
void __init iotable_init(struct map_desc *io_desc, int nr)
{
	int i;

	for (i = 0; i < nr; i++)
		create_mapping(io_desc + i);
}

static inline void
free_memmap(int node, unsigned long start_pfn, unsigned long end_pfn)
{
	struct page *start_pg, *end_pg;
	unsigned long pg, pgend;

	/*
	 * Convert start_pfn/end_pfn to a struct page pointer.
	 */
	start_pg = pfn_to_page(start_pfn);
	end_pg = pfn_to_page(end_pfn);

	/*
	 * Convert to physical addresses, and
	 * round start upwards and end downwards.
	 */
	pg = PAGE_ALIGN(__pa(start_pg));
	pgend = __pa(end_pg) & PAGE_MASK;

	/*
	 * If there are free pages between these,
	 * free the section of the memmap array.
	 */
	if (pg < pgend)
		free_bootmem_node(NODE_DATA(node), pg, pgend - pg);
}

static inline void free_unused_memmap_node(int node, struct meminfo *mi)
{
	unsigned long bank_start, prev_bank_end = 0;
	unsigned int i;

	/*
	 * [FIXME] This relies on each bank being in address order.  This
	 * may not be the case, especially if the user has provided the
	 * information on the command line.
	 */
	for (i = 0; i < mi->nr_banks; i++) {
		if (mi->bank[i].size == 0 || mi->bank[i].node != node)
			continue;

		bank_start = mi->bank[i].start >> PAGE_SHIFT;
		if (bank_start < prev_bank_end) {
			printk(KERN_ERR "MEM: unordered memory banks.  "
				"Not freeing memmap.\n");
			break;
		}

		/*
		 * If we had a previous bank, and there is a space
		 * between the current bank and the previous, free it.
		 */
		if (prev_bank_end && prev_bank_end != bank_start)
			free_memmap(node, prev_bank_end, bank_start);

		prev_bank_end = PAGE_ALIGN(mi->bank[i].start +
					   mi->bank[i].size) >> PAGE_SHIFT;
	}
}

/*
 * The mem_map array can get very big.  Free
 * the unused area of the memory map.
 */
void __init create_memmap_holes(struct meminfo *mi)
{
	int node;

	for (node = 0; node < numnodes; node++)
		free_unused_memmap_node(node, mi);
}