vmalloc.c

最新最稳定的Linux内存管理模块源代码

	}

	kfree(area);
	return;
}

/**
 *	vfree  -  release memory allocated by vmalloc()
 *	@addr:		memory base address
 *
 *	Free the virtually continuous memory area starting at @addr, as
 *	obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is
 *	NULL, no operation is performed.
 *
 *	Must not be called in interrupt context.
 */
void vfree(const void *addr)
{
	BUG_ON(in_interrupt());
	__vunmap(addr, 1);
}
EXPORT_SYMBOL(vfree);

/**
 *	vunmap  -  release virtual mapping obtained by vmap()
 *	@addr:		memory base address
 *
 *	Free the virtually contiguous memory area starting at @addr,
 *	which was created from the page array passed to vmap().
 *
 *	Must not be called in interrupt context.
 */
void vunmap(const void *addr)
{
	BUG_ON(in_interrupt());
	__vunmap(addr, 0);
}
EXPORT_SYMBOL(vunmap);

/**
 *	vmap  -  map an array of pages into virtually contiguous space
 *	@pages:		array of page pointers
 *	@count:		number of pages to map
 *	@flags:		vm_area->flags
 *	@prot:		page protection for the mapping
 *
 *	Maps @count pages from @pages into contiguous kernel virtual
 *	space.
 */
void *vmap(struct page **pages, unsigned int count,
		unsigned long flags, pgprot_t prot)
{
	struct vm_struct *area;

	if (count > num_physpages)
		return NULL;

	area = get_vm_area_caller((count << PAGE_SHIFT), flags,
					__builtin_return_address(0));
	if (!area)
		return NULL;

	if (map_vm_area(area, prot, &pages)) {
		vunmap(area->addr);
		return NULL;
	}

	return area->addr;
}
EXPORT_SYMBOL(vmap);

static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
			    int node, void *caller);
static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
				 pgprot_t prot, int node, void *caller)
{
	struct page **pages;
	unsigned int nr_pages, array_size, i;

	nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT;
	array_size = (nr_pages * sizeof(struct page *));

	area->nr_pages = nr_pages;
	/* Please note that the recursion is strictly bounded. */
	if (array_size > PAGE_SIZE) {
		pages = __vmalloc_node(array_size, gfp_mask | __GFP_ZERO,
				PAGE_KERNEL, node, caller);
		area->flags |= VM_VPAGES;
	} else {
		pages = kmalloc_node(array_size,
				(gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO,
				node);
	}
	area->pages = pages;
	area->caller = caller;
	if (!area->pages) {
		remove_vm_area(area->addr);
		kfree(area);
		return NULL;
	}

	for (i = 0; i < area->nr_pages; i++) {
		struct page *page;

		if (node < 0)
			page = alloc_page(gfp_mask);
		else
			page = alloc_pages_node(node, gfp_mask, 0);

		if (unlikely(!page)) {
			/* Successfully allocated i pages, free them in __vunmap() */
			area->nr_pages = i;
			goto fail;
		}
		area->pages[i] = page;
	}

	if (map_vm_area(area, prot, &pages))
		goto fail;
	return area->addr;

fail:
	vfree(area->addr);
	return NULL;
}

void *__vmalloc_area(struct vm_struct *area, gfp_t gfp_mask, pgprot_t prot)
{
	return __vmalloc_area_node(area, gfp_mask, prot, -1,
					__builtin_return_address(0));
}

/**
 *	__vmalloc_node  -  allocate virtually contiguous memory
 *	@size:		allocation size
 *	@gfp_mask:	flags for the page level allocator
 *	@prot:		protection mask for the allocated pages
 *	@node:		node to use for allocation or -1
 *	@caller:	caller's return address
 *
 *	Allocate enough pages to cover @size from the page level
 *	allocator with @gfp_mask flags.  Map them into contiguous
 *	kernel virtual space, using a pagetable protection of @prot.
 */
static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
						int node, void *caller)
{
	struct vm_struct *area;

	size = PAGE_ALIGN(size);
	if (!size || (size >> PAGE_SHIFT) > num_physpages)
		return NULL;

	area = __get_vm_area_node(size, VM_ALLOC, VMALLOC_START, VMALLOC_END,
						node, gfp_mask, caller);

	if (!area)
		return NULL;

	return __vmalloc_area_node(area, gfp_mask, prot, node, caller);
}

void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
{
	return __vmalloc_node(size, gfp_mask, prot, -1,
				__builtin_return_address(0));
}
EXPORT_SYMBOL(__vmalloc);

/**
 *	vmalloc  -  allocate virtually contiguous memory
 *	@size:		allocation size
 *	Allocate enough pages to cover @size from the page level
 *	allocator and map them into contiguous kernel virtual space.
 *
 *	For tight control over page level allocator and protection flags
 *	use __vmalloc() instead.
 */
void *vmalloc(unsigned long size)
{
	return __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
					-1, __builtin_return_address(0));
}
EXPORT_SYMBOL(vmalloc);

/**
 * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
 * @size: allocation size
 *
 * The resulting memory area is zeroed so it can be mapped to userspace
 * without leaking data.
 */
void *vmalloc_user(unsigned long size)
{
	struct vm_struct *area;
	void *ret;

	ret = __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
			     PAGE_KERNEL, -1, __builtin_return_address(0));
	if (ret) {
		area = find_vm_area(ret);
		area->flags |= VM_USERMAP;
	}
	return ret;
}
EXPORT_SYMBOL(vmalloc_user);

/**
 *	vmalloc_node  -  allocate memory on a specific node
 *	@size:		allocation size
 *	@node:		numa node
 *
 *	Allocate enough pages to cover @size from the page level
 *	allocator and map them into contiguous kernel virtual space.
 *
 *	For tight control over page level allocator and protection flags
 *	use __vmalloc() instead.
 */
void *vmalloc_node(unsigned long size, int node)
{
	return __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
					node, __builtin_return_address(0));
}
EXPORT_SYMBOL(vmalloc_node);

#ifndef PAGE_KERNEL_EXEC
# define PAGE_KERNEL_EXEC PAGE_KERNEL
#endif

/**
 *	vmalloc_exec  -  allocate virtually contiguous, executable memory
 *	@size:		allocation size
 *
 *	Kernel-internal function to allocate enough pages to cover @size
 *	the page level allocator and map them into contiguous and
 *	executable kernel virtual space.
 *
 *	For tight control over page level allocator and protection flags
 *	use __vmalloc() instead.
 */

void *vmalloc_exec(unsigned long size)
{
	return __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
			      -1, __builtin_return_address(0));
}

#if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
#define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL
#elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA)
#define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL
#else
#define GFP_VMALLOC32 GFP_KERNEL
#endif

/**
 *	vmalloc_32  -  allocate virtually contiguous memory (32bit addressable)
 *	@size:		allocation size
 *
 *	Allocate enough 32bit PA addressable pages to cover @size from the
 *	page level allocator and map them into contiguous kernel virtual space.
 */
void *vmalloc_32(unsigned long size)
{
	return __vmalloc_node(size, GFP_VMALLOC32, PAGE_KERNEL,
			      -1, __builtin_return_address(0));
}
EXPORT_SYMBOL(vmalloc_32);

/**
 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
 *	@size:		allocation size
 *
 * The resulting memory area is 32bit addressable and zeroed so it can be
 * mapped to userspace without leaking data.
 */
void *vmalloc_32_user(unsigned long size)
{
	struct vm_struct *area;
	void *ret;

	ret = __vmalloc_node(size, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
			     -1, __builtin_return_address(0));
	if (ret) {
		area = find_vm_area(ret);
		area->flags |= VM_USERMAP;
	}
	return ret;
}
EXPORT_SYMBOL(vmalloc_32_user);

long vread(char *buf, char *addr, unsigned long count)
{
	struct vm_struct *tmp;
	char *vaddr, *buf_start = buf;
	unsigned long n;

	/* Don't allow overflow */
	if ((unsigned long) addr + count < count)
		count = -(unsigned long) addr;

	read_lock(&vmlist_lock);
	for (tmp = vmlist; tmp; tmp = tmp->next) {
		vaddr = (char *) tmp->addr;
		if (addr >= vaddr + tmp->size - PAGE_SIZE)
			continue;
		while (addr < vaddr) {
			if (count == 0)
				goto finished;
			*buf = '\0';
			buf++;
			addr++;
			count--;
		}
		n = vaddr + tmp->size - PAGE_SIZE - addr;
		do {
			if (count == 0)
				goto finished;
			*buf = *addr;
			buf++;
			addr++;
			count--;
		} while (--n > 0);
	}
finished:
	read_unlock(&vmlist_lock);
	return buf - buf_start;
}

long vwrite(char *buf, char *addr, unsigned long count)
{
	struct vm_struct *tmp;
	char *vaddr, *buf_start = buf;
	unsigned long n;

	/* Don't allow overflow */
	if ((unsigned long) addr + count < count)
		count = -(unsigned long) addr;

	read_lock(&vmlist_lock);
	for (tmp = vmlist; tmp; tmp = tmp->next) {
		vaddr = (char *) tmp->addr;
		if (addr >= vaddr + tmp->size - PAGE_SIZE)
			continue;
		while (addr < vaddr) {
			if (count == 0)
				goto finished;
			buf++;
			addr++;
			count--;
		}
		n = vaddr + tmp->size - PAGE_SIZE - addr;
		do {
			if (count == 0)
				goto finished;
			*addr = *buf;
			buf++;
			addr++;
			count--;
		} while (--n > 0);
	}
finished:
	read_unlock(&vmlist_lock);
	return buf - buf_start;
}

/**
 *	remap_vmalloc_range  -  map vmalloc pages to userspace
 *	@vma:		vma to cover (map full range of vma)
 *	@addr:		vmalloc memory
 *	@pgoff:		number of pages into addr before first page to map
 *
 *	Returns:	0 for success, -Exxx on failure
 *
 *	This function checks that addr is a valid vmalloc'ed area, and
 *	that it is big enough to cover the vma. Will return failure if
 *	that criteria isn't met.
 *
 *	Similar to remap_pfn_range() (see mm/memory.c)
 */
int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
						unsigned long pgoff)
{
	struct vm_struct *area;
	unsigned long uaddr = vma->vm_start;
	unsigned long usize = vma->vm_end - vma->vm_start;

	if ((PAGE_SIZE-1) & (unsigned long)addr)
		return -EINVAL;

	area = find_vm_area(addr);
	if (!area)
		return -EINVAL;

	if (!(area->flags & VM_USERMAP))
		return -EINVAL;

	if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE)
		return -EINVAL;

	addr += pgoff << PAGE_SHIFT;
	do {
		struct page *page = vmalloc_to_page(addr);
		int ret;

		ret = vm_insert_page(vma, uaddr, page);
		if (ret)
			return ret;

		uaddr += PAGE_SIZE;
		addr += PAGE_SIZE;
		usize -= PAGE_SIZE;
	} while (usize > 0);

	/* Prevent "things" like memory migration? VM_flags need a cleanup... */
	vma->vm_flags |= VM_RESERVED;

	return 0;
}
EXPORT_SYMBOL(remap_vmalloc_range);

/*
 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
 * have one.
 */
void  __attribute__((weak)) vmalloc_sync_all(void)
{
}


static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data)
{
	/* apply_to_page_range() does all the hard work. */
	return 0;
}

/**
 *	alloc_vm_area - allocate a range of kernel address space
 *	@size:		size of the area
 *
 *	Returns:	NULL on failure, vm_struct on success
 *
 *	This function reserves a range of kernel address space, and
 *	allocates pagetables to map that range.  No actual mappings
 *	are created.  If the kernel address space is not shared
 *	between processes, it syncs the pagetable across all
 *	processes.
 */
struct vm_struct *alloc_vm_area(size_t size)
{
	struct vm_struct *area;

	area = get_vm_area_caller(size, VM_IOREMAP,
				__builtin_return_address(0));
	if (area == NULL)
		return NULL;

	/*
	 * This ensures that page tables are constructed for this region
	 * of kernel virtual address space and mapped into init_mm.
	 */
	if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
				area->size, f, NULL)) {
		free_vm_area(area);
		return NULL;
	}

	/* Make sure the pagetables are constructed in process kernel
	   mappings */
	vmalloc_sync_all();

	return area;
}
EXPORT_SYMBOL_GPL(alloc_vm_area);

void free_vm_area(struct vm_struct *area)
{
	struct vm_struct *ret;
	ret = remove_vm_area(area->addr);
	BUG_ON(ret != area);
	kfree(area);
}
EXPORT_SYMBOL_GPL(free_vm_area);


#ifdef CONFIG_PROC_FS
static void *s_start(struct seq_file *m, loff_t *pos)
{
	loff_t n = *pos;
	struct vm_struct *v;

	read_lock(&vmlist_lock);
	v = vmlist;
	while (n > 0 && v) {
		n--;
		v = v->next;
	}
	if (!n)
		return v;

	return NULL;

}

static void *s_next(struct seq_file *m, void *p, loff_t *pos)
{
	struct vm_struct *v = p;

	++*pos;
	return v->next;
}

static void s_stop(struct seq_file *m, void *p)
{
	read_unlock(&vmlist_lock);
}

static void show_numa_info(struct seq_file *m, struct vm_struct *v)
{
	if (NUMA_BUILD) {
		unsigned int nr, *counters = m->private;

		if (!counters)
			return;

		memset(counters, 0, nr_node_ids * sizeof(unsigned int));

		for (nr = 0; nr < v->nr_pages; nr++)
			counters[page_to_nid(v->pages[nr])]++;

		for_each_node_state(nr, N_HIGH_MEMORY)
			if (counters[nr])
				seq_printf(m, " N%u=%u", nr, counters[nr]);
	}
}

static int s_show(struct seq_file *m, void *p)
{
	struct vm_struct *v = p;

	seq_printf(m, "0x%p-0x%p %7ld",
		v->addr, v->addr + v->size, v->size);

	if (v->caller) {
		char buff[KSYM_SYMBOL_LEN];

		seq_putc(m, ' ');
		sprint_symbol(buff, (unsigned long)v->caller);
		seq_puts(m, buff);
	}

	if (v->nr_pages)
		seq_printf(m, " pages=%d", v->nr_pages);

	if (v->phys_addr)
		seq_printf(m, " phys=%lx", v->phys_addr);

	if (v->flags & VM_IOREMAP)
		seq_printf(m, " ioremap");

	if (v->flags & VM_ALLOC)
		seq_printf(m, " vmalloc");

	if (v->flags & VM_MAP)
		seq_printf(m, " vmap");

	if (v->flags & VM_USERMAP)
		seq_printf(m, " user");

	if (v->flags & VM_VPAGES)
		seq_printf(m, " vpages");

	show_numa_info(m, v);
	seq_putc(m, '\n');
	return 0;
}

static const struct seq_operations vmalloc_op = {
	.start = s_start,
	.next = s_next,
	.stop = s_stop,
	.show = s_show,
};

static int vmalloc_open(struct inode *inode, struct file *file)
{
	unsigned int *ptr = NULL;
	int ret;

	if (NUMA_BUILD)
		ptr = kmalloc(nr_node_ids * sizeof(unsigned int), GFP_KERNEL);
	ret = seq_open(file, &vmalloc_op);
	if (!ret) {
		struct seq_file *m = file->private_data;
		m->private = ptr;
	} else
		kfree(ptr);
	return ret;
}

static const struct file_operations proc_vmalloc_operations = {
	.open		= vmalloc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release_private,
};

static int __init proc_vmalloc_init(void)
{
	proc_create("vmallocinfo", S_IRUSR, NULL, &proc_vmalloc_operations);
	return 0;
}
module_init(proc_vmalloc_init);
#endif