1 files changed, 189 insertions, 34 deletions

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 204b8243d8ab..69511e663234 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -25,7 +25,7 @@
 #include <linux/rcupdate.h>
 #include <linux/pfn.h>
 #include <linux/kmemleak.h>
-
+#include <linux/highmem.h>
 #include <asm/atomic.h>
 #include <asm/uaccess.h>
 #include <asm/tlbflush.h>
@@ -168,11 +168,9 @@ static int vmap_page_range_noflush(unsigned long start, unsigned long end,
 		next = pgd_addr_end(addr, end);
 		err = vmap_pud_range(pgd, addr, next, prot, pages, &nr);
 		if (err)
-			break;
+			return err;
 	} while (pgd++, addr = next, addr != end);
 
-	if (unlikely(err))
-		return err;
 	return nr;
 }
 
@@ -186,7 +184,7 @@ static int vmap_page_range(unsigned long start, unsigned long end,
 	return ret;
 }
 
-static inline int is_vmalloc_or_module_addr(const void *x)
+int is_vmalloc_or_module_addr(const void *x)
 {
 	/*
 	 * ARM, x86-64 and sparc64 put modules in a special place,
@@ -1272,17 +1270,21 @@ struct vm_struct *remove_vm_area(const void *addr)
 	if (va && va->flags & VM_VM_AREA) {
 		struct vm_struct *vm = va->private;
 		struct vm_struct *tmp, **p;
-
-		vmap_debug_free_range(va->va_start, va->va_end);
-		free_unmap_vmap_area(va);
-		vm->size -= PAGE_SIZE;
-
+		/*
+		 * remove from list and disallow access to this vm_struct
+		 * before unmap. (address range confliction is maintained by
+		 * vmap.)
+		 */
 		write_lock(&vmlist_lock);
 		for (p = &vmlist; (tmp = *p) != vm; p = &tmp->next)
 			;
 		*p = tmp->next;
 		write_unlock(&vmlist_lock);
 
+		vmap_debug_free_range(va->va_start, va->va_end);
+		free_unmap_vmap_area(va);
+		vm->size -= PAGE_SIZE;
+
 		return vm;
 	}
 	return NULL;
@@ -1384,7 +1386,7 @@ void *vmap(struct page **pages, unsigned int count,
 
 	might_sleep();
 
-	if (count > num_physpages)
+	if (count > totalram_pages)
 		return NULL;
 
 	area = get_vm_area_caller((count << PAGE_SHIFT), flags,
@@ -1491,7 +1493,7 @@ static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
 	unsigned long real_size = size;
 
 	size = PAGE_ALIGN(size);
-	if (!size || (size >> PAGE_SHIFT) > num_physpages)
+	if (!size || (size >> PAGE_SHIFT) > totalram_pages)
 		return NULL;
 
 	area = __get_vm_area_node(size, VM_ALLOC, VMALLOC_START, VMALLOC_END,
@@ -1641,10 +1643,120 @@ void *vmalloc_32_user(unsigned long size)
 }
 EXPORT_SYMBOL(vmalloc_32_user);
 
+/*
+ * small helper routine , copy contents to buf from addr.
+ * If the page is not present, fill zero.
+ */
+
+static int aligned_vread(char *buf, char *addr, unsigned long count)
+{
+	struct page *p;
+	int copied = 0;
+
+	while (count) {
+		unsigned long offset, length;
+
+		offset = (unsigned long)addr & ~PAGE_MASK;
+		length = PAGE_SIZE - offset;
+		if (length > count)
+			length = count;
+		p = vmalloc_to_page(addr);
+		/*
+		 * To do safe access to this _mapped_ area, we need
+		 * lock. But adding lock here means that we need to add
+		 * overhead of vmalloc()/vfree() calles for this _debug_
+		 * interface, rarely used. Instead of that, we'll use
+		 * kmap() and get small overhead in this access function.
+		 */
+		if (p) {
+			/*
+			 * we can expect USER0 is not used (see vread/vwrite's
+			 * function description)
+			 */
+			void *map = kmap_atomic(p, KM_USER0);
+			memcpy(buf, map + offset, length);
+			kunmap_atomic(map, KM_USER0);
+		} else
+			memset(buf, 0, length);
+
+		addr += length;
+		buf += length;
+		copied += length;
+		count -= length;
+	}
+	return copied;
+}
+
+static int aligned_vwrite(char *buf, char *addr, unsigned long count)
+{
+	struct page *p;
+	int copied = 0;
+
+	while (count) {
+		unsigned long offset, length;
+
+		offset = (unsigned long)addr & ~PAGE_MASK;
+		length = PAGE_SIZE - offset;
+		if (length > count)
+			length = count;
+		p = vmalloc_to_page(addr);
+		/*
+		 * To do safe access to this _mapped_ area, we need
+		 * lock. But adding lock here means that we need to add
+		 * overhead of vmalloc()/vfree() calles for this _debug_
+		 * interface, rarely used. Instead of that, we'll use
+		 * kmap() and get small overhead in this access function.
+		 */
+		if (p) {
+			/*
+			 * we can expect USER0 is not used (see vread/vwrite's
+			 * function description)
+			 */
+			void *map = kmap_atomic(p, KM_USER0);
+			memcpy(map + offset, buf, length);
+			kunmap_atomic(map, KM_USER0);
+		}
+		addr += length;
+		buf += length;
+		copied += length;
+		count -= length;
+	}
+	return copied;
+}
+
+/**
+ *	vread() -  read vmalloc area in a safe way.
+ *	@buf:		buffer for reading data
+ *	@addr:		vm address.
+ *	@count:		number of bytes to be read.
+ *
+ *	Returns # of bytes which addr and buf should be increased.
+ *	(same number to @count). Returns 0 if [addr...addr+count) doesn't
+ *	includes any intersect with alive vmalloc area.
+ *
+ *	This function checks that addr is a valid vmalloc'ed area, and
+ *	copy data from that area to a given buffer. If the given memory range
+ *	of [addr...addr+count) includes some valid address, data is copied to
+ *	proper area of @buf. If there are memory holes, they'll be zero-filled.
+ *	IOREMAP area is treated as memory hole and no copy is done.
+ *
+ *	If [addr...addr+count) doesn't includes any intersects with alive
+ *	vm_struct area, returns 0.
+ *	@buf should be kernel's buffer. Because	this function uses KM_USER0,
+ *	the caller should guarantee KM_USER0 is not used.
+ *
+ *	Note: In usual ops, vread() is never necessary because the caller
+ *	should know vmalloc() area is valid and can use memcpy().
+ *	This is for routines which have to access vmalloc area without
+ *	any informaion, as /dev/kmem.
+ *
+ */
+
 long vread(char *buf, char *addr, unsigned long count)
 {
 	struct vm_struct *tmp;
 	char *vaddr, *buf_start = buf;
+	unsigned long buflen = count;
 	unsigned long n;
 
 	/* Don't allow overflow */
@@ -1652,7 +1764,7 @@ long vread(char *buf, char *addr, unsigned long count)
 		count = -(unsigned long) addr;
 
 	read_lock(&vmlist_lock);
-	for (tmp = vmlist; tmp; tmp = tmp->next) {
+	for (tmp = vmlist; count && tmp; tmp = tmp->next) {
 		vaddr = (char *) tmp->addr;
 		if (addr >= vaddr + tmp->size - PAGE_SIZE)
 			continue;
@@ -1665,32 +1777,72 @@ long vread(char *buf, char *addr, unsigned long count)
 			count--;
 		}
 		n = vaddr + tmp->size - PAGE_SIZE - addr;
-		do {
-			if (count == 0)
-				goto finished;
-			*buf = *addr;
-			buf++;
-			addr++;
-			count--;
-		} while (--n > 0);
+		if (n > count)
+			n = count;
+		if (!(tmp->flags & VM_IOREMAP))
+			aligned_vread(buf, addr, n);
+		else /* IOREMAP area is treated as memory hole */
+			memset(buf, 0, n);
+		buf += n;
+		addr += n;
+		count -= n;
 	}
 finished:
 	read_unlock(&vmlist_lock);
-	return buf - buf_start;
+
+	if (buf == buf_start)
+		return 0;
+	/* zero-fill memory holes */
+	if (buf != buf_start + buflen)
+		memset(buf, 0, buflen - (buf - buf_start));
+
+	return buflen;
 }
 
+/**
+ *	vwrite() -  write vmalloc area in a safe way.
+ *	@buf:		buffer for source data
+ *	@addr:		vm address.
+ *	@count:		number of bytes to be read.
+ *
+ *	Returns # of bytes which addr and buf should be incresed.
+ *	(same number to @count).
+ *	If [addr...addr+count) doesn't includes any intersect with valid
+ *	vmalloc area, returns 0.
+ *
+ *	This function checks that addr is a valid vmalloc'ed area, and
+ *	copy data from a buffer to the given addr. If specified range of
+ *	[addr...addr+count) includes some valid address, data is copied from
+ *	proper area of @buf. If there are memory holes, no copy to hole.
+ *	IOREMAP area is treated as memory hole and no copy is done.
+ *
+ *	If [addr...addr+count) doesn't includes any intersects with alive
+ *	vm_struct area, returns 0.
+ *	@buf should be kernel's buffer. Because	this function uses KM_USER0,
+ *	the caller should guarantee KM_USER0 is not used.
+ *
+ *	Note: In usual ops, vwrite() is never necessary because the caller
+ *	should know vmalloc() area is valid and can use memcpy().
+ *	This is for routines which have to access vmalloc area without
+ *	any informaion, as /dev/kmem.
+ *
+ *	The caller should guarantee KM_USER1 is not used.
+ */
+
 long vwrite(char *buf, char *addr, unsigned long count)
 {
 	struct vm_struct *tmp;
-	char *vaddr, *buf_start = buf;
-	unsigned long n;
+	char *vaddr;
+	unsigned long n, buflen;
+	int copied = 0;
 
 	/* Don't allow overflow */
 	if ((unsigned long) addr + count < count)
 		count = -(unsigned long) addr;
+	buflen = count;
 
 	read_lock(&vmlist_lock);
-	for (tmp = vmlist; tmp; tmp = tmp->next) {
+	for (tmp = vmlist; count && tmp; tmp = tmp->next) {
 		vaddr = (char *) tmp->addr;
 		if (addr >= vaddr + tmp->size - PAGE_SIZE)
 			continue;
@@ -1702,18 +1854,21 @@ long vwrite(char *buf, char *addr, unsigned long count)
 			count--;
 		}
 		n = vaddr + tmp->size - PAGE_SIZE - addr;
-		do {
-			if (count == 0)
-				goto finished;
-			*addr = *buf;
-			buf++;
-			addr++;
-			count--;
-		} while (--n > 0);
+		if (n > count)
+			n = count;
+		if (!(tmp->flags & VM_IOREMAP)) {
+			aligned_vwrite(buf, addr, n);
+			copied++;
+		}
+		buf += n;
+		addr += n;
+		count -= n;
 	}
 finished:
 	read_unlock(&vmlist_lock);
-	return buf - buf_start;
+	if (!copied)
+		return 0;
+	return buflen;
 }
 
 /**