X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fchar%2Fmem.c;h=d78365603952d5b364d1c858bc097933972e4a5a;hb=5a05d9046553c6d85fca860f0b3f76f0c735d0cc;hp=1451790337160fb8c9fd6a5af935dea6b236f4ca;hpb=e0d65113a70f1dc514e625cc4e7a7485a4bf72df;p=pandora-kernel.git

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 145179033716..d78365603952 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -58,6 +58,10 @@ static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 #endif
 
 #ifdef CONFIG_STRICT_DEVMEM
+static inline int page_is_allowed(unsigned long pfn)
+{
+	return devmem_is_allowed(pfn);
+}
 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 {
 	u64 from = ((u64)pfn) << PAGE_SHIFT;
@@ -77,6 +81,10 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 	return 1;
 }
 #else
+static inline int page_is_allowed(unsigned long pfn)
+{
+	return 1;
+}
 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 {
 	return 1;
@@ -118,23 +126,31 @@ static ssize_t read_mem(struct file *file, char __user *buf,
 
 	while (count > 0) {
 		unsigned long remaining;
+		int allowed;
 
 		sz = size_inside_page(p, count);
 
-		if (!range_is_allowed(p >> PAGE_SHIFT, count))
+		allowed = page_is_allowed(p >> PAGE_SHIFT);
+		if (!allowed)
 			return -EPERM;
+		if (allowed == 2) {
+			/* Show zeros for restricted memory. */
+			remaining = clear_user(buf, sz);
+		} else {
+			/*
+			 * On ia64 if a page has been mapped somewhere as
+			 * uncached, then it must also be accessed uncached
+			 * by the kernel or data corruption may occur.
+			 */
+			ptr = xlate_dev_mem_ptr(p);
+			if (!ptr)
+				return -EFAULT;
 
-		/*
-		 * On ia64 if a page has been mapped somewhere as uncached, then
-		 * it must also be accessed uncached by the kernel or data
-		 * corruption may occur.
-		 */
-		ptr = xlate_dev_mem_ptr(p);
-		if (!ptr)
-			return -EFAULT;
+			remaining = copy_to_user(buf, ptr, sz);
+
+			unxlate_dev_mem_ptr(p, ptr);
+		}
 
-		remaining = copy_to_user(buf, ptr, sz);
-		unxlate_dev_mem_ptr(p, ptr);
 		if (remaining)
 			return -EFAULT;
 
@@ -174,30 +190,36 @@ static ssize_t write_mem(struct file *file, const char __user *buf,
 #endif
 
 	while (count > 0) {
+		int allowed;
+
 		sz = size_inside_page(p, count);
 
-		if (!range_is_allowed(p >> PAGE_SHIFT, sz))
+		allowed = page_is_allowed(p >> PAGE_SHIFT);
+		if (!allowed)
 			return -EPERM;
 
-		/*
-		 * On ia64 if a page has been mapped somewhere as uncached, then
-		 * it must also be accessed uncached by the kernel or data
-		 * corruption may occur.
-		 */
-		ptr = xlate_dev_mem_ptr(p);
-		if (!ptr) {
-			if (written)
-				break;
-			return -EFAULT;
-		}
+		/* Skip actual writing when a page is marked as restricted. */
+		if (allowed == 1) {
+			/*
+			 * On ia64 if a page has been mapped somewhere as
+			 * uncached, then it must also be accessed uncached
+			 * by the kernel or data corruption may occur.
+			 */
+			ptr = xlate_dev_mem_ptr(p);
+			if (!ptr) {
+				if (written)
+					break;
+				return -EFAULT;
+			}
 
-		copied = copy_from_user(ptr, buf, sz);
-		unxlate_dev_mem_ptr(p, ptr);
-		if (copied) {
-			written += sz - copied;
-			if (written)
-				break;
-			return -EFAULT;
+			copied = copy_from_user(ptr, buf, sz);
+			unxlate_dev_mem_ptr(p, ptr);
+			if (copied) {
+				written += sz - copied;
+				if (written)
+					break;
+				return -EFAULT;
+			}
 		}
 
 		buf += sz;
@@ -300,6 +322,11 @@ static const struct vm_operations_struct mmap_mem_ops = {
 static int mmap_mem(struct file *file, struct vm_area_struct *vma)
 {
 	size_t size = vma->vm_end - vma->vm_start;
+	phys_addr_t offset = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT;
+
+	/* It's illegal to wrap around the end of the physical address space. */
+	if (offset + (phys_addr_t)size - 1 < offset)
+		return -EINVAL;
 
 	if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
 		return -EINVAL;