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authorMarcel Ziswiler <marcel.ziswiler@toradex.com>2017-06-17 17:01:11 +0200
committerMarcel Ziswiler <marcel.ziswiler@toradex.com>2017-06-17 17:01:11 +0200
commitc1d5fe2d54551b95b812143d94d8168da2220dd8 (patch)
treefdde4472ab2b19fcadaae22d68a0c9b008f74373 /drivers/char/mem.c
parent0068a1b36d309f22698f7de7478b72e672360129 (diff)
parent1bd30958ec55d80ca72d2ca4e7e5c3d9fbf3173e (diff)
Merge tag 'v4.4.73' into toradex_vf_4.4-nextColibri-VF_LXDE-Image_2.7b3-20170630
This is the 4.4.73 stable release
Diffstat (limited to 'drivers/char/mem.c')
-rw-r--r--drivers/char/mem.c87
1 files changed, 57 insertions, 30 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 6b1721f978c2..2898d19fadf5 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -59,6 +59,10 @@ 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;
@@ -78,6 +82,10 @@ 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;
@@ -125,23 +133,31 @@ 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;
@@ -184,30 +200,36 @@ 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;
@@ -321,6 +343,11 @@ 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;