1 files changed, 30 insertions, 12 deletions

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 91dd669273e0..5b2d18035073 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -101,6 +101,11 @@ static inline int valid_phys_addr_range(unsigned long addr, size_t *count)
 
         return 1;
 }
+
+static inline int valid_mmap_phys_addr_range(unsigned long addr, size_t *size)
+{
+        return 1;
+}
 #endif
 
 /*
@@ -228,26 +233,36 @@ static ssize_t write_mem(struct file * file, const char __user * buf,
         return written;
 }
 
+#ifndef __HAVE_PHYS_MEM_ACCESS_PROT
+static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
+                                     unsigned long size, pgprot_t vma_prot)
+{
+#ifdef pgprot_noncached
+        unsigned long offset = pfn << PAGE_SHIFT;
+
+        if (uncached_access(file, offset))
+                return pgprot_noncached(vma_prot);
+#endif
+        return vma_prot;
+}
+#endif
+
 static int mmap_mem(struct file * file, struct vm_area_struct * vma)
 {
-#if defined(__HAVE_PHYS_MEM_ACCESS_PROT)
+        size_t size = vma->vm_end - vma->vm_start;
+
+        if (!valid_mmap_phys_addr_range(vma->vm_pgoff << PAGE_SHIFT, &size))
+                return -EINVAL;
+
         vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
-                                                 vma->vm_end - vma->vm_start,
+                                                 size,
                                                  vma->vm_page_prot);
-#elif defined(pgprot_noncached)
-        unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
-        int uncached;
-
-        uncached = uncached_access(file, offset);
-        if (uncached)
-                vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-#endif
 
         /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
         if (remap_pfn_range(vma,
                             vma->vm_start,
                             vma->vm_pgoff,
-                            vma->vm_end-vma->vm_start,
+                            size,
                             vma->vm_page_prot))
                 return -EAGAIN;
         return 0;
@@ -817,7 +832,7 @@ static ssize_t kmsg_write(struct file * file, const char __user * buf,
                           size_t count, loff_t *ppos)
 {
         char *tmp;
-        int ret;
+        ssize_t ret;
 
         tmp = kmalloc(count + 1, GFP_KERNEL);
         if (tmp == NULL)
@@ -826,6 +841,9 @@ static ssize_t kmsg_write(struct file * file, const char __user * buf,
         if (!copy_from_user(tmp, buf, count)) {
                 tmp[count] = 0;
                 ret = printk("%s", tmp);
+                if (ret > count)
+                        /* printk can add a prefix */
+                        ret = count;
         }
         kfree(tmp);
         return ret;