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[linux-2.6.git] / drivers / char / mem.c

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 8b86d01..82ab436 100644 (file)
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -114,13 +114,29 @@ static inline int valid_phys_addr_range(unsigned long addr, size_t *count)
 }
 #endif
 
+extern int page_is_ram(unsigned long pagenr);
+
+static inline int page_is_allowed(unsigned long pagenr)
+{ 
+ #ifdef CONFIG_X86
+       if (pagenr <= 256)
+               return 1;
+       if (!page_is_ram(pagenr))
+               return 1;
+       printk("Access to 0x%lx by %s denied \n", pagenr << PAGE_SHIFT, current->comm);
+       return 0;
+ #else
+       return 1;
+ #endif
+}
+
 static inline int range_is_allowed(unsigned long from, unsigned long to)
 {
        unsigned long cursor;
        
        cursor = from >> PAGE_SHIFT;
-       while ((cursor << PAGE_SHIFT) < to) {
-               if (!devmem_is_allowed(cursor))
+       while ( (cursor << PAGE_SHIFT) < to) {
+               if (!page_is_allowed(cursor))
                        return 0;
                cursor++;
        }
@@ -146,7 +162,7 @@ static ssize_t do_write_mem(void *p, unsigned long realp,
        }
 #endif
        if (!range_is_allowed(realp, realp+count))
-               return -EPERM;
+               return -EFAULT;
        copied = copy_from_user(p, buf, count);
        if (copied) {
                ssize_t ret = written + (count - copied);
@@ -191,7 +207,7 @@ static ssize_t read_mem(struct file * file, char __user * buf,
        }
 #endif
        if (!range_is_allowed(p, p+count))
-               return -EPERM;
+               return -EFAULT;
        if (copy_to_user(buf, __va(p), count))
                return -EFAULT;
        read += count;
@@ -232,8 +248,8 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma)
                
        cursor = vma->vm_pgoff;
        while ((cursor << PAGE_SHIFT) < offset + vma->vm_end-vma->vm_start) {
-               if (!devmem_is_allowed(cursor))
-                       return -EPERM;
+               if (!page_is_allowed(cursor))
+                       return -EFAULT;
                cursor++;
        }
 
@@ -311,6 +327,67 @@ static ssize_t read_kmem(struct file *file, char __user *buf,
        return virtr + read;
 }
 
+/*
+ * This function writes to the *virtual* memory as seen by the kernel.
+ */
+static ssize_t write_kmem(struct file * file, const char __user * buf, 
+                         size_t count, loff_t *ppos)
+{
+       unsigned long p = *ppos;
+       ssize_t wrote = 0;
+       ssize_t virtr = 0;
+       ssize_t written;
+       char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
+       
+       return -EPERM;
+
+       if (p < (unsigned long) high_memory) {
+
+               wrote = count;
+               if (count > (unsigned long) high_memory - p)
+                       wrote = (unsigned long) high_memory - p;
+
+               written = do_write_mem((void*)p, p, buf, wrote, ppos);
+               if (written != wrote)
+                       return written;
+               wrote = written;
+               p += wrote;
+               buf += wrote;
+               count -= wrote;
+       }
+
+       if (count > 0) {
+               kbuf = (char *)__get_free_page(GFP_KERNEL);
+               if (!kbuf)
+                       return wrote ? wrote : -ENOMEM;
+               while (count > 0) {
+                       int len = count;
+
+                       if (len > PAGE_SIZE)
+                               len = PAGE_SIZE;
+                       if (len) {
+                               written = copy_from_user(kbuf, buf, len);
+                               if (written) {
+                                       ssize_t ret;
+
+                                       free_page((unsigned long)kbuf);
+                                       ret = wrote + virtr + (len - written);
+                                       return ret ? ret : -EFAULT;
+                               }
+                       }
+                       len = vwrite(kbuf, (char *)p, len);
+                       count -= len;
+                       buf += len;
+                       virtr += len;
+                       p += len;
+               }
+               free_page((unsigned long)kbuf);
+       }
+
+       *ppos = p;
+       return virtr + wrote;
+}
+
 #if defined(CONFIG_ISA) || !defined(__mc68000__)
 static ssize_t read_port(struct file * file, char __user * buf,
                         size_t count, loff_t *ppos)
@@ -561,6 +638,7 @@ static struct file_operations mem_fops = {
 static struct file_operations kmem_fops = {
        .llseek         = memory_lseek,
        .read           = read_kmem,
+       .write          = write_kmem,
        .mmap           = mmap_kmem,
        .open           = open_kmem,
 };