Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86-pat

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86-pat:
  generic: add ioremap_wc() interface wrapper
  /dev/mem: make promisc the default
  pat: cleanups
  x86: PAT use reserve free memtype in mmap of /dev/mem
  x86: PAT phys_mem_access_prot_allowed for dev/mem mmap
  x86: PAT avoid aliasing in /dev/mem read/write
  devmem: add range_is_allowed() check to mmap of /dev/mem
  x86: introduce /dev/mem restrictions with a config option

1 files changed, 101 insertions, 32 deletions

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 20070b7c573..e83623ead44 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -41,36 +41,7 @@
  */
 static inline int uncached_access(struct file *file, unsigned long addr)
 {
-#if defined(__i386__) && !defined(__arch_um__)
-	/*
-	 * On the PPro and successors, the MTRRs are used to set
-	 * memory types for physical addresses outside main memory,
-	 * so blindly setting PCD or PWT on those pages is wrong.
-	 * For Pentiums and earlier, the surround logic should disable
-	 * caching for the high addresses through the KEN pin, but
-	 * we maintain the tradition of paranoia in this code.
-	 */
-	if (file->f_flags & O_SYNC)
-		return 1;
- 	return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) ||
-		  test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) ||
-		  test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) ||
-		  test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) )
-	  && addr >= __pa(high_memory);
-#elif defined(__x86_64__) && !defined(__arch_um__)
-	/* 
-	 * This is broken because it can generate memory type aliases,
-	 * which can cause cache corruptions
-	 * But it is only available for root and we have to be bug-to-bug
-	 * compatible with i386.
-	 */
-	if (file->f_flags & O_SYNC)
-		return 1;
-	/* same behaviour as i386. PAT always set to cached and MTRRs control the
-	   caching behaviour. 
-	   Hopefully a full PAT implementation will fix that soon. */	   
-	return 0;
-#elif defined(CONFIG_IA64)
+#if defined(CONFIG_IA64)
 	/*
 	 * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases.
 	 */
@@ -108,6 +79,36 @@ static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 }
 #endif
 
+#ifdef CONFIG_NONPROMISC_DEVMEM
+static inline int range_is_allowed(unsigned long pfn, unsigned long size)
+{
+	u64 from = ((u64)pfn) << PAGE_SHIFT;
+	u64 to = from + size;
+	u64 cursor = from;
+
+	while (cursor < to) {
+		if (!devmem_is_allowed(pfn)) {
+			printk(KERN_INFO
+		"Program %s tried to access /dev/mem between %Lx->%Lx.\n",
+				current->comm, from, to);
+			return 0;
+		}
+		cursor += PAGE_SIZE;
+		pfn++;
+	}
+	return 1;
+}
+#else
+static inline int range_is_allowed(unsigned long pfn, unsigned long size)
+{
+	return 1;
+}
+#endif
+
+void __attribute__((weak)) unxlate_dev_mem_ptr(unsigned long phys, void *addr)
+{
+}
+
 /*
  * This funcion reads the *physical* memory. The f_pos points directly to the 
  * memory location. 
@@ -150,15 +151,25 @@ static ssize_t read_mem(struct file * file, char __user * buf,
 
 		sz = min_t(unsigned long, sz, count);
 
+		if (!range_is_allowed(p >> PAGE_SHIFT, count))
+			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)
+			return -EFAULT;
 
-		if (copy_to_user(buf, ptr, sz))
+		if (copy_to_user(buf, ptr, sz)) {
+			unxlate_dev_mem_ptr(p, ptr);
 			return -EFAULT;
+		}
+
+		unxlate_dev_mem_ptr(p, ptr);
+
 		buf += sz;
 		p += sz;
 		count -= sz;
@@ -207,20 +218,32 @@ static ssize_t write_mem(struct file * file, const char __user * buf,
 
 		sz = min_t(unsigned long, sz, count);
 
+		if (!range_is_allowed(p >> PAGE_SHIFT, sz))
+			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;
+		}
 
 		copied = copy_from_user(ptr, buf, sz);
 		if (copied) {
 			written += sz - copied;
+			unxlate_dev_mem_ptr(p, ptr);
 			if (written)
 				break;
 			return -EFAULT;
 		}
+
+		unxlate_dev_mem_ptr(p, ptr);
+
 		buf += sz;
 		p += sz;
 		count -= sz;
@@ -231,6 +254,12 @@ static ssize_t write_mem(struct file * file, const char __user * buf,
 	return written;
 }
 
+int __attribute__((weak)) phys_mem_access_prot_allowed(struct file *file,
+	unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
+{
+	return 1;
+}
+
 #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)
@@ -271,6 +300,35 @@ static inline int private_mapping_ok(struct vm_area_struct *vma)
 }
 #endif
 
+void __attribute__((weak))
+map_devmem(unsigned long pfn, unsigned long len, pgprot_t prot)
+{
+	/* nothing. architectures can override. */
+}
+
+void __attribute__((weak))
+unmap_devmem(unsigned long pfn, unsigned long len, pgprot_t prot)
+{
+	/* nothing. architectures can override. */
+}
+
+static void mmap_mem_open(struct vm_area_struct *vma)
+{
+	map_devmem(vma->vm_pgoff,  vma->vm_end - vma->vm_start,
+			vma->vm_page_prot);
+}
+
+static void mmap_mem_close(struct vm_area_struct *vma)
+{
+	unmap_devmem(vma->vm_pgoff,  vma->vm_end - vma->vm_start,
+			vma->vm_page_prot);
+}
+
+static struct vm_operations_struct mmap_mem_ops = {
+	.open  = mmap_mem_open,
+	.close = mmap_mem_close
+};
+
 static int mmap_mem(struct file * file, struct vm_area_struct * vma)
 {
 	size_t size = vma->vm_end - vma->vm_start;
@@ -281,17 +339,28 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma)
 	if (!private_mapping_ok(vma))
 		return -ENOSYS;
 
+	if (!range_is_allowed(vma->vm_pgoff, size))
+		return -EPERM;
+
+	if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size,
+						&vma->vm_page_prot))
+		return -EINVAL;
+
 	vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
 						 size,
 						 vma->vm_page_prot);
 
+	vma->vm_ops = &mmap_mem_ops;
+
 	/* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
 	if (remap_pfn_range(vma,
 			    vma->vm_start,
 			    vma->vm_pgoff,
 			    size,
-			    vma->vm_page_prot))
+			    vma->vm_page_prot)) {
+		unmap_devmem(vma->vm_pgoff, size, vma->vm_page_prot);
 		return -EAGAIN;
+	}
 	return 0;
 }