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, 29 insertions, 0 deletions

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 36a3f7ded626..d176b23110cc 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -336,6 +336,35 @@ void iounmap(volatile void __iomem *addr)
 }
 EXPORT_SYMBOL(iounmap);
 
+/*
+ * Convert a physical pointer to a virtual kernel pointer for /dev/mem
+ * access
+ */
+void *xlate_dev_mem_ptr(unsigned long phys)
+{
+	void *addr;
+	unsigned long start = phys & PAGE_MASK;
+
+	/* If page is RAM, we can use __va. Otherwise ioremap and unmap. */
+	if (page_is_ram(start >> PAGE_SHIFT))
+		return __va(phys);
+
+	addr = (void *)ioremap(start, PAGE_SIZE);
+	if (addr)
+		addr = (void *)((unsigned long)addr | (phys & ~PAGE_MASK));
+
+	return addr;
+}
+
+void unxlate_dev_mem_ptr(unsigned long phys, void *addr)
+{
+	if (page_is_ram(phys >> PAGE_SHIFT))
+		return;
+
+	iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK));
+	return;
+}
+
 #ifdef CONFIG_X86_32
 
 int __initdata early_ioremap_debug;