[patch 4/4] x86: PAT followup - use ioremap for devmem read of reserved regions

venkatesh.pallipadi
2008-01-16T02:41:44Z

[-- Attachment #1: devmem_read.patch --]
[-- Type: text/plain, Size: 4753 bytes --]

map and unmap reserved regions, before accessing through /dev/mem read
interface. This is for full compatibility with existing /dev/mem
usages.
For regions that are mapped in identity map, we use __va().

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>

Index: linux-2.6.git/arch/x86/mm/ioremap.c
===================================================================
--- linux-2.6.git.orig/arch/x86/mm/ioremap.c 2008-01-15 10:05:13.000000000 -0800
+++ linux-2.6.git/arch/x86/mm/ioremap.c 2008-01-15 10:39:18.000000000 -0800
@@ -32,6 +32,39 @@
}
EXPORT_SYMBOL(ioremap_wc);

+/*
+ * 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 any memory in PAGE_SIZE is valid, then we can use __va. Otherwise
+ * ioremap and unmap the memory.
+ */
+ if (is_memory_any_valid(start, start + PAGE_SIZE))
+ 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)
+{
+ unsigned long start = phys & PAGE_MASK;
+ if (is_memory_any_valid(start, start + PAGE_SIZE))
+ return;
+
+ iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK));
+ return;
+}
+
int valid_phys_addr_range(unsigned long addr, size_t count)
{
if (addr + count > __pa(high_memory))
Index: linux-2.6.git/drivers/char/mem.c
===================================================================
--- linux-2.6.git.orig/drivers/char/mem.c 2008-01-15 10:05:13.000000000 -0800
+++ linux-2.6.git/drivers/char/mem.c 2008-01-15 10:05:51.000000000 -0800
@@ -127,9 +127,14 @@
* 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))
return -EFAULT;
+
+ unxlate_dev_mem_ptr(p, ptr);
+
buf += sz;
p += sz;
count -= sz;
@@ -184,6 +189,11 @@
* 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) {
@@ -192,6 +202,9 @@
break;
return -EFAULT;
}
+
+ unxlate_dev_mem_ptr(p, ptr);
+
buf += sz;
p += sz;
count -= sz;
Index: linux-2.6.git/include/asm-generic/iomap.h
===================================================================
--- linux-2.6.git.orig/include/asm-generic/iomap.h 2008-01-15 10:05:13.000000000 -0800
+++ linux-2.6.git/include/asm-generic/iomap.h 2008-01-15 10:23:24.000000000 -0800
@@ -69,4 +69,8 @@
#define ioremap_wc ioremap_nocache
#endif

+#ifndef unxlate_dev_mem_ptr
+static inline void unxlate_dev_mem_ptr(unsigned long phys, void *addr) {}
+#endif
+
#endif
Index: linux-2.6.git/include/asm-x86/io.h
===================================================================
--- linux-2.6.git.orig/include/asm-x86/io.h 2008-01-15 10:05:13.000000000 -0800
+++ linux-2.6.git/include/asm-x86/io.h 2008-01-15 10:21:42.000000000 -0800
@@ -2,6 +2,7 @@
#define _ASM_X86_IO_H

#define ioremap_wc ioremap_wc
+#define unxlate_dev_mem_ptr unxlate_dev_mem_ptr

#ifdef CONFIG_X86_32
# include "io_32.h"
@@ -10,6 +11,8 @@
#endif

extern void __iomem * ioremap_wc(unsigned long offset, unsigned long size);
+extern void *xlate_dev_mem_ptr(unsigned long phys);
+extern void unxlate_dev_mem_ptr(unsigned long phys, void *addr);

#define ARCH_HAS_VALID_PHYS_ADDR_RANGE

Index: linux-2.6.git/include/asm-x86/io_32.h
===================================================================
--- linux-2.6.git.orig/include/asm-x86/io_32.h 2008-01-15 10:05:13.000000000 -0800
+++ linux-2.6.git/include/asm-x86/io_32.h 2008-01-15 10:05:51.000000000 -0800
@@ -49,12 +49,6 @@
#include <linux/vmalloc.h>

/*
- * Convert a physical pointer to a virtual kernel pointer for /dev/mem
- * access
- */
-#define xlate_dev_mem_ptr(p) __va(p)
-
-/*
* Convert a virtual cached pointer to an uncached pointer
*/
#define xlate_dev_kmem_ptr(p) p
Index: linux-2.6.git/include/asm-x86/io_64.h
===================================================================
--- linux-2.6.git.orig/include/asm-x86/io_64.h 2008-01-15 10:05:13.000000000 -0800
+++ linux-2.6.git/include/asm-x86/io_64.h 2008-01-15 10:05:51.000000000 -0800
@@ -278,12 +278,6 @@
#define BIO_VMERGE_BOUNDARY iommu_bio_merge

/*
- * Convert a physical pointer to a virtual kernel pointer for /dev/mem
- * access
- */
-#define xlate_dev_mem_ptr(p) __va(p)
-
-/*
* Convert a virtual cached pointer to an uncached pointer
*/
#define xlate_dev_kmem_ptr(p) p

--