[PATCH] paravirt: Be careful about touching BIOS address space

[pandora-kernel.git] / arch / i386 / kernel / e820.c

diff --git a/arch/i386/kernel/e820.c b/arch/i386/kernel/e820.c
index b755255..b704790 100644 (file)
--- a/arch/i386/kernel/e820.c
+++ b/arch/i386/kernel/e820.c
@@ -9,6 +9,7 @@
 #include <linux/mm.h>
 #include <linux/efi.h>
 #include <linux/pfn.h>
+#include <linux/uaccess.h>
 
 #include <asm/pgtable.h>
 #include <asm/page.h>
@@ -155,7 +156,14 @@ static struct resource standard_io_resources[] = { {
        .flags  = IORESOURCE_BUSY | IORESOURCE_IO
 } };
 
-#define romsignature(x) (*(unsigned short *)(x) == 0xaa55)
+static int romsignature(const unsigned char *x)
+{
+       unsigned short sig;
+       int ret = 0;
+       if (probe_kernel_address((const unsigned short *)x, sig) == 0)
+               ret = (sig == 0xaa55);
+       return ret;
+}
 
 static int __init romchecksum(unsigned char *rom, unsigned long length)
 {