[PATCH] i386: probe_roms() cleanup
Remove the assumption that if the first page of a legacy ROM is mapped,
it'll all be mapped. This'll also stop people reading this code from
wondering if they're looking at a bug...
Signed-off-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Martin Murray <murrayma@citi.umich.edu>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/arch/i386/kernel/e820.c b/arch/i386/kernel/e820.c
index 70f3956..31f4670 100644
--- a/arch/i386/kernel/e820.c
+++ b/arch/i386/kernel/e820.c
@@ -161,26 +161,27 @@
static int __init romsignature(const unsigned char *rom)
{
+ const unsigned short * const ptr = (const unsigned short *)rom;
unsigned short sig;
- return probe_kernel_address((const unsigned short *)rom, sig) == 0 &&
- sig == ROMSIGNATURE;
+ return probe_kernel_address(ptr, sig) == 0 && sig == ROMSIGNATURE;
}
-static int __init romchecksum(unsigned char *rom, unsigned long length)
+static int __init romchecksum(const unsigned char *rom, unsigned long length)
{
- unsigned char sum;
+ unsigned char sum, c;
- for (sum = 0; length; length--)
- sum += *rom++;
- return sum == 0;
+ for (sum = 0; length && probe_kernel_address(rom++, c) == 0; length--)
+ sum += c;
+ return !length && !sum;
}
static void __init probe_roms(void)
{
+ const unsigned char *rom;
unsigned long start, length, upper;
- unsigned char *rom;
- int i;
+ unsigned char c;
+ int i;
/* video rom */
upper = adapter_rom_resources[0].start;
@@ -191,8 +192,11 @@
video_rom_resource.start = start;
+ if (probe_kernel_address(rom + 2, c) != 0)
+ continue;
+
/* 0 < length <= 0x7f * 512, historically */
- length = rom[2] * 512;
+ length = c * 512;
/* if checksum okay, trust length byte */
if (length && romchecksum(rom, length))
@@ -226,8 +230,11 @@
if (!romsignature(rom))
continue;
+ if (probe_kernel_address(rom + 2, c) != 0)
+ continue;
+
/* 0 < length <= 0x7f * 512, historically */
- length = rom[2] * 512;
+ length = c * 512;
/* but accept any length that fits if checksum okay */
if (!length || start + length > upper || !romchecksum(rom, length))