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[PATCH] i386: probe_roms() cleanup

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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>
This commit is contained in:
Rene Herman 2007-05-02 19:27:05 +02:00 committed by Andi Kleen
parent 0949be3509
commit 0adad171c2
1 changed files with 18 additions and 11 deletions
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29
arch/i386/kernel/e820.c
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@ -161,26 +161,27 @@ static struct resource standard_io_resources[] = { {
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 @@ static void __init probe_roms(void)
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 @@ static void __init probe_roms(void)
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))