diff options
| author | Rene Herman <rene.herman@gmail.com> | 2007-05-02 19:27:05 +0200 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2007-05-02 19:27:05 +0200 |
| commit | 0adad171c2334d43fc2fa208f6b45e88f0679427 (patch) | |
| tree | cff3679ce34f143a9e132889c6cdb42cd867cee3 /arch | |
| parent | 0949be35095b53dbaa72db700cb5074c5c249629 (diff) | |
[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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/i386/kernel/e820.c | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/arch/i386/kernel/e820.c b/arch/i386/kernel/e820.c index 70f39560846..31f4670ef74 100644 --- a/arch/i386/kernel/e820.c +++ b/arch/i386/kernel/e820.c @@ -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)) |