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Commit 0adad171 authored by Rene Herman's avatar Rene Herman Committed by Andi Kleen
Browse files

[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: default avatarRene Herman <rene.herman@gmail.com>
Signed-off-by: default avatarMartin Murray <murrayma@citi.umich.edu>
Signed-off-by: default avatarAndi 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 0949be35

arch/i386/kernel/e820.c

+18 −11
Original line number Original line Diff line number Diff line
@@ -161,25 +161,26 @@ static struct resource standard_io_resources[] = { { 




static int __init romsignature(const unsigned char *rom)

static int __init romsignature(const unsigned char *rom)

{

{

	const unsigned short * const ptr = (const unsigned short *)rom;

	unsigned short sig;

	unsigned short sig;





	return probe_kernel_address((const unsigned short *)rom, sig) == 0 &&

	return probe_kernel_address(ptr, sig) == 0 && sig == ROMSIGNATURE;

	       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--)

	for (sum = 0; length && probe_kernel_address(rom++, c) == 0; length--)

		sum += *rom++;

		sum += c;

	return sum == 0;

	return !length && !sum;

}

}





static void __init probe_roms(void)

static void __init probe_roms(void)

{

{

	const unsigned char *rom;

	unsigned long start, length, upper;

	unsigned long start, length, upper;

	unsigned char *rom;

	unsigned char c;

	int i;

	int i;





	/* video rom */

	/* video rom */
@@ -191,8 +192,11 @@ static void __init probe_roms(void) 




		video_rom_resource.start = start;

		video_rom_resource.start = start;





		if (probe_kernel_address(rom + 2, c) != 0)

			continue;



		/* 0 < length <= 0x7f * 512, historically */

		/* 0 < length <= 0x7f * 512, historically */

		length = rom[2] * 512;

		length = c * 512;





		/* if checksum okay, trust length byte */

		/* if checksum okay, trust length byte */

		if (length && romchecksum(rom, length))

		if (length && romchecksum(rom, length))
@@ -226,8 +230,11 @@ static void __init probe_roms(void) 
		if (!romsignature(rom))

		if (!romsignature(rom))

			continue;

			continue;





		if (probe_kernel_address(rom + 2, c) != 0)

			continue;



		/* 0 < length <= 0x7f * 512, historically */

		/* 0 < length <= 0x7f * 512, historically */

		length = rom[2] * 512;

		length = c * 512;





		/* but accept any length that fits if checksum okay */

		/* but accept any length that fits if checksum okay */

		if (!length || start + length > upper || !romchecksum(rom, length))

		if (!length || start + length > upper || !romchecksum(rom, length))