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x86: sanitize user specified e820 memmap values 

Sanitize user specified e820 memory ranges, using the same logic that is
applied to the values returned by the BIOS.  This ensures consistent
handling regardless of the source of the memory mappings.

Allows overriding portions of the memory map without specifying one in
it's entirety (memmap=exactmap).

E.g. marking a range of bad RAM as reserved with memmap=48M$528M

BIOS supplied range

BIOS-e820: 0000000000100000 - 000000007fe80000 (usable)

becomes

user: 0000000000100000 - 0000000021000000 (usable)
user: 0000000021000000 - 0000000024000000 (reserved)
user: 0000000024000000 - 000000007fe80000 (usable)

Previously this did not work, as the original BIOS range was left
untouched while the user defined range was appended to the end of the
memory map.

[ tglx: arch/x86 adaptation ]

Signed-off-by: Vladimir Berezniker <vmpn@hitechman.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Vladimir Berezniker 2008-01-30 13:30:46 +01:00 committed by Ingo Molnar
parent efd1ca52d0
commit b3ca74a2bf
1 changed files with 8 additions and 0 deletions
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8
arch/x86/kernel/e820_64.c
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@ -691,6 +691,8 @@ static int __init parse_memmap_opt(char *p)
mem_size = memparse(p, &p);
if (p == oldp)
return -EINVAL;
userdef = 1;
if (*p == '@') {
start_at = memparse(p+1, &p);
add_memory_region(start_at, mem_size, E820_RAM);
@ -710,6 +712,12 @@ early_param("memmap", parse_memmap_opt);
void __init finish_e820_parsing(void)
{
if (userdef) {
char nr = e820.nr_map;
if (sanitize_e820_map(e820.map, &nr) < 0)
early_panic("Invalid user supplied memory map");
e820.nr_map = nr;
printk(KERN_INFO "user-defined physical RAM map:\n");
e820_print_map("user");
}