diff options
| -rw-r--r-- | arch/x86/kernel/ebda.c | 34 |
1 files changed, 11 insertions, 23 deletions
diff --git a/arch/x86/kernel/ebda.c b/arch/x86/kernel/ebda.c index 6219eef20e2e..4312f8ae71b7 100644 --- a/arch/x86/kernel/ebda.c +++ b/arch/x86/kernel/ebda.c @@ -65,22 +65,6 @@ void __init reserve_bios_regions(void) if (!x86_platform.legacy.reserve_bios_regions) return; - /* Get the start address of the EBDA page: */ - ebda_start = get_bios_ebda(); - - /* - * Quirk: some old Dells seem to have a 4k EBDA without - * reporting so in their BIOS RAM size value, so just - * consider the memory above 640K to be off limits - * (bugzilla 2990). - * - * We detect this case by filtering for nonsensical EBDA - * addresses below 128K, where we can assume that they - * are bogus and bump it up to a fixed 640K value: - */ - if (ebda_start < BIOS_START_MIN) - ebda_start = BIOS_START_MAX; - /* * BIOS RAM size is encoded in kilobytes, convert it * to bytes to get a first guess at where the BIOS @@ -91,18 +75,22 @@ void __init reserve_bios_regions(void) /* * If bios_start is less than 128K, assume it is bogus - * and bump it up to 640K: + * and bump it up to 640K. Similarly, if bios_start is above 640K, + * don't trust it. */ - if (bios_start < BIOS_START_MIN) + if (bios_start < BIOS_START_MIN || bios_start > BIOS_START_MAX) bios_start = BIOS_START_MAX; + /* Get the start address of the EBDA page: */ + ebda_start = get_bios_ebda(); + /* - * Use the lower of the bios_start and ebda_start - * as the starting point, but don't allow it to - * go beyond 640K: + * If the EBDA start address is sane and is below the BIOS region, + * then also reserve everything from the EBDA start address up to + * the BIOS region. */ - bios_start = min(bios_start, ebda_start); - bios_start = min(bios_start, BIOS_START_MAX); + if (ebda_start >= BIOS_START_MIN && ebda_start < bios_start) + bios_start = ebda_start; /* Reserve all memory between bios_start and the 1MB mark: */ memblock_reserve(bios_start, 0x100000 - bios_start); |