Commit cd670599 authored Apr 01, 2009 by H. Peter Anvin

x86, setup: guard against pre-ACPI 3 e820 code not updating %ecx



Impact: BIOS bug safety

For pre-ACPI 3 BIOSes, pre-initialize the end of the e820 buffer just
in case the BIOS returns an unchanged %ecx but without actually
touching the ACPI 3 extended flags field.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

parent c549e71d

arch/x86/boot/memory.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -31,6 +31,12 @@ static int detect_memory_e820(void)
		struct e820entry *desc = boot_params.e820_map;
		static struct e820_ext_entry buf; /* static so it is zeroed */

		/*
		* Set this here so that if the BIOS doesn't change this field
		* but still doesn't change %ecx, we're still okay...
		*/
		buf.ext_flags = 1;

		do {
		size = sizeof buf;