On Fri, Aug 30, 2019 at 01:17:23AM +0300, Kirill A. Shutemov wrote:
On Thu, Aug 29, 2019 at 02:12:46PM -0400, Sasha Levin wrote:
From: "Kirill A. Shutemov" <[email protected]>
[ Upstream commit 0a46fff2f9108c2c44218380a43a736cf4612541 ]
BIOS on Samsung 500C Chromebook reports very rudimentary E820 table that
consists of 2 entries:
BIOS-e820: [mem 0x0000000000000000-0x0000000000000fff] usable
BIOS-e820: [mem 0x00000000fffff000-0x00000000ffffffff] reserved
It breaks logic in find_trampoline_placement(): bios_start lands on the
end of the first 4k page and trampoline start gets placed below 0.
Detect underflow and don't touch bios_start for such cases. It makes
kernel ignore E820 table on machines that doesn't have two usable pages
below BIOS_START_MAX.
Fixes: 1b3a62643660 ("x86/boot/compressed/64: Validate trampoline placement against
E820")
Signed-off-by: Kirill A. Shutemov <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: x86-ml <[email protected]>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=203463
Link:
https://lkml.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
Please postpone backporting the patch (and into other trees). There's a
fixup for it:
http://lore.kernel.org/r/20190826133326.7cxb4vbmiawffv2r@box
Sure. Should I just queue it up for a week or two later (along with the
fixes), or do you want to let me know when?
--
Thanks,
Sasha
