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 -- Kirill A. Shutemov
