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| author | Kirill A. Shutemov <kirill@shutemov.name> | 2019-08-13 16:16:54 +0300 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2019-08-19 15:59:13 +0200 |
| commit | 0a46fff2f9108c2c44218380a43a736cf4612541 (patch) | |
| tree | 5016769b9c6bd040db7ff680154e4a7acce734d6 /Documentation | |
| parent | f897e60a12f0b9146357780d317879bce2a877dc (diff) | |
x86/boot/compressed/64: Fix boot on machines with broken E820 table
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 <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=203463
Link: https://lkml.kernel.org/r/20190813131654.24378-1-kirill.shutemov@linux.intel.com
Diffstat (limited to 'Documentation')
0 files changed, 0 insertions, 0 deletions