e02aac3edb
[ Upstream commit0a46fff2f9] 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:1b3a626436("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 Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.