0303c9729a
Niklāvs reported a boot regression on an Alderlake machine and bisected it
to commit 9df9d2f0471b ("init: Invoke arch_cpu_finalize_init() earlier").
By moving the invocation of arch_cpu_finalize_init() further down he
identified that efi_enter_virtual_mode() is the function which causes the
boot hang.
The main difference of the earlier invocation is that the boot CPU is
already fully initialized and mitigations and alternatives are applied.
But the only really interesting change turned out to be IBT, which is now
enabled before efi_enter_virtual_mode(). "ibt=off" on the kernel command
line cured the problem.
Inspection of the involved calls in efi_enter_virtual_mode() unearthed that
efi_set_virtual_address_map() is the only place in the kernel which invokes
an EFI call without the IBT safe wrapper. This went obviously unnoticed so
far as IBT was enabled later.
Use arch_efi_call_virt() instead of efi_call() to cure that.
Fixes: fe379fa4d199 ("x86/ibt: Disable IBT around firmware")
Fixes: 9df9d2f0471b ("init: Invoke arch_cpu_finalize_init() earlier")
Reported-by: Niklāvs Koļesņikovs <pinkflames.linux@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217602
Link: https://lore.kernel.org/r/87jzvm12q0.ffs@tglx
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.
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.