If reserve_real_mode() fails, panicing immediately means we're
doomed. Make it safe to try more than once to allocate the
trampoline:
- Degrade a failure from panic() to pr_info(). (If we make it to
setup_real_mode() without reserving the trampoline, we'll panic
them.)
- Factor out helpers so that platform code can supply a specific
address to try.
- Warn if reserve_real_mode() is called after we're done with the
memblock allocator. If that were to happen, we would behave
unpredictably.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mario Limonciello <mario_limonciello@dell.com>
Cc: Matt Fleming <mfleming@suse.de>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/876e383038f3e9971aa72fd20a4f5da05f9d193d.1470821230.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
5ff3e2c3c3