x86/xen: Add stack frame dependency to hypercall inline asm calls
authorJosh Poimboeuf <jpoimboe@redhat.com>
Thu, 21 Jan 2016 22:49:09 +0000 (16:49 -0600)
committerIngo Molnar <mingo@kernel.org>
Wed, 24 Feb 2016 07:35:41 +0000 (08:35 +0100)
commit0e8e2238b52e5301d1d1d4a298ec5b72ac54c702
tree746e51ce70ec89bf7262db41ad58e3340678298b
parent0f68c088c0adb3c3bbeb487c4ebcde91fd5d34be
x86/xen: Add stack frame dependency to hypercall inline asm calls

If a hypercall is inlined at the beginning of a function, gcc can insert
the call instruction before setting up a stack frame, which breaks frame
pointer convention if CONFIG_FRAME_POINTER is enabled and can result in
a bad stack trace.

Force a stack frame to be created if CONFIG_FRAME_POINTER is enabled by
listing the stack pointer as an output operand for the hypercall inline
asm statements.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/c6face5a46713108bded9c4c103637222abc4528.1453405861.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/include/asm/xen/hypercall.h