[CRIU] [PATCH] x86/ia32: fix build with DEBUG=1

[Cyrill Gorcunov]

On Mon, May 29, 2017 at 03:59:08PM +0300, Dmitry Safonov wrote:
> GCC isn't happy if we use %rbp as register for local variable
> with -ggdb3 option.
> Which resulted in the following build error for `make DEBUG=1`:
> > In file included from criu/arch/x86/crtools.c:10:0:
> > criu/arch/x86/include/asm/compat.h: In function ‘do_full_int80’:
> > criu/arch/x86/include/asm/compat.h:50:1: error: bp cannot be used in asm here
> 
> Fix it by saving/restoring %rbp around 32-bit syscall manually.
> Just while at it - add a comment about r8-r11 clobbers.
> 
> Reported-by: Cyrill Gorcunov <gorcunov at openvz.org>
> Signed-off-by: Dmitry Safonov <dsafonov at virtuozzo.com>
Acked-by: Cyrill Gorcunov <gorcunov at openvz.org>