[CRIU] [PATCH] Fix gcc9 build failures

[Adrian Reber]

On Thu, Jan 10, 2019 at 09:02:19AM -0800, Andrei Vagin wrote:
> On Wed, Jan 09, 2019 at 12:49:11PM +0000, Adrian Reber wrote:
> > From: Adrian Reber <areber at redhat.com>
> 
> Should it be "From: Jeff Law <law at redhat.com>"?

Probably. If you want you can change it. I was not sure how interested
Jeff was in the submission process of the patch, so I just sent it out
with my usual command. If you can fix it up, please do.

> > I received this patch from Jeff Law as a fix for build failures with the
> > upcoming GCC 9. The following is Jeff Law's description of the patch:
> > 
> >  Attached you'll find the fix for criu.  You'll see it's just a matter
> >  of dropping the sp/esp clobber from the relevant asm statements.  THe
> >  details:
> > 
> >  criu has a macro which defines an asm which appears to want to set a new
> >  stack pointer, then directly issue a sigreturn call to the kernel.  Some
> >  variants clobber sp (aarch64, arm, x86), others do not (ppc, s390)
> > 
> >  While the asm does indeed set a new stack pointer, we never return from
> >  a sigreturn syscall -- at least not in the normal way.  We actually
> >  return back to the point where the process was interrupted by the
> >  signal.  So describing the affect of the asm on the stack pointer is
> >  pedantically correct, it actually has no real effect and can just be
> >  dropped to avoid the hard error from gcc-9.
> > 
> > Suggested-by: Jeff Law <law at redhat.com>
> > Reviewed-by: Dmitry Safonov <0x7f454c46 at gmail.com>
> > Signed-off-by: Adrian Reber <areber at redhat.com>
> > ---
> >  compel/arch/aarch64/src/lib/include/uapi/asm/sigframe.h | 2 +-
> >  compel/arch/arm/src/lib/include/uapi/asm/sigframe.h     | 2 +-
> >  compel/arch/x86/src/lib/include/uapi/asm/sigframe.h     | 4 ++--
> >  3 files changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/compel/arch/aarch64/src/lib/include/uapi/asm/sigframe.h b/compel/arch/aarch64/src/lib/include/uapi/asm/sigframe.h
> > index 6b511ce..6b9317b 100644
> > --- a/compel/arch/aarch64/src/lib/include/uapi/asm/sigframe.h
> > +++ b/compel/arch/aarch64/src/lib/include/uapi/asm/sigframe.h
> > @@ -39,7 +39,7 @@ struct rt_sigframe {
> >  			"svc #0						\n"	\
> >  			:							\
> >  			: "r"(new_sp)						\
> > -			: "sp", "x8", "memory")
> > +			: "x8", "memory")
> >  
> >  /* cr_sigcontext is copied from arch/arm64/include/uapi/asm/sigcontext.h */
> >  struct cr_sigcontext {
> > diff --git a/compel/arch/arm/src/lib/include/uapi/asm/sigframe.h b/compel/arch/arm/src/lib/include/uapi/asm/sigframe.h
> > index 3e7bc01..b90c0f6 100644
> > --- a/compel/arch/arm/src/lib/include/uapi/asm/sigframe.h
> > +++ b/compel/arch/arm/src/lib/include/uapi/asm/sigframe.h
> > @@ -73,7 +73,7 @@ struct rt_sigframe {
> >  		     "svc #0					    \n"	\
> >  		     :							\
> >  		     : "r"(new_sp)					\
> > -		     : "sp","memory")
> > +		     : "memory")
> >  
> >  #define RT_SIGFRAME_UC(rt_sigframe)		(&rt_sigframe->sig.uc)
> >  #define RT_SIGFRAME_REGIP(rt_sigframe)		(rt_sigframe)->sig.uc.uc_mcontext.arm_ip
> > diff --git a/compel/arch/x86/src/lib/include/uapi/asm/sigframe.h b/compel/arch/x86/src/lib/include/uapi/asm/sigframe.h
> > index 0ad45a5..c29de3b 100644
> > --- a/compel/arch/x86/src/lib/include/uapi/asm/sigframe.h
> > +++ b/compel/arch/x86/src/lib/include/uapi/asm/sigframe.h
> > @@ -162,7 +162,7 @@ struct rt_sigframe {
> >  		     "syscall					    \n"	\
> >  		     :							\
> >  		     : "r"(new_sp)					\
> > -		     : "rax","rsp","memory")
> > +		     : "rax","memory")
> >  #define ARCH_RT_SIGRETURN_COMPAT(new_sp)				\
> >  	asm volatile(							\
> >  		"pushq $"__stringify(USER32_CS)"		\n"	\
> > @@ -176,7 +176,7 @@ struct rt_sigframe {
> >  		".code64					\n"	\
> >  		:							\
> >  		: "rdi"(new_sp)						\
> > -		: "eax","esp", "r8", "r9", "r10", "r11", "memory")
> > +		: "eax", "r8", "r9", "r10", "r11", "memory")
> >  
> >  #define ARCH_RT_SIGRETURN(new_sp, rt_sigframe)				\
> >  do {									\
> > -- 
> > 1.8.3.1
> >