Re: [LTP] [PATCH 1/2] ltp_rt_sigaction: SPARC fixes for -O0

[Jan Stancek <jstancek@redhat.com>]

----- Original Message -----
> From: "Stanislav Kholmanskikh" <stanislav.kholmanskikh@oracle.com>
> To: ltp-list@lists.sourceforge.net
> Cc: "vasily isaenko" <vasily.isaenko@oracle.com>
> Sent: Monday, 17 August, 2015 2:13:17 PM
> Subject: [LTP] [PATCH 1/2] ltp_rt_sigaction: SPARC fixes for -O0
> 
> The *sigreturn_stub functions are copied from glibc, and they
> work only if optimization > 0, since they expect that the compiler
> does not add an epilogue.

Isn't that prologue?
Other than that it looks good to me, ACK.

Regards,
Jan

> 
> For example, with -O > 0:
> 
> 0000000000102140 <__rt_sigreturn_stub>:
>   102140:       82 10 20 65     mov  0x65, %g1  ! 65 <_init-0x101f23>
>   102144:       91 d0 20 6d     ta  0x6d
>   102148:       81 c3 e0 08     retl
>   10214c:       01 00 00 00     nop
> 
> but without -O:
> 
> 000000000010212c <__rt_sigreturn_stub>:
>   10212c:       9d e3 bf 50     save  %sp, -176, %sp  <--- this
>   102130:       82 10 20 65     mov  0x65, %g1
>   102134:       91 d0 20 6d     ta  0x6d
>   102138:       81 cf e0 08     rett  %i7 + 8
>   10213c:       01 00 00 00     nop
> 
> Therefore, if we build LTP with OPT_CFLAGS="", ltp_rt_sigaction() will
> malfunction.
> 
> To avoid this, let's declare a new symbol pointing to the instruction we
> need ('mov ...').
> 
> The trick was proposed by Jose E. Marchesi <jose.marchesi@oracle.com>.
> 
> Signed-off-by: Stanislav Kholmanskikh <stanislav.kholmanskikh@oracle.com>
> ---
>  include/lapi/rt_sigaction.h |   20 ++++++++++++--------
>  1 files changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/include/lapi/rt_sigaction.h b/include/lapi/rt_sigaction.h
> index 46f6a50..f99c372 100644
> --- a/include/lapi/rt_sigaction.h
> +++ b/include/lapi/rt_sigaction.h
> @@ -105,12 +105,14 @@ static inline int sig_initial(int sig)
>  # if defined __arch64__ || defined __sparcv9
>  
>  /*
> - * From glibc/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c
> + * Based on glibc/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c
>   */
>  
> +extern char *__rt_sig_stub;
> +
>  static void __rt_sigreturn_stub(void)
>  {
> -	__asm__ ("mov %0, %%g1\n\t"
> +	__asm__ ("__rt_sig_stub: mov %0, %%g1\n\t"
>  		"ta  0x6d\n\t"
>  		: /* no outputs */
>  		: "i" (__NR_rt_sigreturn));
> @@ -119,12 +121,14 @@ static void __rt_sigreturn_stub(void)
>  # else /* sparc32 */
>  
>  /*
> - * From glibc/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c
> + * Based on glibc/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c
>   */
>  
> +extern char *__rt_sig_stub, *__sig_stub;
> +
>  static void __rt_sigreturn_stub(void)
>  {
> -	__asm__ ("mov %0, %%g1\n\t"
> +	__asm__ ("__rt_sig_stub: mov %0, %%g1\n\t"
>  		"ta  0x10\n\t"
>  		: /* no outputs */
>  		: "i" (__NR_rt_sigreturn));
> @@ -132,7 +136,7 @@ static void __rt_sigreturn_stub(void)
>  
>  static void __sigreturn_stub(void)
>  {
> -	__asm__ ("mov %0, %%g1\n\t"
> +	__asm__ ("__sig_stub: mov %0, %%g1\n\t"
>  		"ta  0x10\n\t"
>  		: /* no outputs */
>  		: "i" (__NR_sigreturn));
> @@ -181,12 +185,12 @@ static int ltp_rt_sigaction(int signum, const struct
> sigaction *act,
>  #ifdef __sparc__
>  	unsigned long stub = 0;
>  # if defined __arch64__ || defined __sparcv9
> -	stub = ((unsigned long) &__rt_sigreturn_stub) - 8;
> +	stub = ((unsigned long) &__rt_sig_stub) - 8;
>  # else /* sparc32 */
>  	if ((kact.sa_flags & SA_SIGINFO) != 0)
> -		stub = ((unsigned long) &__rt_sigreturn_stub) - 8;
> +		stub = ((unsigned long) &__rt_sig_stub) - 8;
>  	else
> -		stub = ((unsigned long) &__sigreturn_stub) - 8;
> +		stub = ((unsigned long) &__sig_stub) - 8;
>  # endif
>  #endif
>  
> --
> 1.7.1
> 
> 
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