[PATCHv2] powerpc64: Fix calls when r2 is not used [BZ #26173]

Message ID 20200701205037.407310-1-tuliom@linux.ibm.com
State New
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  • [PATCHv2] powerpc64: Fix calls when r2 is not used [BZ #26173]
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Commit Message

Adhemerval Zanella via Libc-alpha July 1, 2020, 8:50 p.m.
Paul E Murphy via Libc-alpha <libc-alpha@sourceware.org> writes:

> Will this also require a newer version of binutils?


Yes.  Fixed in this version.

Thanks!

Changes since v1:

 - Detect at configure time if the assembler supports @notoc. Use @notoc only
   when available.

---8<---

Teach the linker that __mcount_internal, __sigjmp_save_symbol,
__syscall_error and __GI_exit do not use r2, so that it does not need to
recover r2 after the call.

Test at configure time if the assembler supports @notoc and define
USE_PPC64_NOTOC.
---
 config.h.in                                   |  3 ++
 sysdeps/powerpc/powerpc64/configure           | 28 +++++++++++++++++++
 sysdeps/powerpc/powerpc64/configure.ac        | 11 ++++++++
 sysdeps/powerpc/powerpc64/ppc-mcount.S        |  2 +-
 sysdeps/powerpc/powerpc64/setjmp-common.S     |  2 +-
 sysdeps/powerpc/powerpc64/sysdep.h            |  8 +++++-
 .../linux/powerpc/powerpc64/makecontext.S     |  2 +-
 7 files changed, 52 insertions(+), 4 deletions(-)

-- 
2.25.4

Comments

Adhemerval Zanella via Libc-alpha July 1, 2020, 9:32 p.m. | #1
On 7/1/20 3:50 PM, Tulio Magno Quites Machado Filho wrote:
> Paul E Murphy via Libc-alpha <libc-alpha@sourceware.org> writes:

> 

>> Will this also require a newer version of binutils?

> 

> Yes.  Fixed in this version.

> 

> Thanks!

> 

> Changes since v1:

> 

>   - Detect at configure time if the assembler supports @notoc. Use @notoc only

>     when available.

> 

> ---8<---

> 

> Teach the linker that __mcount_internal, __sigjmp_save_symbol,

> __syscall_error and __GI_exit do not use r2, so that it does not need to

> recover r2 after the call.

> 

> Test at configure time if the assembler supports @notoc and define

> USE_PPC64_NOTOC.

> ---

>   config.h.in                                   |  3 ++

>   sysdeps/powerpc/powerpc64/configure           | 28 +++++++++++++++++++

>   sysdeps/powerpc/powerpc64/configure.ac        | 11 ++++++++

>   sysdeps/powerpc/powerpc64/ppc-mcount.S        |  2 +-

>   sysdeps/powerpc/powerpc64/setjmp-common.S     |  2 +-

>   sysdeps/powerpc/powerpc64/sysdep.h            |  8 +++++-

>   .../linux/powerpc/powerpc64/makecontext.S     |  2 +-

>   7 files changed, 52 insertions(+), 4 deletions(-)

> 

> diff --git a/config.h.in b/config.h.in

> index 831eca2fe1..6598d4573a 100644

> --- a/config.h.in

> +++ b/config.h.in

> @@ -20,6 +20,9 @@

>   /* On powerpc64, use overlapping .opd entries.  */

>   #undef  USE_PPC64_OVERLAPPING_OPD

>   

> +/* On powerpc64, use @notoc.  */

> +#undef  USE_PPC64_NOTOC

> +

>   /* Define if _Unwind_Find_FDE should be exported from glibc.  */

>   #undef  EXPORT_UNWIND_FIND_FDE

>   

> diff --git a/sysdeps/powerpc/powerpc64/configure b/sysdeps/powerpc/powerpc64/configure

> index 7632a7be04..5ce77af631 100644

> --- a/sysdeps/powerpc/powerpc64/configure

> +++ b/sysdeps/powerpc/powerpc64/configure

> @@ -31,3 +31,31 @@ if test x$libc_cv_overlapping_opd = xyes; then

>     $as_echo "#define USE_PPC64_OVERLAPPING_OPD 1" >>confdefs.h

>   

>   fi

> +

> +# @notoc started to be supported in GNU Binutils 2.31.


An optional rewording suggestion: s/started to be supported/was added/.

I also did a quick compile test with binutils 2.30
and 2.34.  LGTM.
Tulio Magno Quites Machado Filho July 10, 2020, 11:06 p.m. | #2
Paul E Murphy via Libc-alpha <libc-alpha@sourceware.org> writes:

> An optional rewording suggestion: s/started to be supported/was added/.

>

> I also did a quick compile test with binutils 2.30

> and 2.34.  LGTM.


Pushed as 7c7bcf3634e44cf7e001aaa302138c1ee0e58f8c.

Thanks!

-- 
Tulio Magno

Patch

diff --git a/config.h.in b/config.h.in
index 831eca2fe1..6598d4573a 100644
--- a/config.h.in
+++ b/config.h.in
@@ -20,6 +20,9 @@ 
 /* On powerpc64, use overlapping .opd entries.  */
 #undef  USE_PPC64_OVERLAPPING_OPD
 
+/* On powerpc64, use @notoc.  */
+#undef  USE_PPC64_NOTOC
+
 /* Define if _Unwind_Find_FDE should be exported from glibc.  */
 #undef  EXPORT_UNWIND_FIND_FDE
 
diff --git a/sysdeps/powerpc/powerpc64/configure b/sysdeps/powerpc/powerpc64/configure
index 7632a7be04..5ce77af631 100644
--- a/sysdeps/powerpc/powerpc64/configure
+++ b/sysdeps/powerpc/powerpc64/configure
@@ -31,3 +31,31 @@  if test x$libc_cv_overlapping_opd = xyes; then
   $as_echo "#define USE_PPC64_OVERLAPPING_OPD 1" >>confdefs.h
 
 fi
+
+# @notoc started to be supported in GNU Binutils 2.31.
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if the assembler supports @notoc" >&5
+$as_echo_n "checking if the assembler supports @notoc... " >&6; }
+if ${libc_cv_ppc64_notoc+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
+	       cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+void foo (void) {asm("b foo@notoc");}
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  libc_cv_ppc64_notoc=yes
+else
+  libc_cv_ppc64_notoc=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_ppc64_notoc" >&5
+$as_echo "$libc_cv_ppc64_notoc" >&6; }
+if test x$libc_cv_ppc64_notoc = xyes; then :
+  $as_echo "#define USE_PPC64_NOTOC 1" >>confdefs.h
+
+fi
diff --git a/sysdeps/powerpc/powerpc64/configure.ac b/sysdeps/powerpc/powerpc64/configure.ac
index f309ba35a8..b77156f696 100644
--- a/sysdeps/powerpc/powerpc64/configure.ac
+++ b/sysdeps/powerpc/powerpc64/configure.ac
@@ -21,3 +21,14 @@  rm -f conftest.c conftest.s
 if test x$libc_cv_overlapping_opd = xyes; then
   AC_DEFINE(USE_PPC64_OVERLAPPING_OPD)
 fi
+
+# @notoc started to be supported in GNU Binutils 2.31.
+AC_CACHE_CHECK([if the assembler supports @notoc],
+	       libc_cv_ppc64_notoc, [
+	       AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+void foo (void) {asm("b foo@notoc");}
+		  ])],
+		  [libc_cv_ppc64_notoc=yes],
+		  [libc_cv_ppc64_notoc=no])])
+AS_IF([test x$libc_cv_ppc64_notoc = xyes],
+      [AC_DEFINE(USE_PPC64_NOTOC)])
diff --git a/sysdeps/powerpc/powerpc64/ppc-mcount.S b/sysdeps/powerpc/powerpc64/ppc-mcount.S
index f7e9836cae..1adc0a18f3 100644
--- a/sysdeps/powerpc/powerpc64/ppc-mcount.S
+++ b/sysdeps/powerpc/powerpc64/ppc-mcount.S
@@ -29,7 +29,7 @@  ENTRY(_mcount)
 	cfi_adjust_cfa_offset (FRAME_MIN_SIZE)
 	cfi_offset (lr, FRAME_LR_SAVE)
 	ld		 r3, FRAME_LR_SAVE(r11)
-	bl		 JUMPTARGET(__mcount_internal)
+	bl		 JUMPTARGET (NOTOC (__mcount_internal))
 #ifndef SHARED
 	nop
 #endif
diff --git a/sysdeps/powerpc/powerpc64/setjmp-common.S b/sysdeps/powerpc/powerpc64/setjmp-common.S
index eb37000980..2409d17831 100644
--- a/sysdeps/powerpc/powerpc64/setjmp-common.S
+++ b/sysdeps/powerpc/powerpc64/setjmp-common.S
@@ -217,7 +217,7 @@  L(no_vmx):
 	li	r3,0
 	blr
 #elif defined SHARED
-	b	JUMPTARGET (__sigjmp_save_symbol)
+	b	JUMPTARGET (NOTOC (__sigjmp_save_symbol))
 #else
 	mflr	r0
 	std	r0,FRAME_LR_SAVE(r1)
diff --git a/sysdeps/powerpc/powerpc64/sysdep.h b/sysdeps/powerpc/powerpc64/sysdep.h
index d6616ac905..d557098898 100644
--- a/sysdeps/powerpc/powerpc64/sysdep.h
+++ b/sysdeps/powerpc/powerpc64/sysdep.h
@@ -278,7 +278,7 @@  LT_LABELSUFFIX(name,_name_end): ; \
 
 #ifdef SHARED
 #define TAIL_CALL_SYSCALL_ERROR \
-    b JUMPTARGET(__syscall_error)
+    b JUMPTARGET (NOTOC (__syscall_error))
 #else
 /* Static version might be linked into a large app with a toc exceeding
    64k.  We can't put a toc adjusting stub on a plain branch, so can't
@@ -366,6 +366,12 @@  LT_LABELSUFFIX(name,_name_end): ; \
 	lwz	rOUT,0(rOUT)
 #endif
 
+#ifdef USE_PPC64_NOTOC
+# define NOTOC(l) l@notoc
+#else
+# define NOTOC(l) l
+#endif
+
 #else /* !__ASSEMBLER__ */
 
 #if _CALL_ELF != 2
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S
index e4d4575d68..3c528aa4b7 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S
@@ -160,7 +160,7 @@  L(exitcode):
 	li    r3,-1
 L(do_exit):
 #ifdef SHARED
-	b     JUMPTARGET(__GI_exit);
+	b     JUMPTARGET (NOTOC (__GI_exit));
 #else
 	b     JUMPTARGET(exit);
 	nop