Fix profiling on powerpc32 secure-plt shared libs and PIEs

[Alan Modra <amodra at gmail dot com>]

This patch moves the ppc32 _mcount to libc_shared.a, fixing a
long-standing bug with profiling of secure-plt shared libraries and
PIEs.  The problem is that a ppc32 PIC PLT call stub uses r30 (GOT
pointer) to load the function address from the PLT, r30 being set up
in the function prologue, but _mcount is called before the function
prologue.  So chances are good that r30 will be pointing to the
executable GOT when trying to call _mcount in a shared lib function.
A similar problem can occur in a PIE if a shared lib calls a function
in the executable.

This change is one of the simplest out of many possible cures for the
problem.  One other simple cure, forcing bss-plt if _mcount is
dynamic, has already been implemented in ld.

2011-08-15  Alan Modra  <amodra@gmail.com>

	PR 13092
	* sysdeps/powerpc/Makefile (gmon): Move sysdep_routines to..
	* sysdeps/powerpc/powerpc64/Makefile (gmon): ..here..
	* sysdeps/powerpc/powerpc32/Makefile (gmon): ..and here.  Add
	ppc_mcount to static-only-routines.
	* sysdeps/powerpc/powerpc32/Versions: Export GLIBC_PRIVATE
	__mcount_internal.
	* sysdeps/powerpc/powerpc32/ppc-mcount.S (_mcount): Call
	__mcount_internal with usual JUMPTARGET.  Remove useless nop.

diff --git a/sysdeps/powerpc/Makefile b/sysdeps/powerpc/Makefile
index 616458f..e43ca70 100644
--- a/sysdeps/powerpc/Makefile
+++ b/sysdeps/powerpc/Makefile
@@ -2,10 +2,6 @@
 # machine.
 +cflags += -mnew-mnemonics
 
-ifeq ($(subdir),gmon)
-sysdep_routines += ppc-mcount
-endif
-
 ifeq ($(subdir),string)
 CFLAGS-memcmp.c += -Wno-uninitialized
 endif
diff --git a/sysdeps/powerpc/powerpc32/Makefile b/sysdeps/powerpc/powerpc32/Makefile
index 1d58a06..ed24484 100644
--- a/sysdeps/powerpc/powerpc32/Makefile
+++ b/sysdeps/powerpc/powerpc32/Makefile
@@ -5,6 +5,11 @@ ifeq ($(with-fp),no)
 sysdep-LDFLAGS += -msoft-float
 endif
 
+ifeq ($(subdir),gmon)
+sysdep_routines += ppc-mcount
+static-only-routines += ppc-mcount
+endif
+
 ifeq ($(subdir),misc)
 sysdep_routines += gprsave0 gprrest0 gprsave1 gprrest1
 endif
diff --git a/sysdeps/powerpc/powerpc32/Versions b/sysdeps/powerpc/powerpc32/Versions
index 3635c4a..ad4972e 100644
--- a/sysdeps/powerpc/powerpc32/Versions
+++ b/sysdeps/powerpc/powerpc32/Versions
@@ -8,6 +8,9 @@ libc {
     __fixsfdi; __fixunssfdi;
     __floatdidf; __floatdisf;
   }
+  GLIBC_PRIVATE {
+    __mcount_internal;
+  }
 }
 
 libm {
diff --git a/sysdeps/powerpc/powerpc32/ppc-mcount.S b/sysdeps/powerpc/powerpc32/ppc-mcount.S
index 7e39acb..c7720a1 100644
--- a/sysdeps/powerpc/powerpc32/ppc-mcount.S
+++ b/sysdeps/powerpc/powerpc32/ppc-mcount.S
@@ -58,8 +58,7 @@ ENTRY(_mcount)
 	stw	r4, 44(r1)
 	cfi_offset (lr, -4)
 	stw	r5,  8(r1)
-	bl	__mcount_internal@local
-	nop
+	bl	JUMPTARGET(__mcount_internal)
  /* Restore the registers...  */
 	lwz     r6,  8(r1)
 	lwz	r0, 44(r1)
diff --git a/sysdeps/powerpc/powerpc64/Makefile b/sysdeps/powerpc/powerpc64/Makefile
index 136de30..9056e60 100644
--- a/sysdeps/powerpc/powerpc64/Makefile
+++ b/sysdeps/powerpc/powerpc64/Makefile
@@ -45,4 +45,5 @@ ifeq ($(subdir),gmon)
 # Compiling with -msoft-float ensures that fp regs are not used
 # for moving memory around.
 CFLAGS-mcount.c += $(no-special-regs)
+sysdep_routines += ppc-mcount
 endif

-- 
Alan Modra
Australia Development Lab, IBM