Fix profiling on powerpc32 secure-plt shared libs and PIEs
Alan Modra
amodra@gmail.com
Mon Aug 15 15:12:00 GMT 2011
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
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