S390: Save and restore fprs/vrs while resolving symbols.

On s390, no fpr/vrs were saved while resolving a symbol
via _dl_runtime_resolve/_dl_runtime_profile.

According to the abi, the fpr-arguments are defined as call clobbered.
In leaf-functions, gcc 4.9 and newer can use fprs for saving/restoring gprs
instead of saving them to the stack.
If gcc do this in one of the resolver-functions, then the floating point
arguments of a library-function are invalid for the first library-function-call.
Thus, this patch saves/restores the fprs around the resolving code.

The same could occur for vector registers. Furthermore an ifunc-resolver
could also clobber the vector/floating point argument registers.
Thus this patch provides the further variants _dl_runtime_resolve_vx/
_dl_runtime_profile_vx, which are used if the kernel claims, that
we run on a machine with vector registers.

Furthermore, if _dl_runtime_profile calls _dl_call_pltexit,
the pointers to inregs-/outregs-structs were setup invalid.
Now they point to the correct location in the stack-frame.
Before branching back to the caller, the return values are now
restored instead of containing the return values of the
_dl_call_pltexit() call.
On s390-32, an endless loop occurs if _dl_call_pltexit() should be called.
Now, this code-path branches to this function instead of just after the
preceding basr-instruction.

ChangeLog:

	* sysdeps/s390/s390-32/dl-trampoline.S: Include dl-trampoline.h twice
	to create a non-vector/vector version for _dl_runtime_resolve and
	_dl_runtime_profile. Move implementation to ...
	* sysdeps/s390/s390-32/dl-trampoline.h: ... here.
	(_dl_runtime_resolve) Save and restore fpr/vrs.
	(_dl_runtime_profile) Save and restore vrs and fix some issues
	if _dl_call_pltexit is called.
	* sysdeps/s390/s390-32/dl-machine.h (elf_machine_runtime_setup):
	Choose the correct resolver function if running on a machine with vx.
	* sysdeps/s390/s390-64/dl-trampoline.S: Include dl-trampoline.h twice
	to create a non-vector/vector version for _dl_runtime_resolve and
	_dl_runtime_profile. Move implementation to ...
	* sysdeps/s390/s390-64/dl-trampoline.h: ... here.
	(_dl_runtime_resolve) Save and restore fpr/vrs.
	(_dl_runtime_profile) Save and restore vrs and fix some issues
	* sysdeps/s390/s390-64/dl-machine.h: (elf_machine_runtime_setup):
	Choose the correct resolver function if running on a machine with vx.

(cherry picked from commit 4603c51ef7989d7eb800cdd6f42aab206f891077
and commit d8a012c5c9e4bfc1b8db2bc6deacb85b44a2e1eb)

1 files changed, 20 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index c68136ca25..bcacb5782d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,25 @@
 2016-04-04  Stefan Liebler  <stli@linux.vnet.ibm.com>
 
+	* sysdeps/s390/s390-32/dl-trampoline.S: Include dl-trampoline.h twice
+	to create a non-vector/vector version for _dl_runtime_resolve and
+	_dl_runtime_profile. Move implementation to ...
+	* sysdeps/s390/s390-32/dl-trampoline.h: ... here.
+	(_dl_runtime_resolve) Save and restore fpr/vrs.
+	(_dl_runtime_profile) Save and restore vrs and fix some issues
+	if _dl_call_pltexit is called.
+	* sysdeps/s390/s390-32/dl-machine.h (elf_machine_runtime_setup):
+	Choose the correct resolver function if running on a machine with vx.
+	* sysdeps/s390/s390-64/dl-trampoline.S: Include dl-trampoline.h twice
+	to create a non-vector/vector version for _dl_runtime_resolve and
+	_dl_runtime_profile. Move implementation to ...
+	* sysdeps/s390/s390-64/dl-trampoline.h: ... here.
+	(_dl_runtime_resolve) Save and restore fpr/vrs.
+	(_dl_runtime_profile) Save and restore vrs and fix some issues
+	* sysdeps/s390/s390-64/dl-machine.h: (elf_machine_runtime_setup):
+	Choose the correct resolver function if running on a machine with vx.
+
+2016-04-04  Stefan Liebler  <stli@linux.vnet.ibm.com>
+
 	* config.h.in (HAVE_S390_VX_ASM_SUPPORT): New macro undefine.
 	* sysdeps/s390/configure.ac: Add test for S390 vector instruction
 	assembler support.