From 5e95eb8fde93f0de94ae4b6b18e15f184c732ba9 Mon Sep 17 00:00:00 2001
From: Petr Machata <pmachata@redhat.com>
Date: Tue, 26 Mar 2013 13:39:28 +0100
Subject: [PATCH] On s390, set highest bit of PC in 31-bit tracer

---
 ...e-0.7.2-s390-set_instruction_pointer.patch | 94 +++++++++++++++++++
 ltrace.spec                                   | 12 ++-
 2 files changed, 105 insertions(+), 1 deletion(-)
 create mode 100644 ltrace-0.7.2-s390-set_instruction_pointer.patch

diff --git a/ltrace-0.7.2-s390-set_instruction_pointer.patch b/ltrace-0.7.2-s390-set_instruction_pointer.patch
new file mode 100644
index 0000000..c80bcf9
--- /dev/null
+++ b/ltrace-0.7.2-s390-set_instruction_pointer.patch
@@ -0,0 +1,94 @@
+From cb58fdb5a072ad70087a07f67d0c094ff77ca4b7 Mon Sep 17 00:00:00 2001
+From: Petr Machata <pmachata@redhat.com>
+Date: Tue, 26 Mar 2013 13:26:23 +0100
+Subject: [PATCH] s390 set_instruction_pointer: Set highest bit in 31-bit tracer
+
+- The highest bit is used to distinguish between 24-bit and 31-bit
+  addressing modes.  Up until about 3.1, Linux did this automatically,
+  but stopped doing so with the following commit:
+
+    https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d4e81b35b882d96f059afdb0f98e5b6025973b09
+---
+ sysdeps/linux-gnu/s390/regs.c |    3 +++
+ 1 files changed, 3 insertions(+), 0 deletions(-)
+
+diff --git a/sysdeps/linux-gnu/s390/regs.c b/sysdeps/linux-gnu/s390/regs.c
+index bb16c61..656654a 100644
+--- a/sysdeps/linux-gnu/s390/regs.c
++++ b/sysdeps/linux-gnu/s390/regs.c
+@@ -46,7 +46,7 @@
+ #define PSW_MASK	0x7fffffff
+ #endif
+ 
+-void *
++arch_addr_t
+ get_instruction_pointer(struct process *proc)
+ {
+ 	long ret = ptrace(PTRACE_PEEKUSER, proc->pid, PT_PSWADDR, 0) & PSW_MASK;
+@@ -54,20 +54,22 @@ get_instruction_pointer(struct process *proc)
+ 	if (proc->mask_32bit)
+ 		ret &= PSW_MASK31;
+ #endif
+-	return (void *)ret;
++	/* XXX double cast.  */
++	return (arch_addr_t)ret;
+ }
+ 
+ void
+-set_instruction_pointer(struct process *proc, void *addr)
++set_instruction_pointer(struct process *proc, arch_addr_t addr)
+ {
+ #ifdef __s390x__
+ 	if (proc->mask_32bit)
+-		addr = (void *)((long)addr & PSW_MASK31);
++		/* XXX double cast.  */
++		addr = (arch_addr_t)((uintptr_t)addr & PSW_MASK31);
+ #endif
+ 	ptrace(PTRACE_POKEUSER, proc->pid, PT_PSWADDR, addr);
+ }
+ 
+-void *
++arch_addr_t
+ get_stack_pointer(struct process *proc)
+ {
+ 	long ret = ptrace(PTRACE_PEEKUSER, proc->pid, PT_GPR15, 0) & PSW_MASK;
+@@ -75,16 +77,18 @@ get_stack_pointer(struct process *proc)
+ 	if (proc->mask_32bit)
+ 		ret &= PSW_MASK31;
+ #endif
+-	return (void *)ret;
++	/* XXX double cast.  */
++	return (arch_addr_t)ret;
+ }
+ 
+-void *
+-get_return_addr(struct process *proc, void *stack_pointer)
++arch_addr_t
++get_return_addr(struct process *proc, arch_addr_t stack_pointer)
+ {
+ 	long ret = ptrace(PTRACE_PEEKUSER, proc->pid, PT_GPR14, 0) & PSW_MASK;
+ #ifdef __s390x__
+ 	if (proc->mask_32bit)
+ 		ret &= PSW_MASK31;
+ #endif
+-	return (void *)ret;
++	/* XXX double cast.  */
++	return (arch_addr_t)ret;
+ }
+diff --git a/sysdeps/linux-gnu/s390/regs.c b/sysdeps/linux-gnu/s390/regs.c
+index 656654a..51410d7 100644
+--- a/sysdeps/linux-gnu/s390/regs.c
++++ b/sysdeps/linux-gnu/s390/regs.c
+@@ -65,6 +65,9 @@ set_instruction_pointer(struct process *proc, arch_addr_t addr)
+ 	if (proc->mask_32bit)
+ 		/* XXX double cast.  */
+ 		addr = (arch_addr_t)((uintptr_t)addr & PSW_MASK31);
++#else
++	/* XXX double cast.  */
++	addr = (arch_addr_t)((uintptr_t)addr | ~PSW_MASK);
+ #endif
+ 	ptrace(PTRACE_POKEUSER, proc->pid, PT_PSWADDR, addr);
+ }
+-- 
+1.7.6.5
+
diff --git a/ltrace.spec b/ltrace.spec
index f6a6795..b3000f1 100644
--- a/ltrace.spec
+++ b/ltrace.spec
@@ -1,7 +1,7 @@
 Summary: Tracks runtime library calls from dynamically linked executables
 Name: ltrace
 Version: 0.7.2
-Release: 4%{?dist}
+Release: 5%{?dist}
 URL: http://ltrace.alioth.debian.org/
 License: GPLv2+
 Group: Development/Debuggers
@@ -24,6 +24,9 @@ Patch1: ltrace-0.7.2-arm.patch
 # Work around a recently-added GCC warning.
 Patch2: ltrace-0.7.2-unused-typedef.patch
 
+# s390 set_instruction_pointer: Set highest bit in 31-bit tracer
+Patch3: ltrace-0.7.2-s390-set_instruction_pointer.patch
+
 %description
 Ltrace is a debugging program which runs a specified command until the
 command exits.  While the command is executing, ltrace intercepts and
@@ -39,6 +42,7 @@ execution of processes.
 %patch0 -p1
 %patch1 -p1
 %patch2 -p1
+%patch3 -p1
 
 %build
 autoreconf -i
@@ -64,6 +68,12 @@ echo ====================TESTING END=====================
 %config(noreplace) %{_sysconfdir}/ltrace.conf
 
 %changelog
+* Tue Mar 26 2013 Petr Machata <pmachata@redhat.com> - 0.7.2-5
+- On s390, the highest bit in PC address is used to distinguish
+  between 24-bit and 31-bit addressing modes.  Linux used to do this
+  for us, but not anymore.
+  (ltrace-0.7.2-s390-set_instruction_pointer.patch)
+
 * Wed Feb  6 2013 Petr Machata <pmachata@redhat.com> - 0.7.2-4
 - Update the ARM patch (ltrace-0.7.2-arm.patch) with support for
   parameter passing conventions.