PR10602: improved fix for REG_IP lvalue

* runtime/regs.h (SET_REG_IP): Define.
  (REG_IP_LVALUE): Undefine.
* tapsets.cxx (*::emit_module_decls): Use SET_REG_IP() instead
  of old LVALUE? conditional.

Written by jkenisto & jistone.

2 files changed, 26 insertions, 48 deletions

diff --git a/runtime/regs.h b/runtime/regs.h
index d80cdf0a..dc6b50af 100644
--- a/runtime/regs.h
+++ b/runtime/regs.h
@@ -12,53 +12,61 @@
 #define _REGS_H_
 
 #if defined  (STAPCONF_X86_UNIREGS) && (defined (__x86_64__) || defined (__i386__))
+
 #define REG_IP(regs) regs->ip
-#define REG_IP_LVALUE 1
 #define REG_SP(regs) regs->sp
 #define REG_FP(regs) regs->bp
 
 #elif defined  (__x86_64__)
 
 #define REG_IP(regs) regs->rip
-#define REG_IP_LVALUE 1
 #define REG_SP(regs) regs->rsp
 
 #elif defined (__i386__)
 
 #define REG_IP(regs) regs->eip
-#define REG_IP_LVALUE 1
 #define REG_SP(regs) regs->esp
 #define REG_FP(regs) regs->ebp
 
 #elif defined (__ia64__)
+
 #define REG_IP(regs)    ((regs)->cr_iip +ia64_psr(regs)->ri)
 #define REG_SP(regs)    ((regs)->r12)
+#define SET_REG_IP(regs, x) \
+  (((regs)->cr_iip = (x) & ~3UL), (ia64_psr(regs)->ri = (x) & 3UL))
+
 
 #elif defined (__powerpc64__)
 
 #define REG_IP(regs) regs->nip
-#define REG_IP_LVALUE 1
 #define REG_SP(regs) regs->gpr[1]
 #define REG_LINK(regs) regs->link
 
 #elif defined (__arm__)
 
 #define REG_IP(regs) regs->ARM_pc
-#define REG_IP_LVALUE 1
 #define REG_SP(regs) regs->ARM_sp
 #define REG_LINK(regs) regs->ARM_lr
 
 #elif defined (__s390__) || defined (__s390x__)
+
 #ifndef __s390x__
 #define PSW_ADDR_AMODE	0x80000000UL
+#define PSW_ADDR_INSN	0x7FFFFFFFUL
 #else /* __s390x__ */
 #define PSW_ADDR_AMODE	0x0000000000000000UL
+#define PSW_ADDR_INSN	0xFFFFFFFFFFFFFFFFUL
 #endif /* __s390x__ */
-#define REG_IP(regs)	(((regs)->psw.addr) | PSW_ADDR_AMODE)
+#define REG_IP(regs)	(((regs)->psw.addr) & PSW_ADDR_INSN)
 #define REG_SP(regs)	(regs)->gprs[15]
+#define SET_REG_IP(regs,x) (regs)->psw.addr = (x) | PSW_ADDR_AMODE
 
 #else
 #error "Unimplemented architecture"
 #endif
 
+#ifndef SET_REG_IP
+#define SET_REG_IP(regs, x) REG_IP(regs) = x
+#endif
+
 #endif /* _REGS_H_ */
diff --git a/tapsets.cxx b/tapsets.cxx
index 5b3e9169..7912ed99 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -3080,18 +3080,13 @@ dwarf_derived_probe_group::emit_module_decls (systemtap_session& s)
   // Make it look like the IP is set as it wouldn't have been replaced
   // by a breakpoint instruction when calling real probe handler. Reset
   // IP regs on return, so we don't confuse kprobes. PR10458
-  // But only for architectures where REG_IP is a proper lvalue. PR10491
-  s.op->newline() << "#ifdef REG_IP_LVALUE";
   s.op->newline() << "{";
   s.op->indent(1);
   s.op->newline() << "unsigned long kprobes_ip = REG_IP(c->regs);";
-  s.op->newline() << "REG_IP(regs) = (unsigned long) inst->addr;";
+  s.op->newline() << "SET_REG_IP(regs, (unsigned long) inst->addr);";
   s.op->newline() << "(*sdp->ph) (c);";
-  s.op->newline() << "REG_IP(regs) = kprobes_ip;";
+  s.op->newline() << "SET_REG_IP(regs, kprobes_ip);";
   s.op->newline(-1) << "}";
-  s.op->newline() << "#else";
-  s.op->newline() << "(*sdp->ph) (c);";
-  s.op->newline() << "#endif";
 
   common_probe_entryfn_epilogue (s.op);
   s.op->newline() << "return 0;";
@@ -3119,18 +3114,13 @@ dwarf_derived_probe_group::emit_module_decls (systemtap_session& s)
   // Make it look like the IP is set as it wouldn't have been replaced
   // by a breakpoint instruction when calling real probe handler. Reset
   // IP regs on return, so we don't confuse kprobes. PR10458
-  // But only for architectures where REG_IP is a proper lvalue. PR10491
-  s.op->newline() << "#ifdef REG_IP_LVALUE";
   s.op->newline() << "{";
   s.op->indent(1);
   s.op->newline() << "unsigned long kprobes_ip = REG_IP(c->regs);";
-  s.op->newline() << "REG_IP(regs) = (unsigned long) inst->rp->kp.addr;";
+  s.op->newline() << "SET_REG_IP(regs, (unsigned long) inst->rp->kp.addr);";
   s.op->newline() << "(*sdp->ph) (c);";
-  s.op->newline() << "REG_IP(regs) = kprobes_ip;";
+  s.op->newline() << "SET_REG_IP(regs, kprobes_ip);";
   s.op->newline(-1) << "}";
-  s.op->newline() << "#else";
-  s.op->newline() << "(*sdp->ph) (c);";
-  s.op->newline() << "#endif";
 
   common_probe_entryfn_epilogue (s.op);
   s.op->newline() << "return 0;";
@@ -4553,18 +4543,13 @@ uprobe_derived_probe_group::emit_module_decls (systemtap_session& s)
   // Make it look like the IP is set as it would in the actual user
   // task when calling real probe handler. Reset IP regs on return, so
   // we don't confuse uprobes. PR10458
-  // But only for architectures where REG_IP is a proper lvalue. PR10491
-  s.op->newline() << "#ifdef REG_IP_LVALUE";
   s.op->newline() << "{";
   s.op->indent(1);
   s.op->newline() << "unsigned long uprobes_ip = REG_IP(c->regs);";
-  s.op->newline() << "REG_IP(regs) = inst->vaddr;";
+  s.op->newline() << "SET_REG_IP(regs, inst->vaddr);";
   s.op->newline() << "(*sups->ph) (c);";
-  s.op->newline() << "REG_IP(regs) = uprobes_ip;";
+  s.op->newline() << "SET_REG_IP(regs, uprobes_ip);";
   s.op->newline(-1) << "}";
-  s.op->newline() << "#else";
-  s.op->newline() << "(*sdp->ph) (c);";
-  s.op->newline() << "#endif";
 
   common_probe_entryfn_epilogue (s.op);
   s.op->newline(-1) << "}";
@@ -4581,18 +4566,13 @@ uprobe_derived_probe_group::emit_module_decls (systemtap_session& s)
   // Make it look like the IP is set as it would in the actual user
   // task when calling real probe handler. Reset IP regs on return, so
   // we don't confuse uprobes. PR10458
-  // But only for architectures where REG_IP is a proper lvalue. PR10491
-  s.op->newline() << "#ifdef REG_IP_LVALUE";
   s.op->newline() << "{";
   s.op->indent(1);
   s.op->newline() << "unsigned long uprobes_ip = REG_IP(c->regs);";
-  s.op->newline() << "REG_IP(regs) = inst->rp->u.vaddr;";
+  s.op->newline() << "SET_REG_IP(regs, inst->rp->u.vaddr);";
   s.op->newline() << "(*sups->ph) (c);";
-  s.op->newline() << "REG_IP(regs) = uprobes_ip;";
+  s.op->newline() << "SET_REG_IP(regs, uprobes_ip);";
   s.op->newline(-1) << "}";
-  s.op->newline() << "#else";
-  s.op->newline() << "(*sdp->ph) (c);";
-  s.op->newline() << "#endif";
 
   common_probe_entryfn_epilogue (s.op);
   s.op->newline(-1) << "}";
@@ -5166,18 +5146,13 @@ kprobe_derived_probe_group::emit_module_decls (systemtap_session& s)
   // Make it look like the IP is set as it wouldn't have been replaced
   // by a breakpoint instruction when calling real probe handler. Reset
   // IP regs on return, so we don't confuse kprobes. PR10458
-  // But only for architectures where REG_IP is a proper lvalue. PR10491
-  s.op->newline() << "#ifdef REG_IP_LVALUE";
   s.op->newline() << "{";
   s.op->indent(1);
   s.op->newline() << "unsigned long kprobes_ip = REG_IP(c->regs);";
-  s.op->newline() << "REG_IP(regs) = (unsigned long) inst->addr;";
+  s.op->newline() << "SET_REG_IP(regs, (unsigned long) inst->addr);";
   s.op->newline() << "(*sdp->ph) (c);";
-  s.op->newline() << "REG_IP(regs) = kprobes_ip;";
+  s.op->newline() << "SET_REG_IP(regs, kprobes_ip);";
   s.op->newline(-1) << "}";
-  s.op->newline() << "#else";
-  s.op->newline() << "(*sdp->ph) (c);";
-  s.op->newline() << "#endif";
 
   common_probe_entryfn_epilogue (s.op);
   s.op->newline() << "return 0;";
@@ -5205,18 +5180,13 @@ kprobe_derived_probe_group::emit_module_decls (systemtap_session& s)
   // Make it look like the IP is set as it wouldn't have been replaced
   // by a breakpoint instruction when calling real probe handler. Reset
   // IP regs on return, so we don't confuse kprobes. PR10458
-  // But only for architectures where REG_IP is a proper lvalue. PR10491
-  s.op->newline() << "#ifdef REG_IP_LVALUE";
   s.op->newline() << "{";
   s.op->indent(1);
   s.op->newline() << "unsigned long kprobes_ip = REG_IP(c->regs);";
-  s.op->newline() << "REG_IP(regs) = (unsigned long) inst->rp->kp.addr;";
+  s.op->newline() << "SET_REG_IP(regs, (unsigned long) inst->rp->kp.addr);";
   s.op->newline() << "(*sdp->ph) (c);";
-  s.op->newline() << "REG_IP(regs) = kprobes_ip;";
+  s.op->newline() << "SET_REG_IP(regs, kprobes_ip);";
   s.op->newline(-1) << "}";
-  s.op->newline() << "#else";
-  s.op->newline() << "(*sdp->ph) (c);";
-  s.op->newline() << "#endif";
 
   common_probe_entryfn_epilogue (s.op);
   s.op->newline() << "return 0;";