From 212fcc465abe7e7806a9b0a21385bd645cd13177 Mon Sep 17 00:00:00 2001
From: kenistoj <kenistoj>
Date: Thu, 27 Dec 2007 21:30:51 +0000
Subject: * runtime/uprobes/uprobes_x86_64.c: Fix handling of indirect jmps and
 calls that use rip-relative addressing.  Allow probing of opcode 0x63.

---
 ChangeLog                        |  6 ++++++
 runtime/uprobes/uprobes_x86_64.c | 15 ++++++++++-----
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b4f41825..e2a6cc8d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2007-12-27  Jim Keniston  <jkenisto@us.ibm.com>
+
+	* runtime/uprobes/uprobes_x86_64.c: Fix handling of indirect
+	jmps and calls that use rip-relative addressing.  Allow probing
+	of opcode 0x63.
+
 2007-12-13  Masami Hiramatsu  <mhiramat@redhat.com>
 
 	* stap.1.in: Document about relay buffer sharing.
diff --git a/runtime/uprobes/uprobes_x86_64.c b/runtime/uprobes/uprobes_x86_64.c
index 23dcdadb..78969248 100644
--- a/runtime/uprobes/uprobes_x86_64.c
+++ b/runtime/uprobes/uprobes_x86_64.c
@@ -43,7 +43,7 @@ static const unsigned long good_insns_64[256 / 64] = {
 	W(0x30, 1,1,1,1,1,1,0,0,1,1,1,1,1,1,0,0), /* 30 */
 	W(0x40, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 40 */
 	W(0x50, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 50 */
-	W(0x60, 0,0,0,0,0,0,0,0,1,1,1,1,0,0,0,0)| /* 60 */
+	W(0x60, 0,0,0,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 60 */
 	W(0x70, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1), /* 70 */
 	W(0x80, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 80 */
 	W(0x90, 1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1)| /* 90 */
@@ -603,8 +603,13 @@ void uprobe_post_ssout(struct uprobe_task *utask, struct uprobe_probept *ppt,
 			regs->rax = utask->arch_info.saved_scratch_register;
 		else
 			regs->rcx = utask->arch_info.saved_scratch_register;
-		regs->rip += (4 + correction);
-		return;
+		/*
+		 * The original instruction includes a displacement, and so
+		 * is 4 bytes longer than what we've just single-stepped.
+		 * Fall through to handle stuff like "jmpq *...(%rip)" and
+		 * "callq *...(%rip)".
+		 */
+		correction += 4;
 	}
 
 	/*
@@ -613,8 +618,8 @@ void uprobe_post_ssout(struct uprobe_task *utask, struct uprobe_probept *ppt,
 	 * ppt->arch_info.flags.
 	 *
 	 * We don't bother skipping prefixes here because none of the
-	 * non-rip-relative instructions that require special treatment
-	 * involve prefixes.
+	 * instructions that require special treatment (other than
+	 * rip-relative instructions, handled above) involve prefixes.
 	 */
 
 	switch (*insn) {
-- 
cgit