svn commit: r267759 - head/sys/cddl/dev/dtrace/amd64

[Mark Johnston]

Author: markj
Date: Mon Jun 23 01:10:56 2014
New Revision: 267759
URL: http://svnweb.freebsd.org/changeset/base/267759

Log:
  Fix a couple of bugs on amd64 when fetching probe arguments beyond the
  first five for probes entered through a UD fault (i.e. FBT probes).
  
  Specifically, handle the fact that dtrace_invop_callsite must be
  16 byte-aligned and thus may not immediately follow the call to
  dtrace_invop() in dtrace_invop_start(). Also fetch register arguments and
  the stack pointer through a struct trapframe instead of a struct reg.
  
  PR:		191260
  Submitted by:	luke.tw at gmail.com
  MFC after:	3 weeks

Modified:
  head/sys/cddl/dev/dtrace/amd64/dtrace_isa.c

Modified: head/sys/cddl/dev/dtrace/amd64/dtrace_isa.c
==============================================================================
--- head/sys/cddl/dev/dtrace/amd64/dtrace_isa.c	Mon Jun 23 00:54:56 2014	(r267758)
+++ head/sys/cddl/dev/dtrace/amd64/dtrace_isa.c	Mon Jun 23 01:10:56 2014	(r267759)
@@ -349,7 +349,8 @@ dtrace_getarg(int arg, int aframes)
 	for (i = 1; i <= aframes; i++) {
 		fp = fp->f_frame;
 
-		if (fp->f_retaddr == (long)dtrace_invop_callsite) {
+		if (P2ROUNDUP(fp->f_retaddr, 16) ==
+		    (long)dtrace_invop_callsite) {
 			/*
 			 * In the case of amd64, we will use the pointer to the
 			 * regs structure that was pushed when we took the
@@ -363,33 +364,33 @@ dtrace_getarg(int arg, int aframes)
 			 * we're seeking is passed in regsiters, we can just
 			 * load it directly.
 			 */
-			struct reg *rp = (struct reg *)((uintptr_t)&fp[1] +
-			    sizeof (uintptr_t));
+			struct trapframe *tf =
+			    (struct trapframe *)((uintptr_t)&fp[1]);
 
 			if (arg <= inreg) {
 				switch (arg) {
 				case 0:
-					stack = (uintptr_t *)&rp->r_rdi;
+					stack = (uintptr_t *)&tf->tf_rdi;
 					break;
 				case 1:
-					stack = (uintptr_t *)&rp->r_rsi;
+					stack = (uintptr_t *)&tf->tf_rsi;
 					break;
 				case 2:
-					stack = (uintptr_t *)&rp->r_rdx;
+					stack = (uintptr_t *)&tf->tf_rdx;
 					break;
 				case 3:
-					stack = (uintptr_t *)&rp->r_rcx;
+					stack = (uintptr_t *)&tf->tf_rcx;
 					break;
 				case 4:
-					stack = (uintptr_t *)&rp->r_r8;
+					stack = (uintptr_t *)&tf->tf_r8;
 					break;
 				case 5:
-					stack = (uintptr_t *)&rp->r_r9;
+					stack = (uintptr_t *)&tf->tf_r9;
 					break;
 				}
 				arg = 0;
 			} else {
-				stack = (uintptr_t *)(rp->r_rsp);
+				stack = (uintptr_t *)(tf->tf_rsp);
 				arg -= inreg;
 			}
 			goto load;