svn commit: r269531 - in stable/10/sys/cddl: contrib/opensolaris/uts/intel/dtrace dev/dtrace/amd64

[Mark Johnston]

Author: markj
Date: Mon Aug  4 21:41:00 2014
New Revision: 269531
URL: http://svnweb.freebsd.org/changeset/base/269531

Log:
  MFC r256822:
  When fetching function arguments out of a frame on amd64, explicitly select
  the register based on the argument index rather than relying on the fields
  in struct reg to be in the right order. This assumption is incorrect on
  FreeBSD and generally led to bogus argument values for the sixth argument
  of PID and USDT probes; the first five are passed directly to dtrace_probe()
  via the fasttrap trap handler and so were correctly handled.

Modified:
  stable/10/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c
  stable/10/sys/cddl/dev/dtrace/amd64/dtrace_isa.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c
==============================================================================
--- stable/10/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c	Mon Aug  4 21:12:38 2014	(r269530)
+++ stable/10/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c	Mon Aug  4 21:41:00 2014	(r269531)
@@ -273,7 +273,20 @@ fasttrap_anarg(struct reg *rp, int funct
 		 * registers.
 		 */
 		if (argno < 6)
-			return ((&rp->r_rdi)[argno]);
+			switch (argno) {
+			case 0:
+				return (rp->r_rdi);
+			case 1:
+				return (rp->r_rsi);
+			case 2:
+				return (rp->r_rdx);
+			case 3:
+				return (rp->r_rcx);
+			case 4:
+				return (rp->r_r8);
+			case 5:
+				return (rp->r_r9);
+			}
 
 		stack = (uintptr_t *)rp->r_rsp;
 		DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);

Modified: stable/10/sys/cddl/dev/dtrace/amd64/dtrace_isa.c
==============================================================================
--- stable/10/sys/cddl/dev/dtrace/amd64/dtrace_isa.c	Mon Aug  4 21:12:38 2014	(r269530)
+++ stable/10/sys/cddl/dev/dtrace/amd64/dtrace_isa.c	Mon Aug  4 21:41:00 2014	(r269531)
@@ -367,7 +367,27 @@ dtrace_getarg(int arg, int aframes)
 			    sizeof (uintptr_t));
 
 			if (arg <= inreg) {
-				stack = (uintptr_t *)&rp->r_rdi;
+				switch (arg) {
+				case 0:
+					stack = (uintptr_t *)&rp->r_rdi;
+					break;
+				case 1:
+					stack = (uintptr_t *)&rp->r_rsi;
+					break;
+				case 2:
+					stack = (uintptr_t *)&rp->r_rdx;
+					break;
+				case 3:
+					stack = (uintptr_t *)&rp->r_rcx;
+					break;
+				case 4:
+					stack = (uintptr_t *)&rp->r_r8;
+					break;
+				case 5:
+					stack = (uintptr_t *)&rp->r_r9;
+					break;
+				}
+				arg = 0;
 			} else {
 				stack = (uintptr_t *)(rp->r_rsp);
 				arg -= inreg;