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Date:      Mon, 23 Jun 2014 02:00:15 +0000 (UTC)
From:      Mark Johnston <markj@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r267761 - in head/sys/cddl: contrib/opensolaris/uts/common/sys dev/dtrace/i386
Message-ID:  <201406230200.s5N20Fwt011463@svn.freebsd.org>
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Author: markj
Date: Mon Jun 23 02:00:14 2014
New Revision: 267761
URL: http://svnweb.freebsd.org/changeset/base/267761

Log:
  Fix some bugs when fetching probe arguments in i386. Firstly ensure that
  the 4 byte-aligned dtrace_invop_callsite can be found and that it
  immediately follows the call to dtrace_invop(). Secondly, fix some pointer
  arithmetic to account for differences between struct i386_frame and illumos'
  struct frame. Finally, ensure that dtrace_getarg() isn't inlined. It works
  by following a fixed number of frame pointers to the probe site, so inlining
  breaks it.
  
  MFC after:	3 weeks

Modified:
  head/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace_impl.h
  head/sys/cddl/dev/dtrace/i386/dtrace_asm.S
  head/sys/cddl/dev/dtrace/i386/dtrace_isa.c

Modified: head/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace_impl.h
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace_impl.h	Mon Jun 23 01:28:18 2014	(r267760)
+++ head/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace_impl.h	Mon Jun 23 02:00:14 2014	(r267761)
@@ -1268,7 +1268,11 @@ typedef struct dtrace_toxrange {
 	uintptr_t	dtt_limit;		/* limit of toxic range */
 } dtrace_toxrange_t;
 
+#if defined(sun)
 extern uint64_t dtrace_getarg(int, int);
+#else
+extern uint64_t __noinline dtrace_getarg(int, int);
+#endif
 extern greg_t dtrace_getfp(void);
 extern int dtrace_getipl(void);
 extern uintptr_t dtrace_caller(int);

Modified: head/sys/cddl/dev/dtrace/i386/dtrace_asm.S
==============================================================================
--- head/sys/cddl/dev/dtrace/i386/dtrace_asm.S	Mon Jun 23 01:28:18 2014	(r267760)
+++ head/sys/cddl/dev/dtrace/i386/dtrace_asm.S	Mon Jun 23 02:00:14 2014	(r267761)
@@ -49,14 +49,8 @@
 	 * dtrace_invop wants us to do.
 	 */
 	call	dtrace_invop
-
-	/*
-	 * We pushed 3 times for the arguments to dtrace_invop,
-	 * so we need to increment the stack pointer to get rid of
-	 * those values.
-	 */
-	addl	$12, %esp
 	ALTENTRY(dtrace_invop_callsite)
+	addl	$12, %esp
 	cmpl	$DTRACE_INVOP_PUSHL_EBP, %eax
 	je	invop_push
 	cmpl	$DTRACE_INVOP_POPL_EBP, %eax

Modified: head/sys/cddl/dev/dtrace/i386/dtrace_isa.c
==============================================================================
--- head/sys/cddl/dev/dtrace/i386/dtrace_isa.c	Mon Jun 23 01:28:18 2014	(r267760)
+++ head/sys/cddl/dev/dtrace/i386/dtrace_isa.c	Mon Jun 23 02:00:14 2014	(r267761)
@@ -413,7 +413,8 @@ 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, 4) ==
+		    (long)dtrace_invop_callsite) {
 			/*
 			 * If we pass through the invalid op handler, we will
 			 * use the pointer that it passed to the stack as the
@@ -422,7 +423,7 @@ dtrace_getarg(int arg, int aframes)
 			 * beyond the EIP/RIP that was pushed when the trap was
 			 * taken -- hence the "+ 1" below.
 			 */
-			stack = ((uintptr_t **)&fp[1])[1] + 1;
+			stack = ((uintptr_t **)&fp[1])[0] + 1;
 			goto load;
 		}
 
@@ -438,7 +439,7 @@ dtrace_getarg(int arg, int aframes)
 	 */
 	arg++;
 
-	stack = (uintptr_t *)&fp[1];
+	stack = (uintptr_t *)fp + 2;
 
 load:
 	DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);

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