From 08ed94d6e135d58ca9411b6e31fa3b9fd7669a75 Mon Sep 17 00:00:00 2001
From: Kris Van Hees <kris.van.hees@oracle.com>
Date: Thu, 18 Oct 2012 16:56:46 +0100
Subject: [PATCH] dtrace: cater for changes in the way the kernel is linked

3.6 started linking using a shell script, scripts/linux-vmlinux.sh, rather than
the old hair in the top-level Makefile. The SDT stub creation has to move in
there too.

Also, skip debugging sections explicitly when hunting for SDT probes in objdump
output.

Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
---
 scripts/dtrace_sdt.sh   |  3 +--
 scripts/link-vmlinux.sh | 59 ++++++++++++++++++++++++++++++++++++++---
 2 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/scripts/dtrace_sdt.sh b/scripts/dtrace_sdt.sh
index 11c3bf5efd514..8ec0aab766431 100755
--- a/scripts/dtrace_sdt.sh
+++ b/scripts/dtrace_sdt.sh
@@ -40,13 +40,12 @@ lfn="$2"
 		 next;
 	     }
 
-	     /__dtrace_probe_/ {
+	     /__dtrace_probe_/ && sect !~ /debug/ {
 		 $3 = substr($3, 16);
 		 sub(/-.*$/, "", $3);
 		 printf "%16s %s R %s %s\n", sect, $1, $3, sectbase[sect];
 		 next;
 	     }' | \
-tee /tmp/sdt.log | \
 	sort
     [ "x${lfn}" != "x" ] && nm ${lfn}
 ) | \
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 86a4fe75f4537..5cc4baea07289 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -37,6 +37,39 @@ info()
 	fi
 }
 
+# Generate the SDT probe point stubs object file
+# ${1} output file
+sdtstubs()
+{
+	info MKSTUBS ${1}
+	${NM} -u ${KBUILD_VMLINUX_INIT} ${KBUILD_VMLINUX_MAIN} | \
+		grep __dtrace_probe_ | sort | uniq | \
+		${AWK} '{
+			  printf("\t.globl %s\n\t.type %s,@function\n%s:\n",
+				 $2, $2, $2);
+			}' > .tmp_sdtstubs.S
+	echo "  ret" >> .tmp_sdtstubs.S
+
+	local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL}               \
+		      ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
+
+	${CC} ${aflags} -c -o ${1} .tmp_sdtstubs.S
+}
+
+# Generate the SDT probe info for object file ${1} and kernel image ${2}
+# ${3} output file
+sdtinfo()
+{
+	info DT-SDT ${3}
+
+	scripts/dtrace_sdt.sh ${1} ${2} > .tmp_sdtinfo.S
+
+	local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL}               \
+		      ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
+
+	${CC} ${aflags} -c -o ${3} .tmp_sdtinfo.S
+}
+
 # Link of vmlinux.o used for section mismatch analysis
 # ${1} output file
 modpost_link()
@@ -117,6 +150,8 @@ cleanup()
 	rm -f .old_version
 	rm -f .tmp_System.map
 	rm -f .tmp_kallsyms*
+	rm -f .tmp_sdtstubs.*
+	rm -f .tmp_sdtinfo.*
 	rm -f .tmp_version
 	rm -f .tmp_vmlinux*
 	rm -f System.map
@@ -148,6 +183,14 @@ case "${KCONFIG_CONFIG}" in
 	. "./${KCONFIG_CONFIG}"
 esac
 
+sdtstubso=""
+sdtinfoo=""
+if [ -n "${CONFIG_DTRACE}" ]; then
+	sdtstubso=.tmp_sdtstubs.o
+	sdtinfoo=.tmp_sdtinfo.o
+	sdtstubs ${sdtstubso}
+fi
+
 #link vmlinux.o
 info LD vmlinux.o
 modpost_link vmlinux.o
@@ -194,12 +237,20 @@ if [ -n "${CONFIG_KALLSYMS}" ]; then
 	kallsymso=.tmp_kallsyms2.o
 	kallsyms_vmlinux=.tmp_vmlinux2
 
+	if [ -n "${CONFIG_DTRACE}" ]; then
+		sdtinfo vmlinux.o "" ${sdtinfoo}
+	fi
+
 	# step 1
-	vmlinux_link "" .tmp_vmlinux1
+	vmlinux_link "${sdtstubso} ${sdtinfoo}" .tmp_vmlinux1
 	kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
 
+	if [ -n "${CONFIG_DTRACE}" ]; then
+		sdtinfo vmlinux.o .tmp_vmlinux1 ${sdtinfoo}
+	fi
+
 	# step 2
-	vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
+	vmlinux_link "${sdtstubso} .tmp_kallsyms1.o ${sdtinfoo}" .tmp_vmlinux2
 	kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
 
 	# step 2a
@@ -207,14 +258,14 @@ if [ -n "${CONFIG_KALLSYMS}" ]; then
 		kallsymso=.tmp_kallsyms3.o
 		kallsyms_vmlinux=.tmp_vmlinux3
 
-		vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
+		vmlinux_link "${sdtstubso} .tmp_kallsyms2.o ${sdtinfoo}" .tmp_vmlinux3
 
 		kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
 	fi
 fi
 
 info LD vmlinux
-vmlinux_link "${kallsymso}" vmlinux
+vmlinux_link "${sdtstubso} ${kallsymso} ${sdtinfoo}" vmlinux
 
 if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
 	info SORTEX vmlinux
-- 
2.50.1