kbuild: Parameterize kallsyms generation and correct reporting

PATCH In review Kees Cook 2 participants 2 messages Aug 13, 2019 Kbuild

Share & tools

Kees Cook

author

2019-08-13 15:15 UTC #0 lore raw

PATCH v2 1/1 kbuild: Parameterize kallsyms generation and correct reporting

When kallsyms generation happens, temporary vmlinux outputs are linked but the quiet make output didn't report it, giving the impression that the prior command is taking longer than expected.

Instead, report the linking step explicitly. While at it, this consolidates the repeated "kallsyms generation step" into a single function and removes the existing copy/pasting.

Signed-off-by Kees Cook <[email protected]>

---
v2:
- rename $kallsymso_previous to $kallsymso_prev (Masahiro)
- move location of kallsyms_step() (Masahiro)
- report linking step instead of folding it into KSYM (Masahiro)

---
 scripts/link-vmlinux.sh | 38 +++++++++++++++++++-------------------
 1 file changed, 19 insertions(+), 19 deletions(-)

scripts/link-vmlinux.sh +19 ~~-19~~

index a7124f895b24..0b08bfb88f74 100755
@@ -60,6 +60,7 @@ modpost_link()
 # ${2} - output file
 vmlinux_link()
 {
+	info LD ${2}
 	local lds="${objtree}/${KBUILD_LDS}"
 	local objects

@@ -138,6 +139,18 @@ kallsyms()
 	${CC} ${aflags} -c -o ${2} ${afile}
 }
 
+# Perform one step in kallsyms generation, including temporary linking of
+# vmlinux.
+kallsyms_step()
+{
+	kallsymso_prev=${kallsymso}
+	kallsymso=.tmp_kallsyms${1}.o
+	kallsyms_vmlinux=.tmp_vmlinux${1}
+
+	vmlinux_link "${kallsymso_prev}" ${kallsyms_vmlinux}
+	kallsyms ${kallsyms_vmlinux} ${kallsymso}
+}
+
 # Create map file with all symbols from ${1}
 # See mksymap for additional details
 mksysmap()

@@ -216,6 +229,7 @@ info MODINFO modules.builtin.modinfo
 ${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo
 
 kallsymso=""
+kallsymso_prev=""
 kallsyms_vmlinux=""
 if [ -n "${CONFIG_KALLSYMS}" ]; then

@@ -242,32 +256,18 @@ if [ -n "${CONFIG_KALLSYMS}" ]; then
 	# a)  Verify that the System.map from vmlinux matches the map from
 	#     ${kallsymso}.
 
-	kallsymso=.tmp_kallsyms2.o
-	kallsyms_vmlinux=.tmp_vmlinux2
-
-	# step 1
-	vmlinux_link "" .tmp_vmlinux1
-	kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
-
-	# step 2
-	vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
-	kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
+	kallsyms_step 1
+	kallsyms_step 2
 
 	# step 3
-	size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms1.o)
-	size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms2.o)
+	size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})
+	size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
 
 	if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
-		kallsymso=.tmp_kallsyms3.o
-		kallsyms_vmlinux=.tmp_vmlinux3
-
-		vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
-
-		kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
+		kallsyms_step 3
 	fi
 fi
 
-info LD vmlinux
 vmlinux_link "${kallsymso}" vmlinux
 
 if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then

Signature · 5 lines

2.17.1


-- 
Kees Cook

Masahiro Yamada

2019-08-13 15:40 UTC #1 lore raw

Quoted 9 lines · Kees Cook

When kallsyms generation happens, temporary vmlinux outputs are linked but the quiet make output didn't report it, giving the impression that the prior command is taking longer than expected.
Instead, report the linking step explicitly. While at it, this consolidates the repeated "kallsyms generation step" into a single function and removes the existing copy/pasting.

Quoted 6 lines

Signed-off-by Kees Cook <[email protected]>
---
v2:
- rename $kallsymso_previous to $kallsymso_prev (Masahiro)
- move location of kallsyms_step() (Masahiro)
- report linking step instead of folding it into KSYM (Masahiro)

Applied to linux-kbuild.
Thanks!

Signature · 2 lines

Best Regards
Masahiro Yamada