[v5,3/7] kbuild: generate an address ranges map at vmlinux link time

Commit Message

Nick Alcock Oct. 27, 2021, 5:47 p.m. UTC

This emits a new file, .tmp_vmlinux.ranges, which maps address
range/size pairs in vmlinux to the object files which make them up,
e.g., in part:

0x0000000000000000 0x30 arch/x86/kernel/cpu/common.o
0x0000000000001000 0x1000 arch/x86/events/intel/ds.o
0x0000000000002000 0x4000 arch/x86/kernel/irq_64.o
0x0000000000006000 0x5000 arch/x86/kernel/process.o
0x000000000000b000 0x1000 arch/x86/kernel/cpu/common.o
0x000000000000c000 0x5000 arch/x86/mm/cpu_entry_area.o
0x0000000000011000 0x10 arch/x86/kernel/espfix_64.o
0x0000000000011010 0x2 arch/x86/kernel/cpu/common.o
[...]

In my simple tests this seems to work with clang too, but if I'm not
sure how stable the format of clang's linker mapfiles is: if it turns
out not to work in some versions, the mapfile-massaging awk script added
here might need some adjustment.

Signed-off-by: Nick Alcock <[e-mail]>
---
 scripts/link-vmlinux.sh | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

Comments

kernel test robot Oct. 30, 2021, 4:49 p.m. UTC | #1

Hi Nick,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linux/master]
[also build test ERROR on linus/master v5.15-rc7]
[cannot apply to jeyu/modules-next masahiroy/kconfig next-20211029]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Nick-Alcock/kbuild-bring-back-tristate-conf/20211028-024948
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2f111a6fd5b5297b4e92f53798ca086f7c7d33a4
config: um-x86_64_defconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/a5f527e3449ec41735da78a430732e96080d49fe
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Nick-Alcock/kbuild-bring-back-tristate-conf/20211028-024948
        git checkout a5f527e3449ec41735da78a430732e96080d49fe
        # save the attached .config to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=um SUBARCH=x86_64 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[e-mail]>

All errors (new ones prefixed by >>):

>> gcc-9: error: unrecognized command line option '-Map=.tmp_vmlinux.map'

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[e-mail]

Patch

diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index d74cee5c4326..a30075c14a25 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -196,7 +196,7 @@  vmlinux_link()
 	${ld} ${ldflags} -o ${output}					\
 		${wl}--whole-archive ${objs} ${wl}--no-whole-archive	\
 		${wl}--start-group ${libs} ${wl}--end-group		\
-		$@ ${ldlibs}
+		-Map=.tmp_vmlinux.map $@ ${ldlibs}
 }
 
 # generate .BTF typeinfo from DWARF debuginfo
@@ -248,6 +248,19 @@  kallsyms()
 {
 	local kallsymopt;
 
+	# read the linker map to identify ranges of addresses:
+	#   - for each *.o file, report address, size, pathname
+	#       - most such lines will have four fields
+	#       - but sometimes there is a line break after the first field
+	#   - start reading at "Linker script and memory map"
+	#   - stop reading at ".brk"
+	${AWK} '
+	    /\.o$/ && start==1 { print $(NF-2), $(NF-1), $NF }
+	    /^Linker script and memory map/ { start = 1 }
+	    /^\.brk/ { exit(0) }
+	' .tmp_vmlinux.map | sort > .tmp_vmlinux.ranges
+
+	# get kallsyms options
 	if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
 		kallsymopt="${kallsymopt} --all-symbols"
 	fi