2021-10-27 21:32:46

by Nick Alcock

[permalink] [raw]
Subject: [PATCH v5 3/7] kbuild: generate an address ranges map at vmlinux link time

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 <[email protected]>
---
scripts/link-vmlinux.sh | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)

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
--
2.33.0.256.gb827f06fa9


2021-10-30 16:52:11

by kernel test robot

[permalink] [raw]
Subject: Re: [PATCH v5 3/7] kbuild: generate an address ranges map at vmlinux link time

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 <[email protected]>

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/[email protected]


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