Re: [PATCH v2] kbuild: allow symbol whitelisting with TRIM_UNUSED_KSYMS

From: Matthias Maennich
Date: Tue Feb 04 2020 - 09:44:21 EST


On Fri, Jan 31, 2020 at 05:40:55PM +0000, Quentin Perret wrote:
On Friday 31 Jan 2020 at 13:15:08 (+0000), 'Matthias Maennich' via kernel-team wrote:
On Wed, Jan 29, 2020 at 06:15:41PM +0000, Quentin Perret wrote:
> diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh
> index a904bf1f5e67..8e1b7f70e800 100755
> --- a/scripts/adjust_autoksyms.sh
> +++ b/scripts/adjust_autoksyms.sh
> @@ -48,6 +48,7 @@ cat > "$new_ksyms_file" << EOT
> EOT
> sed 's/ko$/mod/' modules.order |
> xargs -n1 sed -n -e '2{s/ /\n/g;/^$/!p;}' -- |
> +cat - "${CONFIG_UNUSED_KSYMS_WHITELIST:-/dev/null}" |

This handles absolute paths very well. I wonder whether we can make this
more useful for folks that want to maintain such a whitelist in their
copy of the tree. Lets say, I have in my sources
arch/x86/configs/x86_64_symbol_whitelist and in my config I have
CONFIG_UNUSED_KSYMS_WHITELIST="arch/x86/configs/x86_64_symbol_whitelist".

If I see it correctly, UNUSED_KSYMS_WHITELIST is currently either an
absolute path or a relative path to the current build directory. I would
prefer if relative paths would be relative to the source directory to
support the above use case. (Note, that scenario above works if I build
directly in the sources, but fails if I build O=/somewhere/else.)

Right, that is an interesting use case. I suppose something like the
below should work (with appropriate documentation of the config option).

---8<---
diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh
index 8e1b7f70e800..d37803fd75ce 100755
--- a/scripts/adjust_autoksyms.sh
+++ b/scripts/adjust_autoksyms.sh
@@ -38,6 +38,12 @@ esac
# We need access to CONFIG_ symbols
. include/config/auto.conf

+ksym_wl="${CONFIG_UNUSED_KSYMS_WHITELIST:-/dev/null}"
+# If the path is relative, it must be relative to the source tree
+if [ "$ksym_wl" == "${ksym_wl#/}" ]; then
+ ksym_wl="$abs_srctree/$ksym_wl"
+fi
+
# Generate a new ksym list file with symbols needed by the current
# set of modules.
cat > "$new_ksyms_file" << EOT
@@ -48,7 +54,7 @@ cat > "$new_ksyms_file" << EOT
EOT
sed 's/ko$/mod/' modules.order |
xargs -n1 sed -n -e '2{s/ /\n/g;/^$/!p;}' -- |
-cat - "${CONFIG_UNUSED_KSYMS_WHITELIST:-/dev/null}" |
+cat - "$ksym_wl" |
sort -u |
sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$new_ksyms_file"
--->8---

Thoughts ?

That definitely looks like I would expect that config option to work.
Thanks for looking into that!

Cheers,
Matthias


Thanks,
Quentin