GDB produces the following warning when debugging kernels built with CONFIG_RELR: BFD: /android0/linux-next/vmlinux: unknown type [0x13] section `.relr.dyn' when loading a kernel built with CONFIG_RELR into GDB. It can also prevent debugging symbols using such relocations. Peter sugguests: [That flag] means that lld will use dynamic tags and section type numbers in the OS-specific range rather than the generic range. The kernel itself doesn't care about these numbers; it determines the location of the RELR section using symbols defined by a linker script. Link: https://github.com/ClangBuiltLinux/linux/issues/1057 Suggested-by: Peter Collingbourne <pcc@xxxxxxxxxx> Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> --- Changes V1 -> V2: * rebase * pick up Nathan's reviewed by tag. Makefile | 2 +- scripts/tools-support-relr.sh | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/Makefile b/Makefile index 0ed7e061c8e9..2dbb56f831d4 100644 --- a/Makefile +++ b/Makefile @@ -1031,7 +1031,7 @@ LDFLAGS_vmlinux += $(call ld-option, -X,) endif ifeq ($(CONFIG_RELR),y) -LDFLAGS_vmlinux += --pack-dyn-relocs=relr +LDFLAGS_vmlinux += --pack-dyn-relocs=relr --use-android-relr-tags endif # We never want expected sections to be placed heuristically by the diff --git a/scripts/tools-support-relr.sh b/scripts/tools-support-relr.sh index 45e8aa360b45..cb55878bd5b8 100755 --- a/scripts/tools-support-relr.sh +++ b/scripts/tools-support-relr.sh @@ -7,7 +7,8 @@ trap "rm -f $tmp_file.o $tmp_file $tmp_file.bin" EXIT cat << "END" | $CC -c -x c - -o $tmp_file.o >/dev/null 2>&1 void *p = &p; END -$LD $tmp_file.o -shared -Bsymbolic --pack-dyn-relocs=relr -o $tmp_file +$LD $tmp_file.o -shared -Bsymbolic --pack-dyn-relocs=relr \ + --use-android-relr-tags -o $tmp_file # Despite printing an error message, GNU nm still exits with exit code 0 if it # sees a relr section. So we need to check that nothing is printed to stderr. base-commit: 45af60e7ced07ae3def41368c3d260dbf496fbce -- 2.31.1.818.g46aad6cb9e-goog
