| Message ID | 20230411200944.2591330-1-maskray@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] Makefile: use -z pack-relative-relocs | expand |
On Tue, Apr 11, 2023 at 08:09:44PM +0000, Fangrui Song wrote: > Commit 27f2a4db76e8 ("Makefile: fix GDB warning with CONFIG_RELR") > added --use-android-relr-tags to fix a GDB warning > > BFD: /android0/linux-next/vmlinux: unknown type [0x13] section `.relr.dyn' > > The GDB warning has been fixed in version 11.2. > > The DT_ANDROID_RELR tag was deprecated since DT_RELR was standardized. > Thus, --use-android-relr-tags should be removed. While making the > change, try -z pack-relative-relocs, which is supported since LLD 15. > Keep supporting --pack-dyn-relocs=relr as well for older LLD versions. > There is no indication of obsolescence for --pack-dyn-relocs=relr. > > As of today, GNU ld supports the latter option for x86 and powerpc64 > ports and has no intention to support --pack-dyn-relocs=relr. In the > absence of the glibc symbol version GLIBC_ABI_DT_RELR, > --pack-dyn-relocs=relr and -z pack-relative-relocs are identical in > ld.lld. > > GNU ld and newer versions of LLD report warnings (instead of errors) for > unknown -z options. Only errors lead to non-zero exit codes. Therefore, > we should test --pack-dyn-relocs=relr before testing > -z pack-relative-relocs. > > Link: https://github.com/ClangBuiltLinux/linux/issues/1057 > Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=a619b58721f0a03fd91c27670d3e4c2fb0d88f1e > Signed-off-by: Fangrui Song <maskray@google.com> > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > --- > Makefile | 3 ++- > scripts/tools-support-relr.sh | 8 ++++++-- > 2 files changed, 8 insertions(+), 3 deletions(-) Acked-by: Will Deacon <will@kernel.org> Masahiro -- are you happy to pick this one up? If not, I can take it via arm64 (as the only arch currently using this reloc format). Cheers, Will
On Thu, Apr 13, 2023 at 11:55 PM Will Deacon <will@kernel.org> wrote: > > On Tue, Apr 11, 2023 at 08:09:44PM +0000, Fangrui Song wrote: > > Commit 27f2a4db76e8 ("Makefile: fix GDB warning with CONFIG_RELR") > > added --use-android-relr-tags to fix a GDB warning > > > > BFD: /android0/linux-next/vmlinux: unknown type [0x13] section `.relr.dyn' > > > > The GDB warning has been fixed in version 11.2. > > > > The DT_ANDROID_RELR tag was deprecated since DT_RELR was standardized. > > Thus, --use-android-relr-tags should be removed. While making the > > change, try -z pack-relative-relocs, which is supported since LLD 15. > > Keep supporting --pack-dyn-relocs=relr as well for older LLD versions. > > There is no indication of obsolescence for --pack-dyn-relocs=relr. > > > > As of today, GNU ld supports the latter option for x86 and powerpc64 > > ports and has no intention to support --pack-dyn-relocs=relr. In the > > absence of the glibc symbol version GLIBC_ABI_DT_RELR, > > --pack-dyn-relocs=relr and -z pack-relative-relocs are identical in > > ld.lld. > > > > GNU ld and newer versions of LLD report warnings (instead of errors) for > > unknown -z options. Only errors lead to non-zero exit codes. Therefore, > > we should test --pack-dyn-relocs=relr before testing > > -z pack-relative-relocs. > > > > Link: https://github.com/ClangBuiltLinux/linux/issues/1057 > > Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=a619b58721f0a03fd91c27670d3e4c2fb0d88f1e > > Signed-off-by: Fangrui Song <maskray@google.com> > > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > > --- > > Makefile | 3 ++- > > scripts/tools-support-relr.sh | 8 ++++++-- > > 2 files changed, 8 insertions(+), 3 deletions(-) > > Acked-by: Will Deacon <will@kernel.org> > > Masahiro -- are you happy to pick this one up? Sure. Applied to linux-kbuild. (I will push it next week.) > If not, I can take it via > arm64 (as the only arch currently using this reloc format). > > Cheers, > > Will
diff --git a/Makefile b/Makefile index 5aeea3d98fc0..d9c6d1839cf0 100644 --- a/Makefile +++ b/Makefile @@ -1113,7 +1113,8 @@ LDFLAGS_vmlinux += -X endif ifeq ($(CONFIG_RELR),y) -LDFLAGS_vmlinux += --pack-dyn-relocs=relr --use-android-relr-tags +# ld.lld before 15 did not support -z pack-relative-relocs. +LDFLAGS_vmlinux += $(call ld-option,--pack-dyn-relocs=relr,-z pack-relative-relocs) 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 cb55878bd5b8..4c121946e517 100755 --- a/scripts/tools-support-relr.sh +++ b/scripts/tools-support-relr.sh @@ -7,8 +7,12 @@ 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 \ - --use-android-relr-tags -o $tmp_file + +# ld.lld before 15 did not support -z pack-relative-relocs. +if ! $LD $tmp_file.o -shared -Bsymbolic --pack-dyn-relocs=relr -o $tmp_file 2>/dev/null; then + $LD $tmp_file.o -shared -Bsymbolic -z pack-relative-relocs -o $tmp_file 2>&1 | + grep -q pack-relative-relocs && exit 1 +fi # 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.
Commit 27f2a4db76e8 ("Makefile: fix GDB warning with CONFIG_RELR") added --use-android-relr-tags to fix a GDB warning BFD: /android0/linux-next/vmlinux: unknown type [0x13] section `.relr.dyn' The GDB warning has been fixed in version 11.2. The DT_ANDROID_RELR tag was deprecated since DT_RELR was standardized. Thus, --use-android-relr-tags should be removed. While making the change, try -z pack-relative-relocs, which is supported since LLD 15. Keep supporting --pack-dyn-relocs=relr as well for older LLD versions. There is no indication of obsolescence for --pack-dyn-relocs=relr. As of today, GNU ld supports the latter option for x86 and powerpc64 ports and has no intention to support --pack-dyn-relocs=relr. In the absence of the glibc symbol version GLIBC_ABI_DT_RELR, --pack-dyn-relocs=relr and -z pack-relative-relocs are identical in ld.lld. GNU ld and newer versions of LLD report warnings (instead of errors) for unknown -z options. Only errors lead to non-zero exit codes. Therefore, we should test --pack-dyn-relocs=relr before testing -z pack-relative-relocs. Link: https://github.com/ClangBuiltLinux/linux/issues/1057 Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=a619b58721f0a03fd91c27670d3e4c2fb0d88f1e Signed-off-by: Fangrui Song <maskray@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> --- Makefile | 3 ++- scripts/tools-support-relr.sh | 8 ++++++-- 2 files changed, 8 insertions(+), 3 deletions(-)