| Message ID | 20210319000708.1694662-1-ndesaulniers@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Makefile: fix GDB warning with CONFIG_RELR | expand |
On Thu, Mar 18, 2021 at 05:07:06PM -0700, Nick Desaulniers wrote: > 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@google.com> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> > --- > Makefile | 2 +- > scripts/tools-support-relr.sh | 3 ++- > 2 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/Makefile b/Makefile > index 5160ff8903c1..47741cb60995 100644 > --- a/Makefile > +++ b/Makefile > @@ -1088,7 +1088,7 @@ 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. > -- > 2.31.0.rc2.261.g7f71774620-goog >
On Fri, May 21, 2021 at 6:36 PM Lee Jones <lee.jones@linaro.org> wrote: > > On Tue, 23 Mar 2021 at 19:06, Nathan Chancellor <nathan@kernel.org> wrote: >> >> On Thu, Mar 18, 2021 at 05:07:06PM -0700, Nick Desaulniers wrote: >> > 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@google.com> >> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> >> >> Reviewed-by: Nathan Chancellor <nathan@kernel.org> > > > Masahiro, > > Would you mind sharing your plans for this reviewed patch please? > Do you want me to pick up this? Or, do you think it should be done by the committer of 5cf896fb6be3effd9aea455b22213e27be8bdb1d ?
On Sat, 22 May 2021, Masahiro Yamada wrote: > On Fri, May 21, 2021 at 6:36 PM Lee Jones <lee.jones@linaro.org> wrote: > > > > On Tue, 23 Mar 2021 at 19:06, Nathan Chancellor <nathan@kernel.org> wrote: > >> > >> On Thu, Mar 18, 2021 at 05:07:06PM -0700, Nick Desaulniers wrote: > >> > 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@google.com> > >> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> > >> > >> Reviewed-by: Nathan Chancellor <nathan@kernel.org> > > > > > > Masahiro, > > > > Would you mind sharing your plans for this reviewed patch please? > > > Do you want me to pick up this? > > Or, do you think it should be done by the committer of > 5cf896fb6be3effd9aea455b22213e27be8bdb1d ? Not sure it matters a whole bunch TBH. If you have the bandwidth and are willing to merge it, please feel free to do so.
diff --git a/Makefile b/Makefile index 5160ff8903c1..47741cb60995 100644 --- a/Makefile +++ b/Makefile @@ -1088,7 +1088,7 @@ 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.
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@google.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> --- Makefile | 2 +- scripts/tools-support-relr.sh | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-)