> On 12 Sep 2024, at 16:43, Eric Gallager <eg...@gwmail.gwu.edu> wrote: > > > > On Wed, Sep 11, 2024 at 11:51 AM Srinath Parvathaneni > <srinath.parvathan...@arm.com> wrote: >> >> This patch adds support for aarch64 gcs build attributes. > > Hi, just wondering if you could clarify what "GCS" stands for in this > context? When I see it, my first thought is "GNU Coding Standards", > but I don't think that's right...
It’s the Guarded Control Stack feature of the Arm architecture: https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/arm-a-profile-architecture-2022 Thanks, Kyrill > >> This support includes generating two new assembler directives >> .aeabi_subsection and .aeabi_attribute. These directives are >> generated as per the syntax mentioned in spec >> "Build Attributes for the Arm® 64-bit Architecture (AArch64)" >> available at [1]. >> >> To check whether the assembler being used to build the toolchain >> supports these directives, a new gcc configure check is added in >> gcc/configure.ac. >> >> If the assembler support these directives, .aeabi_subsection and >> .aeabi_attribute directives are emitted in the generated assembly, >> when -mbranch-protection=gcs is passed. >> >> If the assembler does not support these directives, >> .note.gnu.property section will emit the relevant gcs information >> in the generated assembly, when -mbranch-protection=gcs is passed. >> >> This patch needs to be applied on top of GCC gcs patch series [2]. >> >> Bootstrapped on aarch64-none-linux-gnu and regression tested on >> aarch64-none-elf, no issues. >> >> Ok for master? >> >> Regards, >> Srinath. >> >> [1]: https://github.com/ARM-software/abi-aa/pull/230 >> [2]: >> https://gcc.gnu.org/git/?p=gcc.git;a=shortlog;h=refs/vendors/ARM/heads/gcs >> >> gcc/ChangeLog: >> >> 2024-09-11 Srinath Parvathaneni <srinath.parvathan...@arm.com> >> >> * config.in: Regenerated >> * config/aarch64/aarch64.cc (aarch64_emit_aeabi_attribute): New >> function declaration. >> (aarch64_emit_aeabi_subsection): Likewise. >> (aarch64_start_file): Emit gcs build attributes. >> (aarch64_file_end_indicate_exec_stack): Update gcs bit in >> note.gnu.property section. >> * configure: Regenerated. >> * configure.ac: Add gcc configure check. >> >> gcc/testsuite/ChangeLog: >> >> 2024-09-11 Srinath Parvathaneni <srinath.parvathan...@arm.com> >> >> * gcc.target/aarch64/build-attribute-gcs.c: New test. >> --- >> gcc/config.in | 6 +++ >> gcc/config/aarch64/a.out | Bin 0 -> 656 bytes >> gcc/config/aarch64/aarch64.cc | 43 ++++++++++++++++++ >> gcc/configure | 35 ++++++++++++++ >> gcc/configure.ac | 7 +++ >> .../gcc.target/aarch64/build-attribute-gcs.c | 24 ++++++++++ >> 6 files changed, 115 insertions(+) >> create mode 100644 gcc/config/aarch64/a.out >> create mode 100644 gcc/testsuite/gcc.target/aarch64/build-attribute-gcs.c >>
