[ARM/FDPIC,v3,00/21] FDPIC ABI for ARM

Message ID 20181011133518.17258-1-christophe.lyon@st.com
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  • FDPIC ABI for ARM
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Christophe Lyon Oct. 11, 2018, 1:34 p.m.
Hello,

This patch series implements the GCC contribution of the FDPIC ABI for
ARM targets.

This ABI enables to run Linux on ARM MMU-less cores and supports
shared libraries to reduce the memory footprint.

Without MMU, text and data segments relative distances are different
from one process to another, hence the need for a dedicated FDPIC
register holding the start address of the data segment. One of the
side effects is that function pointers require two words to be
represented: the address of the code, and the data segment start
address. These two words are designated as "Function Descriptor",
hence the "FD PIC" name.

On ARM, the FDPIC register is r9 [1], and the target name is
arm-uclinuxfdpiceabi. Note that arm-uclinux exists, but uses another
ABI and the BFLAT file format; it does not support code sharing.
The -mfdpic option is enabled by default, and -mno-fdpic should be
used to build the Linux kernel.

This work was developed some time ago by STMicroelectronics, and was
presented during Linaro Connect SFO15 (September 2015). You can watch
the discussion and read the slides [2].
This presentation was related to the toolchain published on github [3],
which is based on binutils-2.22, gcc-4.7, uclibc-0.9.33.2, gdb-7.5.1
and qemu-2.3.0, and for which pre-built binaries are available [3].

The ABI itself is described in details in [1].

Our Linux kernel patches have been updated and committed by Nicolas
Pitre (Linaro) in July 2017. They are required so that the loader is
able to handle this new file type. Indeed, the ELF files are tagged
with ELFOSABI_ARM_FDPIC. This new tag has been allocated by ARM, as
well as the new relocations involved.

The binutils, QEMU and uclibc-ng patch series have been merged
recently. [4][5][6]

This series provides support for ARM v7 architecture and has been
tested on arm-linux-gnueabi without regression, as well as
arm-uclinuxfdpiceabi, using QEMU. arm-uclinuxfdpiceabi has more
failures than arm-linux-gnueabi, but is quite functional.

Are the GCC patches OK for inclusion in master?

Changes between v2 and v3:
- added doc entry for -mfdpic new option
- took Kyrill's comments into account (use "Armv7" instead of "7",
  code factorization, use preprocessor instead of hard-coding "r9",
  remove leftover code for thumb1 support, fixed comments)
- rebase over recent trunk
- patches with changes: 1, 2 (commit message), 3 (rebase), 4, 6, 7, 9,
  14 (rebase), 19 (rebase)

Changes between v1 and v2:
- fix GNU coding style
- exit with an error for pre-Armv7
- use ACLE __ARM_ARCH and remove dead code for pre-Armv4
- remove unsupported attempts of pre-Armv7/thumb1 support
- add instructions in comments next to opcodes
- merge patches 11 and 13
- fixed protected visibility handling in patch 8
- merged legitimize_tls_address_fdpic and
  legitimize_tls_address_not_fdpic as requested

Thanks,

Christophe.


[1] https://github.com/mickael-guene/fdpic_doc/blob/master/abi.txt
[2] http://connect.linaro.org/resource/sfo15/sfo15-406-arm-fdpic-toolset-kernel-libraries-for-cortex-m-cortex-r-mmuless-cores/
[3] https://github.com/mickael-guene/fdpic_manifest
[4] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=f1ac0afe481e83c9a33f247b81fa7de789edc4d9
[5] https://git.qemu.org/?p=qemu.git;a=commit;h=e8fa72957419c11984608062c7dcb204a6003a06
[6] https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/commit/?id=13c46fbc1e5a021f2b9ed32d83aecc93ae5e655d

Christophe Lyon (21):
  [ARM] FDPIC: Add -mfdpic option support
  [ARM] FDPIC: Handle arm*-*-uclinuxfdpiceabi in configure scripts
  [ARM] FDPIC: Force FDPIC related options unless -mno-fdpic is provided
  [ARM] FDPIC: Add support for FDPIC for arm architecture
  [ARM] FDPIC: Fix __do_global_dtors_aux and frame_dummy generation
  [ARM] FDPIC: Add support for c++ exceptions
  [ARM] FDPIC: Avoid saving/restoring r9 on stack since it is RO
  [ARM] FDPIC: Ensure local/global binding for function descriptors
  [ARM] FDPIC: Add support for taking address of nested function
  [ARM] FDPIC: Implement TLS support.
  [ARM] FDPIC: Add support to unwind FDPIC signal frame
  [ARM] FDPIC: Restore r9 after we call __aeabi_read_tp
  [ARM] FDPIC: Force LSB bit for PC in Cortex-M architecture
  [ARM][testsuite] FDPIC: Skip unsupported tests
  [ARM][testsuite] FDPIC: Adjust scan-assembler patterns.
  [ARM][testsuite] FDPIC: Skip v8-m and v6-m tests that currently
    produce an ICE
  [ARM][testsuite] FDPIC: Skip tests that don't work in PIC mode
  [ARM][testsuite] FDPIC: Handle *-*-uclinux*
  [ARM][testsuite] FDPIC: Enable tests on pie_enabled targets
  [ARM][testsuite] FDPIC: Adjust pr43698.c to avoid clash with uclibc.
  [ARM][testsuite] FDPIC: Skip tests using architecture older than v7

 config/futex.m4                                    |   2 +-
 config/tls.m4                                      |   2 +-
 gcc/config.gcc                                     |  13 +-
 gcc/config/arm/arm-c.c                             |   2 +
 gcc/config/arm/arm-protos.h                        |   1 +
 gcc/config/arm/arm.c                               | 478 ++++++++++++++++++---
 gcc/config/arm/arm.h                               |   9 +-
 gcc/config/arm/arm.md                              | 125 +++++-
 gcc/config/arm/arm.opt                             |   4 +
 gcc/config/arm/bpabi.h                             |   4 +-
 gcc/config/arm/linux-eabi.h                        |   7 +-
 gcc/config/arm/uclinuxfdpiceabi.h                  |  53 +++
 gcc/config/arm/unspecs.md                          |   1 +
 gcc/doc/invoke.texi                                |  10 +-
 gcc/ginclude/unwind-arm-common.h                   |   4 +-
 gcc/testsuite/g++.dg/abi/forced.C                  |   2 +-
 gcc/testsuite/g++.dg/abi/guard2.C                  |   2 +-
 gcc/testsuite/g++.dg/cpp0x/noexcept03.C            |   2 +-
 gcc/testsuite/g++.dg/ext/cleanup-10.C              |   2 +-
 gcc/testsuite/g++.dg/ext/cleanup-11.C              |   2 +-
 gcc/testsuite/g++.dg/ext/cleanup-8.C               |   2 +-
 gcc/testsuite/g++.dg/ext/cleanup-9.C               |   2 +-
 gcc/testsuite/g++.dg/ext/sync-4.C                  |   2 +-
 gcc/testsuite/g++.dg/ipa/comdat.C                  |   2 +-
 gcc/testsuite/g++.dg/ipa/devirt-c-7.C              |   3 +-
 gcc/testsuite/g++.dg/ipa/ivinline-1.C              |   2 +-
 gcc/testsuite/g++.dg/ipa/ivinline-2.C              |   2 +-
 gcc/testsuite/g++.dg/ipa/ivinline-3.C              |   2 +-
 gcc/testsuite/g++.dg/ipa/ivinline-4.C              |   2 +-
 gcc/testsuite/g++.dg/ipa/ivinline-5.C              |   2 +-
 gcc/testsuite/g++.dg/ipa/ivinline-7.C              |   2 +-
 gcc/testsuite/g++.dg/ipa/ivinline-8.C              |   2 +-
 gcc/testsuite/g++.dg/ipa/ivinline-9.C              |   2 +-
 gcc/testsuite/g++.dg/other/anon5.C                 |   1 +
 gcc/testsuite/g++.dg/tls/pr79288.C                 |   2 +-
 gcc/testsuite/gcc.dg/20020312-2.c                  |   1 +
 gcc/testsuite/gcc.dg/20041106-1.c                  |   2 +-
 gcc/testsuite/gcc.dg/addr_equal-1.c                |   3 +-
 gcc/testsuite/gcc.dg/cleanup-10.c                  |   2 +-
 gcc/testsuite/gcc.dg/cleanup-11.c                  |   2 +-
 gcc/testsuite/gcc.dg/cleanup-8.c                   |   2 +-
 gcc/testsuite/gcc.dg/cleanup-9.c                   |   2 +-
 gcc/testsuite/gcc.dg/const-1.c                     |   2 +-
 gcc/testsuite/gcc.dg/fdata-sections-1.c            |   2 +-
 gcc/testsuite/gcc.dg/fdata-sections-2.c            |   2 +-
 gcc/testsuite/gcc.dg/ipa/pure-const-1.c            |   2 +-
 gcc/testsuite/gcc.dg/noreturn-8.c                  |   2 +-
 gcc/testsuite/gcc.dg/pr33826.c                     |   3 +-
 gcc/testsuite/gcc.dg/pr39323-1.c                   |   2 +-
 gcc/testsuite/gcc.dg/pr39323-2.c                   |   2 +-
 gcc/testsuite/gcc.dg/pr39323-3.c                   |   2 +-
 gcc/testsuite/gcc.dg/pr65780-1.c                   |   2 +-
 gcc/testsuite/gcc.dg/pr65780-2.c                   |   2 +-
 gcc/testsuite/gcc.dg/pr67338.c                     |   2 +-
 gcc/testsuite/gcc.dg/pr78185.c                     |   2 +-
 gcc/testsuite/gcc.dg/pr83100-1.c                   |   2 +-
 gcc/testsuite/gcc.dg/pr83100-4.c                   |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-12g.c               |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-14g.c               |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-14gf.c              |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-16g.c               |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-17g.c               |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-18g.c               |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-1f.c                |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-22g.c               |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-2f.c                |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-31g.c               |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-33g.c               |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-4g.c                |   2 +-
 gcc/testsuite/gcc.dg/strlenopt-4gf.c               |   2 +-
 gcc/testsuite/gcc.dg/strncmp-2.c                   |   2 +-
 gcc/testsuite/gcc.dg/struct-ret-3.c                |   2 +-
 gcc/testsuite/gcc.dg/torture/ipa-pta-1.c           |   2 +-
 gcc/testsuite/gcc.dg/torture/pr69760.c             |   2 +-
 gcc/testsuite/gcc.dg/tree-ssa/alias-2.c            |   2 +-
 gcc/testsuite/gcc.dg/tree-ssa/ipa-split-5.c        |   2 +-
 gcc/testsuite/gcc.dg/tree-ssa/loadpre6.c           |   2 +-
 gcc/testsuite/gcc.target/arm/20051215-1.c          |   1 +
 .../gcc.target/arm/armv6-unaligned-load-ice.c      |   1 +
 .../arm/atomic-comp-swap-release-acquire-3.c       |   1 +
 gcc/testsuite/gcc.target/arm/atomic-op-acq_rel-3.c |   1 +
 gcc/testsuite/gcc.target/arm/atomic-op-acquire-3.c |   1 +
 gcc/testsuite/gcc.target/arm/atomic-op-char-3.c    |   1 +
 gcc/testsuite/gcc.target/arm/atomic-op-consume-3.c |   1 +
 gcc/testsuite/gcc.target/arm/atomic-op-int-3.c     |   1 +
 gcc/testsuite/gcc.target/arm/atomic-op-relaxed-3.c |   1 +
 gcc/testsuite/gcc.target/arm/atomic-op-release-3.c |   1 +
 gcc/testsuite/gcc.target/arm/atomic-op-seq_cst-3.c |   1 +
 gcc/testsuite/gcc.target/arm/atomic-op-short-3.c   |   1 +
 .../gcc.target/arm/attr-unaligned-load-ice.c       |   1 +
 gcc/testsuite/gcc.target/arm/attr_arm-err.c        |   1 +
 gcc/testsuite/gcc.target/arm/data-rel-2.c          |   1 +
 gcc/testsuite/gcc.target/arm/data-rel-3.c          |   1 +
 gcc/testsuite/gcc.target/arm/div64-unwinding.c     |   2 +-
 gcc/testsuite/gcc.target/arm/eliminate.c           |   2 +-
 gcc/testsuite/gcc.target/arm/ftest-armv4-arm.c     |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv4t-arm.c    |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv4t-thumb.c  |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv5t-arm.c    |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv5t-thumb.c  |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv5te-arm.c   |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv5te-thumb.c |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv6-arm.c     |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv6-thumb.c   |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv6k-arm.c    |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv6k-thumb.c  |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv6m-thumb.c  |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv6t2-arm.c   |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv6t2-thumb.c |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv6z-arm.c    |   1 +
 gcc/testsuite/gcc.target/arm/ftest-armv6z-thumb.c  |   1 +
 gcc/testsuite/gcc.target/arm/g2.c                  |   1 +
 gcc/testsuite/gcc.target/arm/interrupt-1.c         |   6 +-
 gcc/testsuite/gcc.target/arm/interrupt-2.c         |   6 +-
 gcc/testsuite/gcc.target/arm/ivopts-2.c            |   2 +-
 gcc/testsuite/gcc.target/arm/ivopts-3.c            |   2 +-
 gcc/testsuite/gcc.target/arm/ivopts-4.c            |   2 +-
 gcc/testsuite/gcc.target/arm/ivopts-5.c            |   2 +-
 gcc/testsuite/gcc.target/arm/macro_defs1.c         |   1 +
 gcc/testsuite/gcc.target/arm/mmx-1.c               |   1 +
 gcc/testsuite/gcc.target/arm/pr19599.c             |   1 +
 gcc/testsuite/gcc.target/arm/pr40887.c             |   1 +
 gcc/testsuite/gcc.target/arm/pr43597.c             |   2 +-
 gcc/testsuite/gcc.target/arm/pr43698.c             |   4 +-
 gcc/testsuite/gcc.target/arm/pr43920-2.c           |   2 +-
 gcc/testsuite/gcc.target/arm/pr45701-1.c           |   4 +-
 gcc/testsuite/gcc.target/arm/pr45701-2.c           |   4 +-
 gcc/testsuite/gcc.target/arm/pr59858.c             |   1 +
 gcc/testsuite/gcc.target/arm/pr61948.c             |   1 +
 gcc/testsuite/gcc.target/arm/pr65647-2.c           |   1 +
 gcc/testsuite/gcc.target/arm/pr65647.c             |   1 +
 gcc/testsuite/gcc.target/arm/pr66912.c             |   2 +-
 gcc/testsuite/gcc.target/arm/pr70830.c             |   3 +-
 gcc/testsuite/gcc.target/arm/pr77933-1.c           |   1 +
 gcc/testsuite/gcc.target/arm/pr77933-2.c           |   1 +
 gcc/testsuite/gcc.target/arm/pr79058.c             |   1 +
 gcc/testsuite/gcc.target/arm/pr83712.c             |   1 +
 .../gcc.target/arm/pragma_arch_switch_2.c          |   1 +
 gcc/testsuite/gcc.target/arm/scd42-1.c             |   1 +
 gcc/testsuite/gcc.target/arm/scd42-2.c             |   1 +
 gcc/testsuite/gcc.target/arm/scd42-3.c             |   1 +
 gcc/testsuite/gcc.target/arm/sibcall-1.c           |   1 +
 gcc/testsuite/gcc.target/arm/stack-checking.c      |   2 +-
 gcc/testsuite/gcc.target/arm/stack-red-zone.c      |   2 +-
 gcc/testsuite/gcc.target/arm/synchronize.c         |   2 +-
 gcc/testsuite/gcc.target/arm/tail-long-call.c      |   1 +
 gcc/testsuite/gcc.target/arm/tlscall.c             |   1 +
 gcc/testsuite/gcc.target/arm/vfp-longcall-apcs.c   |   1 +
 gcc/testsuite/lib/target-supports.exp              |   4 +
 libatomic/configure                                |   8 +-
 libatomic/configure.tgt                            |   2 +-
 libgcc/config.host                                 |   4 +-
 libgcc/config/arm/linux-atomic.c                   |  38 ++
 libgcc/config/arm/unwind-arm.c                     |   5 +
 libgcc/config/arm/unwind-arm.h                     |  29 +-
 libgcc/crtstuff.c                                  |  16 +
 libgcc/unwind-arm-common.inc                       | 215 +++++++++
 libgcc/unwind-pe.h                                 |  17 +
 libitm/configure                                   |  20 +-
 libitm/configure.tgt                               |   2 +-
 libsanitizer/configure.tgt                         |   3 +
 libstdc++-v3/acinclude.m4                          |  12 +-
 libstdc++-v3/configure                             |  36 +-
 libstdc++-v3/configure.host                        |   6 +-
 libstdc++-v3/libsupc++/eh_personality.cc           |  10 +-
 libtool.m4                                         |  14 +-
 166 files changed, 1175 insertions(+), 210 deletions(-)
 create mode 100644 gcc/config/arm/uclinuxfdpiceabi.h

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