On 29/08/2019 15:57, Christophe Lyon wrote: > Hi, > > On 15/05/2019 14:39, Christophe Lyon wrote: >> 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 a few >> months ago. [4][5][6] >> >> This series provides support for architectures that support ARM and/or >> Thumb-2 and has been tested on arm-linux-gnueabi without regression, >> as well as arm-uclinuxfdpiceabi, using QEMU. arm-uclinuxfdpiceabi has >> a few more failures than arm-linux-gnueabi, but is quite functional. >> >> I have also booted an STM32 board (stm32f469) which uses a cortex-m4 >> with linux-4.20.17 and ran successfully several tools. >> >> Are the GCC patches OK for inclusion in master? >> > I have addressed the comments I received on v5, and I am going to post updated versions of the patches that needed changes as follow-ups in this thread. I hope this will help reviewers as I will provide answers and updated patches next to their comments. After that, I will rebase the whole series and send it as v6 if that helps (several testsuite patches have already been approved as-is, but committing them now would change the patch numbering, thus possibly confusing reviewers). > > However, note that several patches in the series haven't received feedback yet, so this is a ping for them :-) > [ARM/FDPIC v5 06/21] [ARM] FDPIC: Add support for c++ exceptions > [ARM/FDPIC v5 10/21] [ARM] FDPIC: Implement TLS support. > [ARM/FDPIC v5 11/21] [ARM] FDPIC: Add support to unwind FDPIC signal frame > [ARM/FDPIC v5 12/21] [ARM] FDPIC: Restore r9 after we call __aeabi_read_tp > [ARM/FDPIC v5 13/21] [ARM] FDPIC: Force LSB bit for PC in Cortex-M architecture > I forgot to mention that I found a problem in libitm's sjlj.S, worth this additional patch. Christophe > Thanks, > > Christophe > >> Changes between v4 and v5: >> - rebased on top of recent gcc-10 master (April 26th, 2019) >> - fixed handling of stack-protector combined patterns in FDPIC mode >> >> Changes between v3 and v4: >> >> - improved documentation (patch 1) >> - emit an error message (sorry) if the target architecture does not >>    support arm nor thumb-2 modes (patch 4) >> - handle Richard's comments on patch 4 (comments, unspec) >> - added .align directive (patch 5) >> - fixed use of kernel helpers (__kernel_cmpxchg, __kernel_dmb) (patch 6) >> - code factorization in patch 7 >> - typos/internal function name in patch 8 >> - improved patch 12 >> - dropped patch 16 >> - patch 20 introduces arm_arch*_thumb_ok effective targets to help >>    skip some tests >> - I tested patch 2 on xtensa-buildroot-uclinux-uclibc, it adds many >>    new tests, but a few regressions >>    (https://gcc.gnu.org/ml/gcc-patches/2018-11/msg00713.html) >> - I compiled and executed several LTP tests to exercise pthreads and signals >> - I wrote and executed a simple testcase to change the interaction >>    with __kernel_cmpxchg (ie. call the kernel helper rather than use an >>    implementation in libgcc as requested by Richard) >> >> 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 read-only >>    [ARM] FDPIC: Enforce 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 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 architectures unsupported by >>      FDPIC >>    [ARM] FDPIC: Handle stack-protector combined patterns >> >>   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                               | 485 ++++++++++++++++++--- >>   gcc/config/arm/arm.h                               |  16 +- >>   gcc/config/arm/arm.md                              | 151 ++++++- >>   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                                |  20 +- >>   gcc/ginclude/unwind-arm-common.h                   |   2 +- >>   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.c-torture/compile/pr82096.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 + >>   .../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/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              |  10 + >>   libatomic/configure                                |   8 +- >>   libatomic/configure.tgt                            |   2 +- >>   libgcc/config.host                                 |   4 +- >>   libgcc/config/arm/linux-atomic.c                   |  55 ++- >>   libgcc/config/arm/unwind-arm.c                     |   5 + >>   libgcc/config/arm/unwind-arm.h                     |  31 +- >>   libgcc/crtstuff.c                                  |  18 + >>   libgcc/unwind-arm-common.inc                       | 216 +++++++++ >>   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 +- >>   156 files changed, 1233 insertions(+), 219 deletions(-) >>   create mode 100644 gcc/config/arm/uclinuxfdpiceabi.h >> >