Re: [PATCH v2 0/9] Add MTE stubs for aarch64 user mode

["Alex Bennée" <alex.bennee@linaro.org>]

Gustavo Romero <gustavo.romero@linaro.org> writes:

> This patchset adds the stubs necessary to support GDB memory tagging
> commands on QEMU aarch64 user mode.
>
> These new stubs handle the qIsAddressTagged, qMemTag, and QMemTag
> packets, which allow GDB memory tagging subcommands 'check',
> 'print-allocation-tag', and 'set-allocation-tag' to work. The remaining
> memory tagging commands ('print-logical-tag' and 'with-logical-tag')
> will also work, but they don't rely on any stub because they perform
> local operations.
>
> Since the memory tagging stubs are not common to all architectures, this
> patchset also introduces three functions: gdb_extend_qsupported_features,
> gdb_extend_query_table, and gdb_extend_set_table. These functions can be
> used to extend the target-specific 'qSupported' feature string and the
> handlers for the 'q' (query) and 'Q' (set) packets. These new functions
> are used to add the MTE stubs for the aarch64 gdbstub.
>  
> Note that this patchset requires a GDB that supports the
> qIsAddressTagged packet (recently added to GDB), so the gdbstub MTE
> tests introduced by it must be run using GDB's master branch, since the
> GDB in the distros hasn't picked up the change yet.
>
> Once GDB is built and installed locally, the tests can be exercised, for
> example, this way:
>
> make GDB=~/.local/bin/gdb run-tcg-tests-aarch64-linux-user -j 32

It looks like there might be some BSD build failures as well:

  https://gitlab.com/stsquad/qemu/-/pipelines/1332635371/failures

>
> v2:
>  - Addressed comments from Richard, Phil, and Alex
>  - Made the series more granular by splitting it into more patches
>  - Moved gdbstub command-specific structs and functions into a new header, gdbstub/commands.h
>  - Fixed exception in allocation_tag_mem_probe()
>  - Used MTE helpers ({store,load}_tag1 and allocation_tag_mem_probe) in the MTE stubs
>  - Factored out MTE code to set TCF0, avoiding duplication (both prctl and gdbstub code use it)
>  - Hoisted sscanf() out of loop in handle_Q_memtag stub and use gdb_hextomem instead
>  - Rebased this series on Alex's gdb/next branch
>
>
> Cheers,
> Gustavo
>
> Gustavo Romero (9):
>   gdbstub: Clean up process_string_cmd
>   gdbstub: Move GdbCmdParseEntry into a new header file
>   gdbstub: Add support for target-specific stubs
>   target/arm: Fix exception case in allocation_tag_mem_probe
>   target/arm: Make some MTE helpers widely available
>   target/arm: Factor out code for setting MTE TCF0 field
>   gdbstub: Make get cpu and hex conversion functions non-internal
>   gdbstub: Add support for MTE in user mode
>   tests/tcg/aarch64: Add MTE gdbstub tests
>
>  configs/targets/aarch64-linux-user.mak |   2 +-
>  gdb-xml/aarch64-mte.xml                |  11 ++
>  gdbstub/gdbstub.c                      | 211 +++++++++++----------
>  gdbstub/internals.h                    |  24 ---
>  gdbstub/syscalls.c                     |   7 +-
>  gdbstub/system.c                       |   7 +-
>  gdbstub/user-target.c                  |  25 +--
>  gdbstub/user.c                         |   7 +-
>  include/exec/gdbstub.h                 |   5 +
>  include/gdbstub/commands.h             | 102 ++++++++++
>  linux-user/aarch64/target_prctl.h      |  22 +--
>  target/arm/cpu.c                       |   1 +
>  target/arm/gdbstub.c                   | 253 +++++++++++++++++++++++++
>  target/arm/internals.h                 |   2 +
>  target/arm/mte.h                       |  53 ++++++
>  target/arm/tcg/mte_helper.c            | 181 +-----------------
>  target/arm/tcg/mte_helper.h            | 211 +++++++++++++++++++++
>  tests/tcg/aarch64/Makefile.target      |  11 +-
>  tests/tcg/aarch64/gdbstub/test-mte.py  |  86 +++++++++
>  tests/tcg/aarch64/mte-8.c              | 102 ++++++++++
>  20 files changed, 975 insertions(+), 348 deletions(-)
>  create mode 100644 gdb-xml/aarch64-mte.xml
>  create mode 100644 include/gdbstub/commands.h
>  create mode 100644 target/arm/mte.h
>  create mode 100644 target/arm/tcg/mte_helper.h
>  create mode 100644 tests/tcg/aarch64/gdbstub/test-mte.py
>  create mode 100644 tests/tcg/aarch64/mte-8.c

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro