Re: [PATCH v3 00/24] Memory Tagging Support + AArch64 Linux implementation

[Alan Hayward via Gdb-patches <gdb-patches@sourceware.org>]

As mentioned previously, I’m happy with this series.
Approved for the AArch64 parts and the other parts look good to me.

It would be nice to get approval for this as it’ll be really crucial to have
available for when the hardware starts rolling out. I suspect memory tagging
is going cause to lots of bugs in the early days of it being used.


Alan.


> On 7 Dec 2020, at 13:17, Luis Machado <luis.machado@linaro.org> wrote:
> 
> Ping v4.
> 
> On 11/30/20 10:38 AM, Luis Machado wrote:
>> Ping v3. Is there any other feedback on this series or should I take it that the current version looks good (with the suggested fixes)?
>> Thanks,
>> Luis
>> On 11/23/20 1:08 PM, Luis Machado wrote:
>>> Ping v2?
>>> 
>>> On 11/16/20 10:48 AM, Luis Machado wrote:
>>>> Ping?
>>>> 
>>>> FTR, I'm aiming at having this ready for GDB 11.
>>>> 
>>>> On 11/9/20 2:04 PM, Luis Machado wrote:
>>>>> Here's v3 of this patch series.
>>>>> 
>>>>> Memory tagging improves memory safety by tagging various parts of memory and
>>>>> raising exceptions when the allocation tag (the one associated with a range of
>>>>> memory addresses) does not match the logical tag contained in a pointer that is
>>>>> used to access the memory area.
>>>>> 
>>>>> We already have an implementation of such a mechanism for sparc64 (ADI), but
>>>>> it is target-specific and not exposed to the rest of GDB. This series aims to
>>>>> make the infrastructure available to other targets that may wish to support
>>>>> their specific memory tagging approaches. For AArch64 Linux this is called
>>>>> MTE (Memory Tagging Extensions).
>>>>> 
>>>>> The series is split into a set that deals with generic changes to GDB's
>>>>> infrastructure (target methods, gdbarch hooks and remote packets), a set that
>>>>> implements support for AArch64 Linux and one last set that implements new
>>>>> commands, updates the documentation and adds tests.
>>>>> 
>>>>> The goal is to make it so the architecture independent parts of GDB don't
>>>>> need to interpret tag formats, given the formats are likely different
>>>>> for each architecture.  For this reason, GDB will handle tags as a sequence of
>>>>> bytes and will not assume a particular format.
>>>>> 
>>>>> The architecture-specific code can handle the sequence of bytes appropriately.
>>>>> 
>>>>> Luis Machado (24):
>>>>>    New target methods for memory tagging support
>>>>>    New gdbarch memory tagging hooks
>>>>>    Add GDB-side remote target support for memory tagging
>>>>>    Unit testing for GDB-side remote memory tagging handling
>>>>>    GDBserver remote packet support for memory tagging
>>>>>    Unit tests for gdbserver memory tagging remote packets
>>>>>    Documentation for memory tagging remote packets
>>>>>    AArch64: Add MTE CPU feature check support
>>>>>    AArch64: Add target description/feature for MTE registers
>>>>>    AArch64: Add MTE register set support for GDB and gdbserver
>>>>>    AArch64: Add MTE ptrace requests
>>>>>    AArch64: Implement memory tagging target methods for AArch64
>>>>>    Refactor parsing of /proc/<pid>/smaps
>>>>>    AArch64: Implement the memory tagging gdbarch hooks
>>>>>    AArch64: Add unit testing for logical tag set/get operations
>>>>>    AArch64: Report tag violation error information
>>>>>    AArch64: Add gdbserver MTE support
>>>>>    AArch64: Add MTE register set support for core files
>>>>>    New mtag commands
>>>>>    Documentation for the new mtag commands
>>>>>    Extend "x" and "print" commands to support memory tagging
>>>>>    Document new "x" and "print" memory tagging extensions
>>>>>    Add NEWS entry.
>>>>>    Add memory tagging testcases
>>>>> 
>>>>>   gdb/Makefile.in                        |   3 +
>>>>>   gdb/NEWS                               |  32 ++
>>>>>   gdb/aarch64-linux-nat.c                | 129 ++++++-
>>>>>   gdb/aarch64-linux-tdep.c               | 334 +++++++++++++++++-
>>>>>   gdb/aarch64-linux-tdep.h               |   3 +
>>>>>   gdb/aarch64-tdep.c                     |  40 ++-
>>>>>   gdb/aarch64-tdep.h                     |  12 +-
>>>>>   gdb/arch-utils.c                       |  50 +++
>>>>>   gdb/arch-utils.h                       |  23 ++
>>>>>   gdb/arch/aarch64-mte-linux.c           |  70 ++++
>>>>>   gdb/arch/aarch64-mte-linux.h           |  66 ++++
>>>>>   gdb/arch/aarch64.c                     |   7 +-
>>>>>   gdb/arch/aarch64.h                     |   7 +-
>>>>>   gdb/configure.nat                      |   3 +-
>>>>>   gdb/configure.tgt                      |   1 +
>>>>>   gdb/doc/gdb.texinfo                    | 215 +++++++++++-
>>>>>   gdb/features/Makefile                  |   1 +
>>>>>   gdb/features/aarch64-mte.c             |  14 +
>>>>>   gdb/features/aarch64-mte.xml           |  11 +
>>>>>   gdb/gdbarch.c                          | 137 ++++++++
>>>>>   gdb/gdbarch.h                          |  53 +++
>>>>>   gdb/gdbarch.sh                         |  36 ++
>>>>>   gdb/linux-tdep.c                       | 358 ++++++++++++-------
>>>>>   gdb/linux-tdep.h                       |   4 +
>>>>>   gdb/nat/aarch64-mte-linux-ptrace.c     | 200 +++++++++++
>>>>>   gdb/nat/aarch64-mte-linux-ptrace.h     |  50 +++
>>>>>   gdb/printcmd.c                         | 468 ++++++++++++++++++++++++-
>>>>>   gdb/remote.c                           | 232 ++++++++++++
>>>>>   gdb/target-delegates.c                 |  84 +++++
>>>>>   gdb/target.h                           |  37 ++
>>>>>   gdb/testsuite/gdb.arch/aarch64-mte.c   | 107 ++++++
>>>>>   gdb/testsuite/gdb.arch/aarch64-mte.exp | 371 ++++++++++++++++++++
>>>>>   gdb/testsuite/gdb.base/memtag.c        |  22 ++
>>>>>   gdb/testsuite/gdb.base/memtag.exp      |  64 ++++
>>>>>   gdb/testsuite/lib/gdb.exp              |  16 +
>>>>>   gdb/valprint.h                         |   1 +
>>>>>   gdbserver/Makefile.in                  |   1 +
>>>>>   gdbserver/configure.srv                |   2 +
>>>>>   gdbserver/linux-aarch64-ipa.cc         |   8 +-
>>>>>   gdbserver/linux-aarch64-low.cc         |  97 ++++-
>>>>>   gdbserver/linux-aarch64-tdesc.cc       |  10 +-
>>>>>   gdbserver/linux-aarch64-tdesc.h        |   3 +-
>>>>>   gdbserver/remote-utils.cc              |  43 ++-
>>>>>   gdbserver/remote-utils.h               |   7 +-
>>>>>   gdbserver/server.cc                    | 245 +++++++++++++
>>>>>   gdbserver/server.h                     |   3 +
>>>>>   gdbserver/target.cc                    |  20 ++
>>>>>   gdbserver/target.h                     |  17 +
>>>>>   gdbsupport/rsp-low.cc                  |   2 +-
>>>>>   include/elf/common.h                   |   3 +
>>>>>   50 files changed, 3536 insertions(+), 186 deletions(-)
>>>>>   create mode 100644 gdb/arch/aarch64-mte-linux.c
>>>>>   create mode 100644 gdb/arch/aarch64-mte-linux.h
>>>>>   create mode 100644 gdb/features/aarch64-mte.c
>>>>>   create mode 100644 gdb/features/aarch64-mte.xml
>>>>>   create mode 100644 gdb/nat/aarch64-mte-linux-ptrace.c
>>>>>   create mode 100644 gdb/nat/aarch64-mte-linux-ptrace.h
>>>>>   create mode 100644 gdb/testsuite/gdb.arch/aarch64-mte.c
>>>>>   create mode 100644 gdb/testsuite/gdb.arch/aarch64-mte.exp
>>>>>   create mode 100644 gdb/testsuite/gdb.base/memtag.c
>>>>>   create mode 100644 gdb/testsuite/gdb.base/memtag.exp
>>>>>