[PATCH 00/23] Memory Tagging Support + AArch64 Linux implementation
Alan Hayward
Alan.Hayward@arm.com
Thu Jul 16 16:49:52 GMT 2020
> On 15 Jul 2020, at 20:44, Luis Machado <luis.machado@linaro.org> wrote:
>
> This patch series implements general memory tagging support for GDB, as well
> as an implementation for AArch64 Linux.
>
> 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.
I’ve reviewed earlier versions of this series, and my comments have been applied.
I’ve still taken a look through each patch in this latest series, and I’m mostly
happy now. Instead of replying to each patch in turn, these are my bulk set of
comments:
[PATCH 01/23] New target methods for memory tagging support
[PATCH 02/23] New gdbarch memory tagging hooks
- Looks good to me.
[PATCH 03/23] Add GDB-side remote target support for memory tagging
[PATCH 04/23] Unit testing for GDB-side remote memory tagging handling
[PATCH 05/23] GDBserver remote packet support for memory tagging
[PATCH 06/23] Unit tests for gdbserver memory tagging remote packets
[PATCH 07/23] Documentation for memory tagging remote packets
- Looks ok, but I’m not that familiar with the remote packet interface.
Worth someone else looking over.
[PATCH 08/23] AArch64: Add MTE CPU feature check support
[PATCH 09/23] AArch64: Add target description/feature for MTE registers
[PATCH 10/23] AArch64: Add MTE register set support for GDB and gdbserver
[PATCH 11/23] AArch64: Add MTE ptrace requests
[PATCH 12/23] AArch64: Implement memory tagging target methods for AArch64
[PATCH 13/23] Refactor parsing of /proc/<pid>/smaps
[PATCH 14/23] AArch64: Implement the memory tagging gdbarch hooks
[PATCH 15/23] AArch64: Add unit testing for logical tag set/get operations
[PATCH 16/23] AArch64: Report tag violation error information
[PATCH 17/23] AArch64: Add gdbserver MTE support
- These all Look good to me. My only concern here is that the Linux kernel support
is a WIP. But given GDB is the main user of these interfaces, and that you’ve been
reviewing the Linux patches, then I’m happy as long as they have all been tested
together.
[PATCH 18/23] New mtag commands
[PATCH 19/23] Documentation for the new mtag commands
- I’m happy with the new commands. But would like to know what others think, and
I’m not familiar enough with the implementation of the commands to do a detailed
review.
[PATCH 20/23] Extend "x" and "print" commands to support memory tagging
- Am I correct in thinking that p/x cannot cause a segfault? (we don’t want
one to happen)
[PATCH 21/23] Document new "x" and "print" memory tagging extensions
[PATCH 22/23] Add NEWS entry.
- Looks good (assuming the commands aren’t changed)
>
> Luis Machado (23):
> 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
> 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 | 121 ++++++-
> gdb/aarch64-linux-tdep.c | 330 ++++++++++++++++-
> 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 | 174 ++++++++-
> 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 | 356 ++++++++++++-------
> 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 | 230 ++++++++++++
> gdb/target-delegates.c | 84 +++++
> gdb/target.h | 25 ++
> 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 | 89 ++++-
> gdbserver/linux-aarch64-tdesc.cc | 10 +-
> gdbserver/linux-aarch64-tdesc.h | 3 +-
> gdbserver/remote-utils.cc | 40 +--
> gdbserver/remote-utils.h | 2 +
> gdbserver/server.cc | 214 +++++++++++
> gdbserver/server.h | 3 +
> gdbserver/target.cc | 20 ++
> gdbserver/target.h | 17 +
> gdbsupport/rsp-low.cc | 2 +-
> include/elf/common.h | 3 +
> 49 files changed, 3421 insertions(+), 182 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
>
> --
> 2.17.1
>
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