Re: [PATCH v5 00/12] Add CET shadow stack support

[Luis Machado <luis.machado@arm.com>]

Hi Christina,

I went through v5 and I have no further comments.

I did try running the testsuite on my local x86-64 machine and noticed a couple additional failures for native gdb testing.

FAIL: gdb.base/gcore.exp: corefile restored general registers
FAIL: gdb.base/gcore.exp: corefile restored all registers

Have you seen those? The problem seems to be that the pl3_ssp register is showing up in a live session, but not in the core file.

pl3_ssp        <unavailable>

On 6/28/25 09:27, Christina Schimpe wrote:
> Hi all,
> 
> this is my v5 of the series to add amd64 shadow stack support to GDB on linux.
> It addresses the feedback of Luis.
> 
> v4 can be found here:
> https://sourceware.org/pipermail/gdb-patches/2025-June/218744.html
> 
> Changes since v4:
> - Improve some comments.
> - Change the test in "gdb: amd64 linux coredump support with shadow
>   stack." to also test core file generated by the linux kernel.  This
>   requires changes for the core_find procedure to save program output,
>   that have been implemented by Thiago already, so we include this part
>   of the patch in this series: "gdb, testsuite: Extend core_find procedure
>   to save program output.".  The test is now very similar to the test
>   implemented for Guarded Control Stack corefiles.  Thanks to Thiago for
>   providing the input here!
> 
> I am looking forward to your feedback!
> 
> Regards,
> 
> Christina
> 
> Christina Schimpe (12):
>   gdb, testsuite: Extend core_find procedure to save program output.
>   gdbserver: Add optional runtime register set type.
>   gdbserver: Add assert in x86_linux_read_description.
>   gdb: Sync up x86-gcc-cpuid.h with cpuid.h from gcc 14 branch.
>   gdb, gdbserver: Use xstate_bv for target description creation on x86.
>   gdb, gdbserver: Add support of Intel shadow stack pointer register.
>   gdb: amd64 linux coredump support with shadow stack.
>   gdb: Handle shadow stack pointer register unwinding for amd64 linux.
>   gdb, gdbarch: Enable inferior calls for shadow stack support.
>   gdb: Implement amd64 linux shadow stack support for inferior calls.
>   gdb, gdbarch: Introduce gdbarch method to get the shadow stack
>     pointer.
>   gdb: Enable displaced stepping with shadow stack on amd64 linux.
> 
>  gdb/NEWS                                      |   6 +
>  gdb/amd64-linux-nat.c                         |  17 ++
>  gdb/amd64-linux-tdep.c                        | 218 +++++++++++++++++-
>  gdb/amd64-tdep.c                              |  35 ++-
>  gdb/amd64-tdep.h                              |   9 +-
>  gdb/arch-utils.c                              |  10 +
>  gdb/arch-utils.h                              |   5 +
>  gdb/arch/amd64-linux-tdesc.c                  |  33 +--
>  gdb/arch/amd64-linux-tdesc.h                  |   7 +-
>  gdb/arch/amd64.c                              |  25 +-
>  gdb/arch/amd64.h                              |  10 +-
>  gdb/arch/i386-linux-tdesc.c                   |  29 +--
>  gdb/arch/i386-linux-tdesc.h                   |   5 +-
>  gdb/arch/i386.c                               |  19 +-
>  gdb/arch/i386.h                               |   8 +-
>  gdb/arch/x86-linux-tdesc-features.c           |  60 ++---
>  gdb/arch/x86-linux-tdesc-features.h           |  25 +-
>  gdb/doc/gdb.texinfo                           |  42 ++++
>  gdb/features/Makefile                         |   2 +
>  gdb/features/i386/32bit-ssp.c                 |  14 ++
>  gdb/features/i386/32bit-ssp.xml               |  11 +
>  gdb/features/i386/64bit-ssp.c                 |  14 ++
>  gdb/features/i386/64bit-ssp.xml               |  11 +
>  gdb/gdbarch-gen.c                             |  54 +++++
>  gdb/gdbarch-gen.h                             |  24 ++
>  gdb/gdbarch_components.py                     |  31 +++
>  gdb/i386-tdep.c                               |  51 +++-
>  gdb/i386-tdep.h                               |  11 +-
>  gdb/infcall.c                                 |  14 +-
>  gdb/linux-tdep.c                              |  47 ++++
>  gdb/linux-tdep.h                              |   7 +
>  gdb/nat/x86-gcc-cpuid.h                       | 153 +++++++++---
>  gdb/nat/x86-linux-tdesc.c                     |  20 +-
>  gdb/nat/x86-linux-tdesc.h                     |   7 +-
>  gdb/nat/x86-linux.c                           |  57 +++++
>  gdb/nat/x86-linux.h                           |   4 +
>  .../gdb.arch/amd64-shadow-stack-cmds.exp      | 141 +++++++++++
>  .../gdb.arch/amd64-shadow-stack-corefile.c    |  42 ++++
>  .../gdb.arch/amd64-shadow-stack-corefile.exp  | 110 +++++++++
>  .../gdb.arch/amd64-shadow-stack-disp-step.exp |  92 ++++++++
>  gdb/testsuite/gdb.arch/amd64-shadow-stack.c   |  35 +++
>  gdb/testsuite/gdb.arch/amd64-ssp.exp          |  50 ++++
>  .../gdb.base/inline-frame-cycle-unwind.py     |   4 +
>  gdb/testsuite/lib/gdb.exp                     |  80 ++++++-
>  gdb/x86-linux-nat.c                           |  50 +++-
>  gdb/x86-linux-nat.h                           |  11 +
>  gdb/x86-tdep.c                                |  21 ++
>  gdb/x86-tdep.h                                |   9 +
>  gdbserver/i387-fp.cc                          |  40 ++--
>  gdbserver/linux-amd64-ipa.cc                  |  10 +-
>  gdbserver/linux-i386-ipa.cc                   |   6 +-
>  gdbserver/linux-low.cc                        |  50 ++--
>  gdbserver/linux-low.h                         |   7 +-
>  gdbserver/linux-x86-low.cc                    |  44 +++-
>  gdbsupport/x86-xstate.h                       |   7 +-
>  55 files changed, 1687 insertions(+), 217 deletions(-)
>  create mode 100644 gdb/features/i386/32bit-ssp.c
>  create mode 100644 gdb/features/i386/32bit-ssp.xml
>  create mode 100644 gdb/features/i386/64bit-ssp.c
>  create mode 100644 gdb/features/i386/64bit-ssp.xml
>  create mode 100644 gdb/testsuite/gdb.arch/amd64-shadow-stack-cmds.exp
>  create mode 100644 gdb/testsuite/gdb.arch/amd64-shadow-stack-corefile.c
>  create mode 100644 gdb/testsuite/gdb.arch/amd64-shadow-stack-corefile.exp
>  create mode 100644 gdb/testsuite/gdb.arch/amd64-shadow-stack-disp-step.exp
>  create mode 100644 gdb/testsuite/gdb.arch/amd64-shadow-stack.c
>  create mode 100644 gdb/testsuite/gdb.arch/amd64-ssp.exp
>