RE: [PATCH 0/9] Add new command to print the shadow stack backtrace

["Schimpe, Christina" <christina.schimpe@intel.com>]

Hi Thiago, 

I did not test the "bt shadow" command for ARM's GCS. Does the command make sense for GCS, too ?
If yes, does the implementation I shared here makes sense to you in general?

I tried to address the different Aarch and Intel behavior we discussed here
https://sourceware.org/pipermail/gdb-patches/2025-June/218947.html 
by introducing a new gdbarch hook top_addr_empty_shadow_stack.

Does that go into the right direction for your purposes?

Thanks,
Christina

> -----Original Message-----
> From: Christina Schimpe <christina.schimpe@intel.com>
> Sent: Tuesday, September 23, 2025 1:19 PM
> To: gdb-patches@sourceware.org
> Subject: [PATCH 0/9] Add new command to print the shadow stack backtrace
> 
> Hi all,
> 
> as already indicated in the discussion
> https://sourceware.org/pipermail/gdb/2023-December/051024.html
> I'd like to add a command to print the shadow stack backtrace.
> 
> In the discussion above the main conclusion was to use the ordinary backtrace
> command with a new flag: "bt -shadow".
> I chose a similar direction, but decided against the flag "-shadow"
> in favor of a new subcommand of the ordinary backtrace command:
> "bt shadow".
> 
> This is an example shadow stack backtrace on amd64:
> ~~~
> (gdb) bt shadow
> #0  0x000000000040111f in call1 at amd64-shadow-stack.c:14
> #1  0x000000000040112f in main at amd64-shadow-stack.c:21
> #2  0x00007ffff7c3fe70 in __libc_start_call_main at
> ../sysdeps/nptl/libc_start_call_main.h:58
> #3  0x00007ffff7c3ff20 in __libc_start_main_impl at ../csu/libc-start.c:128
> #4  0x0000000000401045 in _start
> ~~~
> 
> I am happy about your feedback!
> 
> Christina
> 
> 
> Christina Schimpe (9):
>   gdb: Generalize handling of the shadow stack pointer.
>   gdb: Refactor 'stack.c:print_frame'.
>   gdb: Introduce 'stack.c:print_pc' function without frame argument.
>   gdb: Refactor 'find_symbol_funname' and 'info_frame_command_core' in
>     stack.c.
>   gdb: Refactor 'stack.c:print_frame_info'.
>   gdb: Implement 'bt shadow' to print the shadow stack backtrace.
>   gdb: Provide gdbarch hook to distinguish shadow stack backtrace
>     elements.
>   gdb: Implement the hook 'is_no_return_shadow_stack_address' for amd64
>     linux.
>   gdb, mi: Add -shadow-stack-list-frames command
> 
>  gdb/Makefile.in                               |   2 +
>  gdb/NEWS                                      |  17 +
>  gdb/aarch64-linux-tdep.c                      |  51 +-
>  gdb/aarch64-tdep.c                            |  42 +-
>  gdb/amd64-linux-tdep.c                        | 164 ++---
>  gdb/amd64-tdep.c                              |  20 +
>  gdb/annotate.c                                |  93 ++-
>  gdb/annotate.h                                |  18 +-
>  gdb/doc/gdb.texinfo                           | 114 +++
>  gdb/gdbarch-gen.c                             | 158 ++++-
>  gdb/gdbarch-gen.h                             |  80 ++-
>  gdb/gdbarch.h                                 |   1 +
>  gdb/gdbarch_components.py                     | 100 ++-
>  gdb/infcall.c                                 |   4 +-
>  gdb/linux-tdep.c                              |   2 +
>  gdb/mi/mi-cmd-stack.c                         | 146 ++++
>  gdb/mi/mi-cmds.c                              |   2 +
>  gdb/mi/mi-cmds.h                              |   1 +
>  gdb/shadow-stack.c                            | 662 ++++++++++++++++++
>  gdb/shadow-stack.h                            | 106 +++
>  gdb/stack.c                                   | 382 ++++++----
>  gdb/stack.h                                   |  55 ++
>  .../amd64-shadow-stack-backtrace-signal.exp   |  54 ++
>  .../gdb.arch/amd64-shadow-stack-cmds.exp      |  88 +++
>  .../gdb.arch/amd64-shadow-stack-signal.c      |  31 +
>  gdb/testsuite/gdb.base/help.exp               |   6 +-
>  gdb/testsuite/gdb.base/options.exp            |   7 +-
>  .../gdb.mi/mi-shadow-stack-signal.exp         |  69 ++
>  gdb/testsuite/gdb.mi/mi-shadow-stack.exp      |  65 ++
>  29 files changed, 2105 insertions(+), 435 deletions(-)  create mode 100644
> gdb/shadow-stack.c  create mode 100644 gdb/shadow-stack.h  create mode
> 100644 gdb/testsuite/gdb.arch/amd64-shadow-stack-backtrace-signal.exp
>  create mode 100644 gdb/testsuite/gdb.arch/amd64-shadow-stack-signal.c
>  create mode 100644 gdb/testsuite/gdb.mi/mi-shadow-stack-signal.exp
>  create mode 100644 gdb/testsuite/gdb.mi/mi-shadow-stack.exp
> 
> --
> 2.34.1
> 
> Intel Deutschland GmbH
> Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
> Tel: +49 89 99 8853-0, www.intel.de
> Managing Directors: Sean Fennelly, Jeffrey Schneiderman, Tiffany Doon Silva
> Chairperson of the Supervisory Board: Nicole Lau Registered Office: Munich
> Commercial Register: Amtsgericht Muenchen HRB 186928

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de
Managing Directors: Sean Fennelly, Jeffrey Schneiderman, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928