Re: [PATCH v4 11/11] gdb: Enable displaced stepping with shadow stack on amd64 linux.

[Eli Zaretskii <eliz@gnu.org>]

> From: Christina Schimpe <christina.schimpe@intel.com>
> Cc: thiago.bauermann@linaro.org,
> 	eliz@gnu.org
> Date: Tue, 17 Jun 2025 12:11:47 +0000
> 
> This patch enables displaced stepping to support Intel's Control-Flow
> Enforcement Technology (CET), which provides the shadow stack feature
> for the x86 architecture.
> Following the restriction of the linux kernel, enable displaced stepping
> for amd64 only.
> 
> If displaced stepping is active and the single stepped instruction is a
> call instruction, the return address atop the stack is the address following
> the copied instruction.  However, to allow normal program execution it has
> to be the address following the original instruction.  Due to that reason,
> the return address is corrected in amd64_displaced_step_fixup and
> i386_displaced_step_fixup.
> 
> To avoid a control-protection exception if shadow stack is active,
> the shadow stack top address must be corrected as well.
> 
> Reviewed-By: Eli Zaretskii <eliz@gnu.org>
> ---
>  gdb/NEWS                                      |  3 +
>  gdb/amd64-linux-tdep.c                        | 16 +++-
>  gdb/amd64-tdep.c                              | 15 ++++
>  gdb/doc/gdb.texinfo                           | 11 ++-
>  gdb/i386-tdep.c                               | 15 ++++
>  .../gdb.arch/amd64-shadow-stack-disp-step.exp | 90 +++++++++++++++++++
>  6 files changed, 147 insertions(+), 3 deletions(-)
>  create mode 100644 gdb/testsuite/gdb.arch/amd64-shadow-stack-disp-step.exp

The NEWS part is okay, thanks.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>