Re: [PATCH v2 1/9] gdb: Generalize handling of the shadow stack pointer.

[Thiago Jung Bauermann <thiago.bauermann@linaro.org>]

Hello Christina,

Thank you for addressing my review comments! Just a couple of comments:

Christina Schimpe <christina.schimpe@intel.com> writes:

> +static bool
> +amd64_linux_top_addr_empty_shadow_stack
> +  (gdbarch *gdbarch, const CORE_ADDR addr,
> +   const std::pair<CORE_ADDR, CORE_ADDR> range)
>  {
> -  if (regnum == gdbarch_pc_regnum (gdbarch))
> -    reg->how = DWARF2_FRAME_REG_RA;
> -  else if (regnum == gdbarch_sp_regnum (gdbarch))
> -    reg->how = DWARF2_FRAME_REG_CFA;
> -  else if (regnum == AMD64_PL3_SSP_REGNUM)
> -    {
> -      reg->how = DWARF2_FRAME_REG_FN;
> -      reg->loc.fn = amd64_linux_dwarf2_prev_ssp;
> -    }
> +  return addr == range.second;
>  }

Next week I'll provide the AArch64 implementation of this hook,
if you can squash it into your patch.

> diff --git a/gdb/shadow-stack.c b/gdb/shadow-stack.c
> new file mode 100644
> index 00000000000..77d7c07d970
> --- /dev/null
> +++ b/gdb/shadow-stack.c
> @@ -0,0 +1,166 @@
> +/* Manage a shadow stack pointer for GDB, the GNU debugger.
> +
> +   Copyright (C) 2024-2026 Free Software Foundation, Inc.
> +   This file is part of GDB.
> +
> +   This program is free software; you can redistribute it and/or modify
> +   it under the terms of the GNU General Public License as published by
> +   the Free Software Foundation; either version 3 of the License, or
> +   (at your option) any later version.
> +
> +   This program is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +   GNU General Public License for more details.
> +
> +   You should have received a copy of the GNU General Public License
> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
> +
> +#include "defs.h"
> +#include "arch-utils.h"
> +#include "gdbcore.h"
> +#include "extract-store-integer.h"
> +#include "frame.h"
> +#include "frame-unwind.h"
> +#include "shadow-stack.h"
> +
> +class regcache;

This forward declaration should be in shadow-stack.h, since the
shadow_stack_push prototype declared there uses it.

-- 
Thiago