[PATCH v4 1/6] GDB: Add aarch64-pauth-linux.h to gdb/arch/ and gdb/nat/

Thiago Jung Bauermann
2026-03-03T05:07:50Z

The code supporting Pointer Authentication duplicates the definition of
AARCH64_HWCAP_PACA and of AARCH64_LINUX_SIZEOF_PAUTH between GDB and
gdbserver, so add two new headers to host those definitions.

The target-dependant code should use AARCH64_HWCAP_PACA in
gdb/arch/aarch64-pauth-linux.h while native code should use HWCAP_PACA,
which will hopefully be defined by the system headers but with a backup
definition in gdb/nat/aarch64-pauth-linux.h if it isn't.

Suggested-by: Luis <luis.machado.foss@gmail.com>
Suggested-by: Simon Marchi <simark@simark.ca>
---
Changes since v3:
- Also create gdb/nat/aarch64-pauth-linux.h header.
- Keep AARCH64_HWCAP_PACA untouched.

gdb/Makefile.in | 2 ++
gdb/aarch64-linux-nat.c | 3 ++-
gdb/aarch64-linux-tdep.c | 1 +
gdb/aarch64-linux-tdep.h | 6 ------
gdb/arch/aarch64-pauth-linux.h | 29 +++++++++++++++++++++++++++++
gdb/arch/aarch64.h | 3 ---
gdb/nat/aarch64-pauth-linux.h | 26 ++++++++++++++++++++++++++
gdbserver/linux-aarch64-low.cc | 9 ++++-----
8 files changed, 64 insertions(+), 15 deletions(-)
create mode 100644 gdb/arch/aarch64-pauth-linux.h
create mode 100644 gdb/nat/aarch64-pauth-linux.h

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 2aa95be968ac..a412f3b3c592 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -1306,6 +1306,7 @@ HFILES_NO_SRCDIR = \
arch/aarch64-insn.h \
arch/aarch64-mte.h \
arch/aarch64-mte-linux.h \
+ arch/aarch64-pauth-linux.h \
arch/aarch64-scalable-linux.h \
arch/amd64.h \
arch/amd64-linux-tdesc.h \
@@ -1549,6 +1550,7 @@ HFILES_NO_SRCDIR = \
nat/aarch64-linux.h \
nat/aarch64-linux-hw-point.h \
nat/aarch64-mte-linux-ptrace.h \
+ nat/aarch64-pauth-linux.h \
nat/aarch64-scalable-linux-ptrace.h \
nat/aarch64-scalable-linux-sigcontext.h \
nat/amd64-linux.h \
diff --git a/gdb/aarch64-linux-nat.c b/gdb/aarch64-linux-nat.c
index 028de981588b..f64cc0a97d88 100644
--- a/gdb/aarch64-linux-nat.c
+++ b/gdb/aarch64-linux-nat.c
@@ -34,6 +34,7 @@
#include "arch/arm.h"
#include "nat/aarch64-linux.h"
#include "nat/aarch64-linux-hw-point.h"
+#include "nat/aarch64-pauth-linux.h"
#include "nat/aarch64-scalable-linux-ptrace.h"

#include "elf/external.h"
@@ -1012,7 +1013,7 @@ aarch64_linux_nat_target::read_description ()
or the streaming vector length, depending on whether streaming mode is
active or not. */
features.vq = aarch64_sve_get_vq (tid);
- features.pauth = hwcap & AARCH64_HWCAP_PACA;
+ features.pauth = hwcap & HWCAP_PACA;
features.gcs = features.gcs_linux = hwcap & HWCAP_GCS;
features.mte = hwcap2 & HWCAP2_MTE;
features.tls = aarch64_tls_register_count (tid);
diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
index b85c25ecae1d..d3d4c9e1de38 100644
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -54,6 +54,7 @@
#include "arch/aarch64-gcs-linux.h"
#include "arch/aarch64-mte.h"
#include "arch/aarch64-mte-linux.h"
+#include "arch/aarch64-pauth-linux.h"
#include "arch/aarch64-scalable-linux.h"

#include "arch-utils.h"
diff --git a/gdb/aarch64-linux-tdep.h b/gdb/aarch64-linux-tdep.h
index e926687ff6eb..b99fe91f36bd 100644
--- a/gdb/aarch64-linux-tdep.h
+++ b/gdb/aarch64-linux-tdep.h
@@ -33,16 +33,10 @@
alignment. */
#define AARCH64_LINUX_SIZEOF_FPREGSET (33 * V_REGISTER_SIZE)

-/* The pauth regset consists of 2 X sized registers. */
-#define AARCH64_LINUX_SIZEOF_PAUTH (2 * X_REGISTER_SIZE)
-
/* The MTE regset consists of a 64-bit register. */
#define AARCH64_LINUX_SIZEOF_MTE_REGSET (8)

extern const struct regset aarch64_linux_gregset;
extern const struct regset aarch64_linux_fpregset;

-/* Matches HWCAP_PACA in kernel header arch/arm64/include/uapi/asm/hwcap.h. */
-#define AARCH64_HWCAP_PACA (1 << 30)
-
#endif /* GDB_AARCH64_LINUX_TDEP_H */
diff --git a/gdb/arch/aarch64-pauth-linux.h b/gdb/arch/aarch64-pauth-linux.h
new file mode 100644
index 000000000000..4174dc3a9ded
--- /dev/null
+++ b/gdb/arch/aarch64-pauth-linux.h
@@ -0,0 +1,29 @@
+/* Common Linux target-dependent definitions for AArch64 PAuth.
+
+ Copyright (C) 2019-2026 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/>. */
+
+#ifndef GDB_ARCH_AARCH64_PAUTH_LINUX_H
+#define GDB_ARCH_AARCH64_PAUTH_LINUX_H
+
+/* Feature check for Pointer Authentication Code Extension. */
+#define AARCH64_HWCAP_PACA (1 << 30)
+
+/* The pauth regset consists of 2 64-bit registers. */
+#define AARCH64_LINUX_SIZEOF_PAUTH 16
+
+#endif /* GDB_ARCH_AARCH64_PAUTH_LINUX_H */
diff --git a/gdb/arch/aarch64.h b/gdb/arch/aarch64.h
index 0e9715a4268a..7856d95a93b1 100644
--- a/gdb/arch/aarch64.h
+++ b/gdb/arch/aarch64.h
@@ -178,9 +178,6 @@ enum aarch64_regnum
#define AARCH64_PAUTH_DMASK_HIGH_REGNUM(pauth_reg_base) (pauth_reg_base + 2)
#define AARCH64_PAUTH_CMASK_HIGH_REGNUM(pauth_reg_base) (pauth_reg_base + 3)

-/* This size is only meant for Linux, not bare metal. QEMU exposes 4 masks. */
-#define AARCH64_PAUTH_REGS_SIZE (16)
-
#define AARCH64_X_REGS_NUM 31
#define AARCH64_V_REGS_NUM 32
#define AARCH64_SVE_Z_REGS_NUM AARCH64_V_REGS_NUM
diff --git a/gdb/nat/aarch64-pauth-linux.h b/gdb/nat/aarch64-pauth-linux.h
new file mode 100644
index 000000000000..5ce85fb296c4
--- /dev/null
+++ b/gdb/nat/aarch64-pauth-linux.h
@@ -0,0 +1,26 @@
+/* Common Linux native definitions for AArch64 PAuth.
+
+ Copyright (C) 2019-2026 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/>. */
+
+#ifndef GDB_NAT_AARCH64_PAUTH_LINUX_H
+#define GDB_NAT_AARCH64_PAUTH_LINUX_H
+
+/* Feature check for Pointer Authentication Code Extension. */
+#define HWCAP_PACA (1 << 30)
+
+#endif /* GDB_NAT_AARCH64_PAUTH_LINUX_H */
diff --git a/gdbserver/linux-aarch64-low.cc b/gdbserver/linux-aarch64-low.cc
index b19e605f55d6..07ddfb324466 100644
--- a/gdbserver/linux-aarch64-low.cc
+++ b/gdbserver/linux-aarch64-low.cc
@@ -22,6 +22,7 @@
#include "linux-low.h"
#include "nat/aarch64-linux.h"
#include "nat/aarch64-linux-hw-point.h"
+#include "nat/aarch64-pauth-linux.h"
#include "arch/aarch64-insn.h"
#include "linux-aarch32-low.h"
#include "elf/common.h"
@@ -41,6 +42,7 @@
#include "arch/aarch64.h"
#include "arch/aarch64-gcs-linux.h"
#include "arch/aarch64-mte-linux.h"
+#include "arch/aarch64-pauth-linux.h"
#include "arch/aarch64-scalable-linux.h"
#include "linux-aarch32-tdesc.h"
#include "linux-aarch64-tdesc.h"
@@ -952,7 +954,7 @@ aarch64_adjust_register_sets (const struct aarch64_features &features)
break;
case NT_ARM_PAC_MASK:
if (features.pauth)
- regset->size = AARCH64_PAUTH_REGS_SIZE;
+ regset->size = AARCH64_LINUX_SIZEOF_PAUTH;
break;
case NT_ARM_TAGGED_ADDR_CTRL:
if (features.mte)
@@ -984,9 +986,6 @@ aarch64_adjust_register_sets (const struct aarch64_features &features)
}
}

-/* Matches HWCAP_PACA in kernel header arch/arm64/include/uapi/asm/hwcap.h. */
-#define AARCH64_HWCAP_PACA (1 << 30)
-
/* Implementation of linux target ops method "low_arch_setup". */

void
@@ -1005,7 +1004,7 @@ aarch64_target::low_arch_setup ()

features.vq = aarch64_sve_get_vq (tid);
/* A-profile PAC is 64-bit only. */
- features.pauth = linux_get_hwcap (pid, 8) & AARCH64_HWCAP_PACA;
+ features.pauth = linux_get_hwcap (pid, 8) & HWCAP_PACA;
/* A-profile MTE is 64-bit only. */
features.mte = linux_get_hwcap2 (pid, 8) & HWCAP2_MTE;
features.tls = aarch64_tls_register_count (tid);