[PATCH v3 5/5] [PATCH 5/5] gdb/testsuite: Add FEAT_S1POE testcases

[<srinath.parvathaneni@arm.com>]

From: Srinath Parvathaneni <srinath.parvathaneni@arm.com>

Add testcases for POR_EL0 register access, SIGSEGV diagnostics, fix-and-continue
support (updating $por_el0 after SIGSEGV and continuing with signal 0), and core
file support.
---
 gdb/testsuite/gdb.arch/aarch64-poe-core.exp   | 101 ++++++++++++++++++
 gdb/testsuite/gdb.arch/aarch64-poe-sigsegv.   |   0
 gdb/testsuite/gdb.arch/aarch64-poe-sigsegv.c  |  52 +++++++++
 .../gdb.arch/aarch64-poe-sigsegv.exp          |  58 ++++++++++
 gdb/testsuite/gdb.arch/aarch64-poe.c          |  29 +++++
 gdb/testsuite/gdb.arch/aarch64-poe.exp        |  46 ++++++++
 gdb/testsuite/lib/gdb.exp                     |  55 ++++++++++
 7 files changed, 341 insertions(+)
 create mode 100644 gdb/testsuite/gdb.arch/aarch64-poe-core.exp
 create mode 100644 gdb/testsuite/gdb.arch/aarch64-poe-sigsegv.
 create mode 100644 gdb/testsuite/gdb.arch/aarch64-poe-sigsegv.c
 create mode 100644 gdb/testsuite/gdb.arch/aarch64-poe-sigsegv.exp
 create mode 100644 gdb/testsuite/gdb.arch/aarch64-poe.c
 create mode 100644 gdb/testsuite/gdb.arch/aarch64-poe.exp

diff --git a/gdb/testsuite/gdb.arch/aarch64-poe-core.exp b/gdb/testsuite/gdb.arch/aarch64-poe-core.exp
new file mode 100644
index 00000000000..22fe646ac43
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/aarch64-poe-core.exp
@@ -0,0 +1,101 @@
+# Copyright (C) 2026 Free Software Foundation, Inc.
+#
+# 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/>.
+
+# This file is part of the gdb testsuite.
+
+# Test generating and reading a core file with POR_EL0.
+
+proc check_poe_core_file {core_filename} {
+    # Load the core file.
+    if {
+	[gdb_test "core $core_filename" \
+	    [multi_line \
+		"Core was generated by .*" \
+		"Program terminated with signal SIGSEGV, Segmentation fault" \
+		"Protection Key Violation while accessing address ${::hex} with Protection Key = ${::decimal}\\." \
+		"#0  ${::hex} in main \\(.*\\) at .*" \
+		".*buf\\\[0\\\] = 42;.*"] \
+	    "load core file"]
+    } {
+	untested "failed to load core file"
+	return -1
+    }
+
+    # Check the value of POR_EL0 in the core file.
+    gdb_test "print/x \$por_el0" " = 0x37" \
+	"por_el0 contents from core file"
+}
+
+require allow_aarch64_poe_tests
+
+standard_testfile aarch64-poe-sigsegv.c
+
+if {[prepare_for_testing "failed to prepare" ${testfile} ${srcfile}]} {
+    return
+}
+
+set binfile [standard_output_file ${testfile}]
+
+if {![runto_main]} {
+    return
+}
+
+set poe_crash_re [multi_line \
+    "Program received signal SIGSEGV, Segmentation fault" \
+    "Protection Key Violation while accessing address ${::hex} with Protection Key = ${::decimal}\\." \
+    ".*buf\\\[0\\\] = 42;.*"]
+
+gdb_test_multiple "continue" "run to POE crash" {
+    -re "$poe_crash_re$gdb_prompt $" {
+	pass $gdb_test_name
+    }
+
+    -re ".*exited with code 01.*$gdb_prompt $" {
+	unsupported "POE userspace support unavailable"
+	return
+    }
+}
+
+# Generate the gcore core file.
+set gcore_filename [standard_output_file "${testfile}.gcore"]
+set gcore_generated [gdb_gcore_cmd "$gcore_filename" "generate gcore file"]
+
+# Generate a native core file.
+set core_filename [core_find ${binfile}]
+set core_generated [expr {$core_filename != ""}]
+
+# At this point we have a couple core files, the gcore one generated by GDB
+# and the native one generated by the Linux Kernel.  Make sure GDB can read
+# both correctly.
+
+if {$gcore_generated} {
+    clean_restart
+    gdb_load ${binfile}
+    with_test_prefix "gcore corefile" {
+	check_poe_core_file $gcore_filename
+    }
+} else {
+    fail "gcore corefile not generated"
+}
+
+if {$core_generated} {
+    clean_restart
+    gdb_load ${binfile}
+    with_test_prefix "native corefile" {
+	check_poe_core_file $core_filename
+    }
+} else {
+    untested "native corefile not generated"
+}
diff --git a/gdb/testsuite/gdb.arch/aarch64-poe-sigsegv. b/gdb/testsuite/gdb.arch/aarch64-poe-sigsegv.
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/gdb/testsuite/gdb.arch/aarch64-poe-sigsegv.c b/gdb/testsuite/gdb.arch/aarch64-poe-sigsegv.c
new file mode 100644
index 00000000000..5346e51dbba
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/aarch64-poe-sigsegv.c
@@ -0,0 +1,52 @@
+/* This test program is part of GDB, the GNU debugger.
+
+   Copyright 2026 Free Software Foundation, Inc.
+
+   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/>.  */
+
+/* Exercise AArch64's POE Extension.  */
+
+/* This test is based on the Linux kernel documentation for Memory
+   Protection Keys, including the arm64 Permission Overlay Extension
+   (FEAT_S1POE) support described in
+   Documentation/core-api/protection-keys.rst.  */
+
+#define _GNU_SOURCE
+#include <sys/mman.h>
+#include <unistd.h>
+
+int
+main (void)
+{
+  long pagesize = sysconf (_SC_PAGESIZE);
+
+  int *buf = mmap (NULL, pagesize, PROT_READ | PROT_WRITE,
+		   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  if (buf == MAP_FAILED)
+    return 1;
+
+  int pkey = pkey_alloc (0, 0);
+  if (pkey == -1)
+    return 1;
+
+  if (pkey_mprotect (buf, pagesize, PROT_READ | PROT_WRITE, pkey) == -1)
+    return 1;
+
+  if (pkey_set (pkey, PKEY_DISABLE_WRITE) == -1)
+    return 1;
+
+  buf[0] = 42;  /* Expect SIGSEGV POE violation.  */
+
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.arch/aarch64-poe-sigsegv.exp b/gdb/testsuite/gdb.arch/aarch64-poe-sigsegv.exp
new file mode 100644
index 00000000000..19eafd14a2f
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/aarch64-poe-sigsegv.exp
@@ -0,0 +1,58 @@
+# Copyright (C) 2026 Free Software Foundation, Inc.
+
+# 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/>.
+
+# Test a binary that supports FEAT_S1POE and exposes POR_EL0 register.
+
+global hex
+global decimal
+
+if {![allow_aarch64_poe_tests]} {
+    unsupported "AArch64 POE not supported"
+    return
+}
+
+standard_testfile
+if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile}] } {
+    return
+}
+
+if {![runto_main]} {
+    return
+}
+
+# Display POE violation SIGSEGV error message.
+set poe_sigsegv_re [multi_line \
+    "Program received signal SIGSEGV, Segmentation fault" \
+    "Protection Key Violation while accessing address ${hex} with Protection Key = ${decimal}"]
+
+gdb_test_multiple "continue" "display POE violation information" {
+    -re "$poe_sigsegv_re.*$gdb_prompt $" {
+	pass $gdb_test_name
+    }
+    -re ".*exited with code 01.*$gdb_prompt $" {
+	unsupported "POE userspace support unavailable"
+	return
+    }
+}
+
+# Fix the POE permissions (set $por_el0) and continue without delivering SIGSEGV.
+gdb_test_no_output "set \$por_el0 = 0x57" \
+    "allow write access by updating POR_EL0"
+
+gdb_test_multiple "signal 0" "continue after fixing POE fault" {
+    -re ".*exited normally.*$gdb_prompt $" {
+	pass $gdb_test_name
+    }
+}
diff --git a/gdb/testsuite/gdb.arch/aarch64-poe.c b/gdb/testsuite/gdb.arch/aarch64-poe.c
new file mode 100644
index 00000000000..2c95dc2a99b
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/aarch64-poe.c
@@ -0,0 +1,29 @@
+/* This test program is part of GDB, the GNU debugger.
+
+   Copyright 2026 Free Software Foundation, Inc.
+
+   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/>.  */
+
+/* Exercise AArch64's POE Extension.  */
+
+/* This test is based on the Linux kernel documentation for Memory
+   Protection Keys, including the arm64 Permission Overlay Extension
+   (FEAT_S1POE) support described in
+   Documentation/core-api/protection-keys.rst.  */
+
+int
+main (void)
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.arch/aarch64-poe.exp b/gdb/testsuite/gdb.arch/aarch64-poe.exp
new file mode 100644
index 00000000000..5aea0350d81
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/aarch64-poe.exp
@@ -0,0 +1,46 @@
+# Copyright (C) 2026 Free Software Foundation, Inc.
+
+# 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/>.
+
+# Test a binary that uses POE and exposed POR_EL0 register.
+
+global hex
+global decimal
+
+if {![allow_aarch64_poe_tests]} {
+    unsupported "AArch64 POE not supported"
+    return
+}
+
+standard_testfile
+if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile}] } {
+    return
+}
+
+if {![runto_main]} {
+    return
+}
+
+# Validate the presence of the POE register.
+gdb_test "info registers por_el0" \
+	 "por_el0\[ \t\]+$hex.*" \
+	 "info register por_el0 available"
+
+gdb_test "p \$por_el0" \
+	"\\$\[0-9\]+ = .*" \
+	"print por_el0 available"
+
+gdb_test "p/x \$por_el0" \
+	 "\\$\[0-9\]+ = ${hex}" \
+	 "print/x por_el0 available"
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index a40c87c6727..ab573f50660 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -5645,6 +5645,61 @@ gdb_caching_proc allow_aarch64_gcs_tests {} {
     return $allow_gcs_tests
 }
 
+# Run a test on the target to see if it supports AArch64 POE extensions.
+# Return 1 if so, 0 if it does not.  Note this causes a restart of GDB.
+
+gdb_caching_proc allow_aarch64_poe_tests {} {
+    global srcdir subdir gdb_prompt inferior_exited_re
+
+    set me "allow_aarch64_poe_tests"
+
+    if {![is_aarch64_target]} {
+	return 0
+    }
+
+    # Compile a program that tests the POE feature.
+    set src {
+	#include <stdbool.h>
+	#include <sys/auxv.h>
+
+	/* Feature check for POE feature.  */
+	#ifndef HWCAP2_POE
+	#define HWCAP2_POE (1ULL << 63)
+	#endif
+
+	int main (void) {
+	    bool poe_supported = getauxval (AT_HWCAP2) & HWCAP2_POE;
+
+	    /* Return success if POE is supported.  */
+	    return !poe_supported;
+	}
+    }
+
+    if {![gdb_simple_compile $me $src executable]} {
+	return 0
+    }
+
+    # Compilation succeeded so now run it via gdb.
+    set allow_poe_tests 0
+    clean_restart
+    gdb_load $obj
+    gdb_run_cmd
+    gdb_expect {
+	-re ".*$inferior_exited_re normally.*${gdb_prompt} $" {
+	    verbose -log "\n$me: poe support detected"
+	    set allow_poe_tests 1
+	}
+	-re ".*$inferior_exited_re with code 01.*${gdb_prompt} $" {
+	    verbose -log "\n$me: poe support not detected"
+	}
+    }
+    gdb_exit
+
+    remote_file build delete $obj
+    verbose "$me: returning $allow_poe_tests" 2
+    return $allow_poe_tests
+}
+
 # A helper that compiles a test case to see if __int128 is supported.
 proc gdb_int128_helper {lang} {
     return [gdb_can_simple_compile "i128-for-$lang" {
-- 
2.43.0