tests: check decoding of SEGV_PKUERR

* tests/segv_pkuerr.c: New file.
* tests/gen_tests.in (segv_pkuerr): New test.
* tests/Makefile.am (check_PROGRAMS): Add segv_pkuerr.
* tests/.gitignore: Likewise.
* tests/ptrace.c (main) [HAVE_SIGINFO_T_SI_PKEY]: Check decoding
of SEGV_PKUERR.

tests/.gitignore

@@ -860,6 +860,7 @@ seccomp_get_action_avail
 seccomp_get_notif_sizes
 seccomp_get_notif_sizes-success
 secontext.am
+segv_pkuerr
 select
 select-P
 semop

tests/Makefile.am

@@ -335,6 +335,7 @@ check_PROGRAMS = $(PURE_EXECUTABLES) \
 	seccomp-filter-v \
 	seccomp-strict \
 	seccomp_get_notif_sizes-success \
+	segv_pkuerr \
 	select-P \
 	set_ptracer_any \
 	set_sigblock \

tests/gen_tests.in

@@ -840,6 +840,7 @@ seccomp-filter-v	-v -e trace=seccomp
 seccomp_get_action_avail	-e trace=seccomp
 seccomp_get_notif_sizes		-etrace=seccomp -a42
 seccomp_get_notif_sizes-success	-einject=seccomp:retval=42 -etrace=seccomp -a42
+segv_pkuerr	-qq --trace=none
 select	-a36
 select-P	-a36 -e trace=select -P /dev/full 9>>/dev/full
 semop	-a32

tests/ptrace.c

@@ -1854,6 +1854,22 @@ main(void)
 	       XLAT_ARGS(PTRACE_SETSIGINFO), pid, bad_request,
 	       XLAT_ARGS(SIGPROF), sip->si_code, sip->si_errno, errstr);
 
+#ifdef HAVE_SIGINFO_T_SI_PKEY
+	memset(sip, -1, sizeof(*sip));
+	sip->si_signo = SIGSEGV;
+	sip->si_code = SEGV_PKUERR;
+	sip->si_errno = 0;
+	sip->si_addr = (void *) (unsigned long) 0xfacefeeddeadbeefULL;
+	sip->si_pkey = 0xbadc0ded;
+
+	do_ptrace(PTRACE_SETSIGINFO, pid, bad_request, (uintptr_t) sip);
+	printf("ptrace(" XLAT_FMT ", %d, %#lx, {si_signo=" XLAT_FMT_U
+	       ", si_code=" XLAT_FMT ", si_addr=%p, si_pkey=%u}) = %s\n",
+	       XLAT_ARGS(PTRACE_SETSIGINFO), pid, bad_request,
+	       XLAT_ARGS(SIGSEGV), XLAT_ARGS(SEGV_PKUERR),
+	       sip->si_addr, sip->si_pkey, errstr);
+#endif
+
 #ifdef HAVE_SIGINFO_T_SI_SYSCALL
 	memset(sip, -1, sizeof(*sip));
 	sip->si_signo = SIGSYS;

tests/segv_pkuerr.c

@@ -0,0 +1,56 @@
+/*
+ * Check decoding of SEGV_PKUERR.
+ *
+ * Copyright (c) 2022 Dmitry V. Levin <ldv@strace.io>
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "tests.h"
+#include <signal.h>
+
+#if defined HAVE_SIGINFO_T_SI_PKEY && defined SEGV_PKUERR
+
+# include <stdio.h>
+# include <stdlib.h>
+# include <unistd.h>
+# include <sys/mman.h>
+
+static void
+handler(int sig, siginfo_t *info, void *ucontext)
+{
+	if (info->si_code != SEGV_PKUERR)
+		error_msg_and_skip("SIGSEGV: si_code = %d", info->si_code);
+
+	printf("--- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_PKUERR"
+	       ", si_addr=%p, si_pkey=%u} ---\n",
+	       info->si_addr, info->si_pkey);
+	exit(0);
+}
+
+int
+main(void) {
+	int *p = mmap(NULL, get_page_size(), PROT_EXEC,
+		      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	if (p == MAP_FAILED)
+		perror_msg_and_fail("mmap");
+
+	const struct sigaction act = {
+		.sa_sigaction = handler,
+		.sa_flags = SA_SIGINFO | SA_RESETHAND
+	};
+	if (sigaction(SIGSEGV, &act, NULL))
+		perror_msg_and_fail("sigaction");
+
+	if (*p)
+		__asm__ volatile("":::"memory");
+
+	error_msg_and_skip("PROT_EXEC page is readable");
+}
+
+#else
+
+SKIP_MAIN_UNDEFINED("HAVE_SIGINFO_T_SI_PKEY && SEGV_PKUERR")
+
+#endif