Add some tests for page fault signals and codes

It is useful to have some tests for page fault signals.

More tests would be useful but creating the conditions (such as various
kinds of running out of memory and I/O errors) is more complicated.

The tests page_fault_signal__bus_objerr_1 and
page_fault_signal__bus_objerr_2 depend on https://reviews.freebsd.org/D21566
before they can pass.

PR:		211924
Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D21624

2 files changed, 186 insertions, 1 deletions

diff --git a/tests/sys/vm/Makefile b/tests/sys/vm/Makefile
index 2ba6875f4b2e..c2c95d25407f 100644
--- a/tests/sys/vm/Makefile
+++ b/tests/sys/vm/Makefile
@@ -5,6 +5,7 @@ PACKAGE=	tests
 TESTSDIR=	${TESTSBASE}/sys/vm
 
 ATF_TESTS_C+=	mlock_test \
-		mmap_test
+		mmap_test \
+		page_fault_signal
 
 .include <bsd.test.mk>
diff --git a/tests/sys/vm/page_fault_signal.c b/tests/sys/vm/page_fault_signal.c
new file mode 100644
index 000000000000..f5701d67c8ba
--- /dev/null
+++ b/tests/sys/vm/page_fault_signal.c
@@ -0,0 +1,184 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2019 Jilles Tjoelker
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/mman.h>
+
+#include <atf-c.h>
+#include <fcntl.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdio.h>
+
+static sigjmp_buf sig_env;
+static volatile int last_sig, last_code;
+
+static void
+sighandler(int sig, siginfo_t *info, void *context __unused)
+{
+
+	last_sig = sig;
+	last_code = info->si_code;
+	siglongjmp(sig_env, 1);
+}
+
+static void
+setup_signals(void)
+{
+	struct sigaction sa;
+	int r;
+
+	sa.sa_sigaction = sighandler;
+	sa.sa_flags = SA_RESTART | SA_RESETHAND | SA_SIGINFO;
+	r = sigfillset(&sa.sa_mask);
+	ATF_REQUIRE(r != -1);
+	r = sigaction(SIGILL, &sa, NULL);
+	ATF_REQUIRE(r != -1);
+	r = sigaction(SIGBUS, &sa, NULL);
+	ATF_REQUIRE(r != -1);
+	r = sigaction(SIGSEGV, &sa, NULL);
+	ATF_REQUIRE(r != -1);
+}
+
+ATF_TC_WITHOUT_HEAD(page_fault_signal__segv_maperr_1);
+ATF_TC_BODY(page_fault_signal__segv_maperr_1, tc)
+{
+	int *p;
+	int r;
+	int sz;
+
+	sz = getpagesize();
+	p = mmap(NULL, sz, PROT_READ, MAP_ANON, -1, 0);
+	ATF_REQUIRE(p != MAP_FAILED);
+	r = munmap(p, sz);
+	ATF_REQUIRE(r != -1);
+	if (sigsetjmp(sig_env, 1) == 0) {
+		setup_signals();
+		*(volatile int *)p = 1;
+	}
+	ATF_CHECK_EQ(SIGSEGV, last_sig);
+	ATF_CHECK_EQ(SEGV_MAPERR, last_code);
+}
+
+ATF_TC_WITHOUT_HEAD(page_fault_signal__segv_accerr_1);
+ATF_TC_BODY(page_fault_signal__segv_accerr_1, tc)
+{
+	int *p;
+	int sz;
+
+	sz = getpagesize();
+	p = mmap(NULL, sz, PROT_READ, MAP_ANON, -1, 0);
+	ATF_REQUIRE(p != MAP_FAILED);
+	if (sigsetjmp(sig_env, 1) == 0) {
+		setup_signals();
+		*(volatile int *)p = 1;
+	}
+	(void)munmap(p, sz);
+	ATF_CHECK_EQ(SIGSEGV, last_sig);
+	ATF_CHECK_EQ(SEGV_ACCERR, last_code);
+}
+
+ATF_TC_WITHOUT_HEAD(page_fault_signal__segv_accerr_2);
+ATF_TC_BODY(page_fault_signal__segv_accerr_2, tc)
+{
+	int *p;
+	volatile int dummy;
+	int sz;
+
+	sz = getpagesize();
+	p = mmap(NULL, sz, PROT_NONE, MAP_ANON, -1, 0);
+	ATF_REQUIRE(p != MAP_FAILED);
+	if (sigsetjmp(sig_env, 1) == 0) {
+		setup_signals();
+		dummy = *p;
+	}
+	(void)munmap(p, sz);
+	ATF_CHECK_EQ(SIGSEGV, last_sig);
+	ATF_CHECK_EQ(SEGV_ACCERR, last_code);
+}
+
+ATF_TC_WITHOUT_HEAD(page_fault_signal__bus_objerr_1);
+ATF_TC_BODY(page_fault_signal__bus_objerr_1, tc)
+{
+	int *p;
+	int fd;
+	int sz;
+
+	atf_tc_expect_fail("bug 211924");
+	sz = getpagesize();
+	fd = shm_open(SHM_ANON, O_RDWR | O_CREAT, 0600);
+	ATF_REQUIRE(fd != -1);
+	p = mmap(NULL, sz, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	ATF_REQUIRE(p != MAP_FAILED);
+	if (sigsetjmp(sig_env, 1) == 0) {
+		setup_signals();
+		*(volatile int *)p = 1;
+	}
+	(void)munmap(p, sz);
+	(void)close(fd);
+	ATF_CHECK_EQ(SIGBUS, last_sig);
+	ATF_CHECK_EQ(BUS_OBJERR, last_code);
+}
+
+ATF_TC_WITHOUT_HEAD(page_fault_signal__bus_objerr_2);
+ATF_TC_BODY(page_fault_signal__bus_objerr_2, tc)
+{
+	int *p;
+	int fd;
+	int r;
+	int sz;
+
+	atf_tc_expect_fail("bug 211924");
+	sz = getpagesize();
+	fd = shm_open(SHM_ANON, O_RDWR | O_CREAT, 0600);
+	ATF_REQUIRE(fd != -1);
+	r = ftruncate(fd, sz);
+	ATF_REQUIRE(r != -1);
+	p = mmap(NULL, sz * 2, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	ATF_REQUIRE(p != MAP_FAILED);
+	if (sigsetjmp(sig_env, 1) == 0) {
+		setup_signals();
+		((volatile int *)p)[sz / sizeof(int)] = 1;
+	}
+	(void)munmap(p, sz * 2);
+	(void)close(fd);
+	ATF_CHECK_EQ(SIGBUS, last_sig);
+	ATF_CHECK_EQ(BUS_OBJERR, last_code);
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+
+	ATF_TP_ADD_TC(tp, page_fault_signal__segv_maperr_1);
+	ATF_TP_ADD_TC(tp, page_fault_signal__segv_accerr_1);
+	ATF_TP_ADD_TC(tp, page_fault_signal__segv_accerr_2);
+	ATF_TP_ADD_TC(tp, page_fault_signal__bus_objerr_1);
+	ATF_TP_ADD_TC(tp, page_fault_signal__bus_objerr_2);
+
+	return (atf_no_error());
+}