[ndctl PATCH 13/16] test: Validate strict iomem protections of pmem

From: Dan Williams <dan.j.williams@intel.com>
To: linux-nvdimm@lists.01.org
Cc: vishal.l.verma@intel.com
Subject: [ndctl PATCH 13/16] test: Validate strict iomem protections of pmem
Date: Mon, 06 Jul 2020 19:41:27 -0700	[thread overview]
Message-ID: <159408968753.2386154.12723753534368313736.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <159408961822.2386154.888266173771881937.stgit@dwillia2-desk3.amr.corp.intel.com>


---
 test/Makefile.am     |    9 +++
 test/revoke-devmem.c |  143 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 152 insertions(+)
 create mode 100644 test/revoke-devmem.c

diff --git a/test/Makefile.am b/test/Makefile.am
index 1d24a65ded8b..1dcaa1eb6da5 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -56,6 +56,7 @@ TESTS +=\
 	dax-xfs.sh \
 	align.sh \
 	device-dax \
+	revoke-devmem \
 	device-dax-fio.sh \
 	daxctl-devices.sh \
 	dm.sh \
@@ -71,6 +72,7 @@ check_PROGRAMS +=\
 	dax-dev \
 	dax-pmd \
 	device-dax \
+	revoke-devmem \
 	mmap
 endif
 
@@ -154,6 +156,13 @@ device_dax_LDADD = \
                 $(UUID_LIBS) \
 		../libutil.a
 
+revoke_devmem_SOURCES = \
+		revoke-devmem.c \
+		dax-dev.c \
+		$(testcore)
+
+revoke_devmem_LDADD = $(LIBNDCTL_LIB)
+
 smart_notify_SOURCES = smart-notify.c
 smart_notify_LDADD = $(LIBNDCTL_LIB)
 smart_listen_SOURCES = smart-listen.c
diff --git a/test/revoke-devmem.c b/test/revoke-devmem.c
new file mode 100644
index 000000000000..ffa509e2d7d1
--- /dev/null
+++ b/test/revoke-devmem.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2020 Intel Corporation. All rights reserved. */
+#include <fcntl.h>
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <string.h>
+#include <signal.h>
+#include <setjmp.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <util/size.h>
+#include <linux/falloc.h>
+#include <linux/version.h>
+#include <ndctl/libndctl.h>
+#include <ccan/array_size/array_size.h>
+
+#include <builtin.h>
+#include <test.h>
+
+static sigjmp_buf sj_env;
+
+static void sigbus(int sig, siginfo_t *siginfo, void *d)
+{
+	siglongjmp(sj_env, 1);
+}
+
+#define err(fmt, ...) \
+	fprintf(stderr, "%s: " fmt, __func__, ##__VA_ARGS__)
+
+static int test_devmem(int loglevel, struct ndctl_test *test,
+		struct ndctl_ctx *ctx)
+{
+	void *buf;
+	int fd, rc;
+	struct sigaction act;
+	unsigned long long resource;
+	struct ndctl_namespace *ndns;
+
+	ndctl_set_log_priority(ctx, loglevel);
+
+	/* iostrict devmem started in kernel 4.5 */
+	if (!ndctl_test_attempt(test, KERNEL_VERSION(4, 5, 0)))
+		return 77;
+
+	ndns = ndctl_get_test_dev(ctx);
+	if (!ndns) {
+		err("failed to find suitable namespace\n");
+		return 77;
+	}
+
+	resource = ndctl_namespace_get_resource(ndns);
+	if (resource == ULLONG_MAX) {
+		err("failed to retrieve resource base\n");
+		return 77;
+	}
+
+	rc = ndctl_namespace_disable(ndns);
+	if (rc) {
+		err("failed to disable namespace\n");
+		return rc;
+	}
+
+	/* establish a devmem mapping of the namespace memory */
+	fd = open("/dev/mem", O_RDWR);
+	if (fd < 0) {
+		err("failed to open /dev/mem: %s\n", strerror(errno));
+		rc = -errno;
+		goto out_devmem;
+	}
+
+	buf = mmap(NULL, SZ_2M, PROT_READ|PROT_WRITE, MAP_SHARED, fd, resource);
+	if (buf == MAP_FAILED) {
+		err("failed to map /dev/mem: %s\n", strerror(errno));
+		rc = -errno;
+		goto out_mmap;
+	}
+
+	/* populate and write, should not fail */
+	memset(buf, 0, SZ_2M);
+
+	memset(&act, 0, sizeof(act));
+	act.sa_sigaction = sigbus;
+	act.sa_flags = SA_SIGINFO;
+	if (sigaction(SIGBUS, &act, 0)) {
+		perror("sigaction");
+		rc = EXIT_FAILURE;
+		goto out_sigaction;
+	}
+
+	/* test fault due to devmem revocation */
+	if (sigsetjmp(sj_env, 1)) {
+		/* got sigbus, success */
+		fprintf(stderr, "devmem revoked!\n");
+		rc = 0;
+		goto out_sigaction;
+	}
+
+	rc = ndctl_namespace_enable(ndns);
+	if (rc) {
+		err("failed to enable namespace\n");
+		goto out_sigaction;
+	}
+
+	/* write, should sigbus */
+	memset(buf, 0, SZ_2M);
+
+	err("kernel failed to prevent write after namespace enabled\n");
+	rc = -ENXIO;
+
+out_sigaction:
+	munmap(buf, SZ_2M);
+out_mmap:
+	close(fd);
+out_devmem:
+	if (ndctl_namespace_enable(ndns) != 0)
+		err("failed to re-enable namespace\n");
+	return rc;
+}
+
+int main(int argc, char *argv[])
+{
+	struct ndctl_test *test = ndctl_test_new(0);
+	struct ndctl_ctx *ctx;
+	int rc;
+
+	if (!test) {
+		fprintf(stderr, "failed to initialize test\n");
+		return EXIT_FAILURE;
+	}
+
+	rc = ndctl_new(&ctx);
+	if (rc < 0)
+		return ndctl_test_result(test, rc);
+
+	rc = test_devmem(LOG_DEBUG, test, ctx);
+	ndctl_unref(ctx);
+	return ndctl_test_result(test, rc);
+}
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