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authorLinus Torvalds <torvalds@linux-foundation.org>2020-08-03 17:21:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-03 17:21:10 -0700
commit0a897743ac258927dd29bb91ac663b568f53429d (patch)
treec98ac1b01fe05dc48685fae3f8916ec6e7143cad /tools
parent335ad94c218e96ef12f56d93eadc884731aa23b1 (diff)
parent4185b3b92792eaec5869266e594338343421ffb0 (diff)
downloadlinux-0a897743ac258927dd29bb91ac663b568f53429d.tar.bz2
Merge tag 'x86-fpu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 FPU selftest from Ingo Molnar: "Add the /sys/kernel/debug/selftest_helpers/test_fpu FPU self-test" * tag 'x86-fpu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: selftests/fpu: Add an FPU selftest
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/Makefile1
-rw-r--r--tools/testing/selftests/fpu/.gitignore2
-rw-r--r--tools/testing/selftests/fpu/Makefile9
-rwxr-xr-xtools/testing/selftests/fpu/run_test_fpu.sh46
-rw-r--r--tools/testing/selftests/fpu/test_fpu.c61
5 files changed, 119 insertions, 0 deletions
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 1195bd85af38..227ca78a5b7f 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -15,6 +15,7 @@ TARGETS += filesystems
TARGETS += filesystems/binderfs
TARGETS += filesystems/epoll
TARGETS += firmware
+TARGETS += fpu
TARGETS += ftrace
TARGETS += futex
TARGETS += gpio
diff --git a/tools/testing/selftests/fpu/.gitignore b/tools/testing/selftests/fpu/.gitignore
new file mode 100644
index 000000000000..d6d12ac1d9c3
--- /dev/null
+++ b/tools/testing/selftests/fpu/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0+
+test_fpu
diff --git a/tools/testing/selftests/fpu/Makefile b/tools/testing/selftests/fpu/Makefile
new file mode 100644
index 000000000000..ea62c176ede7
--- /dev/null
+++ b/tools/testing/selftests/fpu/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0+
+
+LDLIBS := -lm
+
+TEST_GEN_PROGS := test_fpu
+
+TEST_PROGS := run_test_fpu.sh
+
+include ../lib.mk
diff --git a/tools/testing/selftests/fpu/run_test_fpu.sh b/tools/testing/selftests/fpu/run_test_fpu.sh
new file mode 100755
index 000000000000..d77be93ec139
--- /dev/null
+++ b/tools/testing/selftests/fpu/run_test_fpu.sh
@@ -0,0 +1,46 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Load kernel module for FPU tests
+
+uid=$(id -u)
+if [ $uid -ne 0 ]; then
+ echo "$0: Must be run as root"
+ exit 1
+fi
+
+if ! which modprobe > /dev/null 2>&1; then
+ echo "$0: You need modprobe installed"
+ exit 4
+fi
+
+if ! modinfo test_fpu > /dev/null 2>&1; then
+ echo "$0: You must have the following enabled in your kernel:"
+ echo "CONFIG_TEST_FPU=m"
+ exit 4
+fi
+
+NR_CPUS=$(getconf _NPROCESSORS_ONLN)
+if [ ! $NR_CPUS ]; then
+ NR_CPUS=1
+fi
+
+modprobe test_fpu
+
+if [ ! -e /sys/kernel/debug/selftest_helpers/test_fpu ]; then
+ mount -t debugfs none /sys/kernel/debug
+
+ if [ ! -e /sys/kernel/debug/selftest_helpers/test_fpu ]; then
+ echo "$0: Error mounting debugfs"
+ exit 4
+ fi
+fi
+
+echo "Running 1000 iterations on all CPUs... "
+for i in $(seq 1 1000); do
+ for c in $(seq 1 $NR_CPUS); do
+ ./test_fpu &
+ done
+done
+
+rmmod test_fpu
diff --git a/tools/testing/selftests/fpu/test_fpu.c b/tools/testing/selftests/fpu/test_fpu.c
new file mode 100644
index 000000000000..200238522a9d
--- /dev/null
+++ b/tools/testing/selftests/fpu/test_fpu.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* This testcase operates with the test_fpu kernel driver.
+ * It modifies the FPU control register in user mode and calls the kernel
+ * module to perform floating point operations in the kernel. The control
+ * register value should be independent between kernel and user mode.
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <fenv.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+const char *test_fpu_path = "/sys/kernel/debug/selftest_helpers/test_fpu";
+
+int main(void)
+{
+ char dummy[1];
+ int fd = open(test_fpu_path, O_RDONLY);
+
+ if (fd < 0) {
+ printf("[SKIP]\tcan't access %s: %s\n",
+ test_fpu_path, strerror(errno));
+ return 0;
+ }
+
+ if (read(fd, dummy, 1) < 0) {
+ printf("[FAIL]\taccess with default rounding mode failed\n");
+ return 1;
+ }
+
+ fesetround(FE_DOWNWARD);
+ if (read(fd, dummy, 1) < 0) {
+ printf("[FAIL]\taccess with downward rounding mode failed\n");
+ return 2;
+ }
+ if (fegetround() != FE_DOWNWARD) {
+ printf("[FAIL]\tusermode rounding mode clobbered\n");
+ return 3;
+ }
+
+ /* Note: the tests up to this point are quite safe and will only return
+ * an error. But the exception mask setting can cause misbehaving kernel
+ * to crash.
+ */
+ feclearexcept(FE_ALL_EXCEPT);
+ feenableexcept(FE_ALL_EXCEPT);
+ if (read(fd, dummy, 1) < 0) {
+ printf("[FAIL]\taccess with fpu exceptions unmasked failed\n");
+ return 4;
+ }
+ if (fegetexcept() != FE_ALL_EXCEPT) {
+ printf("[FAIL]\tusermode fpu exception mask clobbered\n");
+ return 5;
+ }
+
+ printf("[OK]\ttest_fpu\n");
+ return 0;
+}