[PATCH v8 43/43] kselftest/arm64: Check GCR_EL1 after context switch

Andrey Konovalov
2020-11-04T23:21:00Z

From: Vincenzo Frascino <vincenzo.frascino@arm.com>

This test is specific to MTE and verifies that the GCR_EL1 register
is context switched correctly.

It spawn 1024 processes and each process spawns 5 threads. Each thread
writes a random setting of GCR_EL1 through the prctl() system call and
reads it back verifying that it is the same. If the values are not the
same it reports a failure.

Note: The test has been extended to verify that even SYNC and ASYNC mode
setting is preserved correctly over context switching.

Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
Change-Id: Ia917684a2b8e5f29e705ca5cbf360b010df6f61e
---
tools/testing/selftests/arm64/mte/Makefile | 2 +-
.../arm64/mte/check_gcr_el1_cswitch.c | 152 ++++++++++++++++++
2 files changed, 153 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/arm64/mte/check_gcr_el1_cswitch.c

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index 2480226dfe57..0b3af552632a 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2020 ARM Limited

-CFLAGS += -std=gnu99 -I.
+CFLAGS += -std=gnu99 -I. -lpthread
SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
PROGS := $(patsubst %.c,%,$(SRCS))

diff --git a/tools/testing/selftests/arm64/mte/check_gcr_el1_cswitch.c b/tools/testing/selftests/arm64/mte/check_gcr_el1_cswitch.c
new file mode 100644
index 000000000000..55e33d96794c
--- /dev/null
+++ b/tools/testing/selftests/arm64/mte/check_gcr_el1_cswitch.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2020 ARM Limited
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <pthread.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/auxv.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include "kselftest.h"
+#include "mte_common_util.h"
+
+#define PR_SET_TAGGED_ADDR_CTRL 55
+#define PR_GET_TAGGED_ADDR_CTRL 56
+# define PR_TAGGED_ADDR_ENABLE (1UL << 0)
+# define PR_MTE_TCF_SHIFT 1
+# define PR_MTE_TCF_NONE (0UL << PR_MTE_TCF_SHIFT)
+# define PR_MTE_TCF_SYNC (1UL << PR_MTE_TCF_SHIFT)
+# define PR_MTE_TCF_ASYNC (2UL << PR_MTE_TCF_SHIFT)
+# define PR_MTE_TCF_MASK (3UL << PR_MTE_TCF_SHIFT)
+# define PR_MTE_TAG_SHIFT 3
+# define PR_MTE_TAG_MASK (0xffffUL << PR_MTE_TAG_SHIFT)
+
+#include "mte_def.h"
+
+#define NUM_ITERATIONS 1024
+#define MAX_THREADS 5
+#define THREAD_ITERATIONS 1000
+
+void *execute_thread(void *x)
+{
+ pid_t pid = *((pid_t *)x);
+ pid_t tid = gettid();
+ uint64_t prctl_tag_mask;
+ uint64_t prctl_set;
+ uint64_t prctl_get;
+ uint64_t prctl_tcf;
+
+ srand(time(NULL) ^ (pid << 16) ^ (tid << 16));
+
+ prctl_tag_mask = rand() % 0xffff;
+
+ if (prctl_tag_mask % 2)
+ prctl_tcf = PR_MTE_TCF_SYNC;
+ else
+ prctl_tcf = PR_MTE_TCF_ASYNC;
+
+ prctl_set = PR_TAGGED_ADDR_ENABLE | prctl_tcf | (prctl_tag_mask << PR_MTE_TAG_SHIFT);
+
+ for (int j = 0; j < THREAD_ITERATIONS; j++) {
+ if (prctl(PR_SET_TAGGED_ADDR_CTRL, prctl_set, 0, 0, 0)) {
+ perror("prctl() failed");
+ goto fail;
+ }
+
+ prctl_get = prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0);
+
+ if (prctl_set != prctl_get) {
+ ksft_print_msg("Error: prctl_set: 0x%lx != prctl_get: 0x%lx\n",
+ prctl_set, prctl_get);
+ goto fail;
+ }
+ }
+
+ return (void *)KSFT_PASS;
+
+fail:
+ return (void *)KSFT_FAIL;
+}
+
+int execute_test(pid_t pid)
+{
+ pthread_t thread_id[MAX_THREADS];
+ int thread_data[MAX_THREADS];
+
+ for (int i = 0; i < MAX_THREADS; i++)
+ pthread_create(&thread_id[i], NULL,
+ execute_thread, (void *)&pid);
+
+ for (int i = 0; i < MAX_THREADS; i++)
+ pthread_join(thread_id[i], (void *)&thread_data[i]);
+
+ for (int i = 0; i < MAX_THREADS; i++)
+ if (thread_data[i] == KSFT_FAIL)
+ return KSFT_FAIL;
+
+ return KSFT_PASS;
+}
+
+int mte_gcr_fork_test()
+{
+ pid_t pid[NUM_ITERATIONS];
+ int results[NUM_ITERATIONS];
+ pid_t cpid;
+ int res;
+
+ for (int i = 0; i < NUM_ITERATIONS; i++) {
+ pid[i] = fork();
+
+ if (pid[i] == 0) {
+ cpid = getpid();
+
+ res = execute_test(cpid);
+
+ exit(res);
+ }
+ }
+
+ for (int i = 0; i < NUM_ITERATIONS; i++) {
+ wait(&res);
+
+ if(WIFEXITED(res))
+ results[i] = WEXITSTATUS(res);
+ else
+ --i;
+ }
+
+ for (int i = 0; i < NUM_ITERATIONS; i++)
+ if (results[i] == KSFT_FAIL)
+ return KSFT_FAIL;
+
+ return KSFT_PASS;
+}
+
+int main(int argc, char *argv[])
+{
+ int err;
+
+ err = mte_default_setup();
+ if (err)
+ return err;
+
+ ksft_set_plan(1);
+
+ evaluate_test(mte_gcr_fork_test(),
+ "Verify that GCR_EL1 is set correctly on context switch\n");
+
+ mte_restore_setup();
+ ksft_print_cnts();
+
+ return ksft_get_fail_cnt() == 0 ? KSFT_PASS : KSFT_FAIL;
+}
+
--
2.29.1.341.ge80a0c044ae-goog