kselftest/arm64: check GCR_EL1 after context switch

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

It spawns 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.

Link: https://lkml.kernel.org/r/b51a165426e906e7ec8a68d806ef3f8cd92581a6.1606161801.git.andreyknvl@google.com
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index 2480226..0b3af55 100644 (file)
--- 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 (file)
index 0000000..a876db1
--- /dev/null
+++ b/tools/testing/selftests/arm64/mte/check_gcr_el1_cswitch.c
@@ -0,0 +1,154 @@
+// 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(void)
+{
+       pid_t pid;
+       int results[NUM_ITERATIONS];
+       pid_t cpid;
+       int res;
+
+       for (int i = 0; i < NUM_ITERATIONS; i++) {
+               pid = fork();
+
+               if (pid < 0)
+                       return KSFT_FAIL;
+
+               if (pid == 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;
+}