new file mode 100644
@@ -0,0 +1,60 @@
+/*
+ * Linux kernel fallback API definitions for MTE and test helpers.
+ *
+ * Copyright (c) 2021 Linaro Ltd
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <assert.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+
+#ifndef PR_SET_TAGGED_ADDR_CTRL
+# define PR_SET_TAGGED_ADDR_CTRL 55
+#endif
+#ifndef PR_TAGGED_ADDR_ENABLE
+# define PR_TAGGED_ADDR_ENABLE (1UL << 0)
+#endif
+#ifndef PR_MTE_TCF_SHIFT
+# 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_TAG_SHIFT 3
+#endif
+
+#ifndef PROT_MTE
+# define PROT_MTE 0x20
+#endif
+
+#ifndef SEGV_MTEAERR
+# define SEGV_MTEAERR 8
+# define SEGV_MTESERR 9
+#endif
+
+static void enable_mte(int tcf)
+{
+ int r = prctl(PR_SET_TAGGED_ADDR_CTRL,
+ PR_TAGGED_ADDR_ENABLE | tcf | (0xfffe << PR_MTE_TAG_SHIFT),
+ 0, 0, 0);
+ if (r < 0) {
+ perror("PR_SET_TAGGED_ADDR_CTRL");
+ exit(2);
+ }
+}
+
+static void *alloc_mte_mem(size_t size)
+{
+ void *p = mmap(NULL, size, PROT_READ | PROT_WRITE | PROT_MTE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (p == MAP_FAILED) {
+ perror("mmap PROT_MTE");
+ exit(2);
+ }
+ return p;
+}
new file mode 100644
@@ -0,0 +1,28 @@
+/*
+ * Memory tagging, basic pass cases.
+ *
+ * Copyright (c) 2021 Linaro Ltd
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "mte.h"
+
+int main(int ac, char **av)
+{
+ int *p0, *p1, *p2;
+ long c;
+
+ enable_mte(PR_MTE_TCF_NONE);
+ p0 = alloc_mte_mem(sizeof(*p0));
+
+ asm("irg %0,%1,%2" : "=r"(p1) : "r"(p0), "r"(1));
+ assert(p1 != p0);
+ asm("subp %0,%1,%2" : "=r"(c) : "r"(p0), "r"(p1));
+ assert(c == 0);
+
+ asm("stg %0, [%0]" : : "r"(p1));
+ asm("ldg %0, [%1]" : "=r"(p2) : "r"(p0), "0"(p0));
+ assert(p1 == p2);
+
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,45 @@
+/*
+ * Memory tagging, basic fail cases, synchronous signals.
+ *
+ * Copyright (c) 2021 Linaro Ltd
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "mte.h"
+
+void pass(int sig, siginfo_t *info, void *uc)
+{
+ assert(info->si_code == SEGV_MTESERR);
+ exit(0);
+}
+
+int main(int ac, char **av)
+{
+ struct sigaction sa;
+ int *p0, *p1, *p2;
+ long excl = 1;
+
+ enable_mte(PR_MTE_TCF_SYNC);
+ p0 = alloc_mte_mem(sizeof(*p0));
+
+ /* Create two differently tagged pointers. */
+ asm("irg %0,%1,%2" : "=r"(p1) : "r"(p0), "r"(excl));
+ asm("gmi %0,%1,%0" : "+r"(excl) : "r" (p1));
+ assert(excl != 1);
+ asm("irg %0,%1,%2" : "=r"(p2) : "r"(p0), "r"(excl));
+ assert(p1 != p2);
+
+ /* Store the tag from the first pointer. */
+ asm("stg %0, [%0]" : : "r"(p1));
+
+ *p1 = 0;
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = pass;
+ sa.sa_flags = SA_SIGINFO;
+ sigaction(SIGSEGV, &sa, NULL);
+
+ *p2 = 0;
+
+ abort();
+}
new file mode 100644
@@ -0,0 +1,51 @@
+/*
+ * Memory tagging, basic fail cases, asynchronous signals.
+ *
+ * Copyright (c) 2021 Linaro Ltd
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "mte.h"
+
+void pass(int sig, siginfo_t *info, void *uc)
+{
+ assert(info->si_code == SEGV_MTEAERR);
+ exit(0);
+}
+
+int main(int ac, char **av)
+{
+ struct sigaction sa;
+ long *p0, *p1, *p2;
+ long excl = 1;
+
+ enable_mte(PR_MTE_TCF_ASYNC);
+ p0 = alloc_mte_mem(sizeof(*p0));
+
+ /* Create two differently tagged pointers. */
+ asm("irg %0,%1,%2" : "=r"(p1) : "r"(p0), "r"(excl));
+ asm("gmi %0,%1,%0" : "+r"(excl) : "r" (p1));
+ assert(excl != 1);
+ asm("irg %0,%1,%2" : "=r"(p2) : "r"(p0), "r"(excl));
+ assert(p1 != p2);
+
+ /* Store the tag from the first pointer. */
+ asm("stg %0, [%0]" : : "r"(p1));
+
+ *p1 = 0;
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = pass;
+ sa.sa_flags = SA_SIGINFO;
+ sigaction(SIGSEGV, &sa, NULL);
+
+ /*
+ * Signal for async error will happen eventually.
+ * For a real kernel this should be after the next IRQ (e.g. timer).
+ * For qemu linux-user, we kick the cpu and exit at the next TB.
+ * In either case, loop until this happens (or killed by timeout).
+ * For extra sauce, yield, producing EXCP_YIELD to cpu_loop().
+ */
+ asm("str %0, [%0]; yield" : : "r"(p2));
+ while (1);
+}
new file mode 100644
@@ -0,0 +1,45 @@
+/*
+ * Memory tagging, re-reading tag checks.
+ *
+ * Copyright (c) 2021 Linaro Ltd
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "mte.h"
+
+void __attribute__((noinline)) tagset(void *p, size_t size)
+{
+ size_t i;
+ for (i = 0; i < size; i += 16) {
+ asm("stg %0, [%0]" : : "r"(p + i));
+ }
+}
+
+void __attribute__((noinline)) tagcheck(void *p, size_t size)
+{
+ size_t i;
+ void *c;
+
+ for (i = 0; i < size; i += 16) {
+ asm("ldg %0, [%1]" : "=r"(c) : "r"(p + i), "0"(p));
+ assert(c == p);
+ }
+}
+
+int main(int ac, char **av)
+{
+ size_t size = getpagesize() * 4;
+ long excl = 1;
+ int *p0, *p1;
+
+ enable_mte(PR_MTE_TCF_ASYNC);
+ p0 = alloc_mte_mem(size);
+
+ /* Tag the pointer. */
+ asm("irg %0,%1,%2" : "=r"(p1) : "r"(p0), "r"(excl));
+
+ tagset(p1, size);
+ tagcheck(p1, size);
+
+ return 0;
+}
@@ -35,6 +35,12 @@ endif
# bti-2 tests PROT_BTI, so no special compiler support required.
AARCH64_TESTS += bti-2
+# MTE Tests
+ifneq ($(DOCKER_IMAGE)$(CROSS_CC_HAS_ARMV8_MTE),)
+AARCH64_TESTS += mte-1 mte-2 mte-3 mte-4
+mte-%: CFLAGS += -march=armv8.5-a+memtag
+endif
+
# Semihosting smoke test for linux-user
AARCH64_TESTS += semihosting
run-semihosting: semihosting
@@ -244,6 +244,10 @@ for target in $target_list; do
-mbranch-protection=standard -o $TMPE $TMPC; then
echo "CROSS_CC_HAS_ARMV8_BTI=y" >> $config_target_mak
fi
+ if do_compiler "$target_compiler" $target_compiler_cflags \
+ -march=armv8.5-a+memtag -o $TMPE $TMPC; then
+ echo "CROSS_CC_HAS_ARMV8_MTE=y" >> $config_target_mak
+ fi
;;
esac