1 files changed, 142 insertions, 0 deletions
diff --git a/string/test/mte.h b/string/test/mte.h
new file mode 100644
index 0000000..e67cbd9
--- /dev/null
+++ b/string/test/mte.h
@@ -0,0 +1,142 @@
+/*
+ * Memory tagging testing code.
+ *
+ * Copyright (c) 2020, Arm Limited.
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef __TEST_MTE_H
+#define __TEST_MTE_H
+
+#include <stdlib.h>
+
+#if __ARM_FEATURE_MEMORY_TAGGING && WANT_MTE_TEST
+#include <arm_acle.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+
+// These depend on a not yet merged kernel ABI.
+#define PR_SET_TAGGED_ADDR_CTRL 55
+#define PR_TAGGED_ADDR_ENABLE (1UL << 0)
+#define PR_MTE_TCF_SHIFT 1
+#define PR_MTE_TCF_SYNC (1UL << PR_MTE_TCF_SHIFT)
+#define PR_MTE_TAG_SHIFT 3
+#define PROT_MTE 0x20
+
+#define MTE_GRANULE_SIZE 16
+
+int
+mte_enabled ()
+{
+  static int enabled = -1;
+  if (enabled == -1)
+    {
+      int res = prctl (PR_SET_TAGGED_ADDR_CTRL,
+		       PR_TAGGED_ADDR_ENABLE | PR_MTE_TCF_SYNC
+			 | (0xfffe << PR_MTE_TAG_SHIFT),
+		       0, 0, 0);
+      enabled = (res == 0);
+    }
+  return enabled;
+}
+
+static void *
+mte_mmap (size_t size)
+{
+  if (mte_enabled ())
+    {
+      return mmap (NULL, size, PROT_READ | PROT_WRITE | PROT_MTE,
+		   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+    }
+  else
+    {
+      return malloc (size);
+    }
+}
+
+void *
+alignup_mte (void *p)
+{
+  return (void *) (((uintptr_t) p + MTE_GRANULE_SIZE - 1)
+		   & ~(MTE_GRANULE_SIZE - 1));
+}
+
+void *
+aligndown_mte (void *p)
+{
+  return (void *) ((uintptr_t) p & ~(MTE_GRANULE_SIZE - 1));
+}
+
+void *
+untag_pointer (void *p)
+{
+  return (void *) ((unsigned long long) p & (~0ULL >> 8));
+}
+
+void
+tag_buffer_helper (void *p, int len)
+{
+  char *ptr = p;
+  char *end = alignup_mte (ptr + len);
+  ptr = aligndown_mte (p);
+  for (; ptr < end; ptr += MTE_GRANULE_SIZE)
+    {
+      __arm_mte_set_tag (ptr);
+    }
+}
+
+void *
+tag_buffer (void *p, int len, int test_mte)
+{
+  if (test_mte && mte_enabled ())
+    {
+      p = __arm_mte_increment_tag (p, 1);
+      tag_buffer_helper (p, len);
+    }
+  return p;
+}
+
+void *
+untag_buffer (void *p, int len, int test_mte)
+{
+  p = untag_pointer (p);
+  if (test_mte && mte_enabled ())
+    {
+      tag_buffer_helper (p, len);
+    }
+  return p;
+}
+
+#else  // __ARM_FEATURE_MEMORY_TAGGING
+int
+mte_enabled ()
+{
+  return 0;
+}
+static void *
+mte_mmap (size_t size)
+{
+  return malloc (size);
+}
+void *
+tag_buffer (void *p, int len, int test_mte)
+{
+  (void) len;
+  (void) test_mte;
+  return p;
+}
+void *
+untag_buffer (void *p, int len, int test_mte)
+{
+  (void) len;
+  (void) test_mte;
+  return p;
+}
+void *
+untag_pointer (void *p)
+{
+  return p;
+}
+#endif // __ARM_FEATURE_MEMORY_TAGGING
+
+#endif