1 files changed, 147 insertions, 0 deletions
diff --git a/string/test/__mtag_tag_zero_region.c b/string/test/__mtag_tag_zero_region.c
new file mode 100644
index 0000000..221c223
--- /dev/null
+++ b/string/test/__mtag_tag_zero_region.c
@@ -0,0 +1,147 @@
+/*
+ * __mtag_tag_zero_region test.
+ *
+ * Copyright (c) 2021, Arm Limited.
+ * SPDX-License-Identifier: MIT
+ */
+
+#if __ARM_FEATURE_MEMORY_TAGGING && WANT_MTE_TEST
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "mte.h"
+#include "stringlib.h"
+#include "stringtest.h"
+
+static void
+mtag_quoteat (const char *prefix, void *p, int len, int at)
+{
+  /* Print tag, untag and quote the context.  */
+  printf ("location: %p\n", __arm_mte_get_tag ((char *) p + at));
+  untag_buffer (p, len, 1);
+  p = untag_pointer (p);
+  quoteat (prefix, p, len, at);
+}
+
+#define F(x) {#x, x},
+
+static const struct fun
+{
+  const char *name;
+  void *(*fun) (void *s, size_t n);
+} funtab[] = {
+// clang-format off
+#if __aarch64__
+  F(__mtag_tag_zero_region)
+#endif
+  {0, 0}
+  // clang-format on
+};
+#undef F
+
+#define A 64
+#define LEN 250000
+static unsigned char *sbuf;
+
+static void *
+alignup (void *p)
+{
+  return (void *) (((uintptr_t) p + A - 1) & -A);
+}
+
+static void
+test (const struct fun *fun, int salign, int len)
+{
+  unsigned char *src = alignup (sbuf);
+  unsigned char *s = src + salign;
+  void *p;
+  int i;
+
+  if (err_count >= ERR_LIMIT)
+    return;
+  if (len > LEN || salign >= A)
+    abort ();
+  for (i = 0; i < len + 2 * A; i++)
+    src[i] = '?';
+  for (i = 0; i < len; i++)
+    s[i] = 'a' + i % 23;
+
+  src = tag_buffer (src, len + 2 * A, 1);
+  s = src + salign;
+  /* Use different tag.  */
+  s = __arm_mte_increment_tag (s, 1);
+  p = fun->fun (s, len);
+
+  if (p != s)
+    ERR ("%s(%p,..) returned %p\n", fun->name, s, p);
+
+  for (i = 0; i < salign; i++)
+    {
+      if (src[i] != '?')
+	{
+	  ERR ("%s(align %d, %d) failed\n", fun->name, salign, len);
+	  mtag_quoteat ("got head", src, len + 2 * A, i);
+	  return;
+	}
+    }
+
+  for (; i < salign + len; i++)
+    {
+      if (s[i - salign] != 0)
+	{
+	  ERR ("%s(align %d, %d) failed\n", fun->name, salign, len);
+	  mtag_quoteat ("got body", src, len + 2 * A, i);
+	  return;
+	}
+    }
+
+  for (; i < len + 2 * A; i++)
+    {
+      if (src[i] != '?')
+	{
+	  ERR ("%s(align %d, %d) failed\n", fun->name, salign, len);
+	  mtag_quoteat ("got tail", src, len + 2 * A, i);
+	  return;
+	}
+    }
+
+  untag_buffer (src, len + 2 * A, 1);
+}
+
+int
+main ()
+{
+  if (!mte_enabled ())
+    return 0;
+
+  sbuf = mte_mmap (LEN + 3 * A);
+  int r = 0;
+  for (int i = 0; funtab[i].name; i++)
+    {
+      err_count = 0;
+      for (int s = 0; s < A; s += 16)
+	{
+	  int n;
+	  for (n = 0; n < 200; n += 16)
+	    {
+	      test (funtab + i, s, n);
+	    }
+	  for (; n < LEN; n *= 2)
+	    {
+	      test (funtab + i, s, n);
+	    }
+	}
+      printf ("%s %s\n", err_count ? "FAIL" : "PASS", funtab[i].name);
+      if (err_count)
+	r = -1;
+    }
+  return r;
+}
+#else
+int
+main ()
+{
+  return 0;
+}
+#endif