#include <stddef.h>
#include <sys/mman.h>
#include <sys/prctl.h>

void *__memchr_aarch64 (const void *, int, size_t);

#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

int main (void)
{
  int r = prctl (PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE | PR_MTE_TCF_SYNC | (0xfffe << PR_MTE_TAG_SHIFT), 0, 0, 0);
  if (r < 0) return -1;
  char *s = mmap (NULL, 4096, PROT_READ | PROT_WRITE | PROT_MTE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  if (s == MAP_FAILED) return -1;
  s[0] = 1;
  __memchr_aarch64(s, 1, 4096);
  return 0;
}