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-rw-r--r--tools/testing/selftests/mm/map_hugetlb.c97
1 files changed, 97 insertions, 0 deletions
diff --git a/tools/testing/selftests/mm/map_hugetlb.c b/tools/testing/selftests/mm/map_hugetlb.c
new file mode 100644
index 0000000000..193281560b
--- /dev/null
+++ b/tools/testing/selftests/mm/map_hugetlb.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Example of using hugepage memory in a user application using the mmap
+ * system call with MAP_HUGETLB flag. Before running this program make
+ * sure the administrator has allocated enough default sized huge pages
+ * to cover the 256 MB allocation.
+ *
+ * For ia64 architecture, Linux kernel reserves Region number 4 for hugepages.
+ * That means the addresses starting with 0x800000... will need to be
+ * specified. Specifying a fixed address is not required on ppc64, i386
+ * or x86_64.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+
+#define LENGTH (256UL*1024*1024)
+#define PROTECTION (PROT_READ | PROT_WRITE)
+
+/* Only ia64 requires this */
+#ifdef __ia64__
+#define ADDR (void *)(0x8000000000000000UL)
+#define FLAGS (MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB | MAP_FIXED)
+#else
+#define ADDR (void *)(0x0UL)
+#define FLAGS (MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB)
+#endif
+
+static void check_bytes(char *addr)
+{
+ printf("First hex is %x\n", *((unsigned int *)addr));
+}
+
+static void write_bytes(char *addr, size_t length)
+{
+ unsigned long i;
+
+ for (i = 0; i < length; i++)
+ *(addr + i) = (char)i;
+}
+
+static int read_bytes(char *addr, size_t length)
+{
+ unsigned long i;
+
+ check_bytes(addr);
+ for (i = 0; i < length; i++)
+ if (*(addr + i) != (char)i) {
+ printf("Mismatch at %lu\n", i);
+ return 1;
+ }
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ void *addr;
+ int ret;
+ size_t length = LENGTH;
+ int flags = FLAGS;
+ int shift = 0;
+
+ if (argc > 1)
+ length = atol(argv[1]) << 20;
+ if (argc > 2) {
+ shift = atoi(argv[2]);
+ if (shift)
+ flags |= (shift & MAP_HUGE_MASK) << MAP_HUGE_SHIFT;
+ }
+
+ if (shift)
+ printf("%u kB hugepages\n", 1 << (shift - 10));
+ else
+ printf("Default size hugepages\n");
+ printf("Mapping %lu Mbytes\n", (unsigned long)length >> 20);
+
+ addr = mmap(ADDR, length, PROTECTION, flags, -1, 0);
+ if (addr == MAP_FAILED) {
+ perror("mmap");
+ exit(1);
+ }
+
+ printf("Returned address is %p\n", addr);
+ check_bytes(addr);
+ write_bytes(addr, length);
+ ret = read_bytes(addr, length);
+
+ /* munmap() length of MAP_HUGETLB memory must be hugepage aligned */
+ if (munmap(addr, length)) {
+ perror("munmap");
+ exit(1);
+ }
+
+ return ret;
+}