1 files changed, 73 insertions, 16 deletions

diff --git a/tools/testing/selftests/vm/mremap_dontunmap.c b/tools/testing/selftests/mm/mremap_dontunmap.c
index 3a7b5ef0b0c6..1d75084b9ca5 100644
--- a/tools/testing/selftests/vm/mremap_dontunmap.c
+++ b/tools/testing/selftests/mm/mremap_dontunmap.c
@@ -7,6 +7,7 @@
  */
 #define _GNU_SOURCE
 #include <sys/mman.h>
+#include <linux/mman.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -15,10 +16,6 @@
 
 #include "../kselftest.h"
 
-#ifndef MREMAP_DONTUNMAP
-#define MREMAP_DONTUNMAP 4
-#endif
-
 unsigned long page_size;
 char *page_buffer;
 
@@ -30,14 +27,14 @@ static void dump_maps(void)
 	system(cmd);
 }
 
-#define BUG_ON(condition, description)					      \
-	do {								      \
-		if (condition) {					      \
-			fprintf(stderr, "[FAIL]\t%s():%d\t%s:%s\n", __func__, \
-				__LINE__, (description), strerror(errno));    \
-			dump_maps();					  \
-			exit(1);					      \
-		} 							      \
+#define BUG_ON(condition, description)						\
+	do {									\
+		if (condition) {						\
+			dump_maps();						\
+			ksft_exit_fail_msg("[FAIL]\t%s:%d\t%s:%s\n",		\
+					   __func__, __LINE__, (description),	\
+					   strerror(errno));			\
+		}								\
 	} while (0)
 
 // Try a simple operation for to "test" for kernel support this prevents
@@ -125,6 +122,59 @@ static void mremap_dontunmap_simple()
 	       "unable to unmap destination mapping");
 	BUG_ON(munmap(source_mapping, num_pages * page_size) == -1,
 	       "unable to unmap source mapping");
+	ksft_test_result_pass("%s\n", __func__);
+}
+
+// This test validates that MREMAP_DONTUNMAP on a shared mapping works as expected.
+static void mremap_dontunmap_simple_shmem()
+{
+	unsigned long num_pages = 5;
+
+	int mem_fd = memfd_create("memfd", MFD_CLOEXEC);
+	BUG_ON(mem_fd < 0, "memfd_create");
+
+	BUG_ON(ftruncate(mem_fd, num_pages * page_size) < 0,
+			"ftruncate");
+
+	void *source_mapping =
+	    mmap(NULL, num_pages * page_size, PROT_READ | PROT_WRITE,
+		 MAP_FILE | MAP_SHARED, mem_fd, 0);
+	BUG_ON(source_mapping == MAP_FAILED, "mmap");
+
+	BUG_ON(close(mem_fd) < 0, "close");
+
+	memset(source_mapping, 'a', num_pages * page_size);
+
+	// Try to just move the whole mapping anywhere (not fixed).
+	void *dest_mapping =
+	    mremap(source_mapping, num_pages * page_size, num_pages * page_size,
+		   MREMAP_DONTUNMAP | MREMAP_MAYMOVE, NULL);
+	if (dest_mapping == MAP_FAILED && errno == EINVAL) {
+		// Old kernel which doesn't support MREMAP_DONTUNMAP on shmem.
+		BUG_ON(munmap(source_mapping, num_pages * page_size) == -1,
+			"unable to unmap source mapping");
+		return;
+	}
+
+	BUG_ON(dest_mapping == MAP_FAILED, "mremap");
+
+	// Validate that the pages have been moved, we know they were moved if
+	// the dest_mapping contains a's.
+	BUG_ON(check_region_contains_byte
+	       (dest_mapping, num_pages * page_size, 'a') != 0,
+	       "pages did not migrate");
+
+	// Because the region is backed by shmem, we will actually see the same
+	// memory at the source location still.
+	BUG_ON(check_region_contains_byte
+	       (source_mapping, num_pages * page_size, 'a') != 0,
+	       "source should have no ptes");
+
+	BUG_ON(munmap(dest_mapping, num_pages * page_size) == -1,
+	       "unable to unmap destination mapping");
+	BUG_ON(munmap(source_mapping, num_pages * page_size) == -1,
+	       "unable to unmap source mapping");
+	ksft_test_result_pass("%s\n", __func__);
 }
 
 // This test validates MREMAP_DONTUNMAP will move page tables to a specific
@@ -171,6 +221,7 @@ static void mremap_dontunmap_simple_fixed()
 	       "unable to unmap destination mapping");
 	BUG_ON(munmap(source_mapping, num_pages * page_size) == -1,
 	       "unable to unmap source mapping");
+	ksft_test_result_pass("%s\n", __func__);
 }
 
 // This test validates that we can MREMAP_DONTUNMAP for a portion of an
@@ -221,6 +272,7 @@ static void mremap_dontunmap_partial_mapping()
 	       "unable to unmap destination mapping");
 	BUG_ON(munmap(source_mapping, num_pages * page_size) == -1,
 	       "unable to unmap source mapping");
+	ksft_test_result_pass("%s\n", __func__);
 }
 
 // This test validates that we can remap over only a portion of a mapping.
@@ -280,19 +332,24 @@ static void mremap_dontunmap_partial_mapping_overwrite(void)
 	       "unable to unmap destination mapping");
 	BUG_ON(munmap(source_mapping, 5 * page_size) == -1,
 	       "unable to unmap source mapping");
+	ksft_test_result_pass("%s\n", __func__);
 }
 
 int main(void)
 {
+	ksft_print_header();
+
 	page_size = sysconf(_SC_PAGE_SIZE);
 
 	// test for kernel support for MREMAP_DONTUNMAP skipping the test if
 	// not.
 	if (kernel_support_for_mremap_dontunmap() != 0) {
-		printf("No kernel support for MREMAP_DONTUNMAP\n");
-		return KSFT_SKIP;
+		ksft_print_msg("No kernel support for MREMAP_DONTUNMAP\n");
+		ksft_finished();
 	}
 
+	ksft_set_plan(5);
+
 	// Keep a page sized buffer around for when we need it.
 	page_buffer =
 	    mmap(NULL, page_size, PROT_READ | PROT_WRITE,
@@ -300,6 +357,7 @@ int main(void)
 	BUG_ON(page_buffer == MAP_FAILED, "unable to mmap a page.");
 
 	mremap_dontunmap_simple();
+	mremap_dontunmap_simple_shmem();
 	mremap_dontunmap_simple_fixed();
 	mremap_dontunmap_partial_mapping();
 	mremap_dontunmap_partial_mapping_overwrite();
@@ -307,6 +365,5 @@ int main(void)
 	BUG_ON(munmap(page_buffer, page_size) == -1,
 	       "unable to unmap page buffer");
 
-	printf("OK\n");
-	return 0;
+	ksft_finished();
 }