40 // Try a simple operation for to "test" for kernel support this prevents
97 	unsigned long num_pages = 5;  in mremap_dontunmap_simple()
104 	memset(source_mapping, 'a', num_pages * page_size);  in mremap_dontunmap_simple()
113 	// the dest_mapping contains a's.  in mremap_dontunmap_simple()
115 	       (dest_mapping, num_pages * page_size, 'a') != 0,  in mremap_dontunmap_simple()
127 // This test validates that MREMAP_DONTUNMAP on a shared mapping works as expected.
130 	unsigned long num_pages = 5;  in mremap_dontunmap_simple_shmem()
145 	memset(source_mapping, 'a', num_pages * page_size);  in mremap_dontunmap_simple_shmem()
161 	// the dest_mapping contains a's.  in mremap_dontunmap_simple_shmem()
163 	       (dest_mapping, num_pages * page_size, 'a') != 0,  in mremap_dontunmap_simple_shmem()
169 	       (source_mapping, num_pages * page_size, 'a') != 0,  in mremap_dontunmap_simple_shmem()
178 // This test validates MREMAP_DONTUNMAP will move page tables to a specific
183 	unsigned long num_pages = 5;  in mremap_dontunmap_simple_fixed()
185 	// Since we want to guarantee that we can remap to a point, we will  in mremap_dontunmap_simple_fixed()
186 	// create a mapping up front.  in mremap_dontunmap_simple_fixed()
197 	memset(source_mapping, 'a', num_pages * page_size);  in mremap_dontunmap_simple_fixed()
208 	// to be gone and replaced with a's.  in mremap_dontunmap_simple_fixed()
210 	       (dest_mapping, num_pages * page_size, 'a') != 0,  in mremap_dontunmap_simple_fixed()
224 // This test validates that we can MREMAP_DONTUNMAP for a portion of an
237 	 *  With the destination mapping containing 5 pages of As.  in mremap_dontunmap_partial_mapping()
247 	memset(source_mapping, 'a', num_pages * page_size);  in mremap_dontunmap_partial_mapping()
249 	// We will grab the last 5 pages of the source and move them.  in mremap_dontunmap_partial_mapping()
251 	    mremap(source_mapping + (5 * page_size), 5 * page_size,  in mremap_dontunmap_partial_mapping()
252 		   5 * page_size,  in mremap_dontunmap_partial_mapping()
256 	// We expect the first 5 pages of the source to contain a's and the  in mremap_dontunmap_partial_mapping()
257 	// final 5 pages to contain zeros.  in mremap_dontunmap_partial_mapping()
258 	BUG_ON(check_region_contains_byte(source_mapping, 5 * page_size, 'a') !=  in mremap_dontunmap_partial_mapping()
259 	       0, "first 5 pages of source should have original pages");  in mremap_dontunmap_partial_mapping()
261 	       (source_mapping + (5 * page_size), 5 * page_size, 0) != 0,  in mremap_dontunmap_partial_mapping()
262 	       "final 5 pages of source should have no ptes");  in mremap_dontunmap_partial_mapping()
264 	// Finally we expect the destination to have 5 pages worth of a's.  in mremap_dontunmap_partial_mapping()
265 	BUG_ON(check_region_contains_byte(dest_mapping, 5 * page_size, 'a') !=  in mremap_dontunmap_partial_mapping()
268 	BUG_ON(munmap(dest_mapping, 5 * page_size) == -1,  in mremap_dontunmap_partial_mapping()
274 // This test validates that we can remap over only a portion of a mapping.
290 	 *  With the destination mapping containing 5 pages of As.  in mremap_dontunmap_partial_mapping_overwrite()
296 	    mmap(NULL, 5 * page_size, PROT_READ | PROT_WRITE,  in mremap_dontunmap_partial_mapping_overwrite()
299 	memset(source_mapping, 'a', 5 * page_size);  in mremap_dontunmap_partial_mapping_overwrite()
307 	// We will grab the last 5 pages of the source and move them.  in mremap_dontunmap_partial_mapping_overwrite()
309 	    mremap(source_mapping, 5 * page_size,  in mremap_dontunmap_partial_mapping_overwrite()
310 		   5 * page_size,  in mremap_dontunmap_partial_mapping_overwrite()
315 	BUG_ON(check_region_contains_byte(source_mapping, 5 * page_size, 0) !=  in mremap_dontunmap_partial_mapping_overwrite()
316 	       0, "first 5 pages of source should have no ptes");  in mremap_dontunmap_partial_mapping_overwrite()
318 	// Finally we expect the destination to have 5 pages worth of a's.  in mremap_dontunmap_partial_mapping_overwrite()
319 	BUG_ON(check_region_contains_byte(dest_mapping, 5 * page_size, 'a') != 0,  in mremap_dontunmap_partial_mapping_overwrite()
322 	// Finally the last 5 pages shouldn't have been touched.  in mremap_dontunmap_partial_mapping_overwrite()
323 	BUG_ON(check_region_contains_byte(dest_mapping + (5 * page_size),  in mremap_dontunmap_partial_mapping_overwrite()
324 				5 * page_size, 'X') != 0,  in mremap_dontunmap_partial_mapping_overwrite()
325 			"dest mapping should have retained the last 5 pages");  in mremap_dontunmap_partial_mapping_overwrite()
329 	BUG_ON(munmap(source_mapping, 5 * page_size) == -1,  in mremap_dontunmap_partial_mapping_overwrite()
344 	// Keep a page sized buffer around for when we need it.  in main()
348 	BUG_ON(page_buffer == MAP_FAILED, "unable to mmap a page.");  in main()