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Signed-off-by: Andrei Vagin Reviewed-by: Lorenzo Stoakes --- tools/testing/selftests/mm/guard-regions.c | 57 ++++++++++++++++++++++ 1 file changed, 57 insertions(+) diff --git a/tools/testing/selftests/mm/guard-regions.c b/tools/testing/selftests/mm/guard-regions.c index 0c7183e8b661..c99f3da8bfb7 100644 --- a/tools/testing/selftests/mm/guard-regions.c +++ b/tools/testing/selftests/mm/guard-regions.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -2079,4 +2080,60 @@ TEST_F(guard_regions, pagemap) ASSERT_EQ(munmap(ptr, 10 * page_size), 0); } +/* + * Assert that PAGEMAP_SCAN correctly reports guard region ranges. + */ +TEST_F(guard_regions, pagemap_scan) +{ + const unsigned long page_size = self->page_size; + struct page_region pm_regs[10]; + struct pm_scan_arg pm_scan_args = { + .size = sizeof(struct pm_scan_arg), + .category_anyof_mask = PAGE_IS_GUARD, + .return_mask = PAGE_IS_GUARD, + .vec = (long)&pm_regs, + .vec_len = ARRAY_SIZE(pm_regs), + }; + int proc_fd, i; + char *ptr; + + proc_fd = open("/proc/self/pagemap", O_RDONLY); + ASSERT_NE(proc_fd, -1); + + ptr = mmap_(self, variant, NULL, 10 * page_size, + PROT_READ | PROT_WRITE, 0, 0); + ASSERT_NE(ptr, MAP_FAILED); + + pm_scan_args.start = (long)ptr; + pm_scan_args.end = (long)ptr + 10 * page_size; + ASSERT_EQ(ioctl(proc_fd, PAGEMAP_SCAN, &pm_scan_args), 0); + ASSERT_EQ(pm_scan_args.walk_end, (long)ptr + 10 * page_size); + + /* Install a guard region in every other page. */ + for (i = 0; i < 10; i += 2) { + char *ptr_p = &ptr[i * page_size]; + + ASSERT_EQ(syscall(__NR_madvise, ptr_p, page_size, MADV_GUARD_INSTALL), 0); + } + + /* + * Assert ioctl() returns the count of located regions, where each + * region spans every other page within the range of 10 pages. + */ + ASSERT_EQ(ioctl(proc_fd, PAGEMAP_SCAN, &pm_scan_args), 5); + ASSERT_EQ(pm_scan_args.walk_end, (long)ptr + 10 * page_size); + + /* Re-read from pagemap, and assert guard regions are detected. */ + for (i = 0; i < 5; i++) { + long ptr_p = (long)&ptr[2 * i * page_size]; + + ASSERT_EQ(pm_regs[i].start, ptr_p); + ASSERT_EQ(pm_regs[i].end, ptr_p + page_size); + ASSERT_EQ(pm_regs[i].categories, PAGE_IS_GUARD); + } + + ASSERT_EQ(close(proc_fd), 0); + ASSERT_EQ(munmap(ptr, 10 * page_size), 0); +} + TEST_HARNESS_MAIN