From 600bca580579d8d8454cc8fe3290e2f8b9c01884 Mon Sep 17 00:00:00 2001 From: Andrei Vagin Date: Mon, 6 Nov 2023 14:09:59 -0800 Subject: [PATCH] selftests/mm: check that PAGEMAP_SCAN returns correct categories MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Right now, tests read page flags from /proc/pid/pagemap files. With this change, tests will check that PAGEMAP_SCAN return correct information too. [colin.i.king@gmail.com: fix spelling mistake "succedded" -> "succeeded"] Link: https://lkml.kernel.org/r/20231121093104.1728332-1-colin.i.king@gmail.com Link: https://lkml.kernel.org/r/20231106220959.296568-2-avagin@google.com Signed-off-by: Andrei Vagin Signed-off-by: Colin Ian King Reviewed-by: Muhammad Usama Anjum Tested-by: Muhammad Usama Anjum Cc: Michał Mirosław [avagin@google.com: allow running tests on old kernels] Link: https://lkml.kernel.org/r/20231117181127.2574897-1-avagin@google.com Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/vm_util.c | 80 ++++++++++++++++++++++++++-- 1 file changed, 77 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index 3082b40492dd..05736c615734 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -4,6 +4,7 @@ #include #include #include +#include #include #include #include "../kselftest.h" @@ -28,19 +29,92 @@ uint64_t pagemap_get_entry(int fd, char *start) return entry; } +static uint64_t __pagemap_scan_get_categories(int fd, char *start, struct page_region *r) +{ + struct pm_scan_arg arg; + + arg.start = (uintptr_t)start; + arg.end = (uintptr_t)(start + psize()); + arg.vec = (uintptr_t)r; + arg.vec_len = 1; + arg.flags = 0; + arg.size = sizeof(struct pm_scan_arg); + arg.max_pages = 0; + arg.category_inverted = 0; + arg.category_mask = 0; + arg.category_anyof_mask = PAGE_IS_WPALLOWED | PAGE_IS_WRITTEN | PAGE_IS_FILE | + PAGE_IS_PRESENT | PAGE_IS_SWAPPED | PAGE_IS_PFNZERO | + PAGE_IS_HUGE | PAGE_IS_SOFT_DIRTY; + arg.return_mask = arg.category_anyof_mask; + + return ioctl(fd, PAGEMAP_SCAN, &arg); +} + +static uint64_t pagemap_scan_get_categories(int fd, char *start) +{ + struct page_region r; + long ret; + + ret = __pagemap_scan_get_categories(fd, start, &r); + if (ret < 0) + ksft_exit_fail_msg("PAGEMAP_SCAN failed: %s\n", strerror(errno)); + if (ret == 0) + return 0; + return r.categories; +} + +/* `start` is any valid address. */ +static bool pagemap_scan_supported(int fd, char *start) +{ + static int supported = -1; + int ret; + + if (supported != -1) + return supported; + + /* Provide an invalid address in order to trigger EFAULT. */ + ret = __pagemap_scan_get_categories(fd, start, (struct page_region *) ~0UL); + if (ret == 0) + ksft_exit_fail_msg("PAGEMAP_SCAN succeeded unexpectedly\n"); + + supported = errno == EFAULT; + + return supported; +} + +static bool page_entry_is(int fd, char *start, char *desc, + uint64_t pagemap_flags, uint64_t pagescan_flags) +{ + bool m = pagemap_get_entry(fd, start) & pagemap_flags; + + if (pagemap_scan_supported(fd, start)) { + bool s = pagemap_scan_get_categories(fd, start) & pagescan_flags; + + if (m == s) + return m; + + ksft_exit_fail_msg( + "read and ioctl return unmatched results for %s: %d %d", desc, m, s); + } + return m; +} + bool pagemap_is_softdirty(int fd, char *start) { - return pagemap_get_entry(fd, start) & PM_SOFT_DIRTY; + return page_entry_is(fd, start, "soft-dirty", + PM_SOFT_DIRTY, PAGE_IS_SOFT_DIRTY); } bool pagemap_is_swapped(int fd, char *start) { - return pagemap_get_entry(fd, start) & PM_SWAP; + return page_entry_is(fd, start, "swap", PM_SWAP, PAGE_IS_SWAPPED); } bool pagemap_is_populated(int fd, char *start) { - return pagemap_get_entry(fd, start) & (PM_PRESENT | PM_SWAP); + return page_entry_is(fd, start, "populated", + PM_PRESENT | PM_SWAP, + PAGE_IS_PRESENT | PAGE_IS_SWAPPED); } unsigned long pagemap_get_pfn(int fd, char *start) -- 2.20.1