Commit 600bca58 authored by Andrei Vagin's avatar Andrei Vagin Committed by Andrew Morton
Browse files

selftests/mm: check that PAGEMAP_SCAN returns correct categories 

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: default avatarAndrei Vagin <avagin@google.com>
Signed-off-by: default avatarColin Ian King <colin.i.king@gmail.com>
Reviewed-by: default avatarMuhammad Usama Anjum <usama.anjum@collabora.com>
Tested-by: default avatarMuhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Michał Mirosław <mirq-linux@rere.qmqm.pl>
[avagin@google.com: allow running tests on old kernels]
  Link: https://lkml.kernel.org/r/20231117181127.2574897-1-avagin@google.com


Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent e6a9a2cb

tools/testing/selftests/mm/vm_util.c

+77 −3
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
#include <dirent.h>

#include <sys/ioctl.h>

#include <linux/userfaultfd.h>

#include <linux/fs.h>

#include <sys/syscall.h>

#include <unistd.h>

#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)