Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 58c7be84 authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by Linus Torvalds
Browse files

selftest: add simple test for soft-dirty bit 



It creates a mapping of 3 pages and checks that reads, writes and
clear-refs result in present and soft-dirt bits reported from pagemap2
set as expected.

[akpm@linux-foundation.org: alphasort the Makefile TARGETS to reduce rejects]
Signed-off-by: default avatarPavel Emelyanov <xemul@parallels.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 835f2f51

tools/testing/selftests/Makefile

+4 −3
Original line number Diff line number Diff line 
TARGETS = breakpoints

TARGETS += cpu-hotplug

TARGETS += efivarfs

TARGETS += kcmp

TARGETS += memory-hotplug

TARGETS += mqueue

TARGETS += soft-dirty

TARGETS += vm

TARGETS += cpu-hotplug

TARGETS += memory-hotplug

TARGETS += efivarfs



all:

	for TARGET in $(TARGETS); do \

tools/testing/selftests/soft-dirty/Makefile

0 → 100644
+10 −0
Original line number Diff line number Diff line 
CFLAGS += -iquote../../../../include/uapi -Wall

soft-dirty: soft-dirty.c



all: soft-dirty



clean:

	rm -f soft-dirty



run_tests: all

	@./soft-dirty || echo "soft-dirty selftests: [FAIL]"

tools/testing/selftests/soft-dirty/soft-dirty.c

0 → 100644
+114 −0
Original line number Diff line number Diff line 
#include <stdlib.h>

#include <stdio.h>

#include <sys/mman.h>

#include <unistd.h>

#include <fcntl.h>

#include <sys/types.h>



typedef unsigned long long u64;



#define PME_PRESENT	(1ULL << 63)

#define PME_SOFT_DIRTY	(1Ull << 55)



#define PAGES_TO_TEST	3

#ifndef PAGE_SIZE

#define PAGE_SIZE	4096

#endif



static void get_pagemap2(char *mem, u64 *map)

{

	int fd;



	fd = open("/proc/self/pagemap2", O_RDONLY);

	if (fd < 0) {

		perror("Can't open pagemap2");

		exit(1);

	}



	lseek(fd, (unsigned long)mem / PAGE_SIZE * sizeof(u64), SEEK_SET);

	read(fd, map, sizeof(u64) * PAGES_TO_TEST);

	close(fd);

}



static inline char map_p(u64 map)

{

	return map & PME_PRESENT ? 'p' : '-';

}



static inline char map_sd(u64 map)

{

	return map & PME_SOFT_DIRTY ? 'd' : '-';

}



static int check_pte(int step, int page, u64 *map, u64 want)

{

	if ((map[page] & want) != want) {

		printf("Step %d Page %d has %c%c, want %c%c\n",

				step, page,

				map_p(map[page]), map_sd(map[page]),

				map_p(want), map_sd(want));

		return 1;

	}



	return 0;

}



static void clear_refs(void)

{

	int fd;

	char *v = "4";



	fd = open("/proc/self/clear_refs", O_WRONLY);

	if (write(fd, v, 3) < 3) {

		perror("Can't clear soft-dirty bit");

		exit(1);

	}

	close(fd);

}



int main(void)

{

	char *mem, x;

	u64 map[PAGES_TO_TEST];



	mem = mmap(NULL, PAGES_TO_TEST * PAGE_SIZE,

			PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, 0, 0);



	x = mem[0];

	mem[2 * PAGE_SIZE] = 'c';

	get_pagemap2(mem, map);



	if (check_pte(1, 0, map, PME_PRESENT))

		return 1;

	if (check_pte(1, 1, map, 0))

		return 1;

	if (check_pte(1, 2, map, PME_PRESENT | PME_SOFT_DIRTY))

		return 1;



	clear_refs();

	get_pagemap2(mem, map);



	if (check_pte(2, 0, map, PME_PRESENT))

		return 1;

	if (check_pte(2, 1, map, 0))

		return 1;

	if (check_pte(2, 2, map, PME_PRESENT))

		return 1;



	mem[0] = 'a';

	mem[PAGE_SIZE] = 'b';

	x = mem[2 * PAGE_SIZE];

	get_pagemap2(mem, map);



	if (check_pte(3, 0, map, PME_PRESENT | PME_SOFT_DIRTY))

		return 1;

	if (check_pte(3, 1, map, PME_PRESENT | PME_SOFT_DIRTY))

		return 1;

	if (check_pte(3, 2, map, PME_PRESENT))

		return 1;



	(void)x; /* gcc warn */



	printf("PASS\n");

	return 0;

}