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.
Signed-off-by: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
---
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 575ef80..827f2c0 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -6,6 +6,7 @@ TARGETS += cpu-hotplug
TARGETS += memory-hotplug
TARGETS += efivarfs
TARGETS += ptrace
+TARGETS += soft-dirty
all:
for TARGET in $(TARGETS); do \
diff --git a/tools/testing/selftests/soft-dirty/Makefile b/tools/testing/selftests/soft-dirty/Makefile
new file mode 100644
index 0000000..a9cdc82
--- /dev/null
+++ b/tools/testing/selftests/soft-dirty/Makefile
@@ -0,0 +1,10 @@
+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]"
diff --git a/tools/testing/selftests/soft-dirty/soft-dirty.c b/tools/testing/selftests/soft-dirty/soft-dirty.c
new file mode 100644
index 0000000..aba4f87
--- /dev/null
+++ b/tools/testing/selftests/soft-dirty/soft-dirty.c
@@ -0,0 +1,114 @@
+#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;
+}
--
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