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// SPDX-License-Identifier: GPL-2.0-only
/*
* MADV_POPULATE_READ and MADV_POPULATE_WRITE tests
*
* Copyright 2021, Red Hat, Inc.
*
* Author(s): David Hildenbrand <david@redhat.com>
*/
#define _GNU_SOURCE
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <stdint.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/mman.h>
#include "../kselftest.h"
#if defined(MADV_POPULATE_READ) && defined(MADV_POPULATE_WRITE)
/*
* For now, we're using 2 MiB of private anonymous memory for all tests.
*/
#define SIZE (2 * 1024 * 1024)
static size_t pagesize;
static uint64_t pagemap_get_entry(int fd, char *start)
{
const unsigned long pfn = (unsigned long)start / pagesize;
uint64_t entry;
int ret;
ret = pread(fd, &entry, sizeof(entry), pfn * sizeof(entry));
if (ret != sizeof(entry))
ksft_exit_fail_msg("reading pagemap failed\n");
return entry;
}
static bool pagemap_is_populated(int fd, char *start)
{
uint64_t entry = pagemap_get_entry(fd, start);
/* Present or swapped. */
return entry & 0xc000000000000000ull;
}
static bool pagemap_is_softdirty(int fd, char *start)
{
uint64_t entry = pagemap_get_entry(fd, start);
return entry & 0x0080000000000000ull;
}
static void sense_support(void)
{
char *addr;
int ret;
addr = mmap(0, pagesize, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (!addr)
ksft_exit_fail_msg("mmap failed\n");
ret = madvise(addr, pagesize, MADV_POPULATE_READ);
if (ret)
ksft_exit_skip("MADV_POPULATE_READ is not available\n");
ret = madvise(addr, pagesize, MADV_POPULATE_WRITE);
if (ret)
ksft_exit_skip("MADV_POPULATE_WRITE is not available\n");
munmap(addr, pagesize);
}
static void test_prot_read(void)
{
char *addr;
int ret;
ksft_print_msg("[RUN] %s\n", __func__);
addr = mmap(0, SIZE, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (addr == MAP_FAILED)
ksft_exit_fail_msg("mmap failed\n");
ret = madvise(addr, SIZE, MADV_POPULATE_READ);
ksft_test_result(!ret, "MADV_POPULATE_READ with PROT_READ\n");
ret = madvise(addr, SIZE, MADV_POPULATE_WRITE);
ksft_test_result(ret == -1 && errno == EINVAL,
"MADV_POPULATE_WRITE with PROT_READ\n");
munmap(addr, SIZE);
}
static void test_prot_write(void)
{
char *addr;
int ret;
ksft_print_msg("[RUN] %s\n", __func__);
addr = mmap(0, SIZE, PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (addr == MAP_FAILED)
ksft_exit_fail_msg("mmap failed\n");
ret = madvise(addr, SIZE, MADV_POPULATE_READ);
ksft_test_result(ret == -1 && errno == EINVAL,
"MADV_POPULATE_READ with PROT_WRITE\n");
ret = madvise(addr, SIZE, MADV_POPULATE_WRITE);
ksft_test_result(!ret, "MADV_POPULATE_WRITE with PROT_WRITE\n");
munmap(addr, SIZE);
}
static void test_holes(void)
{
char *addr;
int ret;
ksft_print_msg("[RUN] %s\n", __func__);
addr = mmap(0, SIZE, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (addr == MAP_FAILED)
ksft_exit_fail_msg("mmap failed\n");
ret = munmap(addr + pagesize, pagesize);
if (ret)
ksft_exit_fail_msg("munmap failed\n");
/* Hole in the middle */
ret = madvise(addr, SIZE, MADV_POPULATE_READ);
ksft_test_result(ret == -1 && errno == ENOMEM,
"MADV_POPULATE_READ with holes in the middle\n");
ret = madvise(addr, SIZE, MADV_POPULATE_WRITE);
ksft_test_result(ret == -1 && errno == ENOMEM,
"MADV_POPULATE_WRITE with holes in the middle\n");
/* Hole at end */
ret = madvise(addr, 2 * pagesize, MADV_POPULATE_READ);
ksft_test_result(ret == -1 && errno == ENOMEM,
"MADV_POPULATE_READ with holes at the end\n");
ret = madvise(addr, 2 * pagesize, MADV_POPULATE_WRITE);
ksft_test_result(ret == -1 && errno == ENOMEM,
"MADV_POPULATE_WRITE with holes at the end\n");
/* Hole at beginning */
ret = madvise(addr + pagesize, pagesize, MADV_POPULATE_READ);
ksft_test_result(ret == -1 && errno == ENOMEM,
"MADV_POPULATE_READ with holes at the beginning\n");
ret = madvise(addr + pagesize, pagesize, MADV_POPULATE_WRITE);
ksft_test_result(ret == -1 && errno == ENOMEM,
"MADV_POPULATE_WRITE with holes at the beginning\n");
munmap(addr, SIZE);
}
static bool range_is_populated(char *start, ssize_t size)
{
int fd = open("/proc/self/pagemap", O_RDONLY);
bool ret = true;
if (fd < 0)
ksft_exit_fail_msg("opening pagemap failed\n");
for (; size > 0 && ret; size -= pagesize, start += pagesize)
if (!pagemap_is_populated(fd, start))
ret = false;
close(fd);
return ret;
}
static bool range_is_not_populated(char *start, ssize_t size)
{
int fd = open("/proc/self/pagemap", O_RDONLY);
bool ret = true;
if (fd < 0)
ksft_exit_fail_msg("opening pagemap failed\n");
for (; size > 0 && ret; size -= pagesize, start += pagesize)
if (pagemap_is_populated(fd, start))
ret = false;
close(fd);
return ret;
}
static void test_populate_read(void)
{
char *addr;
int ret;
ksft_print_msg("[RUN] %s\n", __func__);
addr = mmap(0, SIZE, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (addr == MAP_FAILED)
ksft_exit_fail_msg("mmap failed\n");
ksft_test_result(range_is_not_populated(addr, SIZE),
"range initially not populated\n");
ret = madvise(addr, SIZE, MADV_POPULATE_READ);
ksft_test_result(!ret, "MADV_POPULATE_READ\n");
ksft_test_result(range_is_populated(addr, SIZE),
"range is populated\n");
munmap(addr, SIZE);
}
static void test_populate_write(void)
{
char *addr;
int ret;
ksft_print_msg("[RUN] %s\n", __func__);
addr = mmap(0, SIZE, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (addr == MAP_FAILED)
ksft_exit_fail_msg("mmap failed\n");
ksft_test_result(range_is_not_populated(addr, SIZE),
"range initially not populated\n");
ret = madvise(addr, SIZE, MADV_POPULATE_WRITE);
ksft_test_result(!ret, "MADV_POPULATE_WRITE\n");
ksft_test_result(range_is_populated(addr, SIZE),
"range is populated\n");
munmap(addr, SIZE);
}
static bool range_is_softdirty(char *start, ssize_t size)
{
int fd = open("/proc/self/pagemap", O_RDONLY);
bool ret = true;
if (fd < 0)
ksft_exit_fail_msg("opening pagemap failed\n");
for (; size > 0 && ret; size -= pagesize, start += pagesize)
if (!pagemap_is_softdirty(fd, start))
ret = false;
close(fd);
return ret;
}
static bool range_is_not_softdirty(char *start, ssize_t size)
{
int fd = open("/proc/self/pagemap", O_RDONLY);
bool ret = true;
if (fd < 0)
ksft_exit_fail_msg("opening pagemap failed\n");
for (; size > 0 && ret; size -= pagesize, start += pagesize)
if (pagemap_is_softdirty(fd, start))
ret = false;
close(fd);
return ret;
}
static void clear_softdirty(void)
{
int fd = open("/proc/self/clear_refs", O_WRONLY);
const char *ctrl = "4";
int ret;
if (fd < 0)
ksft_exit_fail_msg("opening clear_refs failed\n");
ret = write(fd, ctrl, strlen(ctrl));
if (ret != strlen(ctrl))
ksft_exit_fail_msg("writing clear_refs failed\n");
close(fd);
}
static void test_softdirty(void)
{
char *addr;
int ret;
ksft_print_msg("[RUN] %s\n", __func__);
addr = mmap(0, SIZE, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (addr == MAP_FAILED)
ksft_exit_fail_msg("mmap failed\n");
/* Clear any softdirty bits. */
clear_softdirty();
ksft_test_result(range_is_not_softdirty(addr, SIZE),
"range is not softdirty\n");
/* Populating READ should set softdirty. */
ret = madvise(addr, SIZE, MADV_POPULATE_READ);
ksft_test_result(!ret, "MADV_POPULATE_READ\n");
ksft_test_result(range_is_not_softdirty(addr, SIZE),
"range is not softdirty\n");
/* Populating WRITE should set softdirty. */
ret = madvise(addr, SIZE, MADV_POPULATE_WRITE);
ksft_test_result(!ret, "MADV_POPULATE_WRITE\n");
ksft_test_result(range_is_softdirty(addr, SIZE),
"range is softdirty\n");
munmap(addr, SIZE);
}
int main(int argc, char **argv)
{
int err;
pagesize = getpagesize();
ksft_print_header();
ksft_set_plan(21);
sense_support();
test_prot_read();
test_prot_write();
test_holes();
test_populate_read();
test_populate_write();
test_softdirty();
err = ksft_get_fail_cnt();
if (err)
ksft_exit_fail_msg("%d out of %d tests failed\n",
err, ksft_test_num());
return ksft_exit_pass();
}
#else /* defined(MADV_POPULATE_READ) && defined(MADV_POPULATE_WRITE) */
#warning "missing MADV_POPULATE_READ or MADV_POPULATE_WRITE definition"
int main(int argc, char **argv)
{
ksft_print_header();
ksft_exit_skip("MADV_POPULATE_READ or MADV_POPULATE_WRITE not defined\n");
}
#endif /* defined(MADV_POPULATE_READ) && defined(MADV_POPULATE_WRITE) */
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