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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2020 Google LLC
*/
#define _GNU_SOURCE
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
#include <time.h>
#include <stdbool.h>
#include "../kselftest.h"
#define EXPECT_SUCCESS 0
#define EXPECT_FAILURE 1
#define NON_OVERLAPPING 0
#define OVERLAPPING 1
#define NS_PER_SEC 1000000000ULL
#define VALIDATION_DEFAULT_THRESHOLD 4 /* 4MB */
#define VALIDATION_NO_THRESHOLD 0 /* Verify the entire region */
#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
struct config {
unsigned long long src_alignment;
unsigned long long dest_alignment;
unsigned long long region_size;
int overlapping;
};
struct test {
const char *name;
struct config config;
int expect_failure;
};
enum {
_1KB = 1ULL << 10, /* 1KB -> not page aligned */
_4KB = 4ULL << 10,
_8KB = 8ULL << 10,
_1MB = 1ULL << 20,
_2MB = 2ULL << 20,
_4MB = 4ULL << 20,
_1GB = 1ULL << 30,
_2GB = 2ULL << 30,
PMD = _2MB,
PUD = _1GB,
};
#define PTE page_size
#define MAKE_TEST(source_align, destination_align, size, \
overlaps, should_fail, test_name) \
(struct test){ \
.name = test_name, \
.config = { \
.src_alignment = source_align, \
.dest_alignment = destination_align, \
.region_size = size, \
.overlapping = overlaps, \
}, \
.expect_failure = should_fail \
}
/*
* Returns false if the requested remap region overlaps with an
* existing mapping (e.g text, stack) else returns true.
*/
static bool is_remap_region_valid(void *addr, unsigned long long size)
{
void *remap_addr = NULL;
bool ret = true;
/* Use MAP_FIXED_NOREPLACE flag to ensure region is not mapped */
remap_addr = mmap(addr, size, PROT_READ | PROT_WRITE,
MAP_FIXED_NOREPLACE | MAP_ANONYMOUS | MAP_SHARED,
-1, 0);
if (remap_addr == MAP_FAILED) {
if (errno == EEXIST)
ret = false;
} else {
munmap(remap_addr, size);
}
return ret;
}
/* Returns mmap_min_addr sysctl tunable from procfs */
static unsigned long long get_mmap_min_addr(void)
{
FILE *fp;
int n_matched;
static unsigned long long addr;
if (addr)
return addr;
fp = fopen("/proc/sys/vm/mmap_min_addr", "r");
if (fp == NULL) {
ksft_print_msg("Failed to open /proc/sys/vm/mmap_min_addr: %s\n",
strerror(errno));
exit(KSFT_SKIP);
}
n_matched = fscanf(fp, "%llu", &addr);
if (n_matched != 1) {
ksft_print_msg("Failed to read /proc/sys/vm/mmap_min_addr: %s\n",
strerror(errno));
fclose(fp);
exit(KSFT_SKIP);
}
fclose(fp);
return addr;
}
/*
* Returns the start address of the mapping on success, else returns
* NULL on failure.
*/
static void *get_source_mapping(struct config c)
{
unsigned long long addr = 0ULL;
void *src_addr = NULL;
unsigned long long mmap_min_addr;
mmap_min_addr = get_mmap_min_addr();
retry:
addr += c.src_alignment;
if (addr < mmap_min_addr)
goto retry;
src_addr = mmap((void *) addr, c.region_size, PROT_READ | PROT_WRITE,
MAP_FIXED_NOREPLACE | MAP_ANONYMOUS | MAP_SHARED,
-1, 0);
if (src_addr == MAP_FAILED) {
if (errno == EPERM || errno == EEXIST)
goto retry;
goto error;
}
/*
* Check that the address is aligned to the specified alignment.
* Addresses which have alignments that are multiples of that
* specified are not considered valid. For instance, 1GB address is
* 2MB-aligned, however it will not be considered valid for a
* requested alignment of 2MB. This is done to reduce coincidental
* alignment in the tests.
*/
if (((unsigned long long) src_addr & (c.src_alignment - 1)) ||
!((unsigned long long) src_addr & c.src_alignment)) {
munmap(src_addr, c.region_size);
goto retry;
}
if (!src_addr)
goto error;
return src_addr;
error:
ksft_print_msg("Failed to map source region: %s\n",
strerror(errno));
return NULL;
}
/* Returns the time taken for the remap on success else returns -1. */
static long long remap_region(struct config c, unsigned int threshold_mb,
char pattern_seed)
{
void *addr, *src_addr, *dest_addr;
unsigned long long i;
struct timespec t_start = {0, 0}, t_end = {0, 0};
long long start_ns, end_ns, align_mask, ret, offset;
unsigned long long threshold;
if (threshold_mb == VALIDATION_NO_THRESHOLD)
threshold = c.region_size;
else
threshold = MIN(threshold_mb * _1MB, c.region_size);
src_addr = get_source_mapping(c);
if (!src_addr) {
ret = -1;
goto out;
}
/* Set byte pattern */
srand(pattern_seed);
for (i = 0; i < threshold; i++)
memset((char *) src_addr + i, (char) rand(), 1);
/* Mask to zero out lower bits of address for alignment */
align_mask = ~(c.dest_alignment - 1);
/* Offset of destination address from the end of the source region */
offset = (c.overlapping) ? -c.dest_alignment : c.dest_alignment;
addr = (void *) (((unsigned long long) src_addr + c.region_size
+ offset) & align_mask);
/* See comment in get_source_mapping() */
if (!((unsigned long long) addr & c.dest_alignment))
addr = (void *) ((unsigned long long) addr | c.dest_alignment);
/* Don't destroy existing mappings unless expected to overlap */
while (!is_remap_region_valid(addr, c.region_size) && !c.overlapping) {
/* Check for unsigned overflow */
if (addr + c.dest_alignment < addr) {
ksft_print_msg("Couldn't find a valid region to remap to\n");
ret = -1;
goto out;
}
addr += c.dest_alignment;
}
clock_gettime(CLOCK_MONOTONIC, &t_start);
dest_addr = mremap(src_addr, c.region_size, c.region_size,
MREMAP_MAYMOVE|MREMAP_FIXED, (char *) addr);
clock_gettime(CLOCK_MONOTONIC, &t_end);
if (dest_addr == MAP_FAILED) {
ksft_print_msg("mremap failed: %s\n", strerror(errno));
ret = -1;
goto clean_up_src;
}
/* Verify byte pattern after remapping */
srand(pattern_seed);
for (i = 0; i < threshold; i++) {
char c = (char) rand();
if (((char *) dest_addr)[i] != c) {
ksft_print_msg("Data after remap doesn't match at offset %d\n",
i);
ksft_print_msg("Expected: %#x\t Got: %#x\n", c & 0xff,
((char *) dest_addr)[i] & 0xff);
ret = -1;
goto clean_up_dest;
}
}
start_ns = t_start.tv_sec * NS_PER_SEC + t_start.tv_nsec;
end_ns = t_end.tv_sec * NS_PER_SEC + t_end.tv_nsec;
ret = end_ns - start_ns;
/*
* Since the destination address is specified using MREMAP_FIXED, subsequent
* mremap will unmap any previous mapping at the address range specified by
* dest_addr and region_size. This significantly affects the remap time of
* subsequent tests. So we clean up mappings after each test.
*/
clean_up_dest:
munmap(dest_addr, c.region_size);
clean_up_src:
munmap(src_addr, c.region_size);
out:
return ret;
}
static void run_mremap_test_case(struct test test_case, int *failures,
unsigned int threshold_mb,
unsigned int pattern_seed)
{
long long remap_time = remap_region(test_case.config, threshold_mb,
pattern_seed);
if (remap_time < 0) {
if (test_case.expect_failure)
ksft_test_result_pass("%s\n\tExpected mremap failure\n",
test_case.name);
else {
ksft_test_result_fail("%s\n", test_case.name);
*failures += 1;
}
} else {
/*
* Comparing mremap time is only applicable if entire region
* was faulted in.
*/
if (threshold_mb == VALIDATION_NO_THRESHOLD ||
test_case.config.region_size <= threshold_mb * _1MB)
ksft_test_result_pass("%s\n\tmremap time: %12lldns\n",
test_case.name, remap_time);
else
ksft_test_result_pass("%s\n", test_case.name);
}
}
static void usage(const char *cmd)
{
fprintf(stderr,
"Usage: %s [[-t <threshold_mb>] [-p <pattern_seed>]]\n"
"-t\t only validate threshold_mb of the remapped region\n"
" \t if 0 is supplied no threshold is used; all tests\n"
" \t are run and remapped regions validated fully.\n"
" \t The default threshold used is 4MB.\n"
"-p\t provide a seed to generate the random pattern for\n"
" \t validating the remapped region.\n", cmd);
}
static int parse_args(int argc, char **argv, unsigned int *threshold_mb,
unsigned int *pattern_seed)
{
const char *optstr = "t:p:";
int opt;
while ((opt = getopt(argc, argv, optstr)) != -1) {
switch (opt) {
case 't':
*threshold_mb = atoi(optarg);
break;
case 'p':
*pattern_seed = atoi(optarg);
break;
default:
usage(argv[0]);
return -1;
}
}
if (optind < argc) {
usage(argv[0]);
return -1;
}
return 0;
}
#define MAX_TEST 13
#define MAX_PERF_TEST 3
int main(int argc, char **argv)
{
int failures = 0;
int i, run_perf_tests;
unsigned int threshold_mb = VALIDATION_DEFAULT_THRESHOLD;
unsigned int pattern_seed;
struct test test_cases[MAX_TEST];
struct test perf_test_cases[MAX_PERF_TEST];
int page_size;
time_t t;
pattern_seed = (unsigned int) time(&t);
if (parse_args(argc, argv, &threshold_mb, &pattern_seed) < 0)
exit(EXIT_FAILURE);
ksft_print_msg("Test configs:\n\tthreshold_mb=%u\n\tpattern_seed=%u\n\n",
threshold_mb, pattern_seed);
page_size = sysconf(_SC_PAGESIZE);
/* Expected mremap failures */
test_cases[0] = MAKE_TEST(page_size, page_size, page_size,
OVERLAPPING, EXPECT_FAILURE,
"mremap - Source and Destination Regions Overlapping");
test_cases[1] = MAKE_TEST(page_size, page_size/4, page_size,
NON_OVERLAPPING, EXPECT_FAILURE,
"mremap - Destination Address Misaligned (1KB-aligned)");
test_cases[2] = MAKE_TEST(page_size/4, page_size, page_size,
NON_OVERLAPPING, EXPECT_FAILURE,
"mremap - Source Address Misaligned (1KB-aligned)");
/* Src addr PTE aligned */
test_cases[3] = MAKE_TEST(PTE, PTE, PTE * 2,
NON_OVERLAPPING, EXPECT_SUCCESS,
"8KB mremap - Source PTE-aligned, Destination PTE-aligned");
/* Src addr 1MB aligned */
test_cases[4] = MAKE_TEST(_1MB, PTE, _2MB, NON_OVERLAPPING, EXPECT_SUCCESS,
"2MB mremap - Source 1MB-aligned, Destination PTE-aligned");
test_cases[5] = MAKE_TEST(_1MB, _1MB, _2MB, NON_OVERLAPPING, EXPECT_SUCCESS,
"2MB mremap - Source 1MB-aligned, Destination 1MB-aligned");
/* Src addr PMD aligned */
test_cases[6] = MAKE_TEST(PMD, PTE, _4MB, NON_OVERLAPPING, EXPECT_SUCCESS,
"4MB mremap - Source PMD-aligned, Destination PTE-aligned");
test_cases[7] = MAKE_TEST(PMD, _1MB, _4MB, NON_OVERLAPPING, EXPECT_SUCCESS,
"4MB mremap - Source PMD-aligned, Destination 1MB-aligned");
test_cases[8] = MAKE_TEST(PMD, PMD, _4MB, NON_OVERLAPPING, EXPECT_SUCCESS,
"4MB mremap - Source PMD-aligned, Destination PMD-aligned");
/* Src addr PUD aligned */
test_cases[9] = MAKE_TEST(PUD, PTE, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
"2GB mremap - Source PUD-aligned, Destination PTE-aligned");
test_cases[10] = MAKE_TEST(PUD, _1MB, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
"2GB mremap - Source PUD-aligned, Destination 1MB-aligned");
test_cases[11] = MAKE_TEST(PUD, PMD, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
"2GB mremap - Source PUD-aligned, Destination PMD-aligned");
test_cases[12] = MAKE_TEST(PUD, PUD, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
"2GB mremap - Source PUD-aligned, Destination PUD-aligned");
perf_test_cases[0] = MAKE_TEST(page_size, page_size, _1GB, NON_OVERLAPPING, EXPECT_SUCCESS,
"1GB mremap - Source PTE-aligned, Destination PTE-aligned");
/*
* mremap 1GB region - Page table level aligned time
* comparison.
*/
perf_test_cases[1] = MAKE_TEST(PMD, PMD, _1GB, NON_OVERLAPPING, EXPECT_SUCCESS,
"1GB mremap - Source PMD-aligned, Destination PMD-aligned");
perf_test_cases[2] = MAKE_TEST(PUD, PUD, _1GB, NON_OVERLAPPING, EXPECT_SUCCESS,
"1GB mremap - Source PUD-aligned, Destination PUD-aligned");
run_perf_tests = (threshold_mb == VALIDATION_NO_THRESHOLD) ||
(threshold_mb * _1MB >= _1GB);
ksft_set_plan(ARRAY_SIZE(test_cases) + (run_perf_tests ?
ARRAY_SIZE(perf_test_cases) : 0));
for (i = 0; i < ARRAY_SIZE(test_cases); i++)
run_mremap_test_case(test_cases[i], &failures, threshold_mb,
pattern_seed);
if (run_perf_tests) {
ksft_print_msg("\n%s\n",
"mremap HAVE_MOVE_PMD/PUD optimization time comparison for 1GB region:");
for (i = 0; i < ARRAY_SIZE(perf_test_cases); i++)
run_mremap_test_case(perf_test_cases[i], &failures,
threshold_mb, pattern_seed);
}
if (failures > 0)
ksft_exit_fail();
else
ksft_exit_pass();
}
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