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// SPDX-License-Identifier: GPL-2.0
/*
* Example of using hugepage memory in a user application using the mmap
* system call with MAP_HUGETLB flag. Before running this program make
* sure the administrator has allocated enough default sized huge pages
* to cover the 256 MB allocation.
*/
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>
#include <fcntl.h>
#include "vm_util.h"
#include "../kselftest.h"
#define LENGTH (256UL*1024*1024)
#define PROTECTION (PROT_READ | PROT_WRITE)
static void check_bytes(char *addr)
{
ksft_print_msg("First hex is %x\n", *((unsigned int *)addr));
}
static void write_bytes(char *addr, size_t length)
{
unsigned long i;
for (i = 0; i < length; i++)
*(addr + i) = (char)i;
}
static void read_bytes(char *addr, size_t length)
{
unsigned long i;
check_bytes(addr);
for (i = 0; i < length; i++)
if (*(addr + i) != (char)i)
ksft_exit_fail_msg("Mismatch at %lu\n", i);
ksft_test_result_pass("Read correct data\n");
}
int main(int argc, char **argv)
{
void *addr;
size_t hugepage_size;
size_t length = LENGTH;
int flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB;
int shift = 0;
hugepage_size = default_huge_page_size();
/* munmap with fail if the length is not page aligned */
if (hugepage_size > length)
length = hugepage_size;
ksft_print_header();
ksft_set_plan(1);
if (argc > 1)
length = atol(argv[1]) << 20;
if (argc > 2) {
shift = atoi(argv[2]);
if (shift)
flags |= (shift & MAP_HUGE_MASK) << MAP_HUGE_SHIFT;
}
if (shift)
ksft_print_msg("%u kB hugepages\n", 1 << (shift - 10));
else
ksft_print_msg("Default size hugepages\n");
ksft_print_msg("Mapping %lu Mbytes\n", (unsigned long)length >> 20);
addr = mmap(NULL, length, PROTECTION, flags, -1, 0);
if (addr == MAP_FAILED)
ksft_exit_fail_msg("mmap: %s\n", strerror(errno));
ksft_print_msg("Returned address is %p\n", addr);
check_bytes(addr);
write_bytes(addr, length);
read_bytes(addr, length);
/* munmap() length of MAP_HUGETLB memory must be hugepage aligned */
if (munmap(addr, length))
ksft_exit_fail_msg("munmap: %s\n", strerror(errno));
ksft_finished();
}
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