79 lines
1.7 KiB
C
79 lines
1.7 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* hugepage-mmap:
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*
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* Example of using huge page memory in a user application using the mmap
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* system call. Before running this application, make sure that the
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* administrator has mounted the hugetlbfs filesystem (on some directory
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* like /mnt) using the command mount -t hugetlbfs nodev /mnt. In this
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* example, the app is requesting memory of size 256MB that is backed by
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* huge pages.
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*/
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#define _GNU_SOURCE
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <fcntl.h>
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#include "../kselftest.h"
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#define LENGTH (256UL*1024*1024)
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#define PROTECTION (PROT_READ | PROT_WRITE)
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static void check_bytes(char *addr)
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{
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ksft_print_msg("First hex is %x\n", *((unsigned int *)addr));
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}
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static void write_bytes(char *addr)
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{
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unsigned long i;
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for (i = 0; i < LENGTH; i++)
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*(addr + i) = (char)i;
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}
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static int read_bytes(char *addr)
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{
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unsigned long i;
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check_bytes(addr);
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for (i = 0; i < LENGTH; i++)
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if (*(addr + i) != (char)i) {
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ksft_print_msg("Error: Mismatch at %lu\n", i);
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return 1;
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}
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return 0;
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}
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int main(void)
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{
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void *addr;
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int fd, ret;
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ksft_print_header();
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ksft_set_plan(1);
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fd = memfd_create("hugepage-mmap", MFD_HUGETLB);
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if (fd < 0)
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ksft_exit_fail_msg("memfd_create() failed: %s\n", strerror(errno));
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addr = mmap(NULL, LENGTH, PROTECTION, MAP_SHARED, fd, 0);
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if (addr == MAP_FAILED) {
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close(fd);
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ksft_exit_fail_msg("mmap(): %s\n", strerror(errno));
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}
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ksft_print_msg("Returned address is %p\n", addr);
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check_bytes(addr);
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write_bytes(addr);
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ret = read_bytes(addr);
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munmap(addr, LENGTH);
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close(fd);
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ksft_test_result(!ret, "Read same data\n");
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ksft_exit(!ret);
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}
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