89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Example of using hugepage memory in a user application using the mmap
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* system call with MAP_HUGETLB flag. Before running this program make
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* sure the administrator has allocated enough default sized huge pages
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* to cover the 256 MB allocation.
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*/
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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 "vm_util.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, size_t length)
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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 void read_bytes(char *addr, size_t length)
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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_exit_fail_msg("Mismatch at %lu\n", i);
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ksft_test_result_pass("Read correct data\n");
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}
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int main(int argc, char **argv)
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{
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void *addr;
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size_t hugepage_size;
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size_t length = LENGTH;
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int flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB;
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int shift = 0;
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hugepage_size = default_huge_page_size();
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/* munmap with fail if the length is not page aligned */
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if (hugepage_size > length)
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length = hugepage_size;
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ksft_print_header();
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ksft_set_plan(1);
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if (argc > 1)
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length = atol(argv[1]) << 20;
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if (argc > 2) {
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shift = atoi(argv[2]);
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if (shift)
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flags |= (shift & MAP_HUGE_MASK) << MAP_HUGE_SHIFT;
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}
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if (shift)
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ksft_print_msg("%u kB hugepages\n", 1 << (shift - 10));
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else
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ksft_print_msg("Default size hugepages\n");
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ksft_print_msg("Mapping %lu Mbytes\n", (unsigned long)length >> 20);
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addr = mmap(NULL, length, PROTECTION, flags, -1, 0);
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if (addr == MAP_FAILED)
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ksft_exit_fail_msg("mmap: %s\n", strerror(errno));
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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, length);
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read_bytes(addr, length);
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/* munmap() length of MAP_HUGETLB memory must be hugepage aligned */
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if (munmap(addr, length))
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ksft_exit_fail_msg("munmap: %s\n", strerror(errno));
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ksft_finished();
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}
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