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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/testing/selftests/vm/map_hugetlb.c | |
parent | Initial commit. (diff) | |
download | linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/testing/selftests/vm/map_hugetlb.c')
-rw-r--r-- | tools/testing/selftests/vm/map_hugetlb.c | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/tools/testing/selftests/vm/map_hugetlb.c b/tools/testing/selftests/vm/map_hugetlb.c new file mode 100644 index 000000000..312889edb --- /dev/null +++ b/tools/testing/selftests/vm/map_hugetlb.c @@ -0,0 +1,109 @@ +// 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. + * + * For ia64 architecture, Linux kernel reserves Region number 4 for hugepages. + * That means the addresses starting with 0x800000... will need to be + * specified. Specifying a fixed address is not required on ppc64, i386 + * or x86_64. + */ +#include <stdlib.h> +#include <stdio.h> +#include <unistd.h> +#include <sys/mman.h> +#include <fcntl.h> + +#define LENGTH (256UL*1024*1024) +#define PROTECTION (PROT_READ | PROT_WRITE) + +#ifndef MAP_HUGETLB +#define MAP_HUGETLB 0x40000 /* arch specific */ +#endif + +#ifndef MAP_HUGE_SHIFT +#define MAP_HUGE_SHIFT 26 +#endif + +#ifndef MAP_HUGE_MASK +#define MAP_HUGE_MASK 0x3f +#endif + +/* Only ia64 requires this */ +#ifdef __ia64__ +#define ADDR (void *)(0x8000000000000000UL) +#define FLAGS (MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB | MAP_FIXED) +#else +#define ADDR (void *)(0x0UL) +#define FLAGS (MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB) +#endif + +static void check_bytes(char *addr) +{ + printf("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 int read_bytes(char *addr, size_t length) +{ + unsigned long i; + + check_bytes(addr); + for (i = 0; i < length; i++) + if (*(addr + i) != (char)i) { + printf("Mismatch at %lu\n", i); + return 1; + } + return 0; +} + +int main(int argc, char **argv) +{ + void *addr; + int ret; + size_t length = LENGTH; + int flags = FLAGS; + int shift = 0; + + 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) + printf("%u kB hugepages\n", 1 << (shift - 10)); + else + printf("Default size hugepages\n"); + printf("Mapping %lu Mbytes\n", (unsigned long)length >> 20); + + addr = mmap(ADDR, length, PROTECTION, flags, -1, 0); + if (addr == MAP_FAILED) { + perror("mmap"); + exit(1); + } + + printf("Returned address is %p\n", addr); + check_bytes(addr); + write_bytes(addr, length); + ret = read_bytes(addr, length); + + /* munmap() length of MAP_HUGETLB memory must be hugepage aligned */ + if (munmap(addr, length)) { + perror("munmap"); + exit(1); + } + + return ret; +} |