8a1a843381
[ Upstream commit 91b80cc5b39f00399e8e2d17527cad2c7fa535e2 ] On systems with 64k page size and 512M huge page sizes, the allocation and test succeeds but errors out at the munmap. As the comment states, munmap will failure if its not HUGEPAGE aligned. This is due to the length of the mapping being 1/2 the size of the hugepage causing the munmap to not be hugepage aligned. Fix this by making the mapping length the full hugepage if the hugepage is larger than the length of the mapping. Link: https://lkml.kernel.org/r/20240119131429.172448-1-npache@redhat.com Signed-off-by: Nico Pache <npache@redhat.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
116 lines
2.6 KiB
C
Executable file
116 lines
2.6 KiB
C
Executable file
// 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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* For ia64 architecture, Linux kernel reserves Region number 4 for hugepages.
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* That means the addresses starting with 0x800000... will need to be
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* specified. Specifying a fixed address is not required on ppc64, i386
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* or x86_64.
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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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#define LENGTH (256UL*1024*1024)
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#define PROTECTION (PROT_READ | PROT_WRITE)
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#ifndef MAP_HUGETLB
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#define MAP_HUGETLB 0x40000 /* arch specific */
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#endif
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#ifndef MAP_HUGE_SHIFT
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#define MAP_HUGE_SHIFT 26
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#endif
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#ifndef MAP_HUGE_MASK
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#define MAP_HUGE_MASK 0x3f
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#endif
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/* Only ia64 requires this */
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#ifdef __ia64__
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#define ADDR (void *)(0x8000000000000000UL)
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#define FLAGS (MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB | MAP_FIXED)
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#else
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#define ADDR (void *)(0x0UL)
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#define FLAGS (MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB)
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#endif
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static void check_bytes(char *addr)
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{
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printf("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 int 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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printf("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(int argc, char **argv)
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{
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void *addr;
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int ret;
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size_t hugepage_size;
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size_t length = LENGTH;
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int flags = FLAGS;
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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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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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printf("%u kB hugepages\n", 1 << (shift - 10));
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else
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printf("Default size hugepages\n");
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printf("Mapping %lu Mbytes\n", (unsigned long)length >> 20);
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addr = mmap(ADDR, length, PROTECTION, flags, -1, 0);
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if (addr == MAP_FAILED) {
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perror("mmap");
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exit(1);
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}
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printf("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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ret = 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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perror("munmap");
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exit(1);
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}
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return ret;
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}
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