/*
* libhugetlbfs - Easy use of Linux hugepages
* Copyright (C) 2005-2006 David Gibson & Adam Litke, IBM Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/* Test rationale:
*
* ppc64 kernels (prior to 2.6.15-rc5) have a bug in the hugepage SLB
* flushing path. After opening new hugetlb areas, we update the
* masks in the thread_struct, copy to the PACA, then do slbies on
* each CPU. The trouble is we only copy to the PACA on the CPU where
* we're opening the segments, which can leave a stale copy in the
* PACAs on other CPUs.
*
* This can be triggered either with multiple threads sharing the mm,
* or with a single thread which is migrated from one CPU, to another
* (where the mapping occurs), then back again (where we touch the
* stale SLB). We use the second method in this test, since it's
* easier to force (using sched_setaffinity). However it relies on a
* close-to-idle system, if any process other than a kernel thread
* runs on the first CPU between runs of the test process, the SLB
* will be flushed and we won't trigger the bug, hence the
* PASS_INCONCLUSIVE(). Obviously, this test won't work on a 1-cpu
* system (should get CONFIG() on the sched_setaffinity()).
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sched.h>
#include <hugetlbfs.h>
#include "hugetests.h"
int main(int argc, char *argv[])
{
long hpage_size;
int fd;
void *p;
volatile unsigned long *q;
int online_cpus[2], err;
cpu_set_t cpu0, cpu1;
test_init(argc, argv);
hpage_size = check_hugepagesize();
check_online_cpus(online_cpus, 2);
fd = hugetlbfs_unlinked_fd();
if (fd < 0)
FAIL("hugetlbfs_unlinked_fd()");
CPU_ZERO(&cpu0);
CPU_SET(online_cpus[0], &cpu0);
CPU_ZERO(&cpu1);
CPU_SET(online_cpus[1], &cpu1);
err = sched_setaffinity(getpid(), CPU_SETSIZE/8, &cpu0);
if (err != 0)
CONFIG("sched_setaffinity(cpu%d): %s", online_cpus[0],
strerror(errno));
err = sched_setaffinity(getpid(), CPU_SETSIZE/8, &cpu1);
if (err != 0)
CONFIG("sched_setaffinity(cpu%d): %s", online_cpus[1],
strerror(errno));
p = mmap(NULL, hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (p == MAP_FAILED)
FAIL("mmap(): %s", strerror(errno));
err = sched_setaffinity(getpid(), CPU_SETSIZE/8, &cpu0);
if (err != 0)
CONFIG("sched_setaffinity(cpu%d): %s", online_cpus[0],
strerror(errno));
q = (volatile unsigned long *)(p + getpagesize());
*q = 0xdeadbeef;
PASS_INCONCLUSIVE();
}