glibc/sysdeps/unix/sysv/linux/tst-rseq-disable.c
Florian Weimer c901c3e764 nptl: Add public rseq symbols and <sys/rseq.h>
The relationship between the thread pointer and the rseq area
is made explicit.  The constant offset can be used by JIT compilers
to optimize rseq access (e.g., for really fast sched_getcpu).

Extensibility is provided through __rseq_size and __rseq_flags.
(In the future, the kernel could request a different rseq size
via the auxiliary vector.)

Co-Authored-By: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-12-09 09:49:32 +01:00

96 lines
2.5 KiB
C

/* Test disabling of rseq registration via tunable.
Copyright (C) 2021 Free Software Foundation, Inc.
The GNU C 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.
The GNU C 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 the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stdio.h>
#include <support/check.h>
#include <support/namespace.h>
#include <support/xthread.h>
#include <sysdep.h>
#include <thread_pointer.h>
#include <unistd.h>
#ifdef RSEQ_SIG
/* Check that rseq can be registered and has not been taken by glibc. */
static void
check_rseq_disabled (void)
{
struct pthread *pd = THREAD_SELF;
TEST_COMPARE (__rseq_flags, 0);
TEST_VERIFY ((char *) __thread_pointer () + __rseq_offset
== (char *) &pd->rseq_area);
TEST_COMPARE (__rseq_size, 0);
TEST_COMPARE ((int) pd->rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED);
int ret = syscall (__NR_rseq, &pd->rseq_area, sizeof (pd->rseq_area),
0, RSEQ_SIG);
if (ret == 0)
{
ret = syscall (__NR_rseq, &pd->rseq_area, sizeof (pd->rseq_area),
RSEQ_FLAG_UNREGISTER, RSEQ_SIG);
TEST_COMPARE (ret, 0);
pd->rseq_area.cpu_id = RSEQ_CPU_ID_REGISTRATION_FAILED;
}
else
{
TEST_VERIFY (errno != -EINVAL);
TEST_VERIFY (errno != -EBUSY);
}
}
static void *
thread_func (void *ignored)
{
check_rseq_disabled ();
return NULL;
}
static void
proc_func (void *ignored)
{
check_rseq_disabled ();
}
static int
do_test (void)
{
puts ("info: checking main thread");
check_rseq_disabled ();
puts ("info: checking main thread (2)");
check_rseq_disabled ();
puts ("info: checking new thread");
xpthread_join (xpthread_create (NULL, thread_func, NULL));
puts ("info: checking subprocess");
support_isolate_in_subprocess (proc_func, NULL);
return 0;
}
#else /* !RSEQ_SIG */
static int
do_test (void)
{
FAIL_UNSUPPORTED ("glibc does not define RSEQ_SIG, skipping test");
}
#endif
#include <support/test-driver.c>