You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
279 lines
8.8 KiB
279 lines
8.8 KiB
3 years ago
|
commit e3e589829d16af9f7e73c7b70f74f3c5d5003e45
|
||
|
Author: Florian Weimer <fweimer@redhat.com>
|
||
|
Date: Thu Dec 9 09:49:32 2021 +0100
|
||
|
|
||
|
nptl: Add glibc.pthread.rseq tunable to control rseq registration
|
||
|
|
||
|
This tunable allows applications to register the rseq area instead
|
||
|
of glibc.
|
||
|
|
||
|
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
|
||
|
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
|
||
|
|
||
|
diff --git a/manual/tunables.texi b/manual/tunables.texi
|
||
|
index 658547c6137bf177..1f5c410288eeecec 100644
|
||
|
--- a/manual/tunables.texi
|
||
|
+++ b/manual/tunables.texi
|
||
|
@@ -413,6 +413,16 @@ The value is measured in bytes. The default is @samp{41943040}
|
||
|
(fourty mibibytes).
|
||
|
@end deftp
|
||
|
|
||
|
+@deftp Tunable glibc.pthread.rseq
|
||
|
+The @code{glibc.pthread.rseq} tunable can be set to @samp{0}, to disable
|
||
|
+restartable sequences support in @theglibc{}. This enables applications
|
||
|
+to perform direct restartable sequence registration with the kernel.
|
||
|
+The default is @samp{1}, which means that @theglibc{} performs
|
||
|
+registration on behalf of the application.
|
||
|
+
|
||
|
+Restartable sequences are a Linux-specific extension.
|
||
|
+@end deftp
|
||
|
+
|
||
|
@node Hardware Capability Tunables
|
||
|
@section Hardware Capability Tunables
|
||
|
@cindex hardware capability tunables
|
||
|
diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
|
||
|
index d2b40924dafad316..f405fa356c2955ce 100644
|
||
|
--- a/nptl/pthread_create.c
|
||
|
+++ b/nptl/pthread_create.c
|
||
|
@@ -369,7 +369,10 @@ start_thread (void *arg)
|
||
|
__ctype_init ();
|
||
|
|
||
|
/* Register rseq TLS to the kernel. */
|
||
|
- rseq_register_current_thread (pd);
|
||
|
+ {
|
||
|
+ bool do_rseq = THREAD_GETMEM (pd, flags) & ATTR_FLAG_DO_RSEQ;
|
||
|
+ rseq_register_current_thread (pd, do_rseq);
|
||
|
+ }
|
||
|
|
||
|
#ifndef __ASSUME_SET_ROBUST_LIST
|
||
|
if (__nptl_set_robust_list_avail)
|
||
|
@@ -678,6 +681,11 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
|
||
|
pd->flags = ((iattr->flags & ~(ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET))
|
||
|
| (self->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)));
|
||
|
|
||
|
+ /* Inherit rseq registration state. Without seccomp filters, rseq
|
||
|
+ registration will either always fail or always succeed. */
|
||
|
+ if ((int) THREAD_GETMEM_VOLATILE (self, rseq_area.cpu_id) >= 0)
|
||
|
+ pd->flags |= ATTR_FLAG_DO_RSEQ;
|
||
|
+
|
||
|
/* Initialize the field for the ID of the thread which is waiting
|
||
|
for us. This is a self-reference in case the thread is created
|
||
|
detached. */
|
||
|
diff --git a/sysdeps/nptl/dl-tls_init_tp.c b/sysdeps/nptl/dl-tls_init_tp.c
|
||
|
index fedb876fdb2642d2..b39dfbff2c6678d5 100644
|
||
|
--- a/sysdeps/nptl/dl-tls_init_tp.c
|
||
|
+++ b/sysdeps/nptl/dl-tls_init_tp.c
|
||
|
@@ -23,6 +23,9 @@
|
||
|
#include <tls.h>
|
||
|
#include <rseq-internal.h>
|
||
|
|
||
|
+#define TUNABLE_NAMESPACE pthread
|
||
|
+#include <dl-tunables.h>
|
||
|
+
|
||
|
#ifndef __ASSUME_SET_ROBUST_LIST
|
||
|
bool __nptl_set_robust_list_avail;
|
||
|
rtld_hidden_data_def (__nptl_set_robust_list_avail)
|
||
|
@@ -92,7 +95,13 @@ __tls_init_tp (void)
|
||
|
}
|
||
|
}
|
||
|
|
||
|
- rseq_register_current_thread (pd);
|
||
|
+ {
|
||
|
+ bool do_rseq = true;
|
||
|
+#if HAVE_TUNABLES
|
||
|
+ do_rseq = TUNABLE_GET (rseq, int, NULL);
|
||
|
+#endif
|
||
|
+ rseq_register_current_thread (pd, do_rseq);
|
||
|
+ }
|
||
|
|
||
|
/* Set initial thread's stack block from 0 up to __libc_stack_end.
|
||
|
It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
|
||
|
diff --git a/sysdeps/nptl/dl-tunables.list b/sysdeps/nptl/dl-tunables.list
|
||
|
index ac5d053298725468..d24f4be0d08ba407 100644
|
||
|
--- a/sysdeps/nptl/dl-tunables.list
|
||
|
+++ b/sysdeps/nptl/dl-tunables.list
|
||
|
@@ -27,5 +27,11 @@ glibc {
|
||
|
type: SIZE_T
|
||
|
default: 41943040
|
||
|
}
|
||
|
+ rseq {
|
||
|
+ type: INT_32
|
||
|
+ minval: 0
|
||
|
+ maxval: 1
|
||
|
+ default: 1
|
||
|
+ }
|
||
|
}
|
||
|
}
|
||
|
diff --git a/sysdeps/nptl/internaltypes.h b/sysdeps/nptl/internaltypes.h
|
||
|
index 50a2ad19ae7210ae..8205c6d15a918952 100644
|
||
|
--- a/sysdeps/nptl/internaltypes.h
|
||
|
+++ b/sysdeps/nptl/internaltypes.h
|
||
|
@@ -49,6 +49,7 @@ struct pthread_attr
|
||
|
#define ATTR_FLAG_OLDATTR 0x0010
|
||
|
#define ATTR_FLAG_SCHED_SET 0x0020
|
||
|
#define ATTR_FLAG_POLICY_SET 0x0040
|
||
|
+#define ATTR_FLAG_DO_RSEQ 0x0080
|
||
|
|
||
|
/* Used to allocate a pthread_attr_t object which is also accessed
|
||
|
internally. */
|
||
|
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
|
||
|
index f84ccd6bbb3b16ad..d30d21898b402d1e 100644
|
||
|
--- a/sysdeps/unix/sysv/linux/Makefile
|
||
|
+++ b/sysdeps/unix/sysv/linux/Makefile
|
||
|
@@ -135,6 +135,12 @@ tests-internal += \
|
||
|
tst-sigcontext-get_pc \
|
||
|
# tests-internal
|
||
|
|
||
|
+ifneq (no,$(have-tunables))
|
||
|
+tests-internal += \
|
||
|
+ tst-rseq-disable \
|
||
|
+ # tests-internal $(have-tunables)
|
||
|
+endif
|
||
|
+
|
||
|
tests-time64 += \
|
||
|
tst-adjtimex-time64 \
|
||
|
tst-clock_adjtime-time64 \
|
||
|
@@ -226,6 +232,8 @@ $(objpfx)tst-mman-consts.out: ../sysdeps/unix/sysv/linux/tst-mman-consts.py
|
||
|
< /dev/null > $@ 2>&1; $(evaluate-test)
|
||
|
$(objpfx)tst-mman-consts.out: $(sysdeps-linux-python-deps)
|
||
|
|
||
|
+tst-rseq-disable-ENV = GLIBC_TUNABLES=glibc.pthread.rseq=0
|
||
|
+
|
||
|
endif # $(subdir) == misc
|
||
|
|
||
|
ifeq ($(subdir),time)
|
||
|
diff --git a/sysdeps/unix/sysv/linux/rseq-internal.h b/sysdeps/unix/sysv/linux/rseq-internal.h
|
||
|
index 909f5478251d3d13..15bc7ffd6eda632d 100644
|
||
|
--- a/sysdeps/unix/sysv/linux/rseq-internal.h
|
||
|
+++ b/sysdeps/unix/sysv/linux/rseq-internal.h
|
||
|
@@ -21,22 +21,27 @@
|
||
|
#include <sysdep.h>
|
||
|
#include <errno.h>
|
||
|
#include <kernel-features.h>
|
||
|
+#include <stdbool.h>
|
||
|
#include <stdio.h>
|
||
|
#include <sys/rseq.h>
|
||
|
|
||
|
#ifdef RSEQ_SIG
|
||
|
static inline void
|
||
|
-rseq_register_current_thread (struct pthread *self)
|
||
|
+rseq_register_current_thread (struct pthread *self, bool do_rseq)
|
||
|
{
|
||
|
- int ret = INTERNAL_SYSCALL_CALL (rseq,
|
||
|
- &self->rseq_area, sizeof (self->rseq_area),
|
||
|
- 0, RSEQ_SIG);
|
||
|
- if (INTERNAL_SYSCALL_ERROR_P (ret))
|
||
|
- THREAD_SETMEM (self, rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED);
|
||
|
+ if (do_rseq)
|
||
|
+ {
|
||
|
+ int ret = INTERNAL_SYSCALL_CALL (rseq, &self->rseq_area,
|
||
|
+ sizeof (self->rseq_area),
|
||
|
+ 0, RSEQ_SIG);
|
||
|
+ if (!INTERNAL_SYSCALL_ERROR_P (ret))
|
||
|
+ return;
|
||
|
+ }
|
||
|
+ THREAD_SETMEM (self, rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED);
|
||
|
}
|
||
|
#else /* RSEQ_SIG */
|
||
|
static inline void
|
||
|
-rseq_register_current_thread (struct pthread *self)
|
||
|
+rseq_register_current_thread (struct pthread *self, bool do_rseq)
|
||
|
{
|
||
|
THREAD_SETMEM (self, rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED);
|
||
|
}
|
||
|
diff --git a/sysdeps/unix/sysv/linux/tst-rseq-disable.c b/sysdeps/unix/sysv/linux/tst-rseq-disable.c
|
||
|
new file mode 100644
|
||
|
index 0000000000000000..000e351872fc2f76
|
||
|
--- /dev/null
|
||
|
+++ b/sysdeps/unix/sysv/linux/tst-rseq-disable.c
|
||
|
@@ -0,0 +1,89 @@
|
||
|
+/* 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 <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 ((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>
|