after call pthread_condattr_setclock(CLOCK_MONOTONIC)
_lwp_park(2) expects a realtime clock, and it gets passed a monotonic
one. Since monotonic < real, it never sleeps. This patch adjusts
the monotonic clock to be a real one before it passes is to
_lwp_park(2). This is the minimal hacky fix and it will be fixed
properly in _lwp_park(2) in the future.
XXX: pullup to 6.
- Fail if the dlopened libpthread does pthread_create(). From manu@
- Discussed at length in the mailing lists; approved by core@
- This was chosen as the least intrusive patch that will provide
the necessary functionality.
XXX: pullup to 6
and pthread_{g,s}etspecific functions, to one that invalidates
values of keys in other threads when pthread_key_delete() is called.
This fixes chromium, which expects pthread_key_delete() to do
cleanup in all threads.
.Vt type var No = Dv INITIALIZER;
to provide examples of static initialization in SYNOPSIS section.
.Va macro does the wrong thing (check groff PostScript output) and the
need for .Pp kludge (now dropped) should have been an indication too.
While here move static initialization example to be right after the
declaration of *_init().
the TLS pointer, therefore wrecking the pthread environement.
Some ports had _UC_TLSBASE flag or equivalent (_UC_UNIQUE on alpha)
that controlled whether setcontext() would change the TLS pointer.
This change let libpthread override setcontext() with its own version
that unsets _UC_TLSBASE, enabling safe usage of setcontext() with
-lpthread.
We also have the following required changes here:
- rename alpha's _UC_UNIQUE into _UC_TLSBASE
- add _UC_TLSBASE definition in header file for all ports
(powerpc, sh3, sparc and sparc64 lack the implementation for now)
- introduce a libc stub that can be overriden for setcontext()
- modify MD libcs swapcontext() implementations so that they use the
setcontext() libc stub instead of doing a plain system call.
While we are there:
- document various MD _UC_* flags in header file
- add libc and libpthread tests for swapcontext() behavior
(hopefully helpful to spot MD problems introduced with this change)
Future work:
- Deciding whether kernel support or _UC_TLSBASE should be added for
powerpc, sh3, sparc and sparc64 is left to portmasters
sparc64
Approved by core@
pthread__smt_pause. These are implemented using the ARM instructions
SEV (wake) and WFE (pause). These are treated as NOPs on ARM CPUs that
don't support them.
(this is not entirely correct because it can return ENOMEM which is
not mentioned in the spec, but there are other places in pthread_create
whete ENOMEM is returned -- it at all, this should be fixed everywhere)
don't bother with setting up a guard page. Otherwise, round up the size
to page size. Point stack inside the guarded area, without the guard
page. Fix size when mprotect failed.
one. The implementation doesn't provide an async-safe sem_post and can't
without a lot of work on the pthread primitives.
Remove bogus time out requirement in test case, it should have been
a "known failure" if anything.
Require __HAVE_TLS_VARIANT_I or __HAVE_TLS_VARIANT_II as well as
__lwp_getprivate_fast / __lwp_gettcb_fast to exist for libpthread.
Define VAX as going to use TLS variant I, if it is ever implemented.
- Update TCB for the initial thread in pthread__initthread, not
pthread__init to get it valid as soon as possible.
- Don't overwrite the pt_tls field in pthread__initthread.
- Don't deallocate pt_tls in pthread__scrubthread. This worked more by
chance than by design.
- Handle freeing the TLS area in pthread_create after removing the
thread instance from the dead queue.
initialisation order is correct in this case as _lwp_setprivate has been
called already by ld.elf_so for dynamic programs or _libc_init for
statically linked ones.
_rtld_tls_allocate and _rtld_tls_free. libpthread uses this functions to
setup the thread private area of all new threads. ld.elf_so is
responsible for setting up the private area for the initial thread.
Similar functions are called from _libc_init for static binaries, using
dl_iterate_phdr to access the ELF Program Header.
Add test cases to exercise the different TLS storage models. Test cases
are compiled and installed on all platforms, but are skipped on
platforms not marked for TLS support.
This material is based upon work partially supported by
The NetBSD Foundation under a contract with Joerg Sonnenberger.
It is inspired by the TLS support in FreeBSD by Doug Rabson and the
clean ups of the DragonFly port of the original FreeBSD modifications.
libgcc_s's __register_frame_info gets called from libc's CSU code before
the libc constructors are run. __register_frame_info in turn calls
pthread_mutex_lock. libpthread is not initialised at this point and
therefore pthread__self() traps when deferencing the thread register.
This worked before because the garbage from pthread__self() is
effectively ignored.
on all platforms except VAX and IA64. Add fast access via register for
AMD64, i386 and SH3 ports. Use this fast access in libpthread to replace
the stack based pthread_self(). Implement skeleton support for Alpha,
HPPA, PowerPC, SPARC and SPARC64, but leave it disabled.
Ports that support this feature provide __HAVE____LWP_GETPRIVATE_FAST in
machine/types.h and a corresponding __lwp_getprivate_fast in
machine/mcontext.h.
This material is based upon work partially supported by
The NetBSD Foundation under a contract with Joerg Sonnenberger.
the compiler loses information about the size of the object. So instead of
the hacky #define mess we did before, add a way to inject our function between
the user call and the system call.
objects, and the RTLD_NODELETE and RTLD_NOLOAD flags to dlopen(3).
Mark libpthread as DF_1_NOOPEN and use it to test the functionality.
Somewhat taken from FreeBSD.
Fixes PR 42029.
OK from christos and joerg.
the situation, I decided to commit it. There is an inherent problem
with ASLR and the way the pthread library is using the thread stack.
Our pthread library chooses that stack for each thread strategically
so that it can locate the location of the pthread struct for each
thread by masking the stack pointer and looking just below the red
zone it creates. Unfortunately with ASLR you get many random values
for the initial stack, and there are situations where the masked
stack base ends up below the base of the stack. (this happens on
x86 when the stack base happens to be 0x???02000 for example and
your mask is stackmask is 0xffe00000). To fix this, we detect the
pathological cases (this happens only in the main thread), allocate
more stack, and mprotect it appropriately. Then we stash the main
base and the main struct, so that when we look for the pthread
struct in pthread__id, we can special case the main thread.
Another way to work around the problem is unlimiting stacksize,
but the proper way is to use TLS to find the thread structure and
not to play games with the thread stacks.
functions in NetBSD, which does not support additional condition attributes.
Note that these do not conform to SUSv4, where two additional attributes are
mandated.
- pthread_barrier_{init,destroy,wait} into pthread_barrier(3).
- pthread_cond_* into pthread_cond(3).
- pthread_mutex_* into pthread_mutex(3).
- pthread_rwlock_* into pthread_rwlock(3).
- pthread_spin_* into pthread_spin(3).
Cross-link amongst groups.
OK jruoho@
document pthread_attr_getstack() and pthread_attr_setstack(). Try to also
document these a little better (in particular, note some items in the long
list of caveats and questions related to application-controlled thread stack).
to reuse, because if we lose the race with the kernel we are never going
to reuse any elements. Look in the whole list instead.
XXX: should be pulled up to 5.x
- Rely on _lwp_makecontext() to set up the thread identity register.
This is not currently done (a bug), nor does libpthread use the
threadreg yet. I'm doing this so it the code can be used by the
person working on TLS to verify that their threadreg code is working.
Due to limitations in the current pthread implementation, makecontext(3)
and sigaltstack(2) should not be used in programs which link against
libpthread (whether threads are used or not).
Wording from drochner@ and ad@
Bump date for man pages.
Add note in libpthread/README so it's not forgotten to update the man
pages when the problem is fixed.
implementation:
-don't return a difference, this can overflow
-don't try to substract typed pointers which don't belong to the
same object, this gives undefined results
This fixes instabilities of programs which use more than a handful
of threads, eg spuriously failing pthread_join().
XXX This must not be enabled by default because the LWP private mechanism
is reserved for TLS. It is provided only as a test/demo.
XXX Since ucontext_t does not contain the thread private variable, for a
short time after threads are created their thread specific data is unset.
If a signal arrives during that time we are screwed.
- No longer need pthread__osrev.
- Rearrange _lwp_ctl() calls slightly.
other systems. Allows poorly written applications to appear working. If you
are developing pthread apps please turn it on manually by setting the
environment variable.
Builds a libpthread that can be dropped into a NetBSD 2/3/4 chroot.
This makes threading work in the chroot when using a NetBSD 5 kernel, no
other modifications required.
christos