freebsd-dev/lib/libc_r/uthread/uthread_jmp.c

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/*
* Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
* All rights reserved.
* Copyright (C) 2000 Daniel M. Eischen <eischen@vigrid.com>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice(s), this list of conditions and the following disclaimer as
* the first lines of this file unmodified other than the possible
* addition of one or more copyright notices.
* 2. Redistributions in binary form must reproduce the above copyright
* notice(s), this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <unistd.h>
#include <setjmp.h>
#include <sys/param.h>
#include <sys/user.h>
#include <machine/reg.h>
#include <pthread.h>
#include "pthread_private.h"
/* Prototypes: */
static inline int check_stack(pthread_t thread, void *stackp);
__weak_reference(_thread_siglongjmp, siglongjmp);
__weak_reference(_thread_longjmp, longjmp);
__weak_reference(__thread_longjmp, _longjmp);
void
_thread_siglongjmp(sigjmp_buf env, int savemask)
{
struct pthread *curthread = _get_curthread();
if (check_stack(curthread, (void *) GET_STACK_SJB(env)))
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PANIC("siglongjmp()ing between thread contexts is undefined by "
"POSIX 1003.1");
/*
* The stack pointer is somewhere within the threads stack.
* Jump to the users context.
*/
__siglongjmp(env, savemask);
}
void
_thread_longjmp(jmp_buf env, int val)
{
struct pthread *curthread = _get_curthread();
if (check_stack(curthread, (void *) GET_STACK_JB(env)))
PANIC("longjmp()ing between thread contexts is undefined by "
"POSIX 1003.1");
/*
* The stack pointer is somewhere within the threads stack.
* Jump to the users context.
*/
__longjmp(env, val);
}
void
__thread_longjmp(jmp_buf env, int val)
{
struct pthread *curthread = _get_curthread();
if (check_stack(curthread, (void *) GET_STACK_JB(env)))
PANIC("_longjmp()ing between thread contexts is undefined by "
"POSIX 1003.1");
/*
* The stack pointer is somewhere within the threads stack.
* Jump to the users context.
*/
___longjmp(env, val);
}
/* Returns 0 if stack check is OK, non-zero otherwise. */
static inline int
check_stack(pthread_t thread, void *stackp)
{
void *stack_begin, *stack_end;
/* Get the bounds of the current threads stack. */
PTHREAD_ASSERT(thread->stack != NULL,
Implement zero system call thread switching. Performance of thread switches should be on par with that under scheduler activations. o Timing is achieved through the use of a fixed interval timer (ITIMER_PROF) to count scheduling ticks instead of retrieving the time-of-day upon every thread switch and calculating elapsed real time. o Polling for I/O readiness is performed once for each scheduling tick instead of every thread switch. o The non-signal saving/restoring versions of setjmp/longjmp are used to save and restore thread contexts. This may allow the removal of _THREAD_SAFE macros from setjmp() and longjmp() - needs more investigation. Change signal handling so that signals are handled in the context of the thread that is receiving the signal. When signals are dispatched to a thread, a special signal handling frame is created on top of the target threads stack. The frame contains the threads saved state information and a new context in which the thread can run. The applications signal handler is invoked through a wrapper routine that knows how to restore the threads saved state and unwind to previous frames. Fix interruption of threads due to signals. Some states were being improperly interrupted while other states were not being interrupted. This should fix several PRs. Signal handlers, which are invoked as a result of a process signal (not by pthread_kill()), are now called with the code (or siginfo_t if SA_SIGINFO was set in sa_flags) and sigcontext_t as received from the process signal handler. Modify the search for a thread to which a signal is delivered. The search algorithm is now: o First thread found in sigwait() with signal in wait mask. o First thread found sigsuspend()'d on the signal. o Current thread if signal is unmasked. o First thread found with signal unmasked. Collapse machine dependent support into macros defined in pthread_private.h. These should probably eventually be moved into separate MD files. Change the range of settable priorities to be compliant with POSIX (0-31). The threads library uses higher priorities internally for real-time threads (not yet implemented) and threads executing signal handlers. Real-time threads and threads running signal handlers add 64 and 32, respectively, to a threads base priority. Some other small changes and cleanups. PR: 17757 18559 21943 Reviewed by: jasone
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"Thread stack pointer is null");
stack_begin = thread->stack;
stack_end = stack_begin + thread->attr.stacksize_attr;
/*
* Make sure we aren't jumping to a different stack. Make sure
* jmp_stackp is between stack_begin and stack end, to correctly detect
* this condition regardless of whether the stack grows up or down.
*/
if (((stackp < stack_begin) && (stackp < stack_end)) ||
((stackp > stack_begin) && (stackp > stack_end)))
return (1);
else
return (0);
}