void HalStartSerial()
{
int oflags;
// Open the term for reading and writing.
if( (serialInFd = open(SERIAL_INPUT_DEVICE, O_RDWR | O_NOCTTY | O_NONBLOCK)) < 0 ) {
HalPanic("failed to open input fd", errno);
}
if( (serialOutFd = open(SERIAL_OUTPUT_DEVICE, O_WRONLY | O_NOCTTY | O_NONBLOCK) ) < 0 ) {
HalPanic("failed to open output fd", errno);
}
//Get the term settings
tcgetattr(serialInFd, &serialSettingsOld);
// For now, lets reuse whatever terminal settings we were started with.
serialSettings.c_cflag = serialSettingsOld.c_cflag;
serialSettings.c_iflag = serialSettingsOld.c_iflag;
serialSettings.c_oflag = serialSettingsOld.c_oflag;
serialSettings.c_lflag = serialSettingsOld.c_lflag;
serialSettings.c_cc[VEOF] = serialSettingsOld.c_cc[VEOF];
serialSettings.c_cc[VEOL] = serialSettingsOld.c_cc[VEOL];
serialSettings.c_cc[VEOL2] = serialSettingsOld.c_cc[VEOL2];
serialSettings.c_cc[VERASE] = serialSettingsOld.c_cc[VERASE];
serialSettings.c_cc[VWERASE] = serialSettingsOld.c_cc[VWERASE];
serialSettings.c_cc[VKILL] = serialSettingsOld.c_cc[VKILL];
serialSettings.c_cc[VREPRINT] = serialSettingsOld.c_cc[VREPRINT];
serialSettings.c_cc[VINTR] = serialSettingsOld.c_cc[VINTR];
serialSettings.c_cc[VQUIT] = serialSettingsOld.c_cc[VQUIT];
serialSettings.c_cc[VSUSP] = serialSettingsOld.c_cc[VSUSP];
serialSettings.c_cc[VDSUSP] = serialSettingsOld.c_cc[VDSUSP];
serialSettings.c_cc[VSTART] = serialSettingsOld.c_cc[VSTART];
serialSettings.c_cc[VSTOP] = serialSettingsOld.c_cc[VSTOP];
serialSettings.c_cc[VLNEXT] = serialSettingsOld.c_cc[VLNEXT];
serialSettings.c_cc[VDISCARD] = serialSettingsOld.c_cc[VDISCARD];
serialSettings.c_cc[VMIN] = serialSettingsOld.c_cc[VMIN];
serialSettings.c_cc[VTIME] = serialSettingsOld.c_cc[VTIME];
serialSettings.c_cc[VSTATUS] = serialSettingsOld.c_cc[VSTATUS];
serialSettings.c_ispeed = serialSettingsOld.c_ispeed;
serialSettings.c_ospeed = serialSettingsOld.c_ospeed;
tcflush(serialInFd, TCIFLUSH);
tcsetattr(serialInFd,TCSANOW,&serialSettings);
fcntl(serialInFd, F_SETOWN, getpid( ));
oflags = fcntl(serialInFd, F_GETFL);
fcntl(serialInFd, F_SETFL, oflags | FASYNC);
fcntl(serialOutFd, F_SETOWN, getpid( ));
oflags = fcntl(serialOutFd, F_GETFL);
fcntl(serialOutFd, F_SETFL, oflags | FASYNC);
}
void HalSerialWriteChar(char data)
{
int writelen = write(serialOutFd, &data, sizeof(char));
if( writelen > 0 ) {
} else if(writelen == 0) {
HalPanic("Wrote 0 to STDOUT\n", 0);
} else {
HalPanic("Failed to write to STDOUT", errno);
}
}
/*
* sigaltstack will cause this function to be called on an alternate stack.
* This allows us to bootstrap new threads.
*/
void HalStackTrampoline( int SignalNumber )
{
int status;
//Save stack startup state before releaseing the tempContext.
STACK_INIT_ROUTINE * foo = halTempContext->Foo;
void * arg = halTempContext->Arg;
status = _setjmp( halTempContext->Registers );
if( status == 0 ) {
//Because status was 0 we know that this is the creation of
//the stack frame. We can use the locals to construct the frame.
halTempContextProcessed = TRUE;
halTempContext = NULL;
return;
} else {
//If we get here, then someone has jumped into a newly created thread.
//Test to make sure we are atomic
ASSERT( HalIsIrqAtomic(IRQ_LEVEL_MAX) );
foo(arg);
//Returning from a function which was invoked by siglongjmp is not
//supported. Foo should never retrun.
HalPanic("Tried to return from trampoline!");
return;
}
}
/*
* All signals call this routine.
* This routine then calls the appropriate ISR Handler.
*/
void HalIsrHandler( int SignalNumber )
{
INDEX index;
enum IRQ_LEVEL irq;
#ifdef DEBUG
HalUpdateIsrDebugInfo();
#endif
//We dont know which irq is associated with SignalNumber, so lets find it.
for(index = 0; index < IRQ_LEVEL_COUNT; index++) {
if( HalIrqToSignal[index] == SignalNumber ) {
//We found it, call the appropriate ISR.
irq = index;
HalIsrJumpTable[irq]();
#ifdef DEBUG
//We are about to return into an unknown frame.
//I can't predict what the irq will be there.
HalInvalidateIsrDebugInfo();
#endif
return;
}
}
HalPanic("Signal delivered for which no Irq was registered", SignalNumber);
}
/*
* sigaltstack will cause this fuction to be called on an alternate stack.
* This allows us to bootstrap new threads.
*/
void HalStackTrampoline( int SignalNumber )
{
int status;
status = _setjmp( halTempContext->Registers );
if( status == 0 ) {
//Because status was 0 we know that this is the creation of
//the stack frame. We can use the locals to construct the frame.
halTempContextProcessed = TRUE;
halTempContext = NULL;
return;
} else {
//If we get here, then someone has jumped into a newly created thread.
//Test to make sure we are atomic
ASSERT( HalIsIrqAtomic(IRQ_LEVEL_TIMER) );
StackInitRoutine();
//Returning from a function which was invoked by siglongjmp is not
//supported. Foo should never retrun.
HalPanic("Tried to return from StackInitRoutine!\n", 0 );
return;
}
}
/*
* All signals call this routine.
* This routine then calls the appropriate ISR Handler.
*/
void HalIsrHandler( int SignalNumber )
{
enum IRQ_LEVEL irq = HalSignalToIrq[SignalNumber];
HAL_ISR_HANDLER * handler = HalSignalToHandler[SignalNumber];
ASSERT (SignalNumber >= 0 && SignalNumber < NSIG);
if (handler == NULL) {
HalPanic("Signal delivered for which no Irq was registered");
}
ASSERT (handler != NULL);
ASSERT (irq != IRQ_LEVEL_NONE);
#ifdef DEBUG
HalUpdateIsrDebugInfo();
#endif
handler(irq);
#ifdef DEBUG
//We are about to return into an unknown frame.
//I can't predict what the irq will be there.
HalInvalidateIsrDebugInfo();
#endif
}
BOOL HalSerialGetChar(char * out)
{
int readlen = read(serialInFd, out, sizeof(char));
if(readlen > 0) {
return TRUE;
} else if(readlen == 0) {
//We are allowed to recieve zero bytes from the serial.
return FALSE;
} else {
if(errno == EINTR) {
return FALSE; //We are allowed to be interrupted by another signal.
} else if(errno == EAGAIN) {
return FALSE;
} else if(errno == EWOULDBLOCK) {
return FALSE;
} else {
HalPanic("Recieved error from STDIN!\n", errno );
return FALSE;
}
}
}
void HalCreateStackFrame(
struct MACHINE_CONTEXT * Context,
void * stack,
COUNT stackSize,
STACK_INIT_ROUTINE foo,
void * arg)
{
int status;
char * cstack = stack;
stack_t newStack;
sigset_t oldSet;
sigset_t trampolineMask;
struct sigaction switchStackAction;
ASSUME(sigemptyset( &oldSet ), 0);
ASSUME(sigemptyset( &trampolineMask ), 0);
ASSUME(sigaddset( &trampolineMask, HAL_ISR_TRAMPOLINE ), 0);
Context->Foo = foo;
Context->Arg = arg;
//We are about to bootstrap the new thread. Because we have to modify global
//state here, we must make sure no interrupts occur until after we are bootstrapped.
//We do all of this under the nose of the Isr unit.
sigprocmask(SIG_BLOCK, &HalIrqToSigaction[IRQ_LEVEL_MAX].sa_mask, &oldSet);
//NOTE: We use the interrupt mask here, because we want to block all operations.
switchStackAction.sa_handler = HalStackTrampoline;
switchStackAction.sa_mask = HalIrqToSigaction[IRQ_LEVEL_MAX].sa_mask;
switchStackAction.sa_flags = SA_ONSTACK;
sigaction(HAL_ISR_TRAMPOLINE, &switchStackAction, NULL );
halTempContext = Context;
halTempContextProcessed = FALSE;
newStack.ss_sp = cstack;
newStack.ss_size = stackSize;
newStack.ss_flags = 0;
status = sigaltstack( &newStack, NULL );
if (status != 0) {
HalPanicErrno("Failed to turn on sigaltstack.");
}
status = raise( HAL_ISR_TRAMPOLINE );
if (status != 0) {
HalPanicErrno("Failed raise stack bootstrap signal");
}
//At this point we know that we can't be interrupted.
//The trampoline signal has been triggered.
//All signals are blocked.
//We will unblock the Trampoine signal so it gets delivered.
ASSUME(sigprocmask( SIG_UNBLOCK, &trampolineMask, NULL ), 0);
//Make sure that the signal was delivered.
if (!halTempContextProcessed) {
HalPanic("Failed to bootstrap new stack via signal");
}
//Now that trampoline has fired, we can get back to the thread with longjump.
//Lets turn off sigaltstack.
newStack.ss_flags = SS_DISABLE;
status = sigaltstack( &newStack, NULL );
if (status != 0) {
HalPanicErrno("Failed to turn off sigaltstack.");
}
//Now that we have bootstrapped the new thread, lets restore the old mask.
ASSUME(sigprocmask(SIG_SETMASK, &oldSet, NULL), 0);
}
