minix/kernel/interrupt.c
Cristiano Giuffrida cb176df60f New RS and new signal handling for system processes.
UPDATING INFO:
20100317:
        /usr/src/etc/system.conf updated to ignore default kernel calls: copy
        it (or merge it) to /etc/system.conf.
        The hello driver (/dev/hello) added to the distribution:
        # cd /usr/src/commands/scripts && make clean install
        # cd /dev && MAKEDEV hello

KERNEL CHANGES:
- Generic signal handling support. The kernel no longer assumes PM as a signal
manager for every process. The signal manager of a given process can now be
specified in its privilege slot. When a signal has to be delivered, the kernel
performs the lookup and forwards the signal to the appropriate signal manager.
PM is the default signal manager for user processes, RS is the default signal
manager for system processes. To enable ptrace()ing for system processes, it
is sufficient to change the default signal manager to PM. This will temporarily
disable crash recovery, though.
- sys_exit() is now split into sys_exit() (i.e. exit() for system processes,
which generates a self-termination signal), and sys_clear() (i.e. used by PM
to ask the kernel to clear a process slot when a process exits).
- Added a new kernel call (i.e. sys_update()) to swap two process slots and
implement live update.

PM CHANGES:
- Posix signal handling is no longer allowed for system processes. System
signals are split into two fixed categories: termination and non-termination
signals. When a non-termination signaled is processed, PM transforms the signal
into an IPC message and delivers the message to the system process. When a
termination signal is processed, PM terminates the process.
- PM no longer assumes itself as the signal manager for system processes. It now
makes sure that every system signal goes through the kernel before being
actually processes. The kernel will then dispatch the signal to the appropriate
signal manager which may or may not be PM.

SYSLIB CHANGES:
- Simplified SEF init and LU callbacks.
- Added additional predefined SEF callbacks to debug crash recovery and
live update.
- Fixed a temporary ack in the SEF init protocol. SEF init reply is now
completely synchronous.
- Added SEF signal event type to provide a uniform interface for system
processes to deal with signals. A sef_cb_signal_handler() callback is
available for system processes to handle every received signal. A
sef_cb_signal_manager() callback is used by signal managers to process
system signals on behalf of the kernel.
- Fixed a few bugs with memory mapping and DS.

VM CHANGES:
- Page faults and memory requests coming from the kernel are now implemented
using signals.
- Added a new VM call to swap two process slots and implement live update.
- The call is used by RS at update time and in turn invokes the kernel call
sys_update().

RS CHANGES:
- RS has been reworked with a better functional decomposition.
- Better kernel call masks. com.h now defines the set of very basic kernel calls
every system service is allowed to use. This makes system.conf simpler and
easier to maintain. In addition, this guarantees a higher level of isolation
for system libraries that use one or more kernel calls internally (e.g. printf).
- RS is the default signal manager for system processes. By default, RS
intercepts every signal delivered to every system process. This makes crash
recovery possible before bringing PM and friends in the loop.
- RS now supports fast rollback when something goes wrong while initializing
the new version during a live update.
- Live update is now implemented by keeping the two versions side-by-side and
swapping the process slots when the old version is ready to update.
- Crash recovery is now implemented by keeping the two versions side-by-side
and cleaning up the old version only when the recovery process is complete.

DS CHANGES:
- Fixed a bug when the process doing ds_publish() or ds_delete() is not known
by DS.
- Fixed the completely broken support for strings. String publishing is now
implemented in the system library and simply wraps publishing of memory ranges.
Ideally, we should adopt a similar approach for other data types as well.
- Test suite fixed.

DRIVER CHANGES:
- The hello driver has been added to the Minix distribution to demonstrate basic
live update and crash recovery functionalities.
- Other drivers have been adapted to conform the new SEF interface.
2010-03-17 01:15:29 +00:00

169 lines
4.6 KiB
C

/*
* The Minix hardware interrupt system.
*
* This file contains routines for managing the interrupt
* controller.
*
* put_irq_handler: register an interrupt handler.
* rm_irq_handler: deregister an interrupt handler.
* irq_handle: handle a hardware interrupt.
* called by the system dependent part when an
* external interrupt occures.
* enable_irq: enable hook for IRQ.
* disable_irq: disable hook for IRQ.
*/
#include "kernel.h"
#include "proc.h"
#include "archconst.h"
#include "arch/i386/hw_intr.h"
/* number of lists of IRQ hooks, one list per supported line. */
PUBLIC irq_hook_t* irq_handlers[NR_IRQ_VECTORS] = {0};
/*===========================================================================*
* put_irq_handler *
*===========================================================================*/
/* Register an interrupt handler. */
PUBLIC void put_irq_handler( irq_hook_t* hook, int irq, irq_handler_t handler)
{
int id;
irq_hook_t **line;
unsigned long bitmap;
if( irq < 0 || irq >= NR_IRQ_VECTORS )
panic("invalid call to put_irq_handler: %d", irq);
line = &irq_handlers[irq];
bitmap = 0;
while ( *line != NULL ) {
if(hook == *line) return; /* extra initialization */
bitmap |= (*line)->id; /* mark ids in use */
line = &(*line)->next;
}
/* find the lowest id not in use */
for (id = 1; id != 0; id <<= 1)
if (!(bitmap & id)) break;
if(id == 0)
panic("Too many handlers for irq: %d", irq);
hook->next = NULL;
hook->handler = handler;
hook->irq = irq;
hook->id = id;
*line = hook;
irq_use |= 1 << irq; /* this does not work for irq >= 32 */
/* And as last enable the irq at the hardware.
*
* Internal this activates the line or source of the given interrupt.
*/
if((irq_actids[hook->irq] &= ~hook->id) == 0) {
hw_intr_unmask(hook->irq);
}
}
/*===========================================================================*
* rm_irq_handler *
*===========================================================================*/
/* Unregister an interrupt handler. */
PUBLIC void rm_irq_handler( irq_hook_t* hook ) {
int irq = hook->irq;
int id = hook->id;
irq_hook_t **line;
if( irq < 0 || irq >= NR_IRQ_VECTORS )
panic("invalid call to rm_irq_handler: %d", irq);
/* remove the hook */
line = &irq_handlers[irq];
while( (*line) != NULL ) {
if((*line)->id == id) {
(*line) = (*line)->next;
if(!irq_handlers[irq])
irq_use &= ~(1 << irq);
if (irq_actids[irq] & id)
irq_actids[irq] &= ~id;
}
else {
line = &(*line)->next;
}
}
/* Disable the irq if there are no other handlers registered.
* If the irq is shared, reenable it if there is no active handler.
*/
if (irq_handlers[irq] == NULL) {
hw_intr_mask(irq);
}
else if (irq_actids[irq] == 0) {
hw_intr_unmask(irq);
}
}
/*===========================================================================*
* irq_handle *
*===========================================================================*/
/*
* The function first disables interrupt is need be and restores the state at
* the end. Before returning, it unmasks the IRQ if and only if all active ID
* bits are cleared, and restart a process.
*/
PUBLIC void irq_handle(int irq)
{
irq_hook_t * hook;
/* here we need not to get this IRQ until all the handlers had a say */
hw_intr_mask(irq);
hook = irq_handlers[irq];
/* Sanity check. */
if(hook == NULL) {
printf("%s: irq_handle:no handler registered, masking the IRQ...\n",
__FILE__);
return;
}
/* Call list of handlers for an IRQ. */
while( hook != NULL ) {
/* For each handler in the list, mark it active by setting its ID bit,
* call the function, and unmark it if the function returns true.
*/
irq_actids[irq] |= hook->id;
/* Call the hooked function. */
if( (*hook->handler)(hook) )
irq_actids[hook->irq] &= ~hook->id;
/* Next hooked function. */
hook = hook->next;
}
/* reenable the IRQ only if there is no active handler */
if (irq_actids[irq] == 0)
hw_intr_unmask(irq);
}
/* Enable/Disable a interrupt line. */
PUBLIC void enable_irq(hook)
irq_hook_t* hook;
{
if((irq_actids[hook->irq] &= ~hook->id) == 0) {
hw_intr_unmask(hook->irq);
}
}
/* Return true if the interrupt was enabled before call. */
PUBLIC int disable_irq(hook)
irq_hook_t* hook;
{
if(irq_actids[hook->irq] & hook->id) /* already disabled */
return 0;
irq_actids[hook->irq] |= hook->id;
hw_intr_mask(hook->irq);
return TRUE;
}