Add hardware interrupt notification mechanism

This allows privileged userland drivers to get notifications of hardware
interrupts.

Initial work by Zheng Da, reworked by Damien Zammit and myself.

* Makefrag.am (libkernel_a_SOURCES): Add device/intr.c and
device/intr.h.
(include_device_HEADERS): Add include/device/notify.defs and
include/device/notify.h.
* device/dev_hdr.h (name_equal): Add declaration.
* device/ds_routines.c: Include <device/intr.h>
(ds_device_intr_register, ds_device_intr_ack): New functions.
* device/intr.c, device/intr.h: New files.
* doc/mach.texi (Device Interrupt): New section.
* i386/Makefrag.am (libkernel_a_SOURCES): Add i386/i386/irq.c and
i386/i386/irq.h.
* i386/i386/irq.c, i386/i386/irq.h: New files.
* i386/i386at/conf.c: Include <device/intr.h>.
(irqname): New macro.
(dev_name_list): Add irq device.
* include/device/device.defs (device_intr_register, device_intr_ack):
New RPCs.
* include/device/notify.defs, include/device/notify.h: New files.
* kern/startup.c: Include <device/intr.h>
(start_kernel_threads): Start intr_thread thread.
* linux/dev/arch/i386/kernel/irq.c: Include <device/intr.h>
(linux_action): Add user_intr field.
(linux_intr): Call user_intr action if any.
(mask_irq, unmask_irq): Move functions to i386/i386/pic.c
(__disable_irq, __enable_irq): Move functions to i386/i386/irq.c.
(install_user_intr_handler): New function.
(request_irq): Initialize user_intr field.
* linux/src/include/asm-i386/irq.h (__disable_irq, __enable_irq): Remove
prototypes.
* i386/i386/pic.c (mask_irq, unmask_irq): New functions.
* i386/i386/pic.h (mask_irq, unmask_irq): New prototypes.

4 files changed, 408 insertions, 0 deletions

diff --git a/device/dev_hdr.h b/device/dev_hdr.h
index ad98e0bb..4bd12c1c 100644
--- a/device/dev_hdr.h
+++ b/device/dev_hdr.h
@@ -146,4 +146,13 @@ extern void dev_set_indirection(
     dev_ops_t   ops,
     int     	unit);
 
+/*
+ * compare device name
+ */
+extern boolean_t __attribute__ ((pure))
+name_equal(
+    const char  *src,
+    int         len,
+    const char  *target);
+
 #endif	/* _DEVICE_DEV_HDR_H_ */
diff --git a/device/ds_routines.c b/device/ds_routines.c
index fc051e8f..78ff51fe 100644
--- a/device/ds_routines.c
+++ b/device/ds_routines.c
@@ -92,6 +92,7 @@
 #include <device/device_port.h>
 #include <device/device_reply.user.h>
 #include <device/device_emul.h>
+#include <device/intr.h>
 
 #include <machine/machspl.h>
 
@@ -319,6 +320,59 @@ ds_device_map (device_t dev, vm_prot_t prot, vm_offset_t offset,
 				offset, size, pager, unmap);
 }
 
+/* TODO: missing deregister support */
+io_return_t
+ds_device_intr_register (device_t dev, int id,
+                         int flags, ipc_port_t receive_port)
+{
+  kern_return_t err;
+  mach_device_t mdev = dev->emul_data;
+
+  /* Refuse if device is dead or not completely open.  */
+  if (dev == DEVICE_NULL)
+    return D_NO_SUCH_DEVICE;
+
+  /* No flag is defined for now */
+  if (flags != 0)
+    return D_INVALID_OPERATION;
+
+  /* Must be called on the irq device only */
+  if (! name_equal(mdev->dev_ops->d_name, 3, "irq"))
+    return D_INVALID_OPERATION;
+
+  user_intr_t *e = insert_intr_entry (&irqtab, id, receive_port);
+  if (!e)
+    return D_NO_MEMORY;
+
+  // TODO The original port should be replaced
+  // when the same device driver calls it again,
+  // in order to handle the case that the device driver crashes and restarts.
+  err = install_user_intr_handler (&irqtab, id, flags, e);
+  if (err == D_SUCCESS)
+    {
+      /* If the port is installed successfully, increase its reference by 1.
+       * Thus, the port won't be destroyed after its task is terminated. */
+      ip_reference (receive_port);
+    }
+  return err;
+}
+
+kern_return_t
+ds_device_intr_ack (device_t dev, ipc_port_t receive_port)
+{
+  mach_device_t mdev = dev->emul_data;
+
+  /* Refuse if device is dead or not completely open.  */
+  if (dev == DEVICE_NULL)
+    return D_NO_SUCH_DEVICE;
+
+  /* Must be called on the irq device only */
+  if (! name_equal(mdev->dev_ops->d_name, 3, "irq"))
+    return D_INVALID_OPERATION;
+
+  return irq_acknowledge(receive_port);
+}
+
 boolean_t
 ds_notify (mach_msg_header_t *msg)
 {
diff --git a/device/intr.c b/device/intr.c
new file mode 100644
index 00000000..fbb9f495
--- /dev/null
+++ b/device/intr.c
@@ -0,0 +1,283 @@
+/*
+ * Copyright (c) 2010, 2011, 2016, 2019 Free Software Foundation, Inc.
+ *
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * THE FREE SOFTWARE FOUNDATIONALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION.  THE FREE SOFTWARE FOUNDATION DISCLAIMS ANY LIABILITY OF ANY KIND
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ */
+
+#include <device/intr.h>
+#include <device/device_types.h>
+#include <device/device_port.h>
+#include <device/notify.h>
+#include <kern/printf.h>
+#include <machine/spl.h>
+#include <machine/irq.h>
+#include <ipc/ipc_space.h>
+
+#ifndef MACH_XEN
+
+queue_head_t main_intr_queue;
+static boolean_t deliver_intr (int id, ipc_port_t dst_port);
+
+static user_intr_t *
+search_intr (struct irqdev *dev, ipc_port_t dst_port)
+{
+  user_intr_t *e;
+  queue_iterate (dev->intr_queue, e, user_intr_t *, chain)
+    {
+      if (e->dst_port == dst_port)
+	return e;
+    }
+  return NULL;
+}
+
+kern_return_t
+irq_acknowledge (ipc_port_t receive_port)
+{
+  user_intr_t *e;
+  kern_return_t ret = 0;
+
+  spl_t s = splhigh ();
+  e = search_intr (&irqtab, receive_port);
+
+  if (!e)
+    printf("didn't find user intr for interrupt !?\n");
+  else
+    {
+      if (!e->n_unacked)
+        ret = D_INVALID_OPERATION;
+      else
+        e->n_unacked--;
+    }
+  splx (s);
+
+  if (ret)
+    return ret;
+
+  if (irqtab.irqdev_ack)
+    (*(irqtab.irqdev_ack)) (&irqtab, e->id);
+
+  __enable_irq (irqtab.irq[e->id]);
+
+  return D_SUCCESS;
+}
+
+/* This function can only be used in the interrupt handler. */
+static void
+queue_intr (struct irqdev *dev, int id, user_intr_t *e)
+{
+  /* Until userland has handled the IRQ in the driver, we have to keep it
+   * disabled. Level-triggered interrupts would keep raising otherwise. */
+  __disable_irq (dev->irq[id]);
+
+  spl_t s = splhigh ();
+  e->n_unacked++;
+  e->interrupts++;
+  dev->tot_num_intr++;
+  splx (s);
+
+  thread_wakeup ((event_t) &intr_thread);
+}
+
+int
+deliver_user_intr (struct irqdev *dev, int id, user_intr_t *e)
+{
+  /* The reference of the port was increased
+   * when the port was installed.
+   * If the reference is 1, it means the port should
+   * have been destroyed and I destroy it now. */
+  if (e->dst_port
+      && e->dst_port->ip_references == 1)
+    {
+      printf ("irq handler [%d]: release a dead delivery port %p entry %p\n", id, e->dst_port, e);
+      ipc_port_release (e->dst_port);
+      e->dst_port = MACH_PORT_NULL;
+      thread_wakeup ((event_t) &intr_thread);
+      return 0;
+    }
+  else
+    {
+      queue_intr (dev, id, e);
+      return 1;
+    }
+}
+
+/* insert an interrupt entry in the queue.
+ * This entry exists in the queue until
+ * the corresponding interrupt port is removed.*/
+user_intr_t *
+insert_intr_entry (struct irqdev *dev, int id, ipc_port_t dst_port)
+{
+  user_intr_t *e, *new, *ret;
+  int free = 0;
+
+  new = (user_intr_t *) kalloc (sizeof (*new));
+  if (new == NULL)
+    return NULL;
+
+  /* check whether the intr entry has been in the queue. */
+  spl_t s = splhigh ();
+  e = search_intr (dev, dst_port);
+  if (e)
+    {
+      printf ("the interrupt entry for irq[%d] and port %p has already been inserted\n", id, dst_port);
+      free = 1;
+      ret = NULL;
+      goto out;
+    }
+  printf("irq handler [%d]: new delivery port %p entry %p\n", id, dst_port, new);
+  ret = new;
+  new->id = id;
+  new->dst_port = dst_port;
+  new->interrupts = 0;
+  new->n_unacked = 0;
+
+  queue_enter (dev->intr_queue, new, user_intr_t *, chain);
+out:
+  splx (s);
+  if (free)
+    kfree ((vm_offset_t) new, sizeof (*new));
+  return ret;
+}
+
+void
+intr_thread (void)
+{
+  user_intr_t *e;
+  int id;
+  ipc_port_t dst_port;
+  queue_init (&main_intr_queue);
+
+  for (;;)
+    {
+      assert_wait ((event_t) &intr_thread, FALSE);
+      /* Make sure we wake up from times to times to check for aborted processes */
+      thread_set_timeout (hz);
+      spl_t s = splhigh ();
+
+      /* Check for aborted processes */
+      queue_iterate (&main_intr_queue, e, user_intr_t *, chain)
+	{
+	  if ((!e->dst_port || e->dst_port->ip_references == 1) && e->n_unacked)
+	    {
+	      printf ("irq handler [%d]: release dead delivery %d unacked irqs port %p entry %p\n", e->id, e->n_unacked, e->dst_port, e);
+	      /* The reference of the port was increased
+	       * when the port was installed.
+	       * If the reference is 1, it means the port should
+	       * have been destroyed and I clear unacked irqs now, so the Linux
+	       * handling can trigger, and we will cleanup later after the Linux
+	       * handler is cleared. */
+	      /* TODO: rather immediately remove from Linux handler */
+	      while (e->n_unacked)
+	      {
+		__enable_irq (irqtab.irq[e->id]);
+		e->n_unacked--;
+	      }
+	    }
+	}
+
+      /* Now check for interrupts */
+      while (irqtab.tot_num_intr)
+	{
+	  int del = 0;
+
+	  queue_iterate (&main_intr_queue, e, user_intr_t *, chain)
+	    {
+	      /* if an entry doesn't have dest port,
+	       * we should remove it. */
+	      if (e->dst_port == MACH_PORT_NULL)
+		{
+		  clear_wait (current_thread (), 0, 0);
+		  del = 1;
+		  break;
+		}
+
+	      if (e->interrupts)
+		{
+		  clear_wait (current_thread (), 0, 0);
+		  id = e->id;
+		  dst_port = e->dst_port;
+		  e->interrupts--;
+		  irqtab.tot_num_intr--;
+
+		  splx (s);
+		  deliver_intr (id, dst_port);
+		  s = splhigh ();
+		}
+	    }
+
+	  /* remove the entry without dest port from the queue and free it. */
+	  if (del)
+	    {
+	      assert (!queue_empty (&main_intr_queue));
+	      queue_remove (&main_intr_queue, e, user_intr_t *, chain);
+	      if (e->n_unacked)
+		printf("irq handler [%d]: still %d unacked irqs in entry %p\n", e->id, e->n_unacked, e);
+	      while (e->n_unacked)
+	      {
+		__enable_irq (irqtab.irq[e->id]);
+		e->n_unacked--;
+	      }
+	      printf("irq handler [%d]: removed entry %p\n", e->id, e);
+	      splx (s);
+	      kfree ((vm_offset_t) e, sizeof (*e));
+	      s = splhigh ();
+	    }
+	}
+      splx (s);
+      thread_block (NULL);
+    }
+}
+
+static boolean_t
+deliver_intr (int id, ipc_port_t dst_port)
+{
+  ipc_kmsg_t kmsg;
+  device_intr_notification_t *n;
+  mach_port_t dest = (mach_port_t) dst_port;
+
+  if (dest == MACH_PORT_NULL)
+    return FALSE;
+
+  kmsg = ikm_alloc(sizeof *n);
+  if (kmsg == IKM_NULL)
+    return FALSE;
+
+  ikm_init(kmsg, sizeof *n);
+  n = (device_intr_notification_t *) &kmsg->ikm_header;
+
+  mach_msg_header_t *m = &n->intr_header;
+  mach_msg_type_t *t = &n->intr_type;
+
+  m->msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND, 0);
+  m->msgh_size = sizeof *n;
+  m->msgh_seqno = DEVICE_NOTIFY_MSGH_SEQNO;
+  m->msgh_local_port = MACH_PORT_NULL;
+  m->msgh_remote_port = MACH_PORT_NULL;
+  m->msgh_id = DEVICE_INTR_NOTIFY;
+
+  t->msgt_name = MACH_MSG_TYPE_INTEGER_32;
+  t->msgt_size = 32;
+  t->msgt_number = 1;
+  t->msgt_inline = TRUE;
+  t->msgt_longform = FALSE;
+  t->msgt_deallocate = FALSE;
+  t->msgt_unused = 0;
+
+  n->intr_header.msgh_remote_port = dest;
+  n->id = id;
+
+  ipc_port_copy_send (dst_port);
+  ipc_mqueue_send_always(kmsg);
+
+  return TRUE;
+}
+
+#endif	/* MACH_XEN */
diff --git a/device/intr.h b/device/intr.h
new file mode 100644
index 00000000..cd3e0bce
--- /dev/null
+++ b/device/intr.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2010, 2011, 2019 Free Software Foundation, Inc.
+ *
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * THE FREE SOFTWARE FOUNDATIONALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION.  THE FREE SOFTWARE FOUNDATION DISCLAIMS ANY LIABILITY OF ANY KIND
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ */
+
+#ifndef __INTR_H__
+#define __INTR_H__
+
+#ifndef MACH_XEN
+
+#include <mach/kern_return.h>
+#include <mach/port.h>
+#include <kern/queue.h>
+#include <ipc/ipc_port.h>
+#include <device/conf.h>
+
+#define DEVICE_NOTIFY_MSGH_SEQNO 0
+
+#include <sys/types.h>
+
+struct irqdev;
+#include <machine/irq.h>
+
+typedef struct {
+  queue_chain_t chain;
+  int interrupts; /* Number of interrupts occurred since last run of intr_thread */
+  int n_unacked;  /* Number of times irqs were disabled for this */
+  ipc_port_t dst_port; /* Notification port */
+  int id; /* Mapping to machine dependent irq_t array elem */
+} user_intr_t;
+
+struct irqdev {
+  char *name;
+  void (*irqdev_ack)(struct irqdev *dev, int id);
+
+  queue_head_t *intr_queue;
+  int tot_num_intr; /* Total number of unprocessed interrupts */
+
+  /* Machine dependent */
+  irq_t irq[NINTR];
+};
+
+extern queue_head_t main_intr_queue;
+extern int install_user_intr_handler (struct irqdev *dev, int id, unsigned long flags, user_intr_t *e);
+extern int deliver_user_intr (struct irqdev *dev, int id, user_intr_t *e);
+extern user_intr_t *insert_intr_entry (struct irqdev *dev, int id, ipc_port_t receive_port);
+
+void intr_thread (void);
+kern_return_t irq_acknowledge (ipc_port_t receive_port);
+
+#endif /* MACH_XEN */
+
+#endif