From 7ad9c01dad7b1b46eced8290b8b991383d648188 Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Mon, 1 Jul 2024 23:34:57 +0300
Subject: expand notifications into interrupt handlers

+ Terminology is still a bit poor, and will still have to write
  documentation + implement ipis properly
---
 include/kmi/caps.h     |  5 ++++-
 include/kmi/notify.h   |  9 +++++++++
 include/kmi/syscalls.h | 12 +++++++++++-
 include/kmi/tcb.h      |  5 +++++
 include/kmi/uapi.h     | 30 +++++++++++++++++++++++++++++-
 5 files changed, 58 insertions(+), 3 deletions(-)
 create mode 100644 include/kmi/notify.h

(limited to 'include')

diff --git a/include/kmi/caps.h b/include/kmi/caps.h
index 2813634..8af9293 100644
--- a/include/kmi/caps.h
+++ b/include/kmi/caps.h
@@ -26,7 +26,7 @@ enum {
 	/** Thread is allowed to modify process statuses, create/exec/fork/etc. */
 	CAP_PROC = (1 << 1),
 
-	/** Thread is allowed to force interrupt to callback in other thread. */
+	/** Thread is allowed to force notification in other thread. */
 	CAP_CALL = (1 << 2),
 
 	/** Thread is allowed to shut down system. */
@@ -37,6 +37,9 @@ enum {
 
 	/** Thread is allowed to request to handle IRQs. */
 	CAP_IRQ = (1 << 5),
+
+	/** Thread is allowed to request notification handler. */
+	CAP_NOTIFICATION = (1 << 6),
 };
 
 /**
diff --git a/include/kmi/notify.h b/include/kmi/notify.h
new file mode 100644
index 0000000..0a17654
--- /dev/null
+++ b/include/kmi/notify.h
@@ -0,0 +1,9 @@
+#ifndef KMI_NOTIFY_H
+#define KMI_NOTIFY_H
+
+#include <kmi/tcb.h>
+
+/* Implemented in ipc.c */
+void notify(struct tcb *t);
+
+#endif /* KMI_NOTIFY_H */
diff --git a/include/kmi/syscalls.h b/include/kmi/syscalls.h
index e503709..23fc799 100644
--- a/include/kmi/syscalls.h
+++ b/include/kmi/syscalls.h
@@ -18,7 +18,7 @@
 
 /** enum for now, possibly macros in the future once I get an approximate idea of
  * which syscalls are necessary etc. */
-enum {
+enum sys_code {
 	/**
 	 * @name Misc.
 	 * Implementation in \ref dispatch.c instead of a separate file, as I
@@ -96,6 +96,9 @@ enum {
 	/** IPC response from server. */
 	SYS_IPC_RESP,
 
+	/** IPC return without visible side effects. */
+	SYS_IPC_GHOST,
+
 	/** IPC notify thread, essentially interrupt or signal. */
 	SYS_IPC_NOTIFY,
 	/** @} */
@@ -148,11 +151,18 @@ enum {
 	/** Request to handle IRQ. */
 	SYS_IRQ_REQ,
 
+	/** Request a notification handler. */
+	SYS_REQ_NOTIFICATION,
+
 	/** @} */
 
 	SYS_NUM,
 };
 
+enum sys_user {
+	SYS_USER_NOTIFY,
+};
+
 /* function declarations should be somewhere else, this file could be used in
  * userspace applications as well */
 
diff --git a/include/kmi/tcb.h b/include/kmi/tcb.h
index 6614d62..999b6a8 100644
--- a/include/kmi/tcb.h
+++ b/include/kmi/tcb.h
@@ -177,6 +177,11 @@ struct tcb {
 	/** Cpu currently executing this thread. */
 	id_t cpu_id;
 
+	/** In which process to run notifications. Note that this is currently
+	 * set in the syscall handlers due to the different rules for inheriting
+	 * this id, might change in the future. */
+	id_t notify_id;
+
 	/** Capabilities of thread. */
 	capflags_t caps;
 
diff --git a/include/kmi/uapi.h b/include/kmi/uapi.h
index 5e5f446..1631500 100644
--- a/include/kmi/uapi.h
+++ b/include/kmi/uapi.h
@@ -427,7 +427,8 @@ SYSCALL_DECLARE0(ticks);
  *
  * @param t Current tcb.
  * @param ticks Number of ticks from now.
- * @param mult Number of times to trigger.
+ * @param mult Multiplier for \p ticks if we're on 32bit systems to produce a
+ * combined 64 bit value. Ignored on 64bit systems.
  * @param c Unused.
  * @param d Unused.
  * @param e Unused.
@@ -555,6 +556,16 @@ SYSCALL_DECLARE5(ipc_kick, pid, d0, d1, d2, d3);
  */
 SYSCALL_DECLARE4(ipc_resp, d0, d1, d2, d3);
 
+/**
+ * Returns to caller but without changing any visible state. Primarily used when
+ * returning from interrupt handlers, like notifications, timers or external
+ * devices.
+ *
+ * @param r Current tcb.
+ *
+ */
+SYSCALL_DECLARE0(ipc_ghost);
+
 /**
  * Notify thread syscall.
  *
@@ -747,6 +758,22 @@ SYSCALL_DECLARE2(get_cap, tid, off);
  */
 SYSCALL_DECLARE3(clear_cap, tid, off, cap);
 
+/**
+ * Set which process to move notifications to for thread.
+ * @todo Should converge on either calling everything irq or notification or
+ * whatever, but mixing both is a bit dumb.
+ *
+ * @param t Current tcb.
+ * @param tid Thread whose notifications should be moved.
+ * @param pid Process that is willing to handle the notifications.
+ * @param c Unused.
+ * @param d Unused.
+ * @param e Unused.
+ *
+ * Returns \ref OK.
+ */
+SYSCALL_DECLARE2(req_notification, tid, pid);
+
 /**
  * Power off syscall.
  *
@@ -792,6 +819,7 @@ SYSCALL_DECLARE0(sleep);
  * @todo document error codes better.
  */
 SYSCALL_DECLARE1(irq_req, id);
+
 /** @} */
 
 /**
-- 
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