From 8bb9e222183376015c6189e05e9c8a4bbdb7b28b Mon Sep 17 00:00:00 2001
From: "Justin C. Miller" <justin@justin.cm>
Date: Sun, 18 Oct 2020 20:45:06 -0700
Subject: [PATCH] [kernel] Move bind_irq syscall to new system object

In order to implement capabilities on system resources like IRQs so that
they may be restricted to drivers only, add a new 'system' kobject type,
and move the bind_irq functionality from endpoint to system.

Also fix some stack bugs passing the initial handles to a program.
---
 modules.yaml                           |  1 +
 src/drivers/nulldrv/main.cpp           | 12 +++++++-----
 src/drivers/nulldrv/main.s             |  1 -
 src/include/j6/types.h                 | 10 ++++++++--
 src/include/syscalls.inc               |  3 ++-
 src/kernel/device_manager.cpp          |  3 +++
 src/kernel/loader.s                    |  3 +++
 src/kernel/objects/kobject.h           |  4 +++-
 src/kernel/objects/system.cpp          |  3 +++
 src/kernel/objects/system.h            | 18 ++++++++++++++++++
 src/kernel/scheduler.cpp               | 12 ++++++++----
 src/kernel/syscalls/endpoint.cpp       | 12 ------------
 src/kernel/syscalls/system.cpp         | 22 ++++++++++++++++++++++
 src/libraries/libc/arch/x86_64/_Exit.s |  4 ++--
 14 files changed, 80 insertions(+), 28 deletions(-)
 create mode 100644 src/kernel/objects/system.cpp
 create mode 100644 src/kernel/objects/system.h

diff --git a/modules.yaml b/modules.yaml
index 2d227c3..5c7f6b1 100644
--- a/modules.yaml
+++ b/modules.yaml
@@ -39,6 +39,7 @@ modules:
             - src/kernel/objects/kobject.cpp
             - src/kernel/objects/thread.cpp
             - src/kernel/objects/process.cpp
+            - src/kernel/objects/system.cpp
             - src/kernel/objects/vm_area.cpp
             - src/kernel/page_table.cpp
             - src/kernel/pci.cpp
diff --git a/src/drivers/nulldrv/main.cpp b/src/drivers/nulldrv/main.cpp
index d778bbe..a239eb4 100644
--- a/src/drivers/nulldrv/main.cpp
+++ b/src/drivers/nulldrv/main.cpp
@@ -11,10 +11,9 @@
 #include "serial.h"
 
 char inbuf[1024];
+j6_handle_t sys = j6_handle_invalid;
 j6_handle_t endp = j6_handle_invalid;
 
-j6_process_init *init = nullptr;
-
 extern "C" {
 	void _init_libc(j6_process_init *);
 	int main(int, const char **);
@@ -53,9 +52,9 @@ thread_proc()
 }
 
 void
-_init_libc(j6_process_init *i)
+_init_libc(j6_process_init *init)
 {
-	init = i;
+	sys = init->handles[0];
 }
 
 int
@@ -98,6 +97,10 @@ main(int argc, const char **argv)
 	if (tag != 17)
 		_syscall_system_log("GOT WRONG TAG FROM SENDRECV");
 
+	result = _syscall_system_bind_irq(sys, endp, 3);
+	if (result != j6_status_ok)
+		return result;
+
 	_syscall_system_log(message);
 
 	_syscall_system_log("main thread waiting on child");
@@ -108,7 +111,6 @@ main(int argc, const char **argv)
 
 	_syscall_system_log("main testing irqs");
 
-	_syscall_endpoint_bind_irq(endp, 3);
 
 	serial_port com2(COM2);
 
diff --git a/src/drivers/nulldrv/main.s b/src/drivers/nulldrv/main.s
index 07ffdfe..e79154b 100644
--- a/src/drivers/nulldrv/main.s
+++ b/src/drivers/nulldrv/main.s
@@ -13,7 +13,6 @@ _start:
 	mov rbp, rsp
 
 	mov rdi, rsp
-	sub rdi, 8
 	call _init_libc
 
 	mov rdi, 0
diff --git a/src/include/j6/types.h b/src/include/j6/types.h
index 73890af..15d762c 100644
--- a/src/include/j6/types.h
+++ b/src/include/j6/types.h
@@ -38,6 +38,12 @@ typedef uint64_t j6_handle_t;
 /// A process' initial data structure for communicating with the system
 struct j6_process_init
 {
-	j6_handle_t input;
-	j6_handle_t output;
+	j6_handle_t process;
+	j6_handle_t handles[3];
+};
+
+/// A thread's initial data structure
+struct j6_thread_init
+{
+	j6_handle_t thread;
 };
diff --git a/src/include/syscalls.inc b/src/include/syscalls.inc
index d483835..4cd636f 100644
--- a/src/include/syscalls.inc
+++ b/src/include/syscalls.inc
@@ -1,5 +1,7 @@
 SYSCALL(0x00, system_log,        const char *)
 SYSCALL(0x01, system_noop,       void)
+SYSCALL(0x02, system_get_log,    j6_handle_t, j6_handle_t *)
+SYSCALL(0x03, system_bind_irq,   j6_handle_t, j6_handle_t, unsigned)
 
 SYSCALL(0x08, object_koid,       j6_handle_t, j6_koid_t *)
 SYSCALL(0x09, object_wait,       j6_handle_t, j6_signal_t, j6_signal_t *)
@@ -21,7 +23,6 @@ SYSCALL(0x28, endpoint_create,   j6_handle_t *)
 SYSCALL(0x29, endpoint_send,     j6_handle_t, j6_tag_t, size_t, void *)
 SYSCALL(0x2a, endpoint_receive,  j6_handle_t, j6_tag_t *, size_t *, void *)
 SYSCALL(0x2b, endpoint_sendrecv, j6_handle_t, j6_tag_t *, size_t *, void *)
-SYSCALL(0x2c, endpoint_bind_irq, j6_handle_t, unsigned)
 
 SYSCALL(0x30, vma_create,        j6_handle_t *, size_t, uint32_t)
 SYSCALL(0x31, vma_create_map,    j6_handle_t *, size_t, uintptr_t, uint32_t)
diff --git a/src/kernel/device_manager.cpp b/src/kernel/device_manager.cpp
index 530bd7a..6d611c4 100644
--- a/src/kernel/device_manager.cpp
+++ b/src/kernel/device_manager.cpp
@@ -67,6 +67,9 @@ device_manager::device_manager() :
 {
 	m_irqs.ensure_capacity(32);
 	m_irqs.set_size(16);
+	for (int i = 0; i < 16; ++i)
+		m_irqs[i] = nullptr;
+
 	m_irqs[2] = ignore_endpoint;
 }
 
diff --git a/src/kernel/loader.s b/src/kernel/loader.s
index 761231d..07c31e0 100644
--- a/src/kernel/loader.s
+++ b/src/kernel/loader.s
@@ -15,6 +15,9 @@ preloaded_process_init:
 
 	call load_process_image
 
+	; user rsp is now in rax, put it in the right place for iret
+	mov [rsp + 0x18], rax
+
 	; the entrypoint should already be on the stack
 	swapgs
 	iretq
diff --git a/src/kernel/objects/kobject.h b/src/kernel/objects/kobject.h
index 852a741..63843fc 100644
--- a/src/kernel/objects/kobject.h
+++ b/src/kernel/objects/kobject.h
@@ -17,6 +17,7 @@ public:
 	enum class type : uint16_t
 	{
 		none,
+		system,
 
 		event,
 		channel,
@@ -24,9 +25,10 @@ public:
 
 		vma,
 
-		job,
 		process,
 		thread,
+
+		max
 	};
 
 	kobject(type t, j6_signal_t signals = 0ull);
diff --git a/src/kernel/objects/system.cpp b/src/kernel/objects/system.cpp
new file mode 100644
index 0000000..54c09f2
--- /dev/null
+++ b/src/kernel/objects/system.cpp
@@ -0,0 +1,3 @@
+#include "objects/system.h"
+
+system system::s_instance;
diff --git a/src/kernel/objects/system.h b/src/kernel/objects/system.h
new file mode 100644
index 0000000..1491776
--- /dev/null
+++ b/src/kernel/objects/system.h
@@ -0,0 +1,18 @@
+#pragma once
+/// \file system.h
+/// Definition of kobject type representing the system
+
+#include "objects/kobject.h"
+
+class system :
+	public kobject
+{
+public:
+	static constexpr kobject::type type = kobject::type::event;
+
+	inline static system * get() { return &s_instance; }
+
+private:
+	static system s_instance;
+	system() : kobject(type::system) {}
+};
diff --git a/src/kernel/scheduler.cpp b/src/kernel/scheduler.cpp
index e870bcc..a11e692 100644
--- a/src/kernel/scheduler.cpp
+++ b/src/kernel/scheduler.cpp
@@ -13,6 +13,7 @@
 #include "msr.h"
 #include "objects/channel.h"
 #include "objects/process.h"
+#include "objects/system.h"
 #include "objects/vm_area.h"
 #include "scheduler.h"
 
@@ -26,7 +27,7 @@ const uint64_t rflags_int = 0x202;
 
 extern "C" {
 	void preloaded_process_init();
-	void load_process_image(uintptr_t phys, uintptr_t virt, size_t bytes, TCB *tcb);
+	uintptr_t load_process_image(uintptr_t phys, uintptr_t virt, size_t bytes, TCB *tcb);
 };
 
 extern uint64_t idle_stack_end;
@@ -59,7 +60,7 @@ scheduler::scheduler(lapic *apic) :
 	bsp_cpu_data.t = idle;
 }
 
-void
+uintptr_t
 load_process_image(uintptr_t phys, uintptr_t virt, size_t bytes, TCB *tcb)
 {
 	using memory::page_align_down;
@@ -81,10 +82,13 @@ load_process_image(uintptr_t phys, uintptr_t virt, size_t bytes, TCB *tcb)
 	tcb->rsp3 -= sizeof(j6_process_init);
 	j6_process_init *init = reinterpret_cast<j6_process_init*>(tcb->rsp3);
 
-	extern channel *std_out;
-	init->output = proc.add_handle(std_out);
+	init->process = proc.add_handle(&proc);
+	init->handles[0] = proc.add_handle(system::get());
+	init->handles[1] = j6_handle_invalid;
+	init->handles[2] = j6_handle_invalid;
 
 	thread::current().clear_state(thread::state::loading);
+	return tcb->rsp3;
 }
 
 thread *
diff --git a/src/kernel/syscalls/endpoint.cpp b/src/kernel/syscalls/endpoint.cpp
index 6f83bc5..3b5e59c 100644
--- a/src/kernel/syscalls/endpoint.cpp
+++ b/src/kernel/syscalls/endpoint.cpp
@@ -55,16 +55,4 @@ endpoint_sendrecv(j6_handle_t handle, j6_tag_t *tag, size_t *len, void *data)
 	return e->receive(tag, len, data);
 }
 
-j6_status_t
-endpoint_bind_irq(j6_handle_t handle, unsigned irq)
-{
-	endpoint *e = get_handle<endpoint>(handle);
-	if (!e) return j6_err_invalid_arg;
-
-	if (device_manager::get().bind_irq(irq, e))
-		return j6_status_ok;
-
-	return j6_err_invalid_arg;
-}
-
 } // namespace syscalls
diff --git a/src/kernel/syscalls/system.cpp b/src/kernel/syscalls/system.cpp
index bd832c0..9730121 100644
--- a/src/kernel/syscalls/system.cpp
+++ b/src/kernel/syscalls/system.cpp
@@ -1,8 +1,11 @@
 #include "j6/errors.h"
 #include "j6/types.h"
 
+#include "device_manager.h"
 #include "log.h"
+#include "objects/endpoint.h"
 #include "objects/thread.h"
+#include "syscalls/helpers.h"
 
 namespace syscalls {
 
@@ -25,4 +28,23 @@ system_noop()
 	return j6_status_ok;
 }
 
+j6_status_t
+system_get_log(j6_handle_t sys, j6_handle_t *log)
+{
+	return j6_err_nyi;
+}
+
+j6_status_t
+system_bind_irq(j6_handle_t sys, j6_handle_t endp, unsigned irq)
+{
+	// TODO: check capabilities on sys handle
+	endpoint *e = get_handle<endpoint>(endp);
+	if (!e) return j6_err_invalid_arg;
+
+	if (device_manager::get().bind_irq(irq, e))
+		return j6_status_ok;
+
+	return j6_err_invalid_arg;
+}
+
 } // namespace syscalls
diff --git a/src/libraries/libc/arch/x86_64/_Exit.s b/src/libraries/libc/arch/x86_64/_Exit.s
index da96a5c..995783b 100644
--- a/src/libraries/libc/arch/x86_64/_Exit.s
+++ b/src/libraries/libc/arch/x86_64/_Exit.s
@@ -1,5 +1,5 @@
+extern _syscall_process_exit
 global _PDCLIB_Exit
 _PDCLIB_Exit:
 	; arg should already be in rdi
-	mov rax, 0x11 ; Exit syscall
-	syscall
+	jmp _syscall_process_exit