#pypp 0
// Iris: micro-kernel for a capability-based operating system.
// iris.hhp: header file for userspace programs.
// Copyright 2009 Bas Wijnen <wijnen@debian.org>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

#ifndef __IRIS_HHP
#define __IRIS_HHP

// Without the standard library, we don't have this definition.
// I preferred ((void*)0), but C++ has too strict type-checking to
// make that work.
#ifndef NULL
#define NULL 0
#endif

// Number of clock interrupts per second.
#define HZ 100

#define PAGE_BITS (12)
#define PAGE_SIZE (1 << PAGE_BITS)
#define PAGE_MASK (~(PAGE_SIZE - 1))

#define KERNEL_MASK 0xfff
#define CAPTYPE_MASK 0xe00
#define REQUEST_MASK (KERNEL_MASK & ~CAPTYPE_MASK)
#define CAPTYPE_INVALID 0x000
#define CAPTYPE_RECEIVER 0x200
#define CAPTYPE_MEMORY 0x400
#define CAPTYPE_THREAD 0x600
#define CAPTYPE_PAGE 0x800
#define CAPTYPE_CAPS 0xa00
//#define CAPTYPE_??? 0xc00
//#define CAPTYPE_??? 0xe00

// All kernel capabilities have a master capability, which can create others.
#define CAP_MASTER 0

// Create, invoke and forget, with masked data set to 0.
#define CAP_MASTER_DIRECT 0
// Master capabilities can create others.
#define CAP_MASTER_CREATE (1 << 31)

#define __receiver_num 0
#define __thread_num 1
#define __memory_num 2
#define __call_num 3
#define __parent_num 4

// If this flag is set in a capability, it is copied instead of mapped.
// If it is set in the target capability, the Thread waits after the request.
#define CAP_COPY ((unsigned)0x80000000)
// This constant signifies that no capability is passed.
#define CAP_NONE (~CAP_COPY)

namespace Kernel:
	enum Exception_code:
		NO_ERROR
		ERR_WRITE_DENIED
		ERR_UNMAPPED_READ
		ERR_UNMAPPED_WRITE
		ERR_INVALID_ADDRESS_READ
		ERR_INVALID_ADDRESS_WRITE
		ERR_RESERVED_INSTRUCTION
		ERR_COPROCESSOR_UNUSABLE
		ERR_OVERFLOW
		ERR_TRAP
		ERR_WATCHPOINT
		ERR_BREAKPOINT
		ERR_NO_PAGE_DIRECTORY
		ERR_NO_PAGE_TABLE
		ERR_OUT_OF_MEMORY
		// The following are not raised, but returned.
		ERR_INVALID_OPERATION
		NUM_EXCEPTION_CODES

	#ifndef NDEBUG
	static const char *exception_name[NUM_EXCEPTION_CODES] = {
		"no error",
		"write denied",
		"unmapped read",
		"unmapped write",
		"invalid address read",
		"invalid address write",
		"reserved instruction",
		"coprocessor unusable",
		"overflow",
		"trap",
		"watchpoint",
		"breakpoint",
		"no page directory",
		"no page table",
		"out of memory",
		"invalid operation"
	 }
	#endif

	struct Num:
		unsigned l, h
		Num (unsigned long long n = 0) : l (n), h (n >> 32):
		Num (unsigned ll, unsigned hh) : l (ll), h (hh):
		unsigned long long value () const:
			return ((unsigned long long)h << 32) | l
		unsigned &low ():
			return l
		unsigned &high ():
			return h
		unsigned const &low () const:
			return l
		unsigned const &high () const:
			return h

	struct Cap
	struct Caps
	struct Receiver
	struct Thread
	struct Page
	struct Memory

	unsigned alloc_slot ()
	Cap alloc_cap ()
	void free_slot (unsigned slot)
	void free_cap (Cap cap)

	struct Cap:
		unsigned code
		inline Cap copy () const
		inline Cap ()
		explicit inline Cap (unsigned c)
		inline Cap (unsigned slot, unsigned idx)
		inline unsigned slot () const
		inline unsigned idx () const
		struct IMessage
		inline void invoke (Num d0 = 0, Num d1 = 0, Cap arg = Cap (CAP_NONE))
		inline Num call (Num d0 = 0, Num d1 = 0)
		inline Num icall (Num d0 = 0, Num d1 = 0)
		inline Num ocall (Cap c, Num d0 = 0, Num d1 = 0)
		inline Num iocall (Cap c, Num d0 = 0, Num d1 = 0)
		inline void _invoke (IMessage const *i)
		inline void _call (IMessage *i)

	struct __recv_data_t:
		Num data[2]
		Num protected_data
		Cap reply, arg

	extern Receiver my_receiver
	extern Thread my_thread
	extern Memory my_memory
	extern Cap my_call
	extern Cap my_parent
	extern __recv_data_t recv

	inline Cap get_reply ():
		Cap ret = recv.reply
		recv.reply = alloc_cap ()
		return ret
	inline Cap get_arg ():
		Cap ret = recv.arg
		recv.arg = alloc_cap ()
		return ret
	inline void set_recv_arg (Cap c):
		free_cap (recv.arg)
		recv.arg = c

	struct Cap::IMessage:
		Num data[2]
		Cap reply, arg
	Cap Cap::copy () const:
		return Cap (code | CAP_COPY)
	Cap::Cap () : code (CAP_NONE):
	Cap::Cap (unsigned c) : code (c):
	Cap::Cap (unsigned slot, unsigned idx) : code (idx | (slot << 16)):
	unsigned Cap::slot () const:
		return (code >> 16) & 0x7fff
	unsigned Cap::idx () const:
		return code & 0xffff
	void Cap::_invoke (IMessage const *i):
		__recv_data_t *r = &recv
		__asm__ volatile ("lw $v0, %1\n"
				"\tlw $a0, 0($v0)\n"
				"\tlw $a1, 4($v0)\n"
				"\tlw $a2, 8($v0)\n"
				"\tlw $a3, 12($v0)\n"
				"\tlw $t0, 16($v0)\n"
				"\tlw $t1, 20($v0)\n"
				"\tlw $v0, %2\n"
				"\tlw $t2, 24($v0)\n"
				"\tlw $t3, 28($v0)\n"
				"\tlw $v0, %0\n"
				"\tsyscall\n"
				"\tlw $v0, %2\n"
				"\tsw $a0, 0($v0)\n"
				"\tsw $a1, 4($v0)\n"
				"\tsw $a2, 8($v0)\n"
				"\tsw $a3, 12($v0)\n"
				"\tsw $t0, 16($v0)\n"
				"\tsw $t1, 20($v0)"
				:: "m"(code), "m"(i), "m"(r)
				: "memory", "v0", "a0", "a1", "a2", "a3", "t0", "t1", "t2", "t3")
	void Cap::_call (IMessage *i):
		i->reply = *this
		my_call.copy ()._invoke (i)
	void Cap::invoke (Num d0, Num d1, Cap arg):
		IMessage i
		i.data[0] = d0
		i.data[1] = d1
		i.reply = Cap (CAP_NONE)
		i.arg = arg
		_invoke (&i)
	Num Cap::call (Num d0, Num d1):
		IMessage i
		i.data[0] = d0
		i.data[1] = d1
		_call (&i)
		return recv.data[0]
	Num Cap::icall (Num d0, Num d1):
		IMessage i
		i.data[0] = d0
		i.data[1] = d1
		_call (&i)
		return recv.data[0]
	Num Cap::ocall (Cap c, Num d0, Num d1):
		IMessage i
		i.data[0] = d0
		i.data[1] = d1
		i.arg = c
		_call (&i)
		return recv.data[0]
	Num Cap::iocall (Cap c, Num d0, Num d1):
		IMessage i
		i.data[0] = d0
		i.data[1] = d1
		i.arg = c
		_call (&i)
		return recv.data[0]

	struct Receiver : public Cap:
		Receiver (unsigned slot, unsigned idx) : Cap (slot, idx):
		Receiver (Cap c = Cap ()) : Cap (c):
		enum request:
			// Operations
			SET_OWNER = CAPTYPE_RECEIVER + 1
			CREATE_CAPABILITY
			CREATE_CALL_CAPABILITY
			CREATE_ASYNC_CALL_CAPABILITY
			GET_REPLY_PROTECTED_DATA
			SET_REPLY_PROTECTED_DATA
			GET_ALARM
			SET_ALARM
			ADD_ALARM
			// Reply capability.  This can only be created by invoking a CALL or CALL_ASYNC capability.
			REPLY
			// A call capability.  This can only be created by invoking CREATE_CALL_CAPABILITY.
			CALL
			// A call capability, waiting for only this reply is disabled.  This can only be created by invoking CREATE_CALL_ASYNC_CAPABILITY.
			CALL_ASYNC
		void set_owner (Cap owner):
			ocall (owner, CAP_MASTER_DIRECT | Receiver::SET_OWNER)
		Cap create_capability (Num protected_data):
			icall (CAP_MASTER_DIRECT | CREATE_CAPABILITY, protected_data)
			return get_arg ()
		Num get_reply_protected_data ():
			return call (CAP_MASTER_DIRECT | GET_REPLY_PROTECTED_DATA)
		void set_reply_protected_data (Num data):
			call (CAP_MASTER_DIRECT | SET_REPLY_PROTECTED_DATA, data)
		unsigned get_alarm ():
			return call (CAP_MASTER_DIRECT | GET_ALARM).l
		unsigned add_alarm (unsigned data):
			return call (CAP_MASTER_DIRECT | ADD_ALARM, data).l
		void set_alarm (unsigned data):
			call (CAP_MASTER_DIRECT | SET_ALARM, data)
		static inline void sleep (unsigned value)
		Cap create_call_capability ():
			icall (CAP_MASTER_DIRECT | CREATE_CALL_CAPABILITY)
			return get_arg ()
		Cap create_async_call_capability ():
			icall (CAP_MASTER_DIRECT | CREATE_ASYNC_CALL_CAPABILITY)
			return get_arg ()

	struct Thread : public Cap:
		Thread (unsigned slot, unsigned idx) : Cap (slot, idx):
		Thread (Cap c = Cap ()) : Cap (c):
		enum request:
			// Info details are arch-specific.
			GET_INFO = CAPTYPE_THREAD + 1
			SET_INFO
			USE_SLOT
			GET_CAPS
			SCHEDULE
			PRIV_ALLOC_RANGE
			PRIV_PHYSICAL_ADDRESS
			PRIV_ALLOC_PHYSICAL
			PRIV_MAKE_PRIV
			PRIV_GET_TOP_MEMORY
			PRIV_REGISTER_INTERRUPT
			// This is not an operation, but having this capability allows using the thread in Receiver::set_owner.
			SET_OWNER
			DBG_SEND
			PRIV_PANIC
		// These get/set_info are not arch-specific.
		enum info_type:
			PC = ~0
			SP = ~1
			FLAGS = ~2
		enum flags:
			PRIV = 1 << 31
			WAITING = 1 << 30
			RUNNING = 1 << 29
			USER_FLAGS = ~(PRIV | WAITING | RUNNING)
		void make_priv ():
			my_thread.ocall (*this, CAP_MASTER_DIRECT | PRIV_MAKE_PRIV)
		unsigned get_info (unsigned info):
			return call (Num (CAP_MASTER_DIRECT | GET_INFO, info)).l
		void set_info (unsigned info, unsigned value, unsigned mask = ~0):
			call (Num (CAP_MASTER_DIRECT | SET_INFO, info), Num (value, mask))
		void set_pc (unsigned pc):
			set_info (PC, pc)
		void set_sp (unsigned sp):
			set_info (SP, sp)
		void set_flags (unsigned value, unsigned mask):
			set_info (FLAGS, value, mask)
		unsigned get_pc ():
			return get_info (PC)
		unsigned get_sp ():
			return get_info (SP)
		unsigned get_flags ():
			return get_info (FLAGS)
		void run (bool run):
			set_flags (run ? RUNNING : 0, RUNNING)
		void wait (bool wait):
			set_flags (wait ? WAITING : 0, WAITING)
		inline unsigned use (Caps caps, unsigned slot = alloc_slot ())
		inline Caps get_caps (unsigned slot)
		unsigned get_num_caps ():
			return call (CAP_MASTER_DIRECT | GET_CAPS, ~0).l

	struct Caps : public Cap:
		Caps (unsigned slot, unsigned idx) : Cap (slot, idx):
		Caps (Cap c = Cap ()) : Cap (c):
		enum request:
			// Not an operation; this capability can be used in Thread::USE_SLOT.
			USE = CAPTYPE_CAPS + 1
			GET
			GET_SIZE
			SET
			TRUNCATE
			PRINT
		unsigned use (unsigned slot = alloc_slot ()):
			return my_thread.use (*this, slot)
		Cap get (unsigned idx):
			call (CAP_MASTER_DIRECT | GET, idx)
			return get_arg ()
		unsigned get_size ():
			return call (CAP_MASTER_DIRECT | GET_SIZE).l
		void set (unsigned idx, Cap cap):
			ocall (cap, CAP_MASTER_DIRECT | SET, idx)
		void truncate (unsigned new_size):
			call (CAP_MASTER_DIRECT | TRUNCATE, new_size)
		void print (unsigned idx):
			invoke (CAP_MASTER_DIRECT | PRINT, idx)

	Caps Thread::get_caps (unsigned slot):
		call (CAP_MASTER_DIRECT | GET_CAPS, slot)
		return get_arg ()

	unsigned Thread::use (Caps caps, unsigned slot):
		ocall (caps, CAP_MASTER_DIRECT | USE_SLOT, slot)
		return slot

	struct Page : public Cap:
		Page (unsigned slot, unsigned idx) : Cap (slot, idx):
		Page (Cap c = Cap ()) : Cap (c):
		enum request:
			SHARE = CAPTYPE_PAGE + 1
			GET_FLAGS
			SET_FLAGS
			// Not an operation; a capability with this bit cannot write to the page.
			READONLY = 8
		enum share_detail:
			// Operation details for PAGE_SHARE
			// Forget the source page during the operation.  This makes it a move.
			FORGET
			// Make the target independent of the source (make a copy if needed).
			COPY
			// Make the target unwritable.
			//READONLY: use the value from request.
		enum flag_values:
			// This is a read-only flag, which is set if the Page is shared.
			SHARED = 1
			// When paying, the memory's use is incremented.  If a frame is held, it cannot be lost.  Frames are lost when the last payer forgets them.
			PAYING = 2
			// Set if this page has a frame associated with it.  This flag is automatically reset if the frame is lost because of payment problems.
			FRAME = 4
			// A readonly page cannot be written to.  This flag can not be reset while the frame is shared.  The flag is already defined in request.
			//READONLY = 8
			// This is a read-only flag, saying if this is physical memory, which mustn't be freed.
			PHYSICAL = 0x10
			// This is a read-only flag, saying if this is uncachable memory.
			UNCACHED = 0x20
		void share (Cap target, unsigned flags):
			ocall (target, CAP_MASTER_DIRECT | SHARE, flags)
		unsigned get_flags ():
			return call (CAP_MASTER_DIRECT | GET_FLAGS).l
		void set_flags (unsigned new_flags, unsigned mask):
			call (CAP_MASTER_DIRECT | SET_FLAGS, Num (new_flags, mask))
		unsigned physical_address ():
			return my_thread.ocall (*this, CAP_MASTER_DIRECT | Thread::PRIV_PHYSICAL_ADDRESS).l
		void alloc_physical (unsigned address, bool cachable, bool freeable):
			my_thread.ocall (*this, CAP_MASTER_DIRECT | Thread::PRIV_ALLOC_PHYSICAL, (address & PAGE_MASK) | (cachable ? 1 : 0) | (freeable ? 2 : 0))

	struct Memory : public Cap:
		Memory (unsigned slot, unsigned idx) : Cap (slot, idx):
		Memory (Cap c = Cap ()) : Cap (c):
		enum request:
			CREATE = CAPTYPE_MEMORY + 1
			DESTROY
			LIST
			MAP
			MAPPING
			GET_LIMIT
			SET_LIMIT
		Page create_page ():
			icall (Num (CAP_MASTER_DIRECT | CREATE, CAPTYPE_PAGE))
			return get_arg ()
		Thread create_thread (unsigned slots):
			icall (Num (CAP_MASTER_DIRECT | CREATE, CAPTYPE_THREAD), slots)
			return get_arg ()
		Receiver create_receiver ():
			icall (Num (CAP_MASTER_DIRECT | CREATE, CAPTYPE_RECEIVER))
			return get_arg ()
		Memory create_memory ():
			icall (Num (CAP_MASTER_DIRECT | CREATE, CAPTYPE_MEMORY))
			return get_arg ()
		Caps create_caps (unsigned size):
			icall (Num (CAP_MASTER_DIRECT | CREATE, CAPTYPE_CAPS), size)
			return get_arg ()
		void destroy (Cap target):
			ocall (target, CAP_MASTER_DIRECT | DESTROY)
		// TODO: LIST
		void map (Cap page, unsigned address, bool readonly = false):
			if readonly:
				address |= Page::READONLY
			ocall (page, CAP_MASTER_DIRECT | MAP, address)
		Page mapping (void *address):
			icall (CAP_MASTER_DIRECT | MAPPING, Num ((unsigned)address))
			return get_arg ()
		unsigned get_limit (unsigned limit):
			return call (CAP_MASTER_DIRECT | GET_LIMIT).l
		void set_limit (unsigned limit):
			call (CAP_MASTER_DIRECT | SET_LIMIT, limit)
		unsigned alloc_range (unsigned pages):
			return my_thread.ocall (*this, CAP_MASTER_DIRECT | Thread::PRIV_ALLOC_RANGE, pages).l

	inline void wait ():
		Cap::IMessage i
		Cap ().copy ()._invoke (&i)
	inline void schedule ():
		my_thread.invoke (CAP_MASTER_DIRECT | Thread::SCHEDULE)
	inline void register_interrupt (unsigned num):
		my_thread.ocall (my_receiver, CAP_MASTER_DIRECT | Thread::PRIV_REGISTER_INTERRUPT, num)
	inline void unregister_interrupt (unsigned num):
		my_thread.call (CAP_MASTER_DIRECT | Thread::PRIV_REGISTER_INTERRUPT, num)
	inline Cap get_top_memory ():
		my_thread.icall (CAP_MASTER_DIRECT | Thread::PRIV_GET_TOP_MEMORY)
		return get_arg ()
	inline void dbg_send (unsigned code, unsigned bits = 32):
		my_thread.call (CAP_MASTER_DIRECT | Thread::DBG_SEND, Num (code, bits))
	inline void panic (unsigned code):
		my_thread.call (CAP_MASTER_DIRECT | Thread::PRIV_PANIC, code)

	void Receiver::sleep (unsigned value):
		my_receiver.set_alarm (value)
		wait ()

// The start function has this prototype (there is no main function).
Kernel::Num start ()

#if 1
// Use a define instead of an inline function, because this is better visible in disassembly, even when not optimizing.
#define kdebug_char(c) do { unsigned d = (c); __asm__ volatile ("move $a0, $zero\nlw $a1, %0\nbreak" :: "m"(d) : "a0", "a1", "memory"); } while (0)
#else
#define kdebug_char(c) do {} while (0)
#endif
#define kdebug(str) do { const char *s = (str); while (*s) { kdebug_char (*s); ++s; } } while (0)
#define __stringify2(x) #x
#define __stringify(x) __stringify2 (x)
#define kdebug_line() do { kdebug (__stringify (__LINE__)); kdebug_char ('\n'); } while (0)

static void kdebug_num (unsigned n, unsigned digits = 8):
	unsigned i
	const char *encode = "0123456789abcdef"
	for i = 0; i < digits; ++i:
		kdebug_char (encode[(n >> (4 * ((digits - 1) - i))) & 0xf])

#endif