#pypp 0
// Iris: micro-kernel for a capability-based operating system.
// mips/arch.ccp: Most mips-specific parts.
// 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/>.

#define ARCH
#include "kernel.hh"

void kThread_arch_init (kThread *thread):
	thread->arch.at = 0
	for unsigned i = 0; i < 2; ++i:
		thread->arch.v[i] = 0
		thread->arch.k[i] = 0
	for unsigned i = 0; i < 4; ++i:
		thread->arch.a[i] = 0
	for unsigned i = 0; i < 10; ++i:
		thread->arch.t[i] = 0
	thread->arch.gp = 0
	thread->arch.fp = 0
	thread->arch.ra = 0
	thread->arch.hi = 0
	thread->arch.lo = 0

void kThread_arch_receive (kThread *thread, Kernel::Num protected_data, Kernel::Num *data):
	thread->arch.a[0] = data[0].l
	thread->arch.a[1] = data[0].h
	thread->arch.a[2] = data[1].l
	thread->arch.a[3] = data[1].h
	thread->arch.t[0] = protected_data.l
	thread->arch.t[1] = protected_data.h

unsigned *kThread_arch_info (kThread *thread, unsigned num):
	switch num:
		case 1:
			return &thread->arch.at
		case 2:
			return &thread->arch.v[0]
		case 3:
			return &thread->arch.v[1]
		case 4:
			return &thread->arch.a[0]
		case 5:
			return &thread->arch.a[1]
		case 6:
			return &thread->arch.a[2]
		case 7:
			return &thread->arch.a[3]
		case 8:
			return &thread->arch.t[0]
		case 9:
			return &thread->arch.t[1]
		case 10:
			return &thread->arch.t[2]
		case 11:
			return &thread->arch.t[3]
		case 12:
			return &thread->arch.t[4]
		case 13:
			return &thread->arch.t[5]
		case 14:
			return &thread->arch.t[6]
		case 15:
			return &thread->arch.t[7]
		case 16:
			return &thread->arch.s[0]
		case 17:
			return &thread->arch.s[1]
		case 18:
			return &thread->arch.s[2]
		case 19:
			return &thread->arch.s[3]
		case 20:
			return &thread->arch.s[4]
		case 21:
			return &thread->arch.s[5]
		case 22:
			return &thread->arch.s[6]
		case 23:
			return &thread->arch.s[7]
		case 24:
			return &thread->arch.t[8]
		case 25:
			return &thread->arch.t[9]
		case 26:
			return &thread->arch.k[0]
		case 27:
			return &thread->arch.k[1]
		case 28:
			return &thread->arch.gp
		case 29:
			return &thread->sp
		case 30:
			return &thread->arch.fp
		case 31:
			return &thread->arch.ra
		default:
			return NULL

void kMemory_arch_init (kMemory *mem):
	mem->arch.asid = 1
	mem->arch.directory = NULL
	mem->arch.shadow = NULL

void kMemory_arch_free (kMemory *mem):
	while mem->arch.first_page_table:
		mem->unmap (mem->arch.first_page_table->first_page->page, mem->arch.first_page_table->first_page->mapping)
	if (kMemory *)asids[mem->arch.asid] == mem:
		flush_tlb (mem->arch.asid)
		asids[mem->arch.asid] = asids[0]
		asids[0] = mem->arch.asid
	mem->unuse ()
	mem->zfree ((unsigned)mem->arch.directory)

static arch_page_table *alloc_page_table (kMemory *mem):
	arch_page_table *ret = (arch_page_table *)mem->search_free (sizeof (arch_page_table), (void **)&mem->arch.first_page_table)
	if !ret:
		return NULL
	ret->first_page = NULL
	return ret

static arch_page *alloc_page (kMemory *mem, arch_page_table *t):
	arch_page *ret = (arch_page *)mem->search_free (sizeof (arch_page), (void **)&t->first_page)
	if !ret:
		return NULL
	ret->page = NULL
	ret->mapping = ~0
	ret->prev_mapped = NULL
	ret->next_mapped = NULL
	return ret

static void free_page_table (arch_page_table *t, unsigned idx):
	kMemory *mem = t->address_space
	mem->zfree ((unsigned)mem->arch.directory[idx])
	mem->arch.directory[idx] = NULL
	mem->arch.shadow[idx] = NULL
	mem->free_obj (t, (void **)&mem->arch.first_page_table)
	if !mem->arch.first_page_table:
		mem->zfree ((unsigned)mem->arch.directory)
		mem->zfree ((unsigned)mem->arch.shadow)
		mem->arch.directory = NULL
		mem->arch.shadow = NULL

static void tlb_reset (unsigned address, unsigned asid, unsigned value):
	cp0_set (CP0_ENTRY_HI, address | asid)
	__asm__ volatile ("tlbp")
	unsigned idx
	cp0_get (CP0_INDEX, idx)
	if ~idx & 0x80000000:
		if address & (1 << PAGE_BITS):
			cp0_set (CP0_ENTRY_LO1, value)
		else:
			cp0_set (CP0_ENTRY_LO0, value)
		__asm__ volatile ("tlbwi")

static void free_page (arch_page_table *t, arch_page *p):
	dbg_log ("free page ")
	dbg_log_num ((unsigned)p)
	dbg_log_char ('\n')
	if p->prev_mapped:
		p->prev_mapped->next_mapped = p->next_mapped
	else:
		p->page->arch.first_mapped = p->next_mapped
	if p->next_mapped:
		p->next_mapped->prev_mapped = p->prev_mapped
	tlb_reset (p->mapping, p->address_space->arch.asid, 0)
	unsigned idx = p->mapping >> 21
	p->address_space->free_obj (p, (void **)&t->first_page)
	if !t->first_page:
		free_page_table (t, idx)

static unsigned make_entry_lo (kPage *page, bool readonly):
	if !page->frame:
		return 0
	unsigned flags
	if page->flags & Kernel::Page::UNCACHED:
		flags = 0x10 | 0x2
	else:
		// 18 is write-back cache; 00 is write-through cache.
		flags = 0x18 | 0x2
	if !readonly:
		flags |= 0x4
	return ((page->frame & ~0x80000000) >> 6) | flags

bool kMemory_arch_map (kMemory *mem, kPage *page, unsigned address, bool readonly):
	if address >= 0x80000000:
		panic (0x32134293, "trying to map to kernel address")
		return false
	address &= PAGE_MASK
	if !mem->arch.directory:
		mem->arch.directory = (unsigned **)mem->zalloc ()
		if !mem->arch.directory:
			return false
		mem->arch.shadow = (arch_page_table **)mem->zalloc ()
		if !mem->arch.shadow:
			mem->zfree ((unsigned)mem->arch.directory)
			mem->arch.directory = NULL
			return false
	unsigned *table = mem->arch.directory[address >> 21]
	arch_page_table *t = mem->arch.shadow[address >> 21]
	if !table:
		table = (unsigned *)mem->zalloc ()
		if !table:
			if !mem->arch.first_page_table:
				mem->zfree ((unsigned)mem->arch.directory)
				mem->zfree ((unsigned)mem->arch.shadow)
				mem->arch.directory = NULL
				mem->arch.shadow = NULL
			return false
		t = alloc_page_table (mem)
		if !t:
			mem->zfree ((unsigned)table)
			if !mem->arch.first_page_table:
				mem->zfree ((unsigned)mem->arch.directory)
				mem->zfree ((unsigned)mem->arch.shadow)
				mem->arch.directory = NULL
				mem->arch.shadow = NULL
			return false
		mem->arch.directory[address >> 21] = table
		mem->arch.shadow[address >> 21] = t
	arch_page *p = alloc_page (mem, t)
	if !p:
		if !t->first_page:
			// This automatically cleans up the rest.
			free_page_table (t, address >> 21)
		return false
	unsigned idx = (address >> 12) & ((1 << 9) - 1)
	if table[idx]:
		mem->unmap ((kPage *)table[idx + 0x200], address)
	table[idx] = make_entry_lo (page, readonly)
	table[idx + 0x200] = (unsigned)p
	p->mapping = address + readonly
	p->page = page
	p->next_mapped = page->arch.first_mapped
	if p->next_mapped:
		p->next_mapped->prev_mapped = p
	page->arch.first_mapped = p
	return true

void kMemory_arch_unmap (kMemory *mem, kPage *page, unsigned address):
	unsigned didx = address >> 21
	unsigned tidx = (address >> 12) & ((1 << 9) - 1)
	unsigned *table = mem->arch.directory[didx]
	arch_page_table *t = mem->arch.shadow[didx]
	table[tidx] = 0
	arch_page *p = (arch_page *)table[tidx + 0x200]
	table[tidx + 0x200] = 0
	free_page (t, p)

kPage *kMemory_arch_get_mapping (kMemory *mem, unsigned address, bool *readonly):
	if address >= 0x80000000 || !mem->arch.directory:
		return NULL
	unsigned *table = mem->arch.directory[address >> 21]
	if !table:
		return NULL
	unsigned idx = (address >> 12) & ((1 << 9) - 1)
	arch_page *page = (arch_page *)table[idx + 0x200]
	if !page:
		return NULL
	if readonly:
		*readonly = !(table[idx] & 4)
	return page->page

void kPage_arch_update_mapping (kPage *page):
	if !page->arch.first_mapped:
		return
	kMemory *as = page->address_space
	unsigned target = make_entry_lo (page, page->flags & Kernel::Page::READONLY)
	for arch_page *p = page->arch.first_mapped; p; p = p->next_mapped:
		unsigned de = p->mapping >> 21
		unsigned te = (p->mapping >> 12) & ((1 << 9) - 1)
		bool readonly = p->mapping & 1
		unsigned t
		if readonly:
			t = target & ~0x4
		else:
			t = target
		as->arch.directory[de][te] = t
		tlb_reset (p->mapping & ~1, as->arch.asid, t)

void arch_register_interrupt (unsigned num, kReceiver *r):
	arch_interrupt_receiver[num] = r
	// And enable or disable the interrupt.
	if r:
		intc_unmask_irq (num)
	else:
		intc_mask_irq (num)