/*
 * \brief   Cortex A15 specific MMU context initialization
 * \author  Stefan Kalkowski
 * \date    2017-10-17
 */

/*
 * Copyright (C) 2017 Genode Labs GmbH
 *
 * This file is part of the Genode OS framework, which is distributed
 * under the terms of the GNU Affero General Public License version 3.
 */

#include <util/bit_allocator.h>
#include <base/internal/unmanaged_singleton.h>

#include <kernel/thread.h>
#include <spec/cortex_a15/cpu.h>

using Asid_allocator = Genode::Bit_allocator<256>;

static Asid_allocator &alloc() {
	return *unmanaged_singleton<Asid_allocator>(); }


Genode::Cpu::Mmu_context::Mmu_context(addr_t table)
: ttbr0(Ttbr_64bit::Ba::masked((Ttbr_64bit::access_t)table)) {
	Ttbr_64bit::Asid::set(ttbr0, (Genode::uint8_t)alloc().alloc()); }


Genode::Cpu::Mmu_context::~Mmu_context()
{
	/* flush TLB by ASID */
	Cpu::Tlbiasid::write(id());
	alloc().free(id());
}


void Genode::Cpu::mmu_fault_status(Genode::Cpu::Fsr::access_t fsr,
                                   Kernel::Thread_fault & fault)
{
	enum {
		FAULT_MASK  = 0b111100,
		TRANSLATION = 0b000100,
		PERMISSION  = 0b001100,
	};

	using Fault = Kernel::Thread_fault;

	switch(fsr & FAULT_MASK) {
	case TRANSLATION: fault.type = Fault::PAGE_MISSING; return;
	case PERMISSION:  fault.type = Fault::EXEC;         return;
	default:          fault.type = Fault::UNKNOWN;
	};
};