/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation.
 *
 * 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, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Copyright IBM Corp. 2007
 * Copyright 2011 Freescale Semiconductor, Inc.
 *
 * Authors: Hollis Blanchard <hollisb@us.ibm.com>
 */

#include <linux/jiffies.h>
#include <linux/hrtimer.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm_host.h>
#include <linux/clockchips.h>

#include <asm/reg.h>
#include <asm/time.h>
#include <asm/byteorder.h>
#include <asm/kvm_ppc.h>
#include <asm/disassemble.h>
#include <asm/ppc-opcode.h>
#include "timing.h"
#include "trace.h"

/* XXX to do:
 * lhax
 * lhaux
 * lswx
 * lswi
 * stswx
 * stswi
 * lha
 * lhau
 * lmw
 * stmw
 *
 */
int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;
	u32 inst;
	int ra, rs, rt;
	enum emulation_result emulated;
	int advance = 1;

	/* this default type might be overwritten by subcategories */
	kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);

	emulated = kvmppc_get_last_inst(vcpu, INST_GENERIC, &inst);
	if (emulated != EMULATE_DONE)
		return emulated;

	ra = get_ra(inst);
	rs = get_rs(inst);
	rt = get_rt(inst);

	switch (get_op(inst)) {
	case 31:
		switch (get_xop(inst)) {
		case OP_31_XOP_LWZX:
			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
			break;

		case OP_31_XOP_LBZX:
			emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
			break;

		case OP_31_XOP_LBZUX:
			emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
			kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
			break;

		case OP_31_XOP_STWX:
			emulated = kvmppc_handle_store(run, vcpu,
						       kvmppc_get_gpr(vcpu, rs),
			                               4, 1);
			break;

		case OP_31_XOP_STBX:
			emulated = kvmppc_handle_store(run, vcpu,
						       kvmppc_get_gpr(vcpu, rs),
			                               1, 1);
			break;

		case OP_31_XOP_STBUX:
			emulated = kvmppc_handle_store(run, vcpu,
						       kvmppc_get_gpr(vcpu, rs),
			                               1, 1);
			kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
			break;

		case OP_31_XOP_LHAX:
			emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
			break;

		case OP_31_XOP_LHZX:
			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
			break;

		case OP_31_XOP_LHZUX:
			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
			kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
			break;

		case OP_31_XOP_STHX:
			emulated = kvmppc_handle_store(run, vcpu,
						       kvmppc_get_gpr(vcpu, rs),
			                               2, 1);
			break;

		case OP_31_XOP_STHUX:
			emulated = kvmppc_handle_store(run, vcpu,
						       kvmppc_get_gpr(vcpu, rs),
			                               2, 1);
			kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
			break;

		case OP_31_XOP_DCBST:
		case OP_31_XOP_DCBF:
		case OP_31_XOP_DCBI:
			/* Do nothing. The guest is performing dcbi because
			 * hardware DMA is not snooped by the dcache, but
			 * emulated DMA either goes through the dcache as
			 * normal writes, or the host kernel has handled dcache
			 * coherence. */
			break;

		case OP_31_XOP_LWBRX:
			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0);
			break;

		case OP_31_XOP_STWBRX:
			emulated = kvmppc_handle_store(run, vcpu,
						       kvmppc_get_gpr(vcpu, rs),
			                               4, 0);
			break;

		case OP_31_XOP_LHBRX:
			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0);
			break;

		case OP_31_XOP_STHBRX:
			emulated = kvmppc_handle_store(run, vcpu,
						       kvmppc_get_gpr(vcpu, rs),
			                               2, 0);
			break;

		default:
			emulated = EMULATE_FAIL;
			break;
		}
		break;

	case OP_LWZ:
		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
		break;

	/* TBD: Add support for other 64 bit load variants like ldu, ldux, ldx etc. */
	case OP_LD:
		rt = get_rt(inst);
		emulated = kvmppc_handle_load(run, vcpu, rt, 8, 1);
		break;

	case OP_LWZU:
		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
		kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
		break;

	case OP_LBZ:
		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
		break;

	case OP_LBZU:
		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
		kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
		break;

	case OP_STW:
		emulated = kvmppc_handle_store(run, vcpu,
					       kvmppc_get_gpr(vcpu, rs),
		                               4, 1);
		break;

	/* TBD: Add support for other 64 bit store variants like stdu, stdux, stdx etc. */
	case OP_STD:
		rs = get_rs(inst);
		emulated = kvmppc_handle_store(run, vcpu,
					       kvmppc_get_gpr(vcpu, rs),
		                               8, 1);
		break;

	case OP_STWU:
		emulated = kvmppc_handle_store(run, vcpu,
					       kvmppc_get_gpr(vcpu, rs),
		                               4, 1);
		kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
		break;

	case OP_STB:
		emulated = kvmppc_handle_store(run, vcpu,
					       kvmppc_get_gpr(vcpu, rs),
		                               1, 1);
		break;

	case OP_STBU:
		emulated = kvmppc_handle_store(run, vcpu,
					       kvmppc_get_gpr(vcpu, rs),
		                               1, 1);
		kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
		break;

	case OP_LHZ:
		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
		break;

	case OP_LHZU:
		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
		kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
		break;

	case OP_LHA:
		emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
		break;

	case OP_LHAU:
		emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
		kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
		break;

	case OP_STH:
		emulated = kvmppc_handle_store(run, vcpu,
					       kvmppc_get_gpr(vcpu, rs),
		                               2, 1);
		break;

	case OP_STHU:
		emulated = kvmppc_handle_store(run, vcpu,
					       kvmppc_get_gpr(vcpu, rs),
		                               2, 1);
		kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
		break;

	default:
		emulated = EMULATE_FAIL;
		break;
	}

	if (emulated == EMULATE_FAIL) {
		advance = 0;
		kvmppc_core_queue_program(vcpu, 0);
	}

	trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);

	/* Advance past emulated instruction. */
	if (advance)
		kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);

	return emulated;
}