/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * A small micro-assembler. It is intentionally kept simple, does only
 * support a subset of instructions, and does not try to hide pipeline
 * effects like branch delay slots.
 *
 * Copyright (C) 2004, 2005, 2006, 2008	 Thiemo Seufer
 * Copyright (C) 2005, 2007  Maciej W. Rozycki
 * Copyright (C) 2006  Ralf Baechle (ralf@linux-mips.org)
 * Copyright (C) 2012, 2013   MIPS Technologies, Inc.  All rights reserved.
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>

#include <asm/inst.h>
#include <asm/elf.h>
#include <asm/bugs.h>
#define UASM_ISA	_UASM_ISA_MICROMIPS
#include <asm/uasm.h>

#define RS_MASK		0x1f
#define RS_SH		16
#define RT_MASK		0x1f
#define RT_SH		21
#define SCIMM_MASK	0x3ff
#define SCIMM_SH	16

/* This macro sets the non-variable bits of an instruction. */
#define M(a, b, c, d, e, f)					\
	((a) << OP_SH						\
	 | (b) << RT_SH						\
	 | (c) << RS_SH						\
	 | (d) << RD_SH						\
	 | (e) << RE_SH						\
	 | (f) << FUNC_SH)

/* Define these when we are not the ISA the kernel is being compiled with. */
#ifndef CONFIG_CPU_MICROMIPS
#define MM_uasm_i_b(buf, off) ISAOPC(_beq)(buf, 0, 0, off)
#define MM_uasm_i_beqz(buf, rs, off) ISAOPC(_beq)(buf, rs, 0, off)
#define MM_uasm_i_beqzl(buf, rs, off) ISAOPC(_beql)(buf, rs, 0, off)
#define MM_uasm_i_bnez(buf, rs, off) ISAOPC(_bne)(buf, rs, 0, off)
#endif

#include "uasm.c"

static struct insn insn_table_MM[] = {
	{ insn_addu, M(mm_pool32a_op, 0, 0, 0, 0, mm_addu32_op), RT | RS | RD },
	{ insn_addiu, M(mm_addiu32_op, 0, 0, 0, 0, 0), RT | RS | SIMM },
	{ insn_and, M(mm_pool32a_op, 0, 0, 0, 0, mm_and_op), RT | RS | RD },
	{ insn_andi, M(mm_andi32_op, 0, 0, 0, 0, 0), RT | RS | UIMM },
	{ insn_beq, M(mm_beq32_op, 0, 0, 0, 0, 0), RS | RT | BIMM },
	{ insn_beql, 0, 0 },
	{ insn_bgez, M(mm_pool32i_op, mm_bgez_op, 0, 0, 0, 0), RS | BIMM },
	{ insn_bgezl, 0, 0 },
	{ insn_bltz, M(mm_pool32i_op, mm_bltz_op, 0, 0, 0, 0), RS | BIMM },
	{ insn_bltzl, 0, 0 },
	{ insn_bne, M(mm_bne32_op, 0, 0, 0, 0, 0), RT | RS | BIMM },
	{ insn_cache, M(mm_pool32b_op, 0, 0, mm_cache_func, 0, 0), RT | RS | SIMM },
	{ insn_daddu, 0, 0 },
	{ insn_daddiu, 0, 0 },
	{ insn_dmfc0, 0, 0 },
	{ insn_dmtc0, 0, 0 },
	{ insn_dsll, 0, 0 },
	{ insn_dsll32, 0, 0 },
	{ insn_dsra, 0, 0 },
	{ insn_dsrl, 0, 0 },
	{ insn_dsrl32, 0, 0 },
	{ insn_drotr, 0, 0 },
	{ insn_drotr32, 0, 0 },
	{ insn_dsubu, 0, 0 },
	{ insn_eret, M(mm_pool32a_op, 0, 0, 0, mm_eret_op, mm_pool32axf_op), 0 },
	{ insn_ins, M(mm_pool32a_op, 0, 0, 0, 0, mm_ins_op), RT | RS | RD | RE },
	{ insn_ext, M(mm_pool32a_op, 0, 0, 0, 0, mm_ext_op), RT | RS | RD | RE },
	{ insn_j, M(mm_j32_op, 0, 0, 0, 0, 0), JIMM },
	{ insn_jal, M(mm_jal32_op, 0, 0, 0, 0, 0), JIMM },
	{ insn_jr, M(mm_pool32a_op, 0, 0, 0, mm_jalr_op, mm_pool32axf_op), RS },
	{ insn_ld, 0, 0 },
	{ insn_ll, M(mm_pool32c_op, 0, 0, (mm_ll_func << 1), 0, 0), RS | RT | SIMM },
	{ insn_lld, 0, 0 },
	{ insn_lui, M(mm_pool32i_op, mm_lui_op, 0, 0, 0, 0), RS | SIMM },
	{ insn_lw, M(mm_lw32_op, 0, 0, 0, 0, 0), RT | RS | SIMM },
	{ insn_mfc0, M(mm_pool32a_op, 0, 0, 0, mm_mfc0_op, mm_pool32axf_op), RT | RS | RD },
	{ insn_mtc0, M(mm_pool32a_op, 0, 0, 0, mm_mtc0_op, mm_pool32axf_op), RT | RS | RD },
	{ insn_or, M(mm_pool32a_op, 0, 0, 0, 0, mm_or32_op), RT | RS | RD },
	{ insn_ori, M(mm_ori32_op, 0, 0, 0, 0, 0), RT | RS | UIMM },
	{ insn_pref, M(mm_pool32c_op, 0, 0, (mm_pref_func << 1), 0, 0), RT | RS | SIMM },
	{ insn_rfe, 0, 0 },
	{ insn_sc, M(mm_pool32c_op, 0, 0, (mm_sc_func << 1), 0, 0), RT | RS | SIMM },
	{ insn_scd, 0, 0 },
	{ insn_sd, 0, 0 },
	{ insn_sll, M(mm_pool32a_op, 0, 0, 0, 0, mm_sll32_op), RT | RS | RD },
	{ insn_sra, M(mm_pool32a_op, 0, 0, 0, 0, mm_sra_op), RT | RS | RD },
	{ insn_srl, M(mm_pool32a_op, 0, 0, 0, 0, mm_srl32_op), RT | RS | RD },
	{ insn_rotr, M(mm_pool32a_op, 0, 0, 0, 0, mm_rotr_op), RT | RS | RD },
	{ insn_subu, M(mm_pool32a_op, 0, 0, 0, 0, mm_subu32_op), RT | RS | RD },
	{ insn_sw, M(mm_sw32_op, 0, 0, 0, 0, 0), RT | RS | SIMM },
	{ insn_tlbp, M(mm_pool32a_op, 0, 0, 0, mm_tlbp_op, mm_pool32axf_op), 0 },
	{ insn_tlbr, M(mm_pool32a_op, 0, 0, 0, mm_tlbr_op, mm_pool32axf_op), 0 },
	{ insn_tlbwi, M(mm_pool32a_op, 0, 0, 0, mm_tlbwi_op, mm_pool32axf_op), 0 },
	{ insn_tlbwr, M(mm_pool32a_op, 0, 0, 0, mm_tlbwr_op, mm_pool32axf_op), 0 },
	{ insn_xor, M(mm_pool32a_op, 0, 0, 0, 0, mm_xor32_op), RT | RS | RD },
	{ insn_xori, M(mm_xori32_op, 0, 0, 0, 0, 0), RT | RS | UIMM },
	{ insn_dins, 0, 0 },
	{ insn_dinsm, 0, 0 },
	{ insn_syscall, M(mm_pool32a_op, 0, 0, 0, mm_syscall_op, mm_pool32axf_op), SCIMM},
	{ insn_bbit0, 0, 0 },
	{ insn_bbit1, 0, 0 },
	{ insn_lwx, 0, 0 },
	{ insn_ldx, 0, 0 },
	{ insn_invalid, 0, 0 }
};

#undef M

static inline u32 build_bimm(s32 arg)
{
	WARN(arg > 0xffff || arg < -0x10000,
	     KERN_WARNING "Micro-assembler field overflow\n");

	WARN(arg & 0x3, KERN_WARNING "Invalid micro-assembler branch target\n");

	return ((arg < 0) ? (1 << 15) : 0) | ((arg >> 1) & 0x7fff);
}

static inline u32 build_jimm(u32 arg)
{

	WARN(arg & ~((JIMM_MASK << 2) | 1),
	     KERN_WARNING "Micro-assembler field overflow\n");

	return (arg >> 1) & JIMM_MASK;
}

/*
 * The order of opcode arguments is implicitly left to right,
 * starting with RS and ending with FUNC or IMM.
 */
static void build_insn(u32 **buf, enum opcode opc, ...)
{
	struct insn *ip = NULL;
	unsigned int i;
	va_list ap;
	u32 op;

	for (i = 0; insn_table_MM[i].opcode != insn_invalid; i++)
		if (insn_table_MM[i].opcode == opc) {
			ip = &insn_table_MM[i];
			break;
		}

	if (!ip || (opc == insn_daddiu && r4k_daddiu_bug()))
		panic("Unsupported Micro-assembler instruction %d", opc);

	op = ip->match;
	va_start(ap, opc);
	if (ip->fields & RS) {
		if (opc == insn_mfc0 || opc == insn_mtc0)
			op |= build_rt(va_arg(ap, u32));
		else
			op |= build_rs(va_arg(ap, u32));
	}
	if (ip->fields & RT) {
		if (opc == insn_mfc0 || opc == insn_mtc0)
			op |= build_rs(va_arg(ap, u32));
		else
			op |= build_rt(va_arg(ap, u32));
	}
	if (ip->fields & RD)
		op |= build_rd(va_arg(ap, u32));
	if (ip->fields & RE)
		op |= build_re(va_arg(ap, u32));
	if (ip->fields & SIMM)
		op |= build_simm(va_arg(ap, s32));
	if (ip->fields & UIMM)
		op |= build_uimm(va_arg(ap, u32));
	if (ip->fields & BIMM)
		op |= build_bimm(va_arg(ap, s32));
	if (ip->fields & JIMM)
		op |= build_jimm(va_arg(ap, u32));
	if (ip->fields & FUNC)
		op |= build_func(va_arg(ap, u32));
	if (ip->fields & SET)
		op |= build_set(va_arg(ap, u32));
	if (ip->fields & SCIMM)
		op |= build_scimm(va_arg(ap, u32));
	va_end(ap);

#ifdef CONFIG_CPU_LITTLE_ENDIAN
	**buf = ((op & 0xffff) << 16) | (op >> 16);
#else
	**buf = op;
#endif
	(*buf)++;
}

static inline void
__resolve_relocs(struct uasm_reloc *rel, struct uasm_label *lab)
{
	long laddr = (long)lab->addr;
	long raddr = (long)rel->addr;

	switch (rel->type) {
	case R_MIPS_PC16:
#ifdef CONFIG_CPU_LITTLE_ENDIAN
		*rel->addr |= (build_bimm(laddr - (raddr + 4)) << 16);
#else
		*rel->addr |= build_bimm(laddr - (raddr + 4));
#endif
		break;

	default:
		panic("Unsupported Micro-assembler relocation %d",
		      rel->type);
	}
}
