/*
 * 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_CLASSIC
#include <asm/uasm.h>

#define RS_MASK		0x1f
#define RS_SH		21
#define RT_MASK		0x1f
#define RT_SH		16
#define SCIMM_MASK	0xfffff
#define SCIMM_SH	6

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

/* Define these when we are not the ISA the kernel is being compiled with. */
#ifdef CONFIG_CPU_MICROMIPS
#define CL_uasm_i_b(buf, off) ISAOPC(_beq)(buf, 0, 0, off)
#define CL_uasm_i_beqz(buf, rs, off) ISAOPC(_beq)(buf, rs, 0, off)
#define CL_uasm_i_beqzl(buf, rs, off) ISAOPC(_beql)(buf, rs, 0, off)
#define CL_uasm_i_bnez(buf, rs, off) ISAOPC(_bne)(buf, rs, 0, off)
#endif

#include "uasm.c"

static struct insn insn_table[] = {
	{ insn_addiu, M(addiu_op, 0, 0, 0, 0, 0), RS | RT | SIMM },
	{ insn_addu, M(spec_op, 0, 0, 0, 0, addu_op), RS | RT | RD },
	{ insn_andi, M(andi_op, 0, 0, 0, 0, 0), RS | RT | UIMM },
	{ insn_and, M(spec_op, 0, 0, 0, 0, and_op), RS | RT | RD },
	{ insn_bbit0, M(lwc2_op, 0, 0, 0, 0, 0), RS | RT | BIMM },
	{ insn_bbit1, M(swc2_op, 0, 0, 0, 0, 0), RS | RT | BIMM },
	{ insn_beql, M(beql_op, 0, 0, 0, 0, 0), RS | RT | BIMM },
	{ insn_beq, M(beq_op, 0, 0, 0, 0, 0), RS | RT | BIMM },
	{ insn_bgezl, M(bcond_op, 0, bgezl_op, 0, 0, 0), RS | BIMM },
	{ insn_bgez, M(bcond_op, 0, bgez_op, 0, 0, 0), RS | BIMM },
	{ insn_bltzl, M(bcond_op, 0, bltzl_op, 0, 0, 0), RS | BIMM },
	{ insn_bltz, M(bcond_op, 0, bltz_op, 0, 0, 0), RS | BIMM },
	{ insn_bne, M(bne_op, 0, 0, 0, 0, 0), RS | RT | BIMM },
	{ insn_cache,  M(cache_op, 0, 0, 0, 0, 0),  RS | RT | SIMM },
	{ insn_daddiu, M(daddiu_op, 0, 0, 0, 0, 0), RS | RT | SIMM },
	{ insn_daddu, M(spec_op, 0, 0, 0, 0, daddu_op), RS | RT | RD },
	{ insn_dinsm, M(spec3_op, 0, 0, 0, 0, dinsm_op), RS | RT | RD | RE },
	{ insn_dins, M(spec3_op, 0, 0, 0, 0, dins_op), RS | RT | RD | RE },
	{ insn_dmfc0, M(cop0_op, dmfc_op, 0, 0, 0, 0), RT | RD | SET},
	{ insn_dmtc0, M(cop0_op, dmtc_op, 0, 0, 0, 0), RT | RD | SET},
	{ insn_drotr32, M(spec_op, 1, 0, 0, 0, dsrl32_op), RT | RD | RE },
	{ insn_drotr, M(spec_op, 1, 0, 0, 0, dsrl_op), RT | RD | RE },
	{ insn_dsll32, M(spec_op, 0, 0, 0, 0, dsll32_op), RT | RD | RE },
	{ insn_dsll, M(spec_op, 0, 0, 0, 0, dsll_op), RT | RD | RE },
	{ insn_dsra, M(spec_op, 0, 0, 0, 0, dsra_op), RT | RD | RE },
	{ insn_dsrl32, M(spec_op, 0, 0, 0, 0, dsrl32_op), RT | RD | RE },
	{ insn_dsrl, M(spec_op, 0, 0, 0, 0, dsrl_op), RT | RD | RE },
	{ insn_dsubu, M(spec_op, 0, 0, 0, 0, dsubu_op), RS | RT | RD },
	{ insn_eret,  M(cop0_op, cop_op, 0, 0, 0, eret_op),  0 },
	{ insn_ext, M(spec3_op, 0, 0, 0, 0, ext_op), RS | RT | RD | RE },
	{ insn_ins, M(spec3_op, 0, 0, 0, 0, ins_op), RS | RT | RD | RE },
	{ insn_j,  M(j_op, 0, 0, 0, 0, 0),  JIMM },
	{ insn_jal,  M(jal_op, 0, 0, 0, 0, 0),	JIMM },
	{ insn_j,  M(j_op, 0, 0, 0, 0, 0),  JIMM },
	{ insn_jr,  M(spec_op, 0, 0, 0, 0, jr_op),  RS },
	{ insn_ld,  M(ld_op, 0, 0, 0, 0, 0),  RS | RT | SIMM },
	{ insn_ldx, M(spec3_op, 0, 0, 0, ldx_op, lx_op), RS | RT | RD },
	{ insn_lld,  M(lld_op, 0, 0, 0, 0, 0),	RS | RT | SIMM },
	{ insn_ll,  M(ll_op, 0, 0, 0, 0, 0),  RS | RT | SIMM },
	{ insn_lui,  M(lui_op, 0, 0, 0, 0, 0),	RT | SIMM },
	{ insn_lw,  M(lw_op, 0, 0, 0, 0, 0),  RS | RT | SIMM },
	{ insn_lwx, M(spec3_op, 0, 0, 0, lwx_op, lx_op), RS | RT | RD },
	{ insn_mfc0,  M(cop0_op, mfc_op, 0, 0, 0, 0),  RT | RD | SET},
	{ insn_mtc0,  M(cop0_op, mtc_op, 0, 0, 0, 0),  RT | RD | SET},
	{ insn_ori,  M(ori_op, 0, 0, 0, 0, 0),	RS | RT | UIMM },
	{ insn_or,  M(spec_op, 0, 0, 0, 0, or_op),  RS | RT | RD },
	{ insn_pref,  M(pref_op, 0, 0, 0, 0, 0),  RS | RT | SIMM },
	{ insn_rfe,  M(cop0_op, cop_op, 0, 0, 0, rfe_op),  0 },
	{ insn_rotr,  M(spec_op, 1, 0, 0, 0, srl_op),  RT | RD | RE },
	{ insn_scd,  M(scd_op, 0, 0, 0, 0, 0),	RS | RT | SIMM },
	{ insn_sc,  M(sc_op, 0, 0, 0, 0, 0),  RS | RT | SIMM },
	{ insn_sd,  M(sd_op, 0, 0, 0, 0, 0),  RS | RT | SIMM },
	{ insn_sll,  M(spec_op, 0, 0, 0, 0, sll_op),  RT | RD | RE },
	{ insn_sra,  M(spec_op, 0, 0, 0, 0, sra_op),  RT | RD | RE },
	{ insn_srl,  M(spec_op, 0, 0, 0, 0, srl_op),  RT | RD | RE },
	{ insn_subu,  M(spec_op, 0, 0, 0, 0, subu_op),	RS | RT | RD },
	{ insn_sw,  M(sw_op, 0, 0, 0, 0, 0),  RS | RT | SIMM },
	{ insn_syscall, M(spec_op, 0, 0, 0, 0, syscall_op), SCIMM},
	{ insn_tlbp,  M(cop0_op, cop_op, 0, 0, 0, tlbp_op),  0 },
	{ insn_tlbr,  M(cop0_op, cop_op, 0, 0, 0, tlbr_op),  0 },
	{ insn_tlbwi,  M(cop0_op, cop_op, 0, 0, 0, tlbwi_op),  0 },
	{ insn_tlbwr,  M(cop0_op, cop_op, 0, 0, 0, tlbwr_op),  0 },
	{ insn_xori,  M(xori_op, 0, 0, 0, 0, 0),  RS | RT | UIMM },
	{ insn_xor,  M(spec_op, 0, 0, 0, 0, xor_op),  RS | RT | RD },
	{ insn_invalid, 0, 0 }
};

#undef M

static inline u32 build_bimm(s32 arg)
{
	WARN(arg > 0x1ffff || arg < -0x20000,
	     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 >> 2) & 0x7fff);
}

static inline u32 build_jimm(u32 arg)
{
	WARN(arg & ~(JIMM_MASK << 2),
	     KERN_WARNING "Micro-assembler field overflow\n");

	return (arg >> 2) & 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[i].opcode != insn_invalid; i++)
		if (insn_table[i].opcode == opc) {
			ip = &insn_table[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)
		op |= build_rs(va_arg(ap, u32));
	if (ip->fields & RT)
		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);

	**buf = op;
	(*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:
		*rel->addr |= build_bimm(laddr - (raddr + 4));
		break;

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