int handle_misaligned_load()

in kernel/traps_misaligned.c [240:321]

• 76 lines of code
• 20 McCabe index (conditional complexity)

int handle_misaligned_load(struct pt_regs *regs)
{
	union reg_data val;
	unsigned long epc = regs->epc;
	unsigned long insn = get_insn(epc);
	unsigned long addr = csr_read(mtval);
	int i, fp = 0, shift = 0, len = 0;

	regs->epc = 0;

	if ((insn & INSN_MASK_LW) == INSN_MATCH_LW) {
		len = 4;
		shift = 8 * (sizeof(unsigned long) - len);
#if defined(CONFIG_64BIT)
	} else if ((insn & INSN_MASK_LD) == INSN_MATCH_LD) {
		len = 8;
		shift = 8 * (sizeof(unsigned long) - len);
	} else if ((insn & INSN_MASK_LWU) == INSN_MATCH_LWU) {
		len = 4;
#endif
	} else if ((insn & INSN_MASK_FLD) == INSN_MATCH_FLD) {
		fp = 1;
		len = 8;
	} else if ((insn & INSN_MASK_FLW) == INSN_MATCH_FLW) {
		fp = 1;
		len = 4;
	} else if ((insn & INSN_MASK_LH) == INSN_MATCH_LH) {
		len = 2;
		shift = 8 * (sizeof(unsigned long) - len);
	} else if ((insn & INSN_MASK_LHU) == INSN_MATCH_LHU) {
		len = 2;
#if defined(CONFIG_64BIT)
	} else if ((insn & INSN_MASK_C_LD) == INSN_MATCH_C_LD) {
		len = 8;
		shift = 8 * (sizeof(unsigned long) - len);
		insn = RVC_RS2S(insn) << SH_RD;
	} else if ((insn & INSN_MASK_C_LDSP) == INSN_MATCH_C_LDSP &&
		   ((insn >> SH_RD) & 0x1f)) {
		len = 8;
		shift = 8 * (sizeof(unsigned long) - len);
#endif
	} else if ((insn & INSN_MASK_C_LW) == INSN_MATCH_C_LW) {
		len = 4;
		shift = 8 * (sizeof(unsigned long) - len);
		insn = RVC_RS2S(insn) << SH_RD;
	} else if ((insn & INSN_MASK_C_LWSP) == INSN_MATCH_C_LWSP &&
		   ((insn >> SH_RD) & 0x1f)) {
		len = 4;
		shift = 8 * (sizeof(unsigned long) - len);
	} else if ((insn & INSN_MASK_C_FLD) == INSN_MATCH_C_FLD) {
		fp = 1;
		len = 8;
		insn = RVC_RS2S(insn) << SH_RD;
	} else if ((insn & INSN_MASK_C_FLDSP) == INSN_MATCH_C_FLDSP) {
		fp = 1;
		len = 8;
#if defined(CONFIG_32BIT)
	} else if ((insn & INSN_MASK_C_FLW) == INSN_MATCH_C_FLW) {
		fp = 1;
		len = 4;
		insn = RVC_RS2S(insn) << SH_RD;
	} else if ((insn & INSN_MASK_C_FLWSP) == INSN_MATCH_C_FLWSP) {
		fp = 1;
		len = 4;
#endif
	} else {
		regs->epc = epc;
		return -1;
	}

	val.data_u64 = 0;
	for (i = 0; i < len; i++)
		val.data_bytes[i] = load_u8((void *)(addr + i));

	if (fp)
		return -1;
	SET_RD(insn, regs, val.data_ulong << shift >> shift);

	regs->epc = epc + INSN_LEN(insn);

	return 0;
}