예제 #1
0
파일: asm.go 프로젝트: klueska/go-akaros
func archrelocvariant(r *ld.Reloc, s *ld.LSym, t int64) int64 {
	switch r.Variant & ld.RV_TYPE_MASK {
	default:
		ld.Diag("unexpected relocation variant %d", r.Variant)
		fallthrough

	case ld.RV_NONE:
		return t

	case ld.RV_POWER_LO:
		if r.Variant&ld.RV_CHECK_OVERFLOW != 0 {
			// Whether to check for signed or unsigned
			// overflow depends on the instruction
			var o1 uint32
			if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
				o1 = ld.Be32(s.P[r.Off-2:])
			} else {
				o1 = ld.Le32(s.P[r.Off:])
			}
			switch o1 >> 26 {
			case 24, // ori
				26, // xori
				28: // andi
				if t>>16 != 0 {
					goto overflow
				}

			default:
				if int64(int16(t)) != t {
					goto overflow
				}
			}
		}

		return int64(int16(t))

	case ld.RV_POWER_HA:
		t += 0x8000
		fallthrough

		// Fallthrough
	case ld.RV_POWER_HI:
		t >>= 16

		if r.Variant&ld.RV_CHECK_OVERFLOW != 0 {
			// Whether to check for signed or unsigned
			// overflow depends on the instruction
			var o1 uint32
			if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
				o1 = ld.Be32(s.P[r.Off-2:])
			} else {
				o1 = ld.Le32(s.P[r.Off:])
			}
			switch o1 >> 26 {
			case 25, // oris
				27, // xoris
				29: // andis
				if t>>16 != 0 {
					goto overflow
				}

			default:
				if int64(int16(t)) != t {
					goto overflow
				}
			}
		}

		return int64(int16(t))

	case ld.RV_POWER_DS:
		var o1 uint32
		if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
			o1 = uint32(ld.Be16(s.P[r.Off:]))
		} else {
			o1 = uint32(ld.Le16(s.P[r.Off:]))
		}
		if t&3 != 0 {
			ld.Diag("relocation for %s+%d is not aligned: %d", r.Sym.Name, r.Off, t)
		}
		if (r.Variant&ld.RV_CHECK_OVERFLOW != 0) && int64(int16(t)) != t {
			goto overflow
		}
		return int64(o1)&0x3 | int64(int16(t))
	}

overflow:
	ld.Diag("relocation for %s+%d is too big: %d", r.Sym.Name, r.Off, t)
	return t
}
예제 #2
0
파일: asm.go 프로젝트: klueska/go-akaros
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		// TODO(minux): translate R_ADDRPOWER and R_CALLPOWER into standard ELF relocations.
		// R_ADDRPOWER corresponds to R_PPC_ADDR16_HA and R_PPC_ADDR16_LO.
		// R_CALLPOWER corresponds to R_PPC_REL24.
		return -1
	}

	switch r.Type {
	case ld.R_CONST:
		*val = r.Add
		return 0

	case ld.R_GOTOFF:
		*val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ld.Linklookup(ld.Ctxt, ".got", 0))
		return 0

	case ld.R_ADDRPOWER:
		// r->add is two ppc64 instructions holding an immediate 32-bit constant.
		// We want to add r->sym's address to that constant.
		// The encoding of the immediate x<<16 + y,
		// where x is the low 16 bits of the first instruction and y is the low 16
		// bits of the second. Both x and y are signed (int16, not uint16).
		o1 := uint32(r.Add >> 32)
		o2 := uint32(r.Add)
		t := ld.Symaddr(r.Sym)
		if t < 0 {
			ld.Ctxt.Diag("relocation for %s is too big (>=2G): %d", s.Name, ld.Symaddr(r.Sym))
		}

		t += int64((o1&0xffff)<<16 + uint32(int32(o2)<<16>>16))
		if t&0x8000 != 0 {
			t += 0x10000
		}
		o1 = o1&0xffff0000 | (uint32(t)>>16)&0xffff
		o2 = o2&0xffff0000 | uint32(t)&0xffff

		// when laid out, the instruction order must always be o1, o2.
		if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
			*val = int64(o1)<<32 | int64(o2)
		} else {
			*val = int64(o2)<<32 | int64(o1)
		}
		return 0

	case ld.R_CALLPOWER:
		// Bits 6 through 29 = (S + A - P) >> 2
		var o1 uint32
		if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
			o1 = ld.Be32(s.P[r.Off:])
		} else {
			o1 = ld.Le32(s.P[r.Off:])
		}

		t := ld.Symaddr(r.Sym) + r.Add - (s.Value + int64(r.Off))
		if t&3 != 0 {
			ld.Ctxt.Diag("relocation for %s+%d is not aligned: %d", r.Sym.Name, r.Off, t)
		}
		if int64(int32(t<<6)>>6) != t {
			// TODO(austin) This can happen if text > 32M.
			// Add a call trampoline to .text in that case.
			ld.Ctxt.Diag("relocation for %s+%d is too big: %d", r.Sym.Name, r.Off, t)
		}

		*val = int64(o1&0xfc000003 | uint32(t)&^0xfc000003)
		return 0

	case ld.R_POWER_TOC: // S + A - .TOC.
		*val = ld.Symaddr(r.Sym) + r.Add - symtoc(s)

		return 0
	}

	return -1
}