Beispiel #1
0
func elfsetupplt() {
	plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
	got := ld.Linklookup(ld.Ctxt, ".got.plt", 0)
	if plt.Size == 0 {
		// pushl got+4
		ld.Adduint8(ld.Ctxt, plt, 0xff)

		ld.Adduint8(ld.Ctxt, plt, 0x35)
		ld.Addaddrplus(ld.Ctxt, plt, got, 4)

		// jmp *got+8
		ld.Adduint8(ld.Ctxt, plt, 0xff)

		ld.Adduint8(ld.Ctxt, plt, 0x25)
		ld.Addaddrplus(ld.Ctxt, plt, got, 8)

		// zero pad
		ld.Adduint32(ld.Ctxt, plt, 0)

		// assume got->size == 0 too
		ld.Addaddrplus(ld.Ctxt, got, ld.Linklookup(ld.Ctxt, ".dynamic", 0), 0)

		ld.Adduint32(ld.Ctxt, got, 0)
		ld.Adduint32(ld.Ctxt, got, 0)
	}
}
Beispiel #2
0
func elfsetupplt() {
	plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
	got := ld.Linklookup(ld.Ctxt, ".got.plt", 0)
	if plt.Size == 0 {
		// str lr, [sp, #-4]!
		ld.Adduint32(ld.Ctxt, plt, 0xe52de004)

		// ldr lr, [pc, #4]
		ld.Adduint32(ld.Ctxt, plt, 0xe59fe004)

		// add lr, pc, lr
		ld.Adduint32(ld.Ctxt, plt, 0xe08fe00e)

		// ldr pc, [lr, #8]!
		ld.Adduint32(ld.Ctxt, plt, 0xe5bef008)

		// .word &GLOBAL_OFFSET_TABLE[0] - .
		ld.Addpcrelplus(ld.Ctxt, plt, got, 4)

		// the first .plt entry requires 3 .plt.got entries
		ld.Adduint32(ld.Ctxt, got, 0)

		ld.Adduint32(ld.Ctxt, got, 0)
		ld.Adduint32(ld.Ctxt, got, 0)
	}
}
Beispiel #3
0
func elfsetupplt() {
	plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
	got := ld.Linklookup(ld.Ctxt, ".got.plt", 0)
	if plt.Size == 0 {
		// pushq got+8(IP)
		ld.Adduint8(ld.Ctxt, plt, 0xff)

		ld.Adduint8(ld.Ctxt, plt, 0x35)
		ld.Addpcrelplus(ld.Ctxt, plt, got, 8)

		// jmpq got+16(IP)
		ld.Adduint8(ld.Ctxt, plt, 0xff)

		ld.Adduint8(ld.Ctxt, plt, 0x25)
		ld.Addpcrelplus(ld.Ctxt, plt, got, 16)

		// nopl 0(AX)
		ld.Adduint32(ld.Ctxt, plt, 0x00401f0f)

		// assume got->size == 0 too
		ld.Addaddrplus(ld.Ctxt, got, ld.Linklookup(ld.Ctxt, ".dynamic", 0), 0)

		ld.Adduint64(ld.Ctxt, got, 0)
		ld.Adduint64(ld.Ctxt, got, 0)
	}
}
Beispiel #4
0
// Generate the glink resolver stub if necessary and return the .glink section
func ensureglinkresolver() *ld.LSym {
	glink := ld.Linklookup(ld.Ctxt, ".glink", 0)
	if glink.Size != 0 {
		return glink
	}

	// This is essentially the resolver from the ppc64 ELF ABI.
	// At entry, r12 holds the address of the symbol resolver stub
	// for the target routine and the argument registers hold the
	// arguments for the target routine.
	//
	// This stub is PIC, so first get the PC of label 1 into r11.
	// Other things will be relative to this.
	ld.Adduint32(ld.Ctxt, glink, 0x7c0802a6) // mflr r0
	ld.Adduint32(ld.Ctxt, glink, 0x429f0005) // bcl 20,31,1f
	ld.Adduint32(ld.Ctxt, glink, 0x7d6802a6) // 1: mflr r11
	ld.Adduint32(ld.Ctxt, glink, 0x7c0803a6) // mtlf r0

	// Compute the .plt array index from the entry point address.
	// Because this is PIC, everything is relative to label 1b (in
	// r11):
	//   r0 = ((r12 - r11) - (res_0 - r11)) / 4 = (r12 - res_0) / 4
	ld.Adduint32(ld.Ctxt, glink, 0x3800ffd0) // li r0,-(res_0-1b)=-48
	ld.Adduint32(ld.Ctxt, glink, 0x7c006214) // add r0,r0,r12
	ld.Adduint32(ld.Ctxt, glink, 0x7c0b0050) // sub r0,r0,r11
	ld.Adduint32(ld.Ctxt, glink, 0x7800f082) // srdi r0,r0,2

	// r11 = address of the first byte of the PLT
	r := ld.Addrel(glink)

	r.Off = int32(glink.Size)
	r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
	r.Siz = 8
	r.Type = obj.R_ADDRPOWER

	ld.Adduint32(ld.Ctxt, glink, 0x3d600000) // addis r11,0,.plt@ha
	ld.Adduint32(ld.Ctxt, glink, 0x396b0000) // addi r11,r11,.plt@l

	// Load r12 = dynamic resolver address and r11 = DSO
	// identifier from the first two doublewords of the PLT.
	ld.Adduint32(ld.Ctxt, glink, 0xe98b0000) // ld r12,0(r11)
	ld.Adduint32(ld.Ctxt, glink, 0xe96b0008) // ld r11,8(r11)

	// Jump to the dynamic resolver
	ld.Adduint32(ld.Ctxt, glink, 0x7d8903a6) // mtctr r12
	ld.Adduint32(ld.Ctxt, glink, 0x4e800420) // bctr

	// The symbol resolvers must immediately follow.
	//   res_0:

	// Add DT_PPC64_GLINK .dynamic entry, which points to 32 bytes
	// before the first symbol resolver stub.
	s := ld.Linklookup(ld.Ctxt, ".dynamic", 0)

	ld.Elfwritedynentsymplus(s, ld.DT_PPC64_GLINK, glink, glink.Size-32)

	return glink
}
Beispiel #5
0
func gentext() {
	if !ld.DynlinkingGo() {
		return
	}
	addmoduledata := ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
	if addmoduledata.Type == obj.STEXT {
		// we're linking a module containing the runtime -> no need for
		// an init function
		return
	}
	addmoduledata.Reachable = true
	initfunc := ld.Linklookup(ld.Ctxt, "go.link.addmoduledata", 0)
	initfunc.Type = obj.STEXT
	initfunc.Local = true
	initfunc.Reachable = true
	o := func(op uint32) {
		ld.Adduint32(ld.Ctxt, initfunc, op)
	}
	// 0000000000000000 <local.dso_init>:
	// 0:	90000000 	adrp	x0, 0 <runtime.firstmoduledata>
	// 	0: R_AARCH64_ADR_PREL_PG_HI21	local.moduledata
	// 4:	91000000 	add	x0, x0, #0x0
	// 	4: R_AARCH64_ADD_ABS_LO12_NC	local.moduledata
	o(0x90000000)
	o(0x91000000)
	rel := ld.Addrel(initfunc)
	rel.Off = 0
	rel.Siz = 8
	rel.Sym = ld.Ctxt.Moduledata
	rel.Type = obj.R_ADDRARM64

	// 8:	14000000 	bl	0 <runtime.addmoduledata>
	// 	8: R_AARCH64_CALL26	runtime.addmoduledata
	o(0x14000000)
	rel = ld.Addrel(initfunc)
	rel.Off = 8
	rel.Siz = 4
	rel.Sym = ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
	rel.Type = obj.R_CALLARM64 // Really should be R_AARCH64_JUMP26 but doesn't seem to make any difference

	if ld.Ctxt.Etextp != nil {
		ld.Ctxt.Etextp.Next = initfunc
	} else {
		ld.Ctxt.Textp = initfunc
	}
	ld.Ctxt.Etextp = initfunc
	initarray_entry := ld.Linklookup(ld.Ctxt, "go.link.addmoduledatainit", 0)
	initarray_entry.Reachable = true
	initarray_entry.Local = true
	initarray_entry.Type = obj.SINITARR
	ld.Addaddr(ld.Ctxt, initarray_entry, initfunc)
}
Beispiel #6
0
func gentext() {
	if !ld.DynlinkingGo() {
		return
	}
	addmoduledata := ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
	if addmoduledata.Type == obj.STEXT {
		// we're linking a module containing the runtime -> no need for
		// an init function
		return
	}
	addmoduledata.Reachable = true
	initfunc := ld.Linklookup(ld.Ctxt, "go.link.addmoduledata", 0)
	initfunc.Type = obj.STEXT
	initfunc.Local = true
	initfunc.Reachable = true
	o := func(op uint32) {
		ld.Adduint32(ld.Ctxt, initfunc, op)
	}
	o(0xe59f0004)
	o(0xe08f0000)

	o(0xeafffffe)
	rel := ld.Addrel(initfunc)
	rel.Off = 8
	rel.Siz = 4
	rel.Sym = ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
	rel.Type = obj.R_CALLARM
	rel.Add = 0xeafffffe // vomit

	o(0x00000000)
	rel = ld.Addrel(initfunc)
	rel.Off = 12
	rel.Siz = 4
	rel.Sym = ld.Ctxt.Moduledata
	rel.Type = obj.R_PCREL
	rel.Add = 4

	if ld.Ctxt.Etextp != nil {
		ld.Ctxt.Etextp.Next = initfunc
	} else {
		ld.Ctxt.Textp = initfunc
	}
	ld.Ctxt.Etextp = initfunc
	initarray_entry := ld.Linklookup(ld.Ctxt, "go.link.addmoduledatainit", 0)
	initarray_entry.Reachable = true
	initarray_entry.Local = true
	initarray_entry.Type = obj.SINITARR
	ld.Addaddr(ld.Ctxt, initarray_entry, initfunc)
}
Beispiel #7
0
func addgotsym(ctxt *ld.Link, s *ld.LSym) {
	if s.Got >= 0 {
		return
	}

	ld.Adddynsym(ctxt, s)
	got := ld.Linklookup(ctxt, ".got", 0)
	s.Got = int32(got.Size)
	ld.Adduint32(ctxt, got, 0)

	if ld.Iself {
		rel := ld.Linklookup(ctxt, ".rel", 0)
		ld.Addaddrplus(ctxt, rel, got, int64(s.Got))
		ld.Adduint32(ctxt, rel, ld.ELF32_R_INFO(uint32(s.Dynid), ld.R_ARM_GLOB_DAT))
	} else {
		ld.Diag("addgotsym: unsupported binary format")
	}
}
Beispiel #8
0
func addpltsym(ctxt *ld.Link, s *ld.LSym) {
	if s.Plt >= 0 {
		return
	}

	ld.Adddynsym(ctxt, s)

	if ld.Iself {
		plt := ld.Linklookup(ctxt, ".plt", 0)
		rela := ld.Linklookup(ctxt, ".rela.plt", 0)
		if plt.Size == 0 {
			elfsetupplt()
		}

		// Create the glink resolver if necessary
		glink := ensureglinkresolver()

		// Write symbol resolver stub (just a branch to the
		// glink resolver stub)
		r := ld.Addrel(glink)

		r.Sym = glink
		r.Off = int32(glink.Size)
		r.Siz = 4
		r.Type = obj.R_CALLPOWER
		ld.Adduint32(ctxt, glink, 0x48000000) // b .glink

		// In the ppc64 ABI, the dynamic linker is responsible
		// for writing the entire PLT.  We just need to
		// reserve 8 bytes for each PLT entry and generate a
		// JMP_SLOT dynamic relocation for it.
		//
		// TODO(austin): ABI v1 is different
		s.Plt = int32(plt.Size)

		plt.Size += 8

		ld.Addaddrplus(ctxt, rela, plt, int64(s.Plt))
		ld.Adduint64(ctxt, rela, ld.ELF64_R_INFO(uint32(s.Dynid), ld.R_PPC64_JMP_SLOT))
		ld.Adduint64(ctxt, rela, 0)
	} else {
		ld.Diag("addpltsym: unsupported binary format")
	}
}
Beispiel #9
0
func gentext() {
	if !ld.DynlinkingGo() {
		return
	}
	addmoduledata := ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
	if addmoduledata.Type == obj.STEXT {
		// we're linking a module containing the runtime -> no need for
		// an init function
		return
	}
	addmoduledata.Reachable = true
	initfunc := ld.Linklookup(ld.Ctxt, "go.link.addmoduledata", 0)
	initfunc.Type = obj.STEXT
	initfunc.Local = true
	initfunc.Reachable = true
	o := func(op ...uint8) {
		for _, op1 := range op {
			ld.Adduint8(ld.Ctxt, initfunc, op1)
		}
	}
	// 0000000000000000 <local.dso_init>:
	//    0:	48 8d 3d 00 00 00 00 	lea    0x0(%rip),%rdi        # 7 <local.dso_init+0x7>
	// 			3: R_X86_64_PC32	runtime.firstmoduledata-0x4
	o(0x48, 0x8d, 0x3d)
	ld.Addpcrelplus(ld.Ctxt, initfunc, ld.Ctxt.Moduledata, 0)
	//    7:	e8 00 00 00 00       	callq  c <local.dso_init+0xc>
	// 			8: R_X86_64_PLT32	runtime.addmoduledata-0x4
	o(0xe8)
	Addcall(ld.Ctxt, initfunc, addmoduledata)
	//    c:	c3                   	retq
	o(0xc3)
	if ld.Ctxt.Etextp != nil {
		ld.Ctxt.Etextp.Next = initfunc
	} else {
		ld.Ctxt.Textp = initfunc
	}
	ld.Ctxt.Etextp = initfunc
	initarray_entry := ld.Linklookup(ld.Ctxt, "go.link.addmoduledatainit", 0)
	initarray_entry.Reachable = true
	initarray_entry.Local = true
	initarray_entry.Type = obj.SINITARR
	ld.Addaddr(ld.Ctxt, initarray_entry, initfunc)
}
Beispiel #10
0
func elfsetupplt() {
	plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
	if plt.Size == 0 {
		// The dynamic linker stores the address of the
		// dynamic resolver and the DSO identifier in the two
		// doublewords at the beginning of the .plt section
		// before the PLT array.  Reserve space for these.
		plt.Size = 16
	}
}
Beispiel #11
0
func addgotsym(s *ld.LSym) {
	if s.Got >= 0 {
		return
	}

	ld.Adddynsym(ld.Ctxt, s)
	got := ld.Linklookup(ld.Ctxt, ".got", 0)
	s.Got = int32(got.Size)
	ld.Adduint64(ld.Ctxt, got, 0)

	if ld.Iself {
		rela := ld.Linklookup(ld.Ctxt, ".rela", 0)
		ld.Addaddrplus(ld.Ctxt, rela, got, int64(s.Got))
		ld.Adduint64(ld.Ctxt, rela, ld.ELF64_R_INFO(uint32(s.Dynid), ld.R_X86_64_GLOB_DAT))
		ld.Adduint64(ld.Ctxt, rela, 0)
	} else if ld.HEADTYPE == obj.Hdarwin {
		ld.Adduint32(ld.Ctxt, ld.Linklookup(ld.Ctxt, ".linkedit.got", 0), uint32(s.Dynid))
	} else {
		ld.Diag("addgotsym: unsupported binary format")
	}
}
Beispiel #12
0
func addpltsym(ctxt *ld.Link, s *ld.LSym) {
	if s.Plt >= 0 {
		return
	}

	ld.Adddynsym(ctxt, s)

	if ld.Iself {
		plt := ld.Linklookup(ctxt, ".plt", 0)
		got := ld.Linklookup(ctxt, ".got.plt", 0)
		rel := ld.Linklookup(ctxt, ".rel.plt", 0)
		if plt.Size == 0 {
			elfsetupplt()
		}

		// jmpq *got+size
		ld.Adduint8(ctxt, plt, 0xff)

		ld.Adduint8(ctxt, plt, 0x25)
		ld.Addaddrplus(ctxt, plt, got, got.Size)

		// add to got: pointer to current pos in plt
		ld.Addaddrplus(ctxt, got, plt, plt.Size)

		// pushl $x
		ld.Adduint8(ctxt, plt, 0x68)

		ld.Adduint32(ctxt, plt, uint32(rel.Size))

		// jmp .plt
		ld.Adduint8(ctxt, plt, 0xe9)

		ld.Adduint32(ctxt, plt, uint32(-(plt.Size + 4)))

		// rel
		ld.Addaddrplus(ctxt, rel, got, got.Size-4)

		ld.Adduint32(ctxt, rel, ld.ELF32_R_INFO(uint32(s.Dynid), ld.R_386_JMP_SLOT))

		s.Plt = int32(plt.Size - 16)
	} else if ld.HEADTYPE == obj.Hdarwin {
		// Same laziness as in 6l.

		plt := ld.Linklookup(ctxt, ".plt", 0)

		addgotsym(ctxt, s)

		ld.Adduint32(ctxt, ld.Linklookup(ctxt, ".linkedit.plt", 0), uint32(s.Dynid))

		// jmpq *got+size(IP)
		s.Plt = int32(plt.Size)

		ld.Adduint8(ctxt, plt, 0xff)
		ld.Adduint8(ctxt, plt, 0x25)
		ld.Addaddrplus(ctxt, plt, ld.Linklookup(ctxt, ".got", 0), int64(s.Got))
	} else {
		ld.Diag("addpltsym: unsupported binary format")
	}
}
Beispiel #13
0
func addpltsym(ctxt *ld.Link, s *ld.LSym) {
	if s.Plt >= 0 {
		return
	}

	ld.Adddynsym(ctxt, s)

	if ld.Iself {
		plt := ld.Linklookup(ctxt, ".plt", 0)
		got := ld.Linklookup(ctxt, ".got.plt", 0)
		rel := ld.Linklookup(ctxt, ".rel.plt", 0)
		if plt.Size == 0 {
			elfsetupplt()
		}

		// .got entry
		s.Got = int32(got.Size)

		// In theory, all GOT should point to the first PLT entry,
		// Linux/ARM's dynamic linker will do that for us, but FreeBSD/ARM's
		// dynamic linker won't, so we'd better do it ourselves.
		ld.Addaddrplus(ctxt, got, plt, 0)

		// .plt entry, this depends on the .got entry
		s.Plt = int32(plt.Size)

		addpltreloc(ctxt, plt, got, s, obj.R_PLT0) // add lr, pc, #0xXX00000
		addpltreloc(ctxt, plt, got, s, obj.R_PLT1) // add lr, lr, #0xYY000
		addpltreloc(ctxt, plt, got, s, obj.R_PLT2) // ldr pc, [lr, #0xZZZ]!

		// rel
		ld.Addaddrplus(ctxt, rel, got, int64(s.Got))

		ld.Adduint32(ctxt, rel, ld.ELF32_R_INFO(uint32(s.Dynid), ld.R_ARM_JUMP_SLOT))
	} else {
		ld.Diag("addpltsym: unsupported binary format")
	}
}
Beispiel #14
0
func addgotsyminternal(ctxt *ld.Link, s *ld.LSym) {
	if s.Got >= 0 {
		return
	}

	got := ld.Linklookup(ctxt, ".got", 0)
	s.Got = int32(got.Size)

	ld.Addaddrplus(ctxt, got, s, 0)

	if ld.Iself {
	} else {
		ld.Diag("addgotsyminternal: unsupported binary format")
	}
}
Beispiel #15
0
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		return -1
	}
	switch r.Type {
	case obj.R_CONST:
		*val = r.Add
		return 0

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

	return -1
}
Beispiel #16
0
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		return -1
	}

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

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

	case obj.R_ADDRMIPS:
		t := ld.Symaddr(r.Sym) + r.Add
		if t >= 1<<32 || t < -1<<32 {
			ld.Diag("program too large, address relocation = %v", t)
		}

		// the first instruction is always at the lower address, this is endian neutral;
		// but note that o1 and o2 should still use the target endian.
		o1 := ld.Thelinkarch.ByteOrder.Uint32(s.P[r.Off:])
		o2 := ld.Thelinkarch.ByteOrder.Uint32(s.P[r.Off+4:])
		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 obj.R_CALLMIPS,
		obj.R_JMPMIPS:
		// Low 26 bits = (S + A) >> 2
		t := ld.Symaddr(r.Sym) + r.Add
		o1 := ld.Thelinkarch.ByteOrder.Uint32(s.P[r.Off:])
		*val = int64(o1&0xfc000000 | uint32(t>>2)&^0xfc000000)
		return 0
	}

	return -1
}
Beispiel #17
0
// Construct a call stub in stub that calls symbol targ via its PLT
// entry.
func gencallstub(abicase int, stub *ld.LSym, targ *ld.LSym) {
	if abicase != 1 {
		// If we see R_PPC64_TOCSAVE or R_PPC64_REL24_NOTOC
		// relocations, we'll need to implement cases 2 and 3.
		log.Fatalf("gencallstub only implements case 1 calls")
	}

	plt := ld.Linklookup(ld.Ctxt, ".plt", 0)

	stub.Type = obj.STEXT

	// Save TOC pointer in TOC save slot
	ld.Adduint32(ld.Ctxt, stub, 0xf8410018) // std r2,24(r1)

	// Load the function pointer from the PLT.
	r := ld.Addrel(stub)

	r.Off = int32(stub.Size)
	r.Sym = plt
	r.Add = int64(targ.Plt)
	r.Siz = 2
	if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
		r.Off += int32(r.Siz)
	}
	r.Type = obj.R_POWER_TOC
	r.Variant = ld.RV_POWER_HA
	ld.Adduint32(ld.Ctxt, stub, 0x3d820000) // addis r12,r2,targ@plt@toc@ha
	r = ld.Addrel(stub)
	r.Off = int32(stub.Size)
	r.Sym = plt
	r.Add = int64(targ.Plt)
	r.Siz = 2
	if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
		r.Off += int32(r.Siz)
	}
	r.Type = obj.R_POWER_TOC
	r.Variant = ld.RV_POWER_LO
	ld.Adduint32(ld.Ctxt, stub, 0xe98c0000) // ld r12,targ@plt@toc@l(r12)

	// Jump to the loaded pointer
	ld.Adduint32(ld.Ctxt, stub, 0x7d8903a6) // mtctr r12
	ld.Adduint32(ld.Ctxt, stub, 0x4e800420) // bctr
}
Beispiel #18
0
func addpltsym(s *ld.LSym) {
	if s.Plt >= 0 {
		return
	}

	ld.Adddynsym(ld.Ctxt, s)

	if ld.Iself {
		plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
		got := ld.Linklookup(ld.Ctxt, ".got.plt", 0)
		rela := ld.Linklookup(ld.Ctxt, ".rela.plt", 0)
		if plt.Size == 0 {
			elfsetupplt()
		}

		// jmpq *got+size(IP)
		ld.Adduint8(ld.Ctxt, plt, 0xff)

		ld.Adduint8(ld.Ctxt, plt, 0x25)
		ld.Addpcrelplus(ld.Ctxt, plt, got, got.Size)

		// add to got: pointer to current pos in plt
		ld.Addaddrplus(ld.Ctxt, got, plt, plt.Size)

		// pushq $x
		ld.Adduint8(ld.Ctxt, plt, 0x68)

		ld.Adduint32(ld.Ctxt, plt, uint32((got.Size-24-8)/8))

		// jmpq .plt
		ld.Adduint8(ld.Ctxt, plt, 0xe9)

		ld.Adduint32(ld.Ctxt, plt, uint32(-(plt.Size + 4)))

		// rela
		ld.Addaddrplus(ld.Ctxt, rela, got, got.Size-8)

		ld.Adduint64(ld.Ctxt, rela, ld.ELF64_R_INFO(uint32(s.Dynid), ld.R_X86_64_JMP_SLOT))
		ld.Adduint64(ld.Ctxt, rela, 0)

		s.Plt = int32(plt.Size - 16)
	} else if ld.HEADTYPE == obj.Hdarwin {
		// To do lazy symbol lookup right, we're supposed
		// to tell the dynamic loader which library each
		// symbol comes from and format the link info
		// section just so.  I'm too lazy (ha!) to do that
		// so for now we'll just use non-lazy pointers,
		// which don't need to be told which library to use.
		//
		// http://networkpx.blogspot.com/2009/09/about-lcdyldinfoonly-command.html
		// has details about what we're avoiding.

		addgotsym(s)
		plt := ld.Linklookup(ld.Ctxt, ".plt", 0)

		ld.Adduint32(ld.Ctxt, ld.Linklookup(ld.Ctxt, ".linkedit.plt", 0), uint32(s.Dynid))

		// jmpq *got+size(IP)
		s.Plt = int32(plt.Size)

		ld.Adduint8(ld.Ctxt, plt, 0xff)
		ld.Adduint8(ld.Ctxt, plt, 0x25)
		ld.Addpcrelplus(ld.Ctxt, plt, ld.Linklookup(ld.Ctxt, ".got", 0), int64(s.Got))
	} else {
		ld.Diag("addpltsym: unsupported binary format")
	}
}
Beispiel #19
0
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		switch r.Type {
		default:
			return -1

		case obj.R_POWER_TLS, obj.R_POWER_TLS_LE, obj.R_POWER_TLS_IE:
			r.Done = 0
			// check Outer is nil, Type is TLSBSS?
			r.Xadd = r.Add
			r.Xsym = r.Sym
			return 0

		case obj.R_ADDRPOWER,
			obj.R_ADDRPOWER_DS,
			obj.R_ADDRPOWER_TOCREL,
			obj.R_ADDRPOWER_TOCREL_DS,
			obj.R_ADDRPOWER_GOT,
			obj.R_ADDRPOWER_PCREL:
			r.Done = 0

			// set up addend for eventual relocation via outer symbol.
			rs := r.Sym
			r.Xadd = r.Add
			for rs.Outer != nil {
				r.Xadd += ld.Symaddr(rs) - ld.Symaddr(rs.Outer)
				rs = rs.Outer
			}

			if rs.Type != obj.SHOSTOBJ && rs.Type != obj.SDYNIMPORT && rs.Sect == nil {
				ld.Diag("missing section for %s", rs.Name)
			}
			r.Xsym = rs

			return 0

		case obj.R_CALLPOWER:
			r.Done = 0
			r.Xsym = r.Sym
			r.Xadd = r.Add
			return 0
		}
	}

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

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

	case obj.R_ADDRPOWER, obj.R_ADDRPOWER_DS:
		return archrelocaddr(r, s, val)

	case obj.R_CALLPOWER:
		// Bits 6 through 29 = (S + A - P) >> 2

		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(uint32(t) &^ 0xfc000003)
		return 0

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

		return 0

	case obj.R_POWER_TLS_LE:
		// The thread pointer points 0x7000 bytes after the start of the the
		// thread local storage area as documented in section "3.7.2 TLS
		// Runtime Handling" of "Power Architecture 64-Bit ELF V2 ABI
		// Specification".
		v := r.Sym.Value - 0x7000
		if int64(int16(v)) != v {
			ld.Diag("TLS offset out of range %d", v)
		}
		*val = (*val &^ 0xffff) | (v & 0xffff)
		return 0
	}

	return -1
}
Beispiel #20
0
func adddynrel(s *ld.LSym, r *ld.Reloc) {
	targ := r.Sym
	ld.Ctxt.Cursym = s

	switch r.Type {
	default:
		if r.Type >= 256 {
			ld.Diag("unexpected relocation type %d", r.Type)
			return
		}

		// Handle relocations found in ELF object files.
	case 256 + ld.R_X86_64_PC32:
		if targ.Type == obj.SDYNIMPORT {
			ld.Diag("unexpected R_X86_64_PC32 relocation for dynamic symbol %s", targ.Name)
		}
		if targ.Type == 0 || targ.Type == obj.SXREF {
			ld.Diag("unknown symbol %s in pcrel", targ.Name)
		}
		r.Type = obj.R_PCREL
		r.Add += 4
		return

	case 256 + ld.R_X86_64_PLT32:
		r.Type = obj.R_PCREL
		r.Add += 4
		if targ.Type == obj.SDYNIMPORT {
			addpltsym(targ)
			r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
			r.Add += int64(targ.Plt)
		}

		return

	case 256 + ld.R_X86_64_GOTPCREL, 256 + ld.R_X86_64_GOTPCRELX, 256 + ld.R_X86_64_REX_GOTPCRELX:
		if targ.Type != obj.SDYNIMPORT {
			// have symbol
			if r.Off >= 2 && s.P[r.Off-2] == 0x8b {
				// turn MOVQ of GOT entry into LEAQ of symbol itself
				s.P[r.Off-2] = 0x8d

				r.Type = obj.R_PCREL
				r.Add += 4
				return
			}
		}

		// fall back to using GOT and hope for the best (CMOV*)
		// TODO: just needs relocation, no need to put in .dynsym
		addgotsym(targ)

		r.Type = obj.R_PCREL
		r.Sym = ld.Linklookup(ld.Ctxt, ".got", 0)
		r.Add += 4
		r.Add += int64(targ.Got)
		return

	case 256 + ld.R_X86_64_64:
		if targ.Type == obj.SDYNIMPORT {
			ld.Diag("unexpected R_X86_64_64 relocation for dynamic symbol %s", targ.Name)
		}
		r.Type = obj.R_ADDR
		return

	// Handle relocations found in Mach-O object files.
	case 512 + ld.MACHO_X86_64_RELOC_UNSIGNED*2 + 0,
		512 + ld.MACHO_X86_64_RELOC_SIGNED*2 + 0,
		512 + ld.MACHO_X86_64_RELOC_BRANCH*2 + 0:
		// TODO: What is the difference between all these?
		r.Type = obj.R_ADDR

		if targ.Type == obj.SDYNIMPORT {
			ld.Diag("unexpected reloc for dynamic symbol %s", targ.Name)
		}
		return

	case 512 + ld.MACHO_X86_64_RELOC_BRANCH*2 + 1:
		if targ.Type == obj.SDYNIMPORT {
			addpltsym(targ)
			r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
			r.Add = int64(targ.Plt)
			r.Type = obj.R_PCREL
			return
		}
		fallthrough

		// fall through
	case 512 + ld.MACHO_X86_64_RELOC_UNSIGNED*2 + 1,
		512 + ld.MACHO_X86_64_RELOC_SIGNED*2 + 1,
		512 + ld.MACHO_X86_64_RELOC_SIGNED_1*2 + 1,
		512 + ld.MACHO_X86_64_RELOC_SIGNED_2*2 + 1,
		512 + ld.MACHO_X86_64_RELOC_SIGNED_4*2 + 1:
		r.Type = obj.R_PCREL

		if targ.Type == obj.SDYNIMPORT {
			ld.Diag("unexpected pc-relative reloc for dynamic symbol %s", targ.Name)
		}
		return

	case 512 + ld.MACHO_X86_64_RELOC_GOT_LOAD*2 + 1:
		if targ.Type != obj.SDYNIMPORT {
			// have symbol
			// turn MOVQ of GOT entry into LEAQ of symbol itself
			if r.Off < 2 || s.P[r.Off-2] != 0x8b {
				ld.Diag("unexpected GOT_LOAD reloc for non-dynamic symbol %s", targ.Name)
				return
			}

			s.P[r.Off-2] = 0x8d
			r.Type = obj.R_PCREL
			return
		}
		fallthrough

		// fall through
	case 512 + ld.MACHO_X86_64_RELOC_GOT*2 + 1:
		if targ.Type != obj.SDYNIMPORT {
			ld.Diag("unexpected GOT reloc for non-dynamic symbol %s", targ.Name)
		}
		addgotsym(targ)
		r.Type = obj.R_PCREL
		r.Sym = ld.Linklookup(ld.Ctxt, ".got", 0)
		r.Add += int64(targ.Got)
		return
	}

	// Handle references to ELF symbols from our own object files.
	if targ.Type != obj.SDYNIMPORT {
		return
	}

	switch r.Type {
	case obj.R_CALL,
		obj.R_PCREL:
		if ld.HEADTYPE == obj.Hwindows {
			// nothing to do, the relocation will be laid out in pereloc1
			return
		} else {
			// for both ELF and Mach-O
			addpltsym(targ)
			r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
			r.Add = int64(targ.Plt)
			return
		}

	case obj.R_ADDR:
		if s.Type == obj.STEXT && ld.Iself {
			if ld.HEADTYPE == obj.Hsolaris {
				addpltsym(targ)
				r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
				r.Add += int64(targ.Plt)
				return
			}
			// The code is asking for the address of an external
			// function.  We provide it with the address of the
			// correspondent GOT symbol.
			addgotsym(targ)

			r.Sym = ld.Linklookup(ld.Ctxt, ".got", 0)
			r.Add += int64(targ.Got)
			return
		}

		if s.Type != obj.SDATA {
			break
		}
		if ld.Iself {
			ld.Adddynsym(ld.Ctxt, targ)
			rela := ld.Linklookup(ld.Ctxt, ".rela", 0)
			ld.Addaddrplus(ld.Ctxt, rela, s, int64(r.Off))
			if r.Siz == 8 {
				ld.Adduint64(ld.Ctxt, rela, ld.ELF64_R_INFO(uint32(targ.Dynid), ld.R_X86_64_64))
			} else {
				ld.Adduint64(ld.Ctxt, rela, ld.ELF64_R_INFO(uint32(targ.Dynid), ld.R_X86_64_32))
			}
			ld.Adduint64(ld.Ctxt, rela, uint64(r.Add))
			r.Type = 256 // ignore during relocsym
			return
		}

		if ld.HEADTYPE == obj.Hdarwin && s.Size == int64(ld.Thearch.Ptrsize) && r.Off == 0 {
			// Mach-O relocations are a royal pain to lay out.
			// They use a compact stateful bytecode representation
			// that is too much bother to deal with.
			// Instead, interpret the C declaration
			//	void *_Cvar_stderr = &stderr;
			// as making _Cvar_stderr the name of a GOT entry
			// for stderr.  This is separate from the usual GOT entry,
			// just in case the C code assigns to the variable,
			// and of course it only works for single pointers,
			// but we only need to support cgo and that's all it needs.
			ld.Adddynsym(ld.Ctxt, targ)

			got := ld.Linklookup(ld.Ctxt, ".got", 0)
			s.Type = got.Type | obj.SSUB
			s.Outer = got
			s.Sub = got.Sub
			got.Sub = s
			s.Value = got.Size
			ld.Adduint64(ld.Ctxt, got, 0)
			ld.Adduint32(ld.Ctxt, ld.Linklookup(ld.Ctxt, ".linkedit.got", 0), uint32(targ.Dynid))
			r.Type = 256 // ignore during relocsym
			return
		}

		if ld.HEADTYPE == obj.Hwindows {
			// nothing to do, the relocation will be laid out in pereloc1
			return
		}
	}

	ld.Ctxt.Cursym = s
	ld.Diag("unsupported relocation for dynamic symbol %s (type=%d stype=%d)", targ.Name, r.Type, targ.Type)
}
Beispiel #21
0
func asmb() {
	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f asmb\n", obj.Cputime())
	}
	ld.Bso.Flush()

	if ld.Iself {
		ld.Asmbelfsetup()
	}

	sect := ld.Segtext.Sect
	ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
	ld.Codeblk(int64(sect.Vaddr), int64(sect.Length))
	for sect = sect.Next; sect != nil; sect = sect.Next {
		ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
		ld.Datblk(int64(sect.Vaddr), int64(sect.Length))
	}

	if ld.Segrodata.Filelen > 0 {
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f rodatblk\n", obj.Cputime())
		}
		ld.Bso.Flush()

		ld.Cseek(int64(ld.Segrodata.Fileoff))
		ld.Datblk(int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
	}

	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f datblk\n", obj.Cputime())
	}
	ld.Bso.Flush()

	ld.Cseek(int64(ld.Segdata.Fileoff))
	ld.Datblk(int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))

	machlink := uint32(0)
	if ld.HEADTYPE == obj.Hdarwin {
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
		}

		dwarfoff := uint32(ld.Rnd(int64(uint64(ld.HEADR)+ld.Segtext.Length), int64(ld.INITRND)) + ld.Rnd(int64(ld.Segdata.Filelen), int64(ld.INITRND)))
		ld.Cseek(int64(dwarfoff))

		ld.Segdwarf.Fileoff = uint64(ld.Cpos())
		ld.Dwarfemitdebugsections()
		ld.Segdwarf.Filelen = uint64(ld.Cpos()) - ld.Segdwarf.Fileoff

		machlink = uint32(ld.Domacholink())
	}

	ld.Symsize = 0
	ld.Spsize = 0
	ld.Lcsize = 0
	symo := uint32(0)
	if ld.Debug['s'] == 0 {
		// TODO: rationalize
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f sym\n", obj.Cputime())
		}
		ld.Bso.Flush()
		switch ld.HEADTYPE {
		default:
			if ld.Iself {
				symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
				symo = uint32(ld.Rnd(int64(symo), int64(ld.INITRND)))
			}

		case obj.Hplan9:
			symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)

		case obj.Hdarwin:
			symo = uint32(ld.Segdwarf.Fileoff + uint64(ld.Rnd(int64(ld.Segdwarf.Filelen), int64(ld.INITRND))) + uint64(machlink))

		case obj.Hwindows:
			symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
			symo = uint32(ld.Rnd(int64(symo), ld.PEFILEALIGN))
		}

		ld.Cseek(int64(symo))
		switch ld.HEADTYPE {
		default:
			if ld.Iself {
				if ld.Debug['v'] != 0 {
					fmt.Fprintf(&ld.Bso, "%5.2f elfsym\n", obj.Cputime())
				}
				ld.Asmelfsym()
				ld.Cflush()
				ld.Cwrite(ld.Elfstrdat)

				if ld.Debug['v'] != 0 {
					fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
				}
				ld.Dwarfemitdebugsections()

				if ld.Linkmode == ld.LinkExternal {
					ld.Elfemitreloc()
				}
			}

		case obj.Hplan9:
			ld.Asmplan9sym()
			ld.Cflush()

			sym := ld.Linklookup(ld.Ctxt, "pclntab", 0)
			if sym != nil {
				ld.Lcsize = int32(len(sym.P))
				for i := 0; int32(i) < ld.Lcsize; i++ {
					ld.Cput(uint8(sym.P[i]))
				}

				ld.Cflush()
			}

		case obj.Hwindows:
			if ld.Debug['v'] != 0 {
				fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
			}
			ld.Dwarfemitdebugsections()

		case obj.Hdarwin:
			if ld.Linkmode == ld.LinkExternal {
				ld.Machoemitreloc()
			}
		}
	}

	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f headr\n", obj.Cputime())
	}
	ld.Bso.Flush()
	ld.Cseek(0)
	switch ld.HEADTYPE {
	default:
	case obj.Hplan9: /* plan9 */
		magic := int32(4*11*11 + 7)

		ld.Lputb(uint32(magic))              /* magic */
		ld.Lputb(uint32(ld.Segtext.Filelen)) /* sizes */
		ld.Lputb(uint32(ld.Segdata.Filelen))
		ld.Lputb(uint32(ld.Segdata.Length - ld.Segdata.Filelen))
		ld.Lputb(uint32(ld.Symsize))      /* nsyms */
		ld.Lputb(uint32(ld.Entryvalue())) /* va of entry */
		ld.Lputb(uint32(ld.Spsize))       /* sp offsets */
		ld.Lputb(uint32(ld.Lcsize))       /* line offsets */

	case obj.Hdarwin:
		ld.Asmbmacho()

	case obj.Hlinux,
		obj.Hfreebsd,
		obj.Hnetbsd,
		obj.Hopenbsd,
		obj.Hnacl:
		ld.Asmbelf(int64(symo))

	case obj.Hwindows:
		ld.Asmbpe()
	}

	ld.Cflush()
}
Beispiel #22
0
func gentext() {
	if !ld.DynlinkingGo() && ld.Buildmode != ld.BuildmodePIE && ld.Buildmode != ld.BuildmodeCShared {
		return
	}

	thunkfunc := ld.Linklookup(ld.Ctxt, "__x86.get_pc_thunk.cx", 0)
	thunkfunc.Type = obj.STEXT
	thunkfunc.Local = true
	thunkfunc.Reachable = true
	o := func(op ...uint8) {
		for _, op1 := range op {
			ld.Adduint8(ld.Ctxt, thunkfunc, op1)
		}
	}
	// 8b 0c 24	mov    (%esp),%ecx
	o(0x8b, 0x0c, 0x24)
	// c3		ret
	o(0xc3)

	if ld.Ctxt.Etextp != nil {
		ld.Ctxt.Etextp.Next = thunkfunc
	} else {
		ld.Ctxt.Textp = thunkfunc
	}
	ld.Ctxt.Etextp = thunkfunc

	addmoduledata := ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
	if addmoduledata.Type == obj.STEXT {
		// we're linking a module containing the runtime -> no need for
		// an init function
		return
	}

	addmoduledata.Reachable = true

	initfunc := ld.Linklookup(ld.Ctxt, "go.link.addmoduledata", 0)
	initfunc.Type = obj.STEXT
	initfunc.Local = true
	initfunc.Reachable = true
	o = func(op ...uint8) {
		for _, op1 := range op {
			ld.Adduint8(ld.Ctxt, initfunc, op1)
		}
	}

	// go.link.addmoduledata:
	//      53                      push %ebx
	//      e8 00 00 00 00          call __x86.get_pc_thunk.cx + R_CALL __x86.get_pc_thunk.cx
	//      8d 81 00 00 00 00       lea 0x0(%ecx), %eax + R_PCREL ld.Ctxt.Moduledata
	//      8d 99 00 00 00 00       lea 0x0(%ecx), %ebx + R_GOTPC _GLOBAL_OFFSET_TABLE_
	//      e8 00 00 00 00          call runtime.addmoduledata@plt + R_CALL runtime.addmoduledata
	//      5b                      pop %ebx
	//      c3                      ret

	o(0x53)

	o(0xe8)
	addcall(ld.Ctxt, initfunc, ld.Linklookup(ld.Ctxt, "__x86.get_pc_thunk.cx", 0))

	o(0x8d, 0x81)
	ld.Addpcrelplus(ld.Ctxt, initfunc, ld.Ctxt.Moduledata, 6)

	o(0x8d, 0x99)
	i := initfunc.Size
	initfunc.Size += 4
	ld.Symgrow(ld.Ctxt, initfunc, initfunc.Size)
	r := ld.Addrel(initfunc)
	r.Sym = ld.Linklookup(ld.Ctxt, "_GLOBAL_OFFSET_TABLE_", 0)
	r.Off = int32(i)
	r.Type = obj.R_PCREL
	r.Add = 12
	r.Siz = 4

	o(0xe8)
	addcall(ld.Ctxt, initfunc, addmoduledata)

	o(0x5b)

	o(0xc3)

	ld.Ctxt.Etextp.Next = initfunc
	ld.Ctxt.Etextp = initfunc
	initarray_entry := ld.Linklookup(ld.Ctxt, "go.link.addmoduledatainit", 0)
	initarray_entry.Reachable = true
	initarray_entry.Local = true
	initarray_entry.Type = obj.SINITARR
	ld.Addaddr(ld.Ctxt, initarray_entry, initfunc)
}
Beispiel #23
0
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		switch r.Type {
		default:
			return -1

		case obj.R_ARM64_GOTPCREL:
			var o1, o2 uint32
			if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
				o1 = uint32(*val >> 32)
				o2 = uint32(*val)
			} else {
				o1 = uint32(*val)
				o2 = uint32(*val >> 32)
			}
			// Any relocation against a function symbol is redirected to
			// be against a local symbol instead (see putelfsym in
			// symtab.go) but unfortunately the system linker was buggy
			// when confronted with a R_AARCH64_ADR_GOT_PAGE relocation
			// against a local symbol until May 2015
			// (https://sourceware.org/bugzilla/show_bug.cgi?id=18270). So
			// we convert the adrp; ld64 + R_ARM64_GOTPCREL into adrp;
			// add + R_ADDRARM64.
			if !(r.Sym.Version != 0 || (r.Sym.Type&obj.SHIDDEN != 0) || r.Sym.Local) && r.Sym.Type == obj.STEXT && ld.DynlinkingGo() {
				if o2&0xffc00000 != 0xf9400000 {
					ld.Ctxt.Diag("R_ARM64_GOTPCREL against unexpected instruction %x", o2)
				}
				o2 = 0x91000000 | (o2 & 0x000003ff)
				r.Type = obj.R_ADDRARM64
			}
			if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
				*val = int64(o1)<<32 | int64(o2)
			} else {
				*val = int64(o2)<<32 | int64(o1)
			}
			fallthrough

		case obj.R_ADDRARM64:
			r.Done = 0

			// set up addend for eventual relocation via outer symbol.
			rs := r.Sym
			r.Xadd = r.Add
			for rs.Outer != nil {
				r.Xadd += ld.Symaddr(rs) - ld.Symaddr(rs.Outer)
				rs = rs.Outer
			}

			if rs.Type != obj.SHOSTOBJ && rs.Type != obj.SDYNIMPORT && rs.Sect == nil {
				ld.Diag("missing section for %s", rs.Name)
			}
			r.Xsym = rs

			// Note: ld64 currently has a bug that any non-zero addend for BR26 relocation
			// will make the linking fail because it thinks the code is not PIC even though
			// the BR26 relocation should be fully resolved at link time.
			// That is the reason why the next if block is disabled. When the bug in ld64
			// is fixed, we can enable this block and also enable duff's device in cmd/7g.
			if false && ld.HEADTYPE == obj.Hdarwin {
				var o0, o1 uint32

				if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
					o0 = uint32(*val >> 32)
					o1 = uint32(*val)
				} else {
					o0 = uint32(*val)
					o1 = uint32(*val >> 32)
				}
				// Mach-O wants the addend to be encoded in the instruction
				// Note that although Mach-O supports ARM64_RELOC_ADDEND, it
				// can only encode 24-bit of signed addend, but the instructions
				// supports 33-bit of signed addend, so we always encode the
				// addend in place.
				o0 |= (uint32((r.Xadd>>12)&3) << 29) | (uint32((r.Xadd>>12>>2)&0x7ffff) << 5)
				o1 |= uint32(r.Xadd&0xfff) << 10
				r.Xadd = 0

				// when laid out, the instruction order must always be o1, o2.
				if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
					*val = int64(o0)<<32 | int64(o1)
				} else {
					*val = int64(o1)<<32 | int64(o0)
				}
			}

			return 0

		case obj.R_CALLARM64,
			obj.R_ARM64_TLS_LE,
			obj.R_ARM64_TLS_IE:
			r.Done = 0
			r.Xsym = r.Sym
			r.Xadd = r.Add
			return 0
		}
	}

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

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

	case obj.R_ADDRARM64:
		t := ld.Symaddr(r.Sym) + r.Add - ((s.Value + int64(r.Off)) &^ 0xfff)
		if t >= 1<<32 || t < -1<<32 {
			ld.Diag("program too large, address relocation distance = %d", t)
		}

		var o0, o1 uint32

		if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
			o0 = uint32(*val >> 32)
			o1 = uint32(*val)
		} else {
			o0 = uint32(*val)
			o1 = uint32(*val >> 32)
		}

		o0 |= (uint32((t>>12)&3) << 29) | (uint32((t>>12>>2)&0x7ffff) << 5)
		o1 |= uint32(t&0xfff) << 10

		// when laid out, the instruction order must always be o1, o2.
		if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
			*val = int64(o0)<<32 | int64(o1)
		} else {
			*val = int64(o1)<<32 | int64(o0)
		}
		return 0

	case obj.R_ARM64_TLS_LE:
		r.Done = 0
		if ld.HEADTYPE != obj.Hlinux {
			ld.Diag("TLS reloc on unsupported OS %s", ld.Headstr(int(ld.HEADTYPE)))
		}
		// The TCB is two pointers. This is not documented anywhere, but is
		// de facto part of the ABI.
		v := r.Sym.Value + int64(2*ld.Thearch.Ptrsize)
		if v < 0 || v >= 32678 {
			ld.Diag("TLS offset out of range %d", v)
		}
		*val |= v << 5
		return 0

	case obj.R_CALLARM64:
		t := (ld.Symaddr(r.Sym) + r.Add) - (s.Value + int64(r.Off))
		if t >= 1<<27 || t < -1<<27 {
			ld.Diag("program too large, call relocation distance = %d", t)
		}
		*val |= (t >> 2) & 0x03ffffff
		return 0
	}

	return -1
}
Beispiel #24
0
func adddynrel(s *ld.LSym, r *ld.Reloc) {
	targ := r.Sym
	ld.Ctxt.Cursym = s

	switch r.Type {
	default:
		if r.Type >= 256 {
			ld.Diag("unexpected relocation type %d", r.Type)
			return
		}

		// Handle relocations found in ELF object files.
	case 256 + ld.R_ARM_PLT32:
		r.Type = obj.R_CALLARM

		if targ.Type == obj.SDYNIMPORT {
			addpltsym(ld.Ctxt, targ)
			r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
			r.Add = int64(braddoff(int32(r.Add), targ.Plt/4))
		}

		return

	case 256 + ld.R_ARM_THM_PC22: // R_ARM_THM_CALL
		ld.Exitf("R_ARM_THM_CALL, are you using -marm?")
		return

	case 256 + ld.R_ARM_GOT32: // R_ARM_GOT_BREL
		if targ.Type != obj.SDYNIMPORT {
			addgotsyminternal(ld.Ctxt, targ)
		} else {
			addgotsym(ld.Ctxt, targ)
		}

		r.Type = obj.R_CONST // write r->add during relocsym
		r.Sym = nil
		r.Add += int64(targ.Got)
		return

	case 256 + ld.R_ARM_GOT_PREL: // GOT(nil) + A - nil
		if targ.Type != obj.SDYNIMPORT {
			addgotsyminternal(ld.Ctxt, targ)
		} else {
			addgotsym(ld.Ctxt, targ)
		}

		r.Type = obj.R_PCREL
		r.Sym = ld.Linklookup(ld.Ctxt, ".got", 0)
		r.Add += int64(targ.Got) + 4
		return

	case 256 + ld.R_ARM_GOTOFF: // R_ARM_GOTOFF32
		r.Type = obj.R_GOTOFF

		return

	case 256 + ld.R_ARM_GOTPC: // R_ARM_BASE_PREL
		r.Type = obj.R_PCREL

		r.Sym = ld.Linklookup(ld.Ctxt, ".got", 0)
		r.Add += 4
		return

	case 256 + ld.R_ARM_CALL:
		r.Type = obj.R_CALLARM
		if targ.Type == obj.SDYNIMPORT {
			addpltsym(ld.Ctxt, targ)
			r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
			r.Add = int64(braddoff(int32(r.Add), targ.Plt/4))
		}

		return

	case 256 + ld.R_ARM_REL32: // R_ARM_REL32
		r.Type = obj.R_PCREL

		r.Add += 4
		return

	case 256 + ld.R_ARM_ABS32:
		if targ.Type == obj.SDYNIMPORT {
			ld.Diag("unexpected R_ARM_ABS32 relocation for dynamic symbol %s", targ.Name)
		}
		r.Type = obj.R_ADDR
		return

		// we can just ignore this, because we are targeting ARM V5+ anyway
	case 256 + ld.R_ARM_V4BX:
		if r.Sym != nil {
			// R_ARM_V4BX is ABS relocation, so this symbol is a dummy symbol, ignore it
			r.Sym.Type = 0
		}

		r.Sym = nil
		return

	case 256 + ld.R_ARM_PC24,
		256 + ld.R_ARM_JUMP24:
		r.Type = obj.R_CALLARM
		if targ.Type == obj.SDYNIMPORT {
			addpltsym(ld.Ctxt, targ)
			r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
			r.Add = int64(braddoff(int32(r.Add), targ.Plt/4))
		}

		return
	}

	// Handle references to ELF symbols from our own object files.
	if targ.Type != obj.SDYNIMPORT {
		return
	}

	switch r.Type {
	case obj.R_CALLARM:
		addpltsym(ld.Ctxt, targ)
		r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
		r.Add = int64(targ.Plt)
		return

	case obj.R_ADDR:
		if s.Type != obj.SDATA {
			break
		}
		if ld.Iself {
			ld.Adddynsym(ld.Ctxt, targ)
			rel := ld.Linklookup(ld.Ctxt, ".rel", 0)
			ld.Addaddrplus(ld.Ctxt, rel, s, int64(r.Off))
			ld.Adduint32(ld.Ctxt, rel, ld.ELF32_R_INFO(uint32(targ.Dynid), ld.R_ARM_GLOB_DAT)) // we need a nil + A dynamic reloc
			r.Type = obj.R_CONST                                                               // write r->add during relocsym
			r.Sym = nil
			return
		}
	}

	ld.Ctxt.Cursym = s
	ld.Diag("unsupported relocation for dynamic symbol %s (type=%d stype=%d)", targ.Name, r.Type, targ.Type)
}
Beispiel #25
0
func archinit() {
	// getgoextlinkenabled is based on GO_EXTLINK_ENABLED when
	// Go was built; see ../../make.bash.
	if ld.Linkmode == ld.LinkAuto && obj.Getgoextlinkenabled() == "0" {
		ld.Linkmode = ld.LinkInternal
	}

	if ld.Buildmode == ld.BuildmodeCShared || ld.Buildmode == ld.BuildmodePIE || ld.DynlinkingGo() {
		ld.Linkmode = ld.LinkExternal
		got := ld.Linklookup(ld.Ctxt, "_GLOBAL_OFFSET_TABLE_", 0)
		got.Type = obj.SDYNIMPORT
		got.Reachable = true
	}

	switch ld.HEADTYPE {
	default:
		if ld.Linkmode == ld.LinkAuto {
			ld.Linkmode = ld.LinkInternal
		}
		if ld.Linkmode == ld.LinkExternal && obj.Getgoextlinkenabled() != "1" {
			log.Fatalf("cannot use -linkmode=external with -H %s", ld.Headstr(int(ld.HEADTYPE)))
		}

	case obj.Hdarwin,
		obj.Hfreebsd,
		obj.Hlinux,
		obj.Hnetbsd,
		obj.Hopenbsd,
		obj.Hwindows:
		break
	}

	switch ld.HEADTYPE {
	default:
		ld.Exitf("unknown -H option: %v", ld.HEADTYPE)

	case obj.Hplan9: /* plan 9 */
		ld.HEADR = 32

		if ld.INITTEXT == -1 {
			ld.INITTEXT = 4096 + 32
		}
		if ld.INITDAT == -1 {
			ld.INITDAT = 0
		}
		if ld.INITRND == -1 {
			ld.INITRND = 4096
		}

	case obj.Hdarwin: /* apple MACH */
		ld.Machoinit()

		ld.HEADR = ld.INITIAL_MACHO_HEADR
		if ld.INITTEXT == -1 {
			ld.INITTEXT = 4096 + int64(ld.HEADR)
		}
		if ld.INITDAT == -1 {
			ld.INITDAT = 0
		}
		if ld.INITRND == -1 {
			ld.INITRND = 4096
		}

	case obj.Hlinux, /* elf32 executable */
		obj.Hfreebsd,
		obj.Hnetbsd,
		obj.Hopenbsd:
		ld.Elfinit()

		ld.HEADR = ld.ELFRESERVE
		if ld.INITTEXT == -1 {
			ld.INITTEXT = 0x08048000 + int64(ld.HEADR)
		}
		if ld.INITDAT == -1 {
			ld.INITDAT = 0
		}
		if ld.INITRND == -1 {
			ld.INITRND = 4096
		}

	case obj.Hnacl:
		ld.Elfinit()
		ld.HEADR = 0x10000
		ld.Funcalign = 32
		if ld.INITTEXT == -1 {
			ld.INITTEXT = 0x20000
		}
		if ld.INITDAT == -1 {
			ld.INITDAT = 0
		}
		if ld.INITRND == -1 {
			ld.INITRND = 0x10000
		}

	case obj.Hwindows: /* PE executable */
		ld.Peinit()

		ld.HEADR = ld.PEFILEHEADR
		if ld.INITTEXT == -1 {
			ld.INITTEXT = ld.PEBASE + int64(ld.PESECTHEADR)
		}
		if ld.INITDAT == -1 {
			ld.INITDAT = 0
		}
		if ld.INITRND == -1 {
			ld.INITRND = ld.PESECTALIGN
		}
	}

	if ld.INITDAT != 0 && ld.INITRND != 0 {
		fmt.Printf("warning: -D0x%x is ignored because of -R0x%x\n", uint64(ld.INITDAT), uint32(ld.INITRND))
	}
}
Beispiel #26
0
func adddynrel(s *ld.LSym, r *ld.Reloc) {
	targ := r.Sym
	ld.Ctxt.Cursym = s

	switch r.Type {
	default:
		if r.Type >= 256 {
			ld.Diag("unexpected relocation type %d", r.Type)
			return
		}

		// Handle relocations found in ELF object files.
	case 256 + ld.R_386_PC32:
		if targ.Type == obj.SDYNIMPORT {
			ld.Diag("unexpected R_386_PC32 relocation for dynamic symbol %s", targ.Name)
		}
		if targ.Type == 0 || targ.Type == obj.SXREF {
			ld.Diag("unknown symbol %s in pcrel", targ.Name)
		}
		r.Type = obj.R_PCREL
		r.Add += 4
		return

	case 256 + ld.R_386_PLT32:
		r.Type = obj.R_PCREL
		r.Add += 4
		if targ.Type == obj.SDYNIMPORT {
			addpltsym(ld.Ctxt, targ)
			r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
			r.Add += int64(targ.Plt)
		}

		return

	case 256 + ld.R_386_GOT32, 256 + ld.R_386_GOT32X:
		if targ.Type != obj.SDYNIMPORT {
			// have symbol
			if r.Off >= 2 && s.P[r.Off-2] == 0x8b {
				// turn MOVL of GOT entry into LEAL of symbol address, relative to GOT.
				s.P[r.Off-2] = 0x8d

				r.Type = obj.R_GOTOFF
				return
			}

			if r.Off >= 2 && s.P[r.Off-2] == 0xff && s.P[r.Off-1] == 0xb3 {
				// turn PUSHL of GOT entry into PUSHL of symbol itself.
				// use unnecessary SS prefix to keep instruction same length.
				s.P[r.Off-2] = 0x36

				s.P[r.Off-1] = 0x68
				r.Type = obj.R_ADDR
				return
			}

			ld.Diag("unexpected GOT reloc for non-dynamic symbol %s", targ.Name)
			return
		}

		addgotsym(ld.Ctxt, targ)
		r.Type = obj.R_CONST // write r->add during relocsym
		r.Sym = nil
		r.Add += int64(targ.Got)
		return

	case 256 + ld.R_386_GOTOFF:
		r.Type = obj.R_GOTOFF
		return

	case 256 + ld.R_386_GOTPC:
		r.Type = obj.R_PCREL
		r.Sym = ld.Linklookup(ld.Ctxt, ".got", 0)
		r.Add += 4
		return

	case 256 + ld.R_386_32:
		if targ.Type == obj.SDYNIMPORT {
			ld.Diag("unexpected R_386_32 relocation for dynamic symbol %s", targ.Name)
		}
		r.Type = obj.R_ADDR
		return

	case 512 + ld.MACHO_GENERIC_RELOC_VANILLA*2 + 0:
		r.Type = obj.R_ADDR
		if targ.Type == obj.SDYNIMPORT {
			ld.Diag("unexpected reloc for dynamic symbol %s", targ.Name)
		}
		return

	case 512 + ld.MACHO_GENERIC_RELOC_VANILLA*2 + 1:
		if targ.Type == obj.SDYNIMPORT {
			addpltsym(ld.Ctxt, targ)
			r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
			r.Add = int64(targ.Plt)
			r.Type = obj.R_PCREL
			return
		}

		r.Type = obj.R_PCREL
		return

	case 512 + ld.MACHO_FAKE_GOTPCREL:
		if targ.Type != obj.SDYNIMPORT {
			// have symbol
			// turn MOVL of GOT entry into LEAL of symbol itself
			if r.Off < 2 || s.P[r.Off-2] != 0x8b {
				ld.Diag("unexpected GOT reloc for non-dynamic symbol %s", targ.Name)
				return
			}

			s.P[r.Off-2] = 0x8d
			r.Type = obj.R_PCREL
			return
		}

		addgotsym(ld.Ctxt, targ)
		r.Sym = ld.Linklookup(ld.Ctxt, ".got", 0)
		r.Add += int64(targ.Got)
		r.Type = obj.R_PCREL
		return
	}

	// Handle references to ELF symbols from our own object files.
	if targ.Type != obj.SDYNIMPORT {
		return
	}

	switch r.Type {
	case obj.R_CALL,
		obj.R_PCREL:
		addpltsym(ld.Ctxt, targ)
		r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
		r.Add = int64(targ.Plt)
		return

	case obj.R_ADDR:
		if s.Type != obj.SDATA {
			break
		}
		if ld.Iself {
			ld.Adddynsym(ld.Ctxt, targ)
			rel := ld.Linklookup(ld.Ctxt, ".rel", 0)
			ld.Addaddrplus(ld.Ctxt, rel, s, int64(r.Off))
			ld.Adduint32(ld.Ctxt, rel, ld.ELF32_R_INFO(uint32(targ.Dynid), ld.R_386_32))
			r.Type = obj.R_CONST // write r->add during relocsym
			r.Sym = nil
			return
		}

		if ld.HEADTYPE == obj.Hdarwin && s.Size == PtrSize && r.Off == 0 {
			// Mach-O relocations are a royal pain to lay out.
			// They use a compact stateful bytecode representation
			// that is too much bother to deal with.
			// Instead, interpret the C declaration
			//	void *_Cvar_stderr = &stderr;
			// as making _Cvar_stderr the name of a GOT entry
			// for stderr.  This is separate from the usual GOT entry,
			// just in case the C code assigns to the variable,
			// and of course it only works for single pointers,
			// but we only need to support cgo and that's all it needs.
			ld.Adddynsym(ld.Ctxt, targ)

			got := ld.Linklookup(ld.Ctxt, ".got", 0)
			s.Type = got.Type | obj.SSUB
			s.Outer = got
			s.Sub = got.Sub
			got.Sub = s
			s.Value = got.Size
			ld.Adduint32(ld.Ctxt, got, 0)
			ld.Adduint32(ld.Ctxt, ld.Linklookup(ld.Ctxt, ".linkedit.got", 0), uint32(targ.Dynid))
			r.Type = 256 // ignore during relocsym
			return
		}

		if ld.HEADTYPE == obj.Hwindows && s.Size == PtrSize {
			// nothing to do, the relocation will be laid out in pereloc1
			return
		}
	}

	ld.Ctxt.Cursym = s
	ld.Diag("unsupported relocation for dynamic symbol %s (type=%d stype=%d)", targ.Name, r.Type, targ.Type)
}
Beispiel #27
0
func asmb() {
	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f asmb\n", obj.Cputime())
	}
	ld.Bso.Flush()

	if ld.Iself {
		ld.Asmbelfsetup()
	}

	sect := ld.Segtext.Sect
	ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
	ld.Codeblk(int64(sect.Vaddr), int64(sect.Length))
	for sect = sect.Next; sect != nil; sect = sect.Next {
		ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
		ld.Datblk(int64(sect.Vaddr), int64(sect.Length))
	}

	if ld.Segrodata.Filelen > 0 {
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f rodatblk\n", obj.Cputime())
		}
		ld.Bso.Flush()

		ld.Cseek(int64(ld.Segrodata.Fileoff))
		ld.Datblk(int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
	}

	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f datblk\n", obj.Cputime())
	}
	ld.Bso.Flush()

	ld.Cseek(int64(ld.Segdata.Fileoff))
	ld.Datblk(int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))

	/* output symbol table */
	ld.Symsize = 0

	ld.Lcsize = 0
	symo := uint32(0)
	if ld.Debug['s'] == 0 {
		// TODO: rationalize
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f sym\n", obj.Cputime())
		}
		ld.Bso.Flush()
		switch ld.HEADTYPE {
		default:
			if ld.Iself {
				symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
				symo = uint32(ld.Rnd(int64(symo), int64(ld.INITRND)))
			}

		case obj.Hplan9:
			symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
		}

		ld.Cseek(int64(symo))
		switch ld.HEADTYPE {
		default:
			if ld.Iself {
				if ld.Debug['v'] != 0 {
					fmt.Fprintf(&ld.Bso, "%5.2f elfsym\n", obj.Cputime())
				}
				ld.Asmelfsym()
				ld.Cflush()
				ld.Cwrite(ld.Elfstrdat)

				if ld.Debug['v'] != 0 {
					fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
				}
				ld.Dwarfemitdebugsections()

				if ld.Linkmode == ld.LinkExternal {
					ld.Elfemitreloc()
				}
			}

		case obj.Hplan9:
			ld.Asmplan9sym()
			ld.Cflush()

			sym := ld.Linklookup(ld.Ctxt, "pclntab", 0)
			if sym != nil {
				ld.Lcsize = int32(len(sym.P))
				for i := 0; int32(i) < ld.Lcsize; i++ {
					ld.Cput(uint8(sym.P[i]))
				}

				ld.Cflush()
			}
		}
	}

	ld.Ctxt.Cursym = nil
	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f header\n", obj.Cputime())
	}
	ld.Bso.Flush()
	ld.Cseek(0)
	switch ld.HEADTYPE {
	default:
	case obj.Hplan9: /* plan 9 */
		magic := uint32(4*18*18 + 7)
		if ld.Thestring == "mips64le" {
			magic = uint32(4*26*26 + 7)
		}
		ld.Thearch.Lput(uint32(magic))              /* magic */
		ld.Thearch.Lput(uint32(ld.Segtext.Filelen)) /* sizes */
		ld.Thearch.Lput(uint32(ld.Segdata.Filelen))
		ld.Thearch.Lput(uint32(ld.Segdata.Length - ld.Segdata.Filelen))
		ld.Thearch.Lput(uint32(ld.Symsize))      /* nsyms */
		ld.Thearch.Lput(uint32(ld.Entryvalue())) /* va of entry */
		ld.Thearch.Lput(0)
		ld.Thearch.Lput(uint32(ld.Lcsize))

	case obj.Hlinux,
		obj.Hfreebsd,
		obj.Hnetbsd,
		obj.Hopenbsd,
		obj.Hnacl:
		ld.Asmbelf(int64(symo))
	}

	ld.Cflush()
	if ld.Debug['c'] != 0 {
		fmt.Printf("textsize=%d\n", ld.Segtext.Filelen)
		fmt.Printf("datsize=%d\n", ld.Segdata.Filelen)
		fmt.Printf("bsssize=%d\n", ld.Segdata.Length-ld.Segdata.Filelen)
		fmt.Printf("symsize=%d\n", ld.Symsize)
		fmt.Printf("lcsize=%d\n", ld.Lcsize)
		fmt.Printf("total=%d\n", ld.Segtext.Filelen+ld.Segdata.Length+uint64(ld.Symsize)+uint64(ld.Lcsize))
	}
}
Beispiel #28
0
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		switch r.Type {
		case obj.R_CALLARM:
			r.Done = 0

			// set up addend for eventual relocation via outer symbol.
			rs := r.Sym

			r.Xadd = r.Add
			if r.Xadd&0x800000 != 0 {
				r.Xadd |= ^0xffffff
			}
			r.Xadd *= 4
			for rs.Outer != nil {
				r.Xadd += ld.Symaddr(rs) - ld.Symaddr(rs.Outer)
				rs = rs.Outer
			}

			if rs.Type != obj.SHOSTOBJ && rs.Type != obj.SDYNIMPORT && rs.Sect == nil {
				ld.Diag("missing section for %s", rs.Name)
			}
			r.Xsym = rs

			// ld64 for arm seems to want the symbol table to contain offset
			// into the section rather than pseudo virtual address that contains
			// the section load address.
			// we need to compensate that by removing the instruction's address
			// from addend.
			if ld.HEADTYPE == obj.Hdarwin {
				r.Xadd -= ld.Symaddr(s) + int64(r.Off)
			}

			*val = int64(braddoff(int32(0xff000000&uint32(r.Add)), int32(0xffffff&uint32(r.Xadd/4))))
			return 0
		}

		return -1
	}

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

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

		// The following three arch specific relocations are only for generation of
	// Linux/ARM ELF's PLT entry (3 assembler instruction)
	case obj.R_PLT0: // add ip, pc, #0xXX00000
		if ld.Symaddr(ld.Linklookup(ld.Ctxt, ".got.plt", 0)) < ld.Symaddr(ld.Linklookup(ld.Ctxt, ".plt", 0)) {
			ld.Diag(".got.plt should be placed after .plt section.")
		}
		*val = 0xe28fc600 + (0xff & (int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ld.Linklookup(ld.Ctxt, ".plt", 0))+int64(r.Off))+r.Add)) >> 20))
		return 0

	case obj.R_PLT1: // add ip, ip, #0xYY000
		*val = 0xe28cca00 + (0xff & (int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ld.Linklookup(ld.Ctxt, ".plt", 0))+int64(r.Off))+r.Add+4)) >> 12))

		return 0

	case obj.R_PLT2: // ldr pc, [ip, #0xZZZ]!
		*val = 0xe5bcf000 + (0xfff & int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ld.Linklookup(ld.Ctxt, ".plt", 0))+int64(r.Off))+r.Add+8)))

		return 0

	case obj.R_CALLARM: // bl XXXXXX or b YYYYYY
		*val = int64(braddoff(int32(0xff000000&uint32(r.Add)), int32(0xffffff&uint32((ld.Symaddr(r.Sym)+int64((uint32(r.Add))*4)-(s.Value+int64(r.Off)))/4))))

		return 0
	}

	return -1
}
Beispiel #29
0
func asmb() {
	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f asmb\n", obj.Cputime())
	}
	ld.Bso.Flush()

	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f codeblk\n", obj.Cputime())
	}
	ld.Bso.Flush()

	if ld.Iself {
		ld.Asmbelfsetup()
	}

	sect := ld.Segtext.Sect
	ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
	ld.Codeblk(int64(sect.Vaddr), int64(sect.Length))
	for sect = sect.Next; sect != nil; sect = sect.Next {
		ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
		ld.Datblk(int64(sect.Vaddr), int64(sect.Length))
	}

	if ld.Segrodata.Filelen > 0 {
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f rodatblk\n", obj.Cputime())
		}
		ld.Bso.Flush()

		ld.Cseek(int64(ld.Segrodata.Fileoff))
		ld.Datblk(int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
	}

	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f datblk\n", obj.Cputime())
	}
	ld.Bso.Flush()

	ld.Cseek(int64(ld.Segdata.Fileoff))
	ld.Datblk(int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))

	machlink := int64(0)
	if ld.HEADTYPE == obj.Hdarwin {
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
		}

		dwarfoff := ld.Rnd(int64(uint64(ld.HEADR)+ld.Segtext.Length), int64(ld.INITRND)) + ld.Rnd(int64(ld.Segdata.Filelen), int64(ld.INITRND))
		ld.Cseek(dwarfoff)

		ld.Segdwarf.Fileoff = uint64(ld.Cpos())
		ld.Dwarfemitdebugsections()
		ld.Segdwarf.Filelen = uint64(ld.Cpos()) - ld.Segdwarf.Fileoff

		machlink = ld.Domacholink()
	}

	switch ld.HEADTYPE {
	default:
		ld.Diag("unknown header type %d", ld.HEADTYPE)
		fallthrough

	case obj.Hplan9,
		obj.Helf:
		break

	case obj.Hdarwin:
		ld.Debug['8'] = 1 /* 64-bit addresses */

	case obj.Hlinux,
		obj.Hfreebsd,
		obj.Hnetbsd,
		obj.Hopenbsd,
		obj.Hdragonfly,
		obj.Hsolaris:
		ld.Debug['8'] = 1 /* 64-bit addresses */

	case obj.Hnacl,
		obj.Hwindows:
		break
	}

	ld.Symsize = 0
	ld.Spsize = 0
	ld.Lcsize = 0
	symo := int64(0)
	if ld.Debug['s'] == 0 {
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f sym\n", obj.Cputime())
		}
		ld.Bso.Flush()
		switch ld.HEADTYPE {
		default:
		case obj.Hplan9,
			obj.Helf:
			ld.Debug['s'] = 1
			symo = int64(ld.Segdata.Fileoff + ld.Segdata.Filelen)

		case obj.Hdarwin:
			symo = int64(ld.Segdwarf.Fileoff + uint64(ld.Rnd(int64(ld.Segdwarf.Filelen), int64(ld.INITRND))) + uint64(machlink))

		case obj.Hlinux,
			obj.Hfreebsd,
			obj.Hnetbsd,
			obj.Hopenbsd,
			obj.Hdragonfly,
			obj.Hsolaris,
			obj.Hnacl:
			symo = int64(ld.Segdata.Fileoff + ld.Segdata.Filelen)
			symo = ld.Rnd(symo, int64(ld.INITRND))

		case obj.Hwindows:
			symo = int64(ld.Segdata.Fileoff + ld.Segdata.Filelen)
			symo = ld.Rnd(symo, ld.PEFILEALIGN)
		}

		ld.Cseek(symo)
		switch ld.HEADTYPE {
		default:
			if ld.Iself {
				ld.Cseek(symo)
				ld.Asmelfsym()
				ld.Cflush()
				ld.Cwrite(ld.Elfstrdat)

				if ld.Debug['v'] != 0 {
					fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
				}

				ld.Dwarfemitdebugsections()

				if ld.Linkmode == ld.LinkExternal {
					ld.Elfemitreloc()
				}
			}

		case obj.Hplan9:
			ld.Asmplan9sym()
			ld.Cflush()

			sym := ld.Linklookup(ld.Ctxt, "pclntab", 0)
			if sym != nil {
				ld.Lcsize = int32(len(sym.P))
				for i := 0; int32(i) < ld.Lcsize; i++ {
					ld.Cput(uint8(sym.P[i]))
				}

				ld.Cflush()
			}

		case obj.Hwindows:
			if ld.Debug['v'] != 0 {
				fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
			}

			ld.Dwarfemitdebugsections()

		case obj.Hdarwin:
			if ld.Linkmode == ld.LinkExternal {
				ld.Machoemitreloc()
			}
		}
	}

	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f headr\n", obj.Cputime())
	}
	ld.Bso.Flush()
	ld.Cseek(0)
	switch ld.HEADTYPE {
	default:
	case obj.Hplan9: /* plan9 */
		magic := int32(4*26*26 + 7)

		magic |= 0x00008000                  /* fat header */
		ld.Lputb(uint32(magic))              /* magic */
		ld.Lputb(uint32(ld.Segtext.Filelen)) /* sizes */
		ld.Lputb(uint32(ld.Segdata.Filelen))
		ld.Lputb(uint32(ld.Segdata.Length - ld.Segdata.Filelen))
		ld.Lputb(uint32(ld.Symsize)) /* nsyms */
		vl := ld.Entryvalue()
		ld.Lputb(PADDR(uint32(vl))) /* va of entry */
		ld.Lputb(uint32(ld.Spsize)) /* sp offsets */
		ld.Lputb(uint32(ld.Lcsize)) /* line offsets */
		ld.Vputb(uint64(vl))        /* va of entry */

	case obj.Hdarwin:
		ld.Asmbmacho()

	case obj.Hlinux,
		obj.Hfreebsd,
		obj.Hnetbsd,
		obj.Hopenbsd,
		obj.Hdragonfly,
		obj.Hsolaris,
		obj.Hnacl:
		ld.Asmbelf(symo)

	case obj.Hwindows:
		ld.Asmbpe()
	}

	ld.Cflush()
}
Beispiel #30
0
func archinit() {
	// getgoextlinkenabled is based on GO_EXTLINK_ENABLED when
	// Go was built; see ../../make.bash.
	if ld.Linkmode == ld.LinkAuto && obj.Getgoextlinkenabled() == "0" {
		ld.Linkmode = ld.LinkInternal
	}

	switch ld.Buildmode {
	case ld.BuildmodePIE, ld.BuildmodeShared:
		ld.Linkmode = ld.LinkExternal
	}

	if ld.Linkshared {
		ld.Linkmode = ld.LinkExternal
	}

	if ld.Linkmode == ld.LinkExternal {
		toc := ld.Linklookup(ld.Ctxt, ".TOC.", 0)
		toc.Type = obj.SDYNIMPORT
	}

	switch ld.HEADTYPE {
	default:
		if ld.Linkmode == ld.LinkAuto {
			ld.Linkmode = ld.LinkInternal
		}
		if ld.Linkmode == ld.LinkExternal && obj.Getgoextlinkenabled() != "1" {
			log.Fatalf("cannot use -linkmode=external with -H %s", ld.Headstr(int(ld.HEADTYPE)))
		}

	case obj.Hlinux:
		break
	}

	switch ld.HEADTYPE {
	default:
		ld.Exitf("unknown -H option: %v", ld.HEADTYPE)

	case obj.Hplan9: /* plan 9 */
		ld.HEADR = 32

		if ld.INITTEXT == -1 {
			ld.INITTEXT = 4128
		}
		if ld.INITDAT == -1 {
			ld.INITDAT = 0
		}
		if ld.INITRND == -1 {
			ld.INITRND = 4096
		}

	case obj.Hlinux: /* ppc64 elf */
		if ld.Thestring == "ppc64" {
			ld.Debug['d'] = 1 // TODO(austin): ELF ABI v1 not supported yet
		}
		ld.Elfinit()
		ld.HEADR = ld.ELFRESERVE
		if ld.INITTEXT == -1 {
			ld.INITTEXT = 0x10000 + int64(ld.HEADR)
		}
		if ld.INITDAT == -1 {
			ld.INITDAT = 0
		}
		if ld.INITRND == -1 {
			ld.INITRND = 0x10000
		}

	case obj.Hnacl:
		ld.Elfinit()
		ld.HEADR = 0x10000
		ld.Funcalign = 16
		if ld.INITTEXT == -1 {
			ld.INITTEXT = 0x20000
		}
		if ld.INITDAT == -1 {
			ld.INITDAT = 0
		}
		if ld.INITRND == -1 {
			ld.INITRND = 0x10000
		}
	}

	if ld.INITDAT != 0 && ld.INITRND != 0 {
		fmt.Printf("warning: -D0x%x is ignored because of -R0x%x\n", uint64(ld.INITDAT), uint32(ld.INITRND))
	}
}