Exemple #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)
	}
}
Exemple #2
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 = ld.R_ADDRPOWER

	// addis r11,0,.plt@ha; addi r11,r11,.plt@l
	r.Add = 0x3d600000<<32 | 0x396b0000

	glink.Size += 8

	// 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
}
Exemple #3
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)
	}
}
Exemple #4
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)
	}
}
Exemple #5
0
func adddynsym(ctxt *ld.Link, s *ld.LSym) {
	if s.Dynid >= 0 {
		return
	}

	if ld.Iself {
		s.Dynid = int32(ld.Nelfsym)
		ld.Nelfsym++

		d := ld.Linklookup(ctxt, ".dynsym", 0)

		name := s.Extname
		ld.Adduint32(ctxt, d, uint32(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), name)))

		/* type */
		t := ld.STB_GLOBAL << 4

		if s.Cgoexport != 0 && s.Type&ld.SMASK == ld.STEXT {
			t |= ld.STT_FUNC
		} else {
			t |= ld.STT_OBJECT
		}
		ld.Adduint8(ctxt, d, uint8(t))

		/* reserved */
		ld.Adduint8(ctxt, d, 0)

		/* section where symbol is defined */
		if s.Type == ld.SDYNIMPORT {
			ld.Adduint16(ctxt, d, ld.SHN_UNDEF)
		} else {
			ld.Adduint16(ctxt, d, 1)
		}

		/* value */
		if s.Type == ld.SDYNIMPORT {
			ld.Adduint64(ctxt, d, 0)
		} else {
			ld.Addaddr(ctxt, d, s)
		}

		/* size of object */
		ld.Adduint64(ctxt, d, uint64(s.Size))

		if s.Cgoexport&ld.CgoExportDynamic == 0 && s.Dynimplib != "" && needlib(s.Dynimplib) != 0 {
			ld.Elfwritedynent(ld.Linklookup(ctxt, ".dynamic", 0), ld.DT_NEEDED, uint64(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), s.Dynimplib)))
		}
	} else if ld.HEADTYPE == ld.Hdarwin {
		ld.Diag("adddynsym: missed symbol %s (%s)", s.Name, s.Extname)
	} else if ld.HEADTYPE == ld.Hwindows {
	} else // already taken care of
	{
		ld.Diag("adddynsym: unsupported binary format")
	}
}
Exemple #6
0
func adddynsym(ctxt *ld.Link, s *ld.LSym) {
	if s.Dynid >= 0 {
		return
	}

	if ld.Iself {
		s.Dynid = int32(ld.Nelfsym)
		ld.Nelfsym++

		d := ld.Linklookup(ctxt, ".dynsym", 0)

		/* name */
		name := s.Extname

		ld.Adduint32(ctxt, d, uint32(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), name)))

		/* value */
		if s.Type == ld.SDYNIMPORT {
			ld.Adduint32(ctxt, d, 0)
		} else {
			ld.Addaddr(ctxt, d, s)
		}

		/* size */
		ld.Adduint32(ctxt, d, 0)

		/* type */
		t := ld.STB_GLOBAL << 4

		if s.Cgoexport != 0 && s.Type&ld.SMASK == ld.STEXT {
			t |= ld.STT_FUNC
		} else {
			t |= ld.STT_OBJECT
		}
		ld.Adduint8(ctxt, d, uint8(t))
		ld.Adduint8(ctxt, d, 0)

		/* shndx */
		if s.Type == ld.SDYNIMPORT {
			ld.Adduint16(ctxt, d, ld.SHN_UNDEF)
		} else {
			ld.Adduint16(ctxt, d, 1)
		}
	} else if ld.HEADTYPE == ld.Hdarwin {
		ld.Diag("adddynsym: missed symbol %s (%s)", s.Name, s.Extname)
	} else if ld.HEADTYPE == ld.Hwindows {
	} else // already taken care of
	{
		ld.Diag("adddynsym: unsupported binary format")
	}
}
Exemple #7
0
func adddynlib(lib string) {
	if needlib(lib) == 0 {
		return
	}

	if ld.Iself {
		s := ld.Linklookup(ld.Ctxt, ".dynstr", 0)
		if s.Size == 0 {
			ld.Addstring(s, "")
		}
		ld.Elfwritedynent(ld.Linklookup(ld.Ctxt, ".dynamic", 0), ld.DT_NEEDED, uint64(ld.Addstring(s, lib)))
	} else {
		ld.Diag("adddynlib: unsupported binary format")
	}
}
Exemple #8
0
func adddynsym(ctxt *ld.Link, s *ld.LSym) {
	if s.Dynid >= 0 {
		return
	}

	if ld.Iself {
		s.Dynid = int32(ld.Nelfsym)
		ld.Nelfsym++

		d := ld.Linklookup(ctxt, ".dynsym", 0)

		/* name */
		name := s.Extname

		ld.Adduint32(ctxt, d, uint32(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), name)))

		/* value */
		if s.Type == ld.SDYNIMPORT {
			ld.Adduint32(ctxt, d, 0)
		} else {
			ld.Addaddr(ctxt, d, s)
		}

		/* size */
		ld.Adduint32(ctxt, d, 0)

		/* type */
		t := ld.STB_GLOBAL << 4

		if (s.Cgoexport&ld.CgoExportDynamic != 0) && s.Type&ld.SMASK == ld.STEXT {
			t |= ld.STT_FUNC
		} else {
			t |= ld.STT_OBJECT
		}
		ld.Adduint8(ctxt, d, uint8(t))
		ld.Adduint8(ctxt, d, 0)

		/* shndx */
		if s.Type == ld.SDYNIMPORT {
			ld.Adduint16(ctxt, d, ld.SHN_UNDEF)
		} else {
			ld.Adduint16(ctxt, d, 1)
		}
	} else {
		ld.Diag("adddynsym: unsupported binary format")
	}
}
Exemple #9
0
func adddynsym(ctxt *ld.Link, s *ld.LSym) {
	if s.Dynid >= 0 {
		return
	}

	if ld.Iself {
		s.Dynid = int32(ld.Nelfsym)
		ld.Nelfsym++

		d := ld.Linklookup(ctxt, ".dynsym", 0)

		name := s.Extname
		ld.Adduint32(ctxt, d, uint32(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), name)))

		/* type */
		t := ld.STB_GLOBAL << 4

		if s.Cgoexport != 0 && s.Type&ld.SMASK == ld.STEXT {
			t |= ld.STT_FUNC
		} else {
			t |= ld.STT_OBJECT
		}
		ld.Adduint8(ctxt, d, uint8(t))

		/* reserved */
		ld.Adduint8(ctxt, d, 0)

		/* section where symbol is defined */
		if s.Type == ld.SDYNIMPORT {
			ld.Adduint16(ctxt, d, ld.SHN_UNDEF)
		} else {
			ld.Adduint16(ctxt, d, 1)
		}

		/* value */
		if s.Type == ld.SDYNIMPORT {
			ld.Adduint64(ctxt, d, 0)
		} else {
			ld.Addaddr(ctxt, d, s)
		}

		/* size of object */
		ld.Adduint64(ctxt, d, uint64(s.Size))
	} else {
		ld.Diag("adddynsym: unsupported binary format")
	}
}
Exemple #10
0
func addgotsym(ctxt *ld.Link, s *ld.LSym) {
	if s.Got >= 0 {
		return
	}

	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")
	}
}
Exemple #11
0
func addpltsym(ctxt *ld.Link, s *ld.LSym) {
	if s.Plt >= 0 {
		return
	}

	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 = ld.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")
	}
}
Exemple #12
0
func gentext() {
	if !ld.DynlinkingGo() {
		return
	}
	addmoduledata := ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
	if addmoduledata.Type == ld.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 = ld.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.Linklookup(ld.Ctxt, "runtime.firstmoduledata", 0), 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 = ld.SINITARR
	ld.Addaddr(ld.Ctxt, initarray_entry, initfunc)
}
Exemple #13
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
	}
}
Exemple #14
0
func addgotsym(s *ld.LSym) {
	if s.Got >= 0 {
		return
	}

	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 == ld.Hdarwin {
		ld.Adduint32(ld.Ctxt, ld.Linklookup(ld.Ctxt, ".linkedit.got", 0), uint32(s.Dynid))
	} else {
		ld.Diag("addgotsym: unsupported binary format")
	}
}
Exemple #15
0
func addpltsym(ctxt *ld.Link, s *ld.LSym) {
	if s.Plt >= 0 {
		return
	}

	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 == ld.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")
	}
}
Exemple #16
0
func addpltsym(ctxt *ld.Link, s *ld.LSym) {
	if s.Plt >= 0 {
		return
	}

	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, ld.R_PLT0) // add lr, pc, #0xXX00000
		addpltreloc(ctxt, plt, got, s, ld.R_PLT1) // add lr, lr, #0xYY000
		addpltreloc(ctxt, plt, got, s, ld.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")
	}
}
Exemple #17
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")
	}
}
Exemple #18
0
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		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
	}

	return -1
}
Exemple #19
0
func needlib(name string) int {
	if name[0] == '\x00' {
		return 0
	}

	/* reuse hash code in symbol table */
	p := fmt.Sprintf(".dynlib.%s", name)

	s := ld.Linklookup(ld.Ctxt, p, 0)

	if s.Type == 0 {
		s.Type = 100 // avoid SDATA, etc.
		return 1
	}

	return 0
}
Exemple #20
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 = ld.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 = ld.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 = ld.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
}
Exemple #21
0
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		// TODO(minux): translate R_CALLARM64 into standard ELF relocation.
		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_CALLARM64:
		*val = int64((0xfc000000 & uint32(r.Add)) | uint32((ld.Symaddr(r.Sym)+r.Add*4-(s.Value+int64(r.Off)))/4))
		return 0
	}

	return -1
}
Exemple #22
0
func asmb() {
	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f asmb\n", obj.Cputime())
	}
	ld.Bflush(&ld.Bso)

	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.Bflush(&ld.Bso)

		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.Bflush(&ld.Bso)

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

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

		if ld.Debug['w'] == 0 { // TODO(minux): enable DWARF Support
			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())
	}

	/* 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.Bflush(&ld.Bso)
		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 ld.Hplan9:
			symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)

		case ld.Hdarwin:
			symo = uint32(ld.Rnd(int64(uint64(ld.HEADR)+ld.Segtext.Filelen), int64(ld.INITRND)) + ld.Rnd(int64(ld.Segdata.Filelen), int64(ld.INITRND)) + int64(machlink))
		}

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

	ld.Ctxt.Cursym = nil
	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f header\n", obj.Cputime())
	}
	ld.Bflush(&ld.Bso)
	ld.Cseek(0)
	switch ld.HEADTYPE {
	default:
	case ld.Hplan9: /* plan 9 */
		ld.Thearch.Lput(0x647)                      /* 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 ld.Hlinux,
		ld.Hfreebsd,
		ld.Hnetbsd,
		ld.Hopenbsd,
		ld.Hnacl:
		ld.Asmbelf(int64(symo))

	case ld.Hdarwin:
		ld.Asmbmacho()
	}

	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))
	}
}
Exemple #23
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 = ld.R_CALLARM

		if targ.Type == ld.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.Diag("R_ARM_THM_CALL, are you using -marm?")

		ld.Errorexit()
		return

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

		r.Type = ld.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 != ld.SDYNIMPORT {
			addgotsyminternal(ld.Ctxt, targ)
		} else {
			addgotsym(ld.Ctxt, targ)
		}

		r.Type = ld.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 = ld.R_GOTOFF

		return

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

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

	case 256 + ld.R_ARM_CALL:
		r.Type = ld.R_CALLARM
		if targ.Type == ld.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 = ld.R_PCREL

		r.Add += 4
		return

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

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

	case ld.R_ADDR:
		if s.Type != ld.SDATA {
			break
		}
		if ld.Iself {
			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 dynmic reloc
			r.Type = ld.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)
}
Exemple #24
0
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
}
Exemple #25
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_PPC64_REL24:
		r.Type = ld.R_CALLPOWER

		// This is a local call, so the caller isn't setting
		// up r12 and r2 is the same for the caller and
		// callee.  Hence, we need to go to the local entry
		// point.  (If we don't do this, the callee will try
		// to use r12 to compute r2.)
		r.Add += int64(r.Sym.Localentry) * 4

		if targ.Type == ld.SDYNIMPORT {
			// Should have been handled in elfsetupplt
			ld.Diag("unexpected R_PPC64_REL24 for dyn import")
		}

		return

	case 256 + ld.R_PPC64_ADDR64:
		r.Type = ld.R_ADDR
		if targ.Type == ld.SDYNIMPORT {
			// These happen in .toc sections
			adddynsym(ld.Ctxt, targ)

			rela := ld.Linklookup(ld.Ctxt, ".rela", 0)
			ld.Addaddrplus(ld.Ctxt, rela, s, int64(r.Off))
			ld.Adduint64(ld.Ctxt, rela, ld.ELF64_R_INFO(uint32(targ.Dynid), ld.R_PPC64_ADDR64))
			ld.Adduint64(ld.Ctxt, rela, uint64(r.Add))
			r.Type = 256 // ignore during relocsym
		}

		return

	case 256 + ld.R_PPC64_TOC16:
		r.Type = ld.R_POWER_TOC
		r.Variant = ld.RV_POWER_LO | ld.RV_CHECK_OVERFLOW
		return

	case 256 + ld.R_PPC64_TOC16_LO:
		r.Type = ld.R_POWER_TOC
		r.Variant = ld.RV_POWER_LO
		return

	case 256 + ld.R_PPC64_TOC16_HA:
		r.Type = ld.R_POWER_TOC
		r.Variant = ld.RV_POWER_HA | ld.RV_CHECK_OVERFLOW
		return

	case 256 + ld.R_PPC64_TOC16_HI:
		r.Type = ld.R_POWER_TOC
		r.Variant = ld.RV_POWER_HI | ld.RV_CHECK_OVERFLOW
		return

	case 256 + ld.R_PPC64_TOC16_DS:
		r.Type = ld.R_POWER_TOC
		r.Variant = ld.RV_POWER_DS | ld.RV_CHECK_OVERFLOW
		return

	case 256 + ld.R_PPC64_TOC16_LO_DS:
		r.Type = ld.R_POWER_TOC
		r.Variant = ld.RV_POWER_DS
		return

	case 256 + ld.R_PPC64_REL16_LO:
		r.Type = ld.R_PCREL
		r.Variant = ld.RV_POWER_LO
		r.Add += 2 // Compensate for relocation size of 2
		return

	case 256 + ld.R_PPC64_REL16_HI:
		r.Type = ld.R_PCREL
		r.Variant = ld.RV_POWER_HI | ld.RV_CHECK_OVERFLOW
		r.Add += 2
		return

	case 256 + ld.R_PPC64_REL16_HA:
		r.Type = ld.R_PCREL
		r.Variant = ld.RV_POWER_HA | ld.RV_CHECK_OVERFLOW
		r.Add += 2
		return
	}

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

	// TODO(austin): Translate our relocations to ELF

	ld.Diag("unsupported relocation for dynamic symbol %s (type=%d stype=%d)", targ.Name, r.Type, targ.Type)
}
Exemple #26
0
func gentext() {
	var s *ld.LSym
	var stub *ld.LSym
	var pprevtextp **ld.LSym
	var r *ld.Reloc
	var n string
	var o1 uint32
	var i int

	// The ppc64 ABI PLT has similar concepts to other
	// architectures, but is laid out quite differently.  When we
	// see an R_PPC64_REL24 relocation to a dynamic symbol
	// (indicating that the call needs to go through the PLT), we
	// generate up to three stubs and reserve a PLT slot.
	//
	// 1) The call site will be bl x; nop (where the relocation
	//    applies to the bl).  We rewrite this to bl x_stub; ld
	//    r2,24(r1).  The ld is necessary because x_stub will save
	//    r2 (the TOC pointer) at 24(r1) (the "TOC save slot").
	//
	// 2) We reserve space for a pointer in the .plt section (once
	//    per referenced dynamic function).  .plt is a data
	//    section filled solely by the dynamic linker (more like
	//    .plt.got on other architectures).  Initially, the
	//    dynamic linker will fill each slot with a pointer to the
	//    corresponding x@plt entry point.
	//
	// 3) We generate the "call stub" x_stub (once per dynamic
	//    function/object file pair).  This saves the TOC in the
	//    TOC save slot, reads the function pointer from x's .plt
	//    slot and calls it like any other global entry point
	//    (including setting r12 to the function address).
	//
	// 4) We generate the "symbol resolver stub" x@plt (once per
	//    dynamic function).  This is solely a branch to the glink
	//    resolver stub.
	//
	// 5) We generate the glink resolver stub (only once).  This
	//    computes which symbol resolver stub we came through and
	//    invokes the dynamic resolver via a pointer provided by
	//    the dynamic linker.  This will patch up the .plt slot to
	//    point directly at the function so future calls go
	//    straight from the call stub to the real function, and
	//    then call the function.

	// NOTE: It's possible we could make ppc64 closer to other
	// architectures: ppc64's .plt is like .plt.got on other
	// platforms and ppc64's .glink is like .plt on other
	// platforms.

	// Find all R_PPC64_REL24 relocations that reference dynamic
	// imports.  Reserve PLT entries for these symbols and
	// generate call stubs.  The call stubs need to live in .text,
	// which is why we need to do this pass this early.
	//
	// This assumes "case 1" from the ABI, where the caller needs
	// us to save and restore the TOC pointer.
	pprevtextp = &ld.Ctxt.Textp

	for s = *pprevtextp; s != nil; pprevtextp, s = &s.Next, s.Next {
		for i = range s.R {
			r = &s.R[i]
			if r.Type != 256+ld.R_PPC64_REL24 || r.Sym.Type != ld.SDYNIMPORT {
				continue
			}

			// Reserve PLT entry and generate symbol
			// resolver
			addpltsym(ld.Ctxt, r.Sym)

			// Generate call stub
			n = fmt.Sprintf("%s.%s", s.Name, r.Sym.Name)

			stub = ld.Linklookup(ld.Ctxt, n, 0)
			stub.Reachable = stub.Reachable || s.Reachable
			if stub.Size == 0 {
				// Need outer to resolve .TOC.
				stub.Outer = s

				// Link in to textp before s (we could
				// do it after, but would have to skip
				// the subsymbols)
				*pprevtextp = stub

				stub.Next = s
				pprevtextp = &stub.Next

				gencallstub(1, stub, r.Sym)
			}

			// Update the relocation to use the call stub
			r.Sym = stub

			// Restore TOC after bl.  The compiler put a
			// nop here for us to overwrite.
			o1 = 0xe8410018 // ld r2,24(r1)
			ld.Ctxt.Arch.ByteOrder.PutUint32(s.P[r.Off+4:], o1)
		}
	}
}
Exemple #27
0
func addpltsym(s *ld.LSym) {
	if s.Plt >= 0 {
		return
	}

	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 == ld.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")
	}
}
Exemple #28
0
func asmb() {
	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f asmb\n", obj.Cputime())
	}
	ld.Bflush(&ld.Bso)

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

	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.Bflush(&ld.Bso)

		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.Bflush(&ld.Bso)

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

	machlink := int64(0)
	if ld.HEADTYPE == ld.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 ld.Hplan9,
		ld.Helf:
		break

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

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

	case ld.Hnacl,
		ld.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.Bflush(&ld.Bso)
		switch ld.HEADTYPE {
		default:
		case ld.Hplan9,
			ld.Helf:
			ld.Debug['s'] = 1
			symo = int64(ld.Segdata.Fileoff + ld.Segdata.Filelen)

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

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

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

			ld.Dwarfemitdebugsections()

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

	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f headr\n", obj.Cputime())
	}
	ld.Bflush(&ld.Bso)
	ld.Cseek(0)
	switch ld.HEADTYPE {
	default:
	case ld.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 ld.Hdarwin:
		ld.Asmbmacho()

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

	case ld.Hwindows:
		ld.Asmbpe()
	}

	ld.Cflush()
}
Exemple #29
0
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		switch r.Type {
		case ld.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 != ld.SHOSTOBJ && 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 == ld.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 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

		// The following three arch specific relocations are only for generation of
	// Linux/ARM ELF's PLT entry (3 assembler instruction)
	case ld.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 ld.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 ld.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 ld.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
}
Exemple #30
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 == ld.SDYNIMPORT {
			ld.Diag("unexpected R_X86_64_PC32 relocation for dynamic symbol %s", targ.Name)
		}
		if targ.Type == 0 || targ.Type == ld.SXREF {
			ld.Diag("unknown symbol %s in pcrel", targ.Name)
		}
		r.Type = ld.R_PCREL
		r.Add += 4
		return

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

		return

	case 256 + ld.R_X86_64_GOTPCREL:
		if targ.Type != ld.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 = ld.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 = ld.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 == ld.SDYNIMPORT {
			ld.Diag("unexpected R_X86_64_64 relocation for dynamic symbol %s", targ.Name)
		}
		r.Type = ld.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 = ld.R_ADDR

		if targ.Type == ld.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 == ld.SDYNIMPORT {
			addpltsym(targ)
			r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
			r.Add = int64(targ.Plt)
			r.Type = ld.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 = ld.R_PCREL

		if targ.Type == ld.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 != ld.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 = ld.R_PCREL
			return
		}
		fallthrough

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

	switch r.Type {
	case ld.R_CALL,
		ld.R_PCREL:
		if ld.HEADTYPE == ld.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 ld.R_ADDR:
		if s.Type == ld.STEXT && ld.Iself {
			// 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 != ld.SDATA {
			break
		}
		if ld.Iself {
			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 == ld.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.
			adddynsym(ld.Ctxt, targ)

			got := ld.Linklookup(ld.Ctxt, ".got", 0)
			s.Type = got.Type | ld.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 == ld.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)
}