| // Inferno utils/6l/asm.c |
| // https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/asm.c |
| // |
| // Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved. |
| // Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net) |
| // Portions Copyright © 1997-1999 Vita Nuova Limited |
| // Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com) |
| // Portions Copyright © 2004,2006 Bruce Ellis |
| // Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net) |
| // Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others |
| // Portions Copyright © 2009 The Go Authors. All rights reserved. |
| // |
| // Permission is hereby granted, free of charge, to any person obtaining a copy |
| // of this software and associated documentation files (the "Software"), to deal |
| // in the Software without restriction, including without limitation the rights |
| // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| // copies of the Software, and to permit persons to whom the Software is |
| // furnished to do so, subject to the following conditions: |
| // |
| // The above copyright notice and this permission notice shall be included in |
| // all copies or substantial portions of the Software. |
| // |
| // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| // THE SOFTWARE. |
| |
| package amd64 |
| |
| import ( |
| "cmd/internal/objabi" |
| "cmd/internal/sys" |
| "cmd/link/internal/ld" |
| "cmd/link/internal/loader" |
| "cmd/link/internal/sym" |
| "debug/elf" |
| "log" |
| ) |
| |
| func PADDR(x uint32) uint32 { |
| return x &^ 0x80000000 |
| } |
| |
| func gentext(ctxt *ld.Link, ldr *loader.Loader) { |
| initfunc, addmoduledata := ld.PrepareAddmoduledata(ctxt) |
| if initfunc == nil { |
| return |
| } |
| |
| o := func(op ...uint8) { |
| for _, op1 := range op { |
| initfunc.AddUint8(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) |
| initfunc.AddPCRelPlus(ctxt.Arch, 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) |
| initfunc.AddSymRef(ctxt.Arch, addmoduledata, 0, objabi.R_CALL, 4) |
| // c: c3 retq |
| o(0xc3) |
| } |
| |
| func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym, r loader.Reloc, rIdx int) bool { |
| targ := r.Sym() |
| var targType sym.SymKind |
| if targ != 0 { |
| targType = ldr.SymType(targ) |
| } |
| |
| switch rt := r.Type(); rt { |
| default: |
| if rt >= objabi.ElfRelocOffset { |
| ldr.Errorf(s, "unexpected relocation type %d (%s)", r.Type(), sym.RelocName(target.Arch, r.Type())) |
| return false |
| } |
| |
| // Handle relocations found in ELF object files. |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_PC32): |
| if targType == sym.SDYNIMPORT { |
| ldr.Errorf(s, "unexpected R_X86_64_PC32 relocation for dynamic symbol %s", ldr.SymName(targ)) |
| } |
| // TODO(mwhudson): the test of VisibilityHidden here probably doesn't make |
| // sense and should be removed when someone has thought about it properly. |
| if (targType == 0 || targType == sym.SXREF) && !ldr.AttrVisibilityHidden(targ) { |
| ldr.Errorf(s, "unknown symbol %s in pcrel", ldr.SymName(targ)) |
| } |
| su := ldr.MakeSymbolUpdater(s) |
| su.SetRelocType(rIdx, objabi.R_PCREL) |
| su.SetRelocAdd(rIdx, r.Add()+4) |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_PC64): |
| if targType == sym.SDYNIMPORT { |
| ldr.Errorf(s, "unexpected R_X86_64_PC64 relocation for dynamic symbol %s", ldr.SymName(targ)) |
| } |
| if targType == 0 || targType == sym.SXREF { |
| ldr.Errorf(s, "unknown symbol %s in pcrel", ldr.SymName(targ)) |
| } |
| su := ldr.MakeSymbolUpdater(s) |
| su.SetRelocType(rIdx, objabi.R_PCREL) |
| su.SetRelocAdd(rIdx, r.Add()+8) |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_PLT32): |
| su := ldr.MakeSymbolUpdater(s) |
| su.SetRelocType(rIdx, objabi.R_PCREL) |
| su.SetRelocAdd(rIdx, r.Add()+4) |
| if targType == sym.SDYNIMPORT { |
| addpltsym(target, ldr, syms, targ) |
| su.SetRelocSym(rIdx, syms.PLT) |
| su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymPlt(targ))) |
| } |
| |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_GOTPCREL), |
| objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_GOTPCRELX), |
| objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_REX_GOTPCRELX): |
| su := ldr.MakeSymbolUpdater(s) |
| if targType != sym.SDYNIMPORT { |
| // have symbol |
| sData := ldr.Data(s) |
| if r.Off() >= 2 && sData[r.Off()-2] == 0x8b { |
| su.MakeWritable() |
| // turn MOVQ of GOT entry into LEAQ of symbol itself |
| writeableData := su.Data() |
| writeableData[r.Off()-2] = 0x8d |
| su.SetRelocType(rIdx, objabi.R_PCREL) |
| su.SetRelocAdd(rIdx, r.Add()+4) |
| return true |
| } |
| } |
| |
| // fall back to using GOT and hope for the best (CMOV*) |
| // TODO: just needs relocation, no need to put in .dynsym |
| ld.AddGotSym(target, ldr, syms, targ, uint32(elf.R_X86_64_GLOB_DAT)) |
| |
| su.SetRelocType(rIdx, objabi.R_PCREL) |
| su.SetRelocSym(rIdx, syms.GOT) |
| su.SetRelocAdd(rIdx, r.Add()+4+int64(ldr.SymGot(targ))) |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_64): |
| if targType == sym.SDYNIMPORT { |
| ldr.Errorf(s, "unexpected R_X86_64_64 relocation for dynamic symbol %s", ldr.SymName(targ)) |
| } |
| su := ldr.MakeSymbolUpdater(s) |
| su.SetRelocType(rIdx, objabi.R_ADDR) |
| if target.IsPIE() && target.IsInternal() { |
| // For internal linking PIE, this R_ADDR relocation cannot |
| // be resolved statically. We need to generate a dynamic |
| // relocation. Let the code below handle it. |
| break |
| } |
| return true |
| |
| // Handle relocations found in Mach-O object files. |
| case objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_UNSIGNED*2 + 0, |
| objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_SIGNED*2 + 0, |
| objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_BRANCH*2 + 0: |
| su := ldr.MakeSymbolUpdater(s) |
| su.SetRelocType(rIdx, objabi.R_ADDR) |
| |
| if targType == sym.SDYNIMPORT { |
| ldr.Errorf(s, "unexpected reloc for dynamic symbol %s", ldr.SymName(targ)) |
| } |
| if target.IsPIE() && target.IsInternal() { |
| // For internal linking PIE, this R_ADDR relocation cannot |
| // be resolved statically. We need to generate a dynamic |
| // relocation. Let the code below handle it. |
| if rt == objabi.MachoRelocOffset+ld.MACHO_X86_64_RELOC_UNSIGNED*2 { |
| break |
| } else { |
| // MACHO_X86_64_RELOC_SIGNED or MACHO_X86_64_RELOC_BRANCH |
| // Can this happen? The object is expected to be PIC. |
| ldr.Errorf(s, "unsupported relocation for PIE: %v", rt) |
| } |
| } |
| return true |
| |
| case objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_BRANCH*2 + 1: |
| if targType == sym.SDYNIMPORT { |
| addpltsym(target, ldr, syms, targ) |
| su := ldr.MakeSymbolUpdater(s) |
| su.SetRelocSym(rIdx, syms.PLT) |
| su.SetRelocType(rIdx, objabi.R_PCREL) |
| su.SetRelocAdd(rIdx, int64(ldr.SymPlt(targ))) |
| return true |
| } |
| fallthrough |
| |
| case objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_UNSIGNED*2 + 1, |
| objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_SIGNED*2 + 1, |
| objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_SIGNED_1*2 + 1, |
| objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_SIGNED_2*2 + 1, |
| objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_SIGNED_4*2 + 1: |
| su := ldr.MakeSymbolUpdater(s) |
| su.SetRelocType(rIdx, objabi.R_PCREL) |
| |
| if targType == sym.SDYNIMPORT { |
| ldr.Errorf(s, "unexpected pc-relative reloc for dynamic symbol %s", ldr.SymName(targ)) |
| } |
| return true |
| |
| case objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_GOT_LOAD*2 + 1: |
| if targType != sym.SDYNIMPORT { |
| // have symbol |
| // turn MOVQ of GOT entry into LEAQ of symbol itself |
| sdata := ldr.Data(s) |
| if r.Off() < 2 || sdata[r.Off()-2] != 0x8b { |
| ldr.Errorf(s, "unexpected GOT_LOAD reloc for non-dynamic symbol %s", ldr.SymName(targ)) |
| return false |
| } |
| |
| su := ldr.MakeSymbolUpdater(s) |
| su.MakeWritable() |
| sdata = su.Data() |
| sdata[r.Off()-2] = 0x8d |
| su.SetRelocType(rIdx, objabi.R_PCREL) |
| return true |
| } |
| fallthrough |
| |
| case objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_GOT*2 + 1: |
| if targType != sym.SDYNIMPORT { |
| ldr.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", ldr.SymName(targ)) |
| } |
| ld.AddGotSym(target, ldr, syms, targ, 0) |
| su := ldr.MakeSymbolUpdater(s) |
| su.SetRelocType(rIdx, objabi.R_PCREL) |
| su.SetRelocSym(rIdx, syms.GOT) |
| su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymGot(targ))) |
| return true |
| } |
| |
| // Reread the reloc to incorporate any changes in type above. |
| relocs := ldr.Relocs(s) |
| r = relocs.At(rIdx) |
| |
| switch r.Type() { |
| case objabi.R_CALL, |
| objabi.R_PCREL: |
| if targType != sym.SDYNIMPORT { |
| // nothing to do, the relocation will be laid out in reloc |
| return true |
| } |
| if target.IsExternal() { |
| // External linker will do this relocation. |
| return true |
| } |
| // Internal linking, for both ELF and Mach-O. |
| // Build a PLT entry and change the relocation target to that entry. |
| addpltsym(target, ldr, syms, targ) |
| su := ldr.MakeSymbolUpdater(s) |
| su.SetRelocSym(rIdx, syms.PLT) |
| su.SetRelocAdd(rIdx, int64(ldr.SymPlt(targ))) |
| return true |
| |
| case objabi.R_ADDR: |
| if ldr.SymType(s) == sym.STEXT && target.IsElf() { |
| su := ldr.MakeSymbolUpdater(s) |
| if target.IsSolaris() { |
| addpltsym(target, ldr, syms, targ) |
| su.SetRelocSym(rIdx, syms.PLT) |
| su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymPlt(targ))) |
| return true |
| } |
| // The code is asking for the address of an external |
| // function. We provide it with the address of the |
| // correspondent GOT symbol. |
| ld.AddGotSym(target, ldr, syms, targ, uint32(elf.R_X86_64_GLOB_DAT)) |
| |
| su.SetRelocSym(rIdx, syms.GOT) |
| su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymGot(targ))) |
| return true |
| } |
| |
| // Process dynamic relocations for the data sections. |
| if target.IsPIE() && target.IsInternal() { |
| // When internally linking, generate dynamic relocations |
| // for all typical R_ADDR relocations. The exception |
| // are those R_ADDR that are created as part of generating |
| // the dynamic relocations and must be resolved statically. |
| // |
| // There are three phases relevant to understanding this: |
| // |
| // dodata() // we are here |
| // address() // symbol address assignment |
| // reloc() // resolution of static R_ADDR relocs |
| // |
| // At this point symbol addresses have not been |
| // assigned yet (as the final size of the .rela section |
| // will affect the addresses), and so we cannot write |
| // the Elf64_Rela.r_offset now. Instead we delay it |
| // until after the 'address' phase of the linker is |
| // complete. We do this via Addaddrplus, which creates |
| // a new R_ADDR relocation which will be resolved in |
| // the 'reloc' phase. |
| // |
| // These synthetic static R_ADDR relocs must be skipped |
| // now, or else we will be caught in an infinite loop |
| // of generating synthetic relocs for our synthetic |
| // relocs. |
| // |
| // Furthermore, the rela sections contain dynamic |
| // relocations with R_ADDR relocations on |
| // Elf64_Rela.r_offset. This field should contain the |
| // symbol offset as determined by reloc(), not the |
| // final dynamically linked address as a dynamic |
| // relocation would provide. |
| switch ldr.SymName(s) { |
| case ".dynsym", ".rela", ".rela.plt", ".got.plt", ".dynamic": |
| return false |
| } |
| } else { |
| // Either internally linking a static executable, |
| // in which case we can resolve these relocations |
| // statically in the 'reloc' phase, or externally |
| // linking, in which case the relocation will be |
| // prepared in the 'reloc' phase and passed to the |
| // external linker in the 'asmb' phase. |
| if ldr.SymType(s) != sym.SDATA && ldr.SymType(s) != sym.SRODATA { |
| break |
| } |
| } |
| |
| if target.IsElf() { |
| // Generate R_X86_64_RELATIVE relocations for best |
| // efficiency in the dynamic linker. |
| // |
| // As noted above, symbol addresses have not been |
| // assigned yet, so we can't generate the final reloc |
| // entry yet. We ultimately want: |
| // |
| // r_offset = s + r.Off |
| // r_info = R_X86_64_RELATIVE |
| // r_addend = targ + r.Add |
| // |
| // The dynamic linker will set *offset = base address + |
| // addend. |
| // |
| // AddAddrPlus is used for r_offset and r_addend to |
| // generate new R_ADDR relocations that will update |
| // these fields in the 'reloc' phase. |
| rela := ldr.MakeSymbolUpdater(syms.Rela) |
| rela.AddAddrPlus(target.Arch, s, int64(r.Off())) |
| if r.Siz() == 8 { |
| rela.AddUint64(target.Arch, elf.R_INFO(0, uint32(elf.R_X86_64_RELATIVE))) |
| } else { |
| ldr.Errorf(s, "unexpected relocation for dynamic symbol %s", ldr.SymName(targ)) |
| } |
| rela.AddAddrPlus(target.Arch, targ, int64(r.Add())) |
| // Not mark r done here. So we still apply it statically, |
| // so in the file content we'll also have the right offset |
| // to the relocation target. So it can be examined statically |
| // (e.g. go version). |
| return true |
| } |
| |
| if target.IsDarwin() { |
| // Mach-O relocations are a royal pain to lay out. |
| // They use a compact stateful bytecode representation. |
| // Here we record what are needed and encode them later. |
| ld.MachoAddRebase(s, int64(r.Off())) |
| // Not mark r done here. So we still apply it statically, |
| // so in the file content we'll also have the right offset |
| // to the relocation target. So it can be examined statically |
| // (e.g. go version). |
| return true |
| } |
| } |
| |
| return false |
| } |
| |
| func elfreloc1(ctxt *ld.Link, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym, r loader.ExtReloc, ri int, sectoff int64) bool { |
| out.Write64(uint64(sectoff)) |
| |
| elfsym := ld.ElfSymForReloc(ctxt, r.Xsym) |
| siz := r.Size |
| switch r.Type { |
| default: |
| return false |
| case objabi.R_ADDR, objabi.R_DWARFSECREF: |
| if siz == 4 { |
| out.Write64(uint64(elf.R_X86_64_32) | uint64(elfsym)<<32) |
| } else if siz == 8 { |
| out.Write64(uint64(elf.R_X86_64_64) | uint64(elfsym)<<32) |
| } else { |
| return false |
| } |
| case objabi.R_TLS_LE: |
| if siz == 4 { |
| out.Write64(uint64(elf.R_X86_64_TPOFF32) | uint64(elfsym)<<32) |
| } else { |
| return false |
| } |
| case objabi.R_TLS_IE: |
| if siz == 4 { |
| out.Write64(uint64(elf.R_X86_64_GOTTPOFF) | uint64(elfsym)<<32) |
| } else { |
| return false |
| } |
| case objabi.R_CALL: |
| if siz == 4 { |
| if ldr.SymType(r.Xsym) == sym.SDYNIMPORT { |
| out.Write64(uint64(elf.R_X86_64_PLT32) | uint64(elfsym)<<32) |
| } else { |
| out.Write64(uint64(elf.R_X86_64_PC32) | uint64(elfsym)<<32) |
| } |
| } else { |
| return false |
| } |
| case objabi.R_PCREL: |
| if siz == 4 { |
| if ldr.SymType(r.Xsym) == sym.SDYNIMPORT && ldr.SymElfType(r.Xsym) == elf.STT_FUNC { |
| out.Write64(uint64(elf.R_X86_64_PLT32) | uint64(elfsym)<<32) |
| } else { |
| out.Write64(uint64(elf.R_X86_64_PC32) | uint64(elfsym)<<32) |
| } |
| } else { |
| return false |
| } |
| case objabi.R_GOTPCREL: |
| if siz == 4 { |
| out.Write64(uint64(elf.R_X86_64_GOTPCREL) | uint64(elfsym)<<32) |
| } else { |
| return false |
| } |
| } |
| |
| out.Write64(uint64(r.Xadd)) |
| return true |
| } |
| |
| func machoreloc1(arch *sys.Arch, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym, r loader.ExtReloc, sectoff int64) bool { |
| var v uint32 |
| |
| rs := r.Xsym |
| rt := r.Type |
| |
| if ldr.SymType(rs) == sym.SHOSTOBJ || rt == objabi.R_PCREL || rt == objabi.R_GOTPCREL || rt == objabi.R_CALL { |
| if ldr.SymDynid(rs) < 0 { |
| ldr.Errorf(s, "reloc %d (%s) to non-macho symbol %s type=%d (%s)", rt, sym.RelocName(arch, rt), ldr.SymName(rs), ldr.SymType(rs), ldr.SymType(rs)) |
| return false |
| } |
| |
| v = uint32(ldr.SymDynid(rs)) |
| v |= 1 << 27 // external relocation |
| } else { |
| v = uint32(ldr.SymSect(rs).Extnum) |
| if v == 0 { |
| ldr.Errorf(s, "reloc %d (%s) to symbol %s in non-macho section %s type=%d (%s)", rt, sym.RelocName(arch, rt), ldr.SymName(rs), ldr.SymSect(rs).Name, ldr.SymType(rs), ldr.SymType(rs)) |
| return false |
| } |
| } |
| |
| switch rt { |
| default: |
| return false |
| |
| case objabi.R_ADDR: |
| v |= ld.MACHO_X86_64_RELOC_UNSIGNED << 28 |
| |
| case objabi.R_CALL: |
| v |= 1 << 24 // pc-relative bit |
| v |= ld.MACHO_X86_64_RELOC_BRANCH << 28 |
| |
| // NOTE: Only works with 'external' relocation. Forced above. |
| case objabi.R_PCREL: |
| v |= 1 << 24 // pc-relative bit |
| v |= ld.MACHO_X86_64_RELOC_SIGNED << 28 |
| case objabi.R_GOTPCREL: |
| v |= 1 << 24 // pc-relative bit |
| v |= ld.MACHO_X86_64_RELOC_GOT_LOAD << 28 |
| } |
| |
| switch r.Size { |
| default: |
| return false |
| |
| case 1: |
| v |= 0 << 25 |
| |
| case 2: |
| v |= 1 << 25 |
| |
| case 4: |
| v |= 2 << 25 |
| |
| case 8: |
| v |= 3 << 25 |
| } |
| |
| out.Write32(uint32(sectoff)) |
| out.Write32(v) |
| return true |
| } |
| |
| func pereloc1(arch *sys.Arch, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym, r loader.ExtReloc, sectoff int64) bool { |
| var v uint32 |
| |
| rs := r.Xsym |
| rt := r.Type |
| |
| if ldr.SymDynid(rs) < 0 { |
| ldr.Errorf(s, "reloc %d (%s) to non-coff symbol %s type=%d (%s)", rt, sym.RelocName(arch, rt), ldr.SymName(rs), ldr.SymType(rs), ldr.SymType(rs)) |
| return false |
| } |
| |
| out.Write32(uint32(sectoff)) |
| out.Write32(uint32(ldr.SymDynid(rs))) |
| |
| switch rt { |
| default: |
| return false |
| |
| case objabi.R_DWARFSECREF: |
| v = ld.IMAGE_REL_AMD64_SECREL |
| |
| case objabi.R_ADDR: |
| if r.Size == 8 { |
| v = ld.IMAGE_REL_AMD64_ADDR64 |
| } else { |
| v = ld.IMAGE_REL_AMD64_ADDR32 |
| } |
| |
| case objabi.R_CALL, |
| objabi.R_PCREL: |
| v = ld.IMAGE_REL_AMD64_REL32 |
| } |
| |
| out.Write16(uint16(v)) |
| |
| return true |
| } |
| |
| func archreloc(*ld.Target, *loader.Loader, *ld.ArchSyms, loader.Reloc, loader.Sym, int64) (int64, int, bool) { |
| return -1, 0, false |
| } |
| |
| func archrelocvariant(*ld.Target, *loader.Loader, loader.Reloc, sym.RelocVariant, loader.Sym, int64) int64 { |
| log.Fatalf("unexpected relocation variant") |
| return -1 |
| } |
| |
| func elfsetupplt(ctxt *ld.Link, plt, got *loader.SymbolBuilder, dynamic loader.Sym) { |
| if plt.Size() == 0 { |
| // pushq got+8(IP) |
| plt.AddUint8(0xff) |
| |
| plt.AddUint8(0x35) |
| plt.AddPCRelPlus(ctxt.Arch, got.Sym(), 8) |
| |
| // jmpq got+16(IP) |
| plt.AddUint8(0xff) |
| |
| plt.AddUint8(0x25) |
| plt.AddPCRelPlus(ctxt.Arch, got.Sym(), 16) |
| |
| // nopl 0(AX) |
| plt.AddUint32(ctxt.Arch, 0x00401f0f) |
| |
| // assume got->size == 0 too |
| got.AddAddrPlus(ctxt.Arch, dynamic, 0) |
| |
| got.AddUint64(ctxt.Arch, 0) |
| got.AddUint64(ctxt.Arch, 0) |
| } |
| } |
| |
| func addpltsym(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym) { |
| if ldr.SymPlt(s) >= 0 { |
| return |
| } |
| |
| ld.Adddynsym(ldr, target, syms, s) |
| |
| if target.IsElf() { |
| plt := ldr.MakeSymbolUpdater(syms.PLT) |
| got := ldr.MakeSymbolUpdater(syms.GOTPLT) |
| rela := ldr.MakeSymbolUpdater(syms.RelaPLT) |
| if plt.Size() == 0 { |
| panic("plt is not set up") |
| } |
| |
| // jmpq *got+size(IP) |
| plt.AddUint8(0xff) |
| |
| plt.AddUint8(0x25) |
| plt.AddPCRelPlus(target.Arch, got.Sym(), got.Size()) |
| |
| // add to got: pointer to current pos in plt |
| got.AddAddrPlus(target.Arch, plt.Sym(), plt.Size()) |
| |
| // pushq $x |
| plt.AddUint8(0x68) |
| |
| plt.AddUint32(target.Arch, uint32((got.Size()-24-8)/8)) |
| |
| // jmpq .plt |
| plt.AddUint8(0xe9) |
| |
| plt.AddUint32(target.Arch, uint32(-(plt.Size() + 4))) |
| |
| // rela |
| rela.AddAddrPlus(target.Arch, got.Sym(), got.Size()-8) |
| |
| sDynid := ldr.SymDynid(s) |
| rela.AddUint64(target.Arch, elf.R_INFO(uint32(sDynid), uint32(elf.R_X86_64_JMP_SLOT))) |
| rela.AddUint64(target.Arch, 0) |
| |
| ldr.SetPlt(s, int32(plt.Size()-16)) |
| } else if target.IsDarwin() { |
| ld.AddGotSym(target, ldr, syms, s, 0) |
| |
| sDynid := ldr.SymDynid(s) |
| lep := ldr.MakeSymbolUpdater(syms.LinkEditPLT) |
| lep.AddUint32(target.Arch, uint32(sDynid)) |
| |
| plt := ldr.MakeSymbolUpdater(syms.PLT) |
| ldr.SetPlt(s, int32(plt.Size())) |
| |
| // jmpq *got+size(IP) |
| plt.AddUint8(0xff) |
| plt.AddUint8(0x25) |
| plt.AddPCRelPlus(target.Arch, syms.GOT, int64(ldr.SymGot(s))) |
| } else { |
| ldr.Errorf(s, "addpltsym: unsupported binary format") |
| } |
| } |
| |
| func tlsIEtoLE(P []byte, off, size int) { |
| // Transform the PC-relative instruction into a constant load. |
| // That is, |
| // |
| // MOVQ X(IP), REG -> MOVQ $Y, REG |
| // |
| // To determine the instruction and register, we study the op codes. |
| // Consult an AMD64 instruction encoding guide to decipher this. |
| if off < 3 { |
| log.Fatal("R_X86_64_GOTTPOFF reloc not preceded by MOVQ or ADDQ instruction") |
| } |
| op := P[off-3 : off] |
| reg := op[2] >> 3 |
| |
| if op[1] == 0x8b || reg == 4 { |
| // MOVQ |
| if op[0] == 0x4c { |
| op[0] = 0x49 |
| } else if size == 4 && op[0] == 0x44 { |
| op[0] = 0x41 |
| } |
| if op[1] == 0x8b { |
| op[1] = 0xc7 |
| } else { |
| op[1] = 0x81 // special case for SP |
| } |
| op[2] = 0xc0 | reg |
| } else { |
| // An alternate op is ADDQ. This is handled by GNU gold, |
| // but right now is not generated by the Go compiler: |
| // ADDQ X(IP), REG -> ADDQ $Y, REG |
| // Consider adding support for it here. |
| log.Fatalf("expected TLS IE op to be MOVQ, got %v", op) |
| } |
| } |