| // Inferno utils/5l/asm.c |
| // https://bitbucket.org/inferno-os/inferno-os/src/default/utils/5l/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 ppc64 |
| |
| import ( |
| "cmd/internal/objabi" |
| "cmd/internal/sys" |
| "cmd/link/internal/ld" |
| "cmd/link/internal/sym" |
| "debug/elf" |
| "encoding/binary" |
| "fmt" |
| "log" |
| ) |
| |
| func genplt(ctxt *ld.Link) { |
| // 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. |
| var stubs []*sym.Symbol |
| for _, s := range ctxt.Textp { |
| for i := range s.R { |
| r := &s.R[i] |
| if r.Type != 256+objabi.RelocType(elf.R_PPC64_REL24) || r.Sym.Type != sym.SDYNIMPORT { |
| continue |
| } |
| |
| // Reserve PLT entry and generate symbol |
| // resolver |
| addpltsym(ctxt, r.Sym) |
| |
| // Generate call stub |
| n := fmt.Sprintf("%s.%s", s.Name, r.Sym.Name) |
| |
| stub := ctxt.Syms.Lookup(n, 0) |
| if s.Attr.Reachable() { |
| stub.Attr |= sym.AttrReachable |
| } |
| if stub.Size == 0 { |
| // Need outer to resolve .TOC. |
| stub.Outer = s |
| stubs = append(stubs, stub) |
| gencallstub(ctxt, 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. |
| const o1 = 0xe8410018 // ld r2,24(r1) |
| ctxt.Arch.ByteOrder.PutUint32(s.P[r.Off+4:], o1) |
| } |
| } |
| // Put call stubs at the beginning (instead of the end). |
| // So when resolving the relocations to calls to the stubs, |
| // the addresses are known and trampolines can be inserted |
| // when necessary. |
| ctxt.Textp = append(stubs, ctxt.Textp...) |
| } |
| |
| func genaddmoduledata(ctxt *ld.Link) { |
| addmoduledata := ctxt.Syms.ROLookup("runtime.addmoduledata", sym.SymVerABI0) |
| if addmoduledata.Type == sym.STEXT && ctxt.BuildMode != ld.BuildModePlugin { |
| return |
| } |
| addmoduledata.Attr |= sym.AttrReachable |
| initfunc := ctxt.Syms.Lookup("go.link.addmoduledata", 0) |
| initfunc.Type = sym.STEXT |
| initfunc.Attr |= sym.AttrLocal |
| initfunc.Attr |= sym.AttrReachable |
| o := func(op uint32) { |
| initfunc.AddUint32(ctxt.Arch, op) |
| } |
| // addis r2, r12, .TOC.-func@ha |
| rel := initfunc.AddRel() |
| rel.Off = int32(initfunc.Size) |
| rel.Siz = 8 |
| rel.Sym = ctxt.Syms.Lookup(".TOC.", 0) |
| rel.Sym.Attr |= sym.AttrReachable |
| rel.Type = objabi.R_ADDRPOWER_PCREL |
| o(0x3c4c0000) |
| // addi r2, r2, .TOC.-func@l |
| o(0x38420000) |
| // mflr r31 |
| o(0x7c0802a6) |
| // stdu r31, -32(r1) |
| o(0xf801ffe1) |
| // addis r3, r2, local.moduledata@got@ha |
| rel = initfunc.AddRel() |
| rel.Off = int32(initfunc.Size) |
| rel.Siz = 8 |
| if s := ctxt.Syms.ROLookup("local.moduledata", 0); s != nil { |
| rel.Sym = s |
| } else if s := ctxt.Syms.ROLookup("local.pluginmoduledata", 0); s != nil { |
| rel.Sym = s |
| } else { |
| rel.Sym = ctxt.Syms.Lookup("runtime.firstmoduledata", 0) |
| } |
| rel.Sym.Attr |= sym.AttrReachable |
| rel.Sym.Attr |= sym.AttrLocal |
| rel.Type = objabi.R_ADDRPOWER_GOT |
| o(0x3c620000) |
| // ld r3, local.moduledata@got@l(r3) |
| o(0xe8630000) |
| // bl runtime.addmoduledata |
| rel = initfunc.AddRel() |
| rel.Off = int32(initfunc.Size) |
| rel.Siz = 4 |
| rel.Sym = addmoduledata |
| rel.Type = objabi.R_CALLPOWER |
| o(0x48000001) |
| // nop |
| o(0x60000000) |
| // ld r31, 0(r1) |
| o(0xe8010000) |
| // mtlr r31 |
| o(0x7c0803a6) |
| // addi r1,r1,32 |
| o(0x38210020) |
| // blr |
| o(0x4e800020) |
| |
| if ctxt.BuildMode == ld.BuildModePlugin { |
| ctxt.Textp = append(ctxt.Textp, addmoduledata) |
| } |
| initarray_entry := ctxt.Syms.Lookup("go.link.addmoduledatainit", 0) |
| ctxt.Textp = append(ctxt.Textp, initfunc) |
| initarray_entry.Attr |= sym.AttrReachable |
| initarray_entry.Attr |= sym.AttrLocal |
| initarray_entry.Type = sym.SINITARR |
| initarray_entry.AddAddr(ctxt.Arch, initfunc) |
| } |
| |
| func gentext(ctxt *ld.Link) { |
| if ctxt.DynlinkingGo() { |
| genaddmoduledata(ctxt) |
| } |
| |
| if ctxt.LinkMode == ld.LinkInternal { |
| genplt(ctxt) |
| } |
| } |
| |
| // Construct a call stub in stub that calls symbol targ via its PLT |
| // entry. |
| func gencallstub(ctxt *ld.Link, abicase int, stub *sym.Symbol, targ *sym.Symbol) { |
| 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 := ctxt.Syms.Lookup(".plt", 0) |
| |
| stub.Type = sym.STEXT |
| |
| // Save TOC pointer in TOC save slot |
| stub.AddUint32(ctxt.Arch, 0xf8410018) // std r2,24(r1) |
| |
| // Load the function pointer from the PLT. |
| r := stub.AddRel() |
| |
| r.Off = int32(stub.Size) |
| r.Sym = plt |
| r.Add = int64(targ.Plt()) |
| r.Siz = 2 |
| if ctxt.Arch.ByteOrder == binary.BigEndian { |
| r.Off += int32(r.Siz) |
| } |
| r.Type = objabi.R_POWER_TOC |
| r.Variant = sym.RV_POWER_HA |
| stub.AddUint32(ctxt.Arch, 0x3d820000) // addis r12,r2,targ@plt@toc@ha |
| r = stub.AddRel() |
| r.Off = int32(stub.Size) |
| r.Sym = plt |
| r.Add = int64(targ.Plt()) |
| r.Siz = 2 |
| if ctxt.Arch.ByteOrder == binary.BigEndian { |
| r.Off += int32(r.Siz) |
| } |
| r.Type = objabi.R_POWER_TOC |
| r.Variant = sym.RV_POWER_LO |
| stub.AddUint32(ctxt.Arch, 0xe98c0000) // ld r12,targ@plt@toc@l(r12) |
| |
| // Jump to the loaded pointer |
| stub.AddUint32(ctxt.Arch, 0x7d8903a6) // mtctr r12 |
| stub.AddUint32(ctxt.Arch, 0x4e800420) // bctr |
| } |
| |
| func adddynrel(ctxt *ld.Link, s *sym.Symbol, r *sym.Reloc) bool { |
| if ctxt.IsELF { |
| return addelfdynrel(ctxt, s, r) |
| } else if ctxt.HeadType == objabi.Haix { |
| return ld.Xcoffadddynrel(ctxt, s, r) |
| } |
| return false |
| } |
| func addelfdynrel(ctxt *ld.Link, s *sym.Symbol, r *sym.Reloc) bool { |
| targ := r.Sym |
| |
| switch r.Type { |
| default: |
| if r.Type >= 256 { |
| ld.Errorf(s, "unexpected relocation type %d (%s)", r.Type, sym.RelocName(ctxt.Arch, r.Type)) |
| return false |
| } |
| |
| // Handle relocations found in ELF object files. |
| case 256 + objabi.RelocType(elf.R_PPC64_REL24): |
| r.Type = objabi.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 == sym.SDYNIMPORT { |
| // Should have been handled in elfsetupplt |
| ld.Errorf(s, "unexpected R_PPC64_REL24 for dyn import") |
| } |
| |
| return true |
| |
| case 256 + objabi.RelocType(elf.R_PPC_REL32): |
| r.Type = objabi.R_PCREL |
| r.Add += 4 |
| |
| if targ.Type == sym.SDYNIMPORT { |
| ld.Errorf(s, "unexpected R_PPC_REL32 for dyn import") |
| } |
| |
| return true |
| |
| case 256 + objabi.RelocType(elf.R_PPC64_ADDR64): |
| r.Type = objabi.R_ADDR |
| if targ.Type == sym.SDYNIMPORT { |
| // These happen in .toc sections |
| ld.Adddynsym(ctxt, targ) |
| |
| rela := ctxt.Syms.Lookup(".rela", 0) |
| rela.AddAddrPlus(ctxt.Arch, s, int64(r.Off)) |
| rela.AddUint64(ctxt.Arch, ld.ELF64_R_INFO(uint32(targ.Dynid), uint32(elf.R_PPC64_ADDR64))) |
| rela.AddUint64(ctxt.Arch, uint64(r.Add)) |
| r.Type = 256 // ignore during relocsym |
| } |
| |
| return true |
| |
| case 256 + objabi.RelocType(elf.R_PPC64_TOC16): |
| r.Type = objabi.R_POWER_TOC |
| r.Variant = sym.RV_POWER_LO | sym.RV_CHECK_OVERFLOW |
| return true |
| |
| case 256 + objabi.RelocType(elf.R_PPC64_TOC16_LO): |
| r.Type = objabi.R_POWER_TOC |
| r.Variant = sym.RV_POWER_LO |
| return true |
| |
| case 256 + objabi.RelocType(elf.R_PPC64_TOC16_HA): |
| r.Type = objabi.R_POWER_TOC |
| r.Variant = sym.RV_POWER_HA | sym.RV_CHECK_OVERFLOW |
| return true |
| |
| case 256 + objabi.RelocType(elf.R_PPC64_TOC16_HI): |
| r.Type = objabi.R_POWER_TOC |
| r.Variant = sym.RV_POWER_HI | sym.RV_CHECK_OVERFLOW |
| return true |
| |
| case 256 + objabi.RelocType(elf.R_PPC64_TOC16_DS): |
| r.Type = objabi.R_POWER_TOC |
| r.Variant = sym.RV_POWER_DS | sym.RV_CHECK_OVERFLOW |
| return true |
| |
| case 256 + objabi.RelocType(elf.R_PPC64_TOC16_LO_DS): |
| r.Type = objabi.R_POWER_TOC |
| r.Variant = sym.RV_POWER_DS |
| return true |
| |
| case 256 + objabi.RelocType(elf.R_PPC64_REL16_LO): |
| r.Type = objabi.R_PCREL |
| r.Variant = sym.RV_POWER_LO |
| r.Add += 2 // Compensate for relocation size of 2 |
| return true |
| |
| case 256 + objabi.RelocType(elf.R_PPC64_REL16_HI): |
| r.Type = objabi.R_PCREL |
| r.Variant = sym.RV_POWER_HI | sym.RV_CHECK_OVERFLOW |
| r.Add += 2 |
| return true |
| |
| case 256 + objabi.RelocType(elf.R_PPC64_REL16_HA): |
| r.Type = objabi.R_PCREL |
| r.Variant = sym.RV_POWER_HA | sym.RV_CHECK_OVERFLOW |
| r.Add += 2 |
| return true |
| } |
| |
| // Handle references to ELF symbols from our own object files. |
| if targ.Type != sym.SDYNIMPORT { |
| return true |
| } |
| |
| // TODO(austin): Translate our relocations to ELF |
| |
| return false |
| } |
| |
| func elfreloc1(ctxt *ld.Link, r *sym.Reloc, sectoff int64) bool { |
| // Beware that bit0~bit15 start from the third byte of a instruction in Big-Endian machines. |
| if r.Type == objabi.R_ADDR || r.Type == objabi.R_POWER_TLS || r.Type == objabi.R_CALLPOWER { |
| } else { |
| if ctxt.Arch.ByteOrder == binary.BigEndian { |
| sectoff += 2 |
| } |
| } |
| ctxt.Out.Write64(uint64(sectoff)) |
| |
| elfsym := r.Xsym.ElfsymForReloc() |
| switch r.Type { |
| default: |
| return false |
| case objabi.R_ADDR: |
| switch r.Siz { |
| case 4: |
| ctxt.Out.Write64(uint64(elf.R_PPC64_ADDR32) | uint64(elfsym)<<32) |
| case 8: |
| ctxt.Out.Write64(uint64(elf.R_PPC64_ADDR64) | uint64(elfsym)<<32) |
| default: |
| return false |
| } |
| case objabi.R_POWER_TLS: |
| ctxt.Out.Write64(uint64(elf.R_PPC64_TLS) | uint64(elfsym)<<32) |
| case objabi.R_POWER_TLS_LE: |
| ctxt.Out.Write64(uint64(elf.R_PPC64_TPREL16) | uint64(elfsym)<<32) |
| case objabi.R_POWER_TLS_IE: |
| ctxt.Out.Write64(uint64(elf.R_PPC64_GOT_TPREL16_HA) | uint64(elfsym)<<32) |
| ctxt.Out.Write64(uint64(r.Xadd)) |
| ctxt.Out.Write64(uint64(sectoff + 4)) |
| ctxt.Out.Write64(uint64(elf.R_PPC64_GOT_TPREL16_LO_DS) | uint64(elfsym)<<32) |
| case objabi.R_ADDRPOWER: |
| ctxt.Out.Write64(uint64(elf.R_PPC64_ADDR16_HA) | uint64(elfsym)<<32) |
| ctxt.Out.Write64(uint64(r.Xadd)) |
| ctxt.Out.Write64(uint64(sectoff + 4)) |
| ctxt.Out.Write64(uint64(elf.R_PPC64_ADDR16_LO) | uint64(elfsym)<<32) |
| case objabi.R_ADDRPOWER_DS: |
| ctxt.Out.Write64(uint64(elf.R_PPC64_ADDR16_HA) | uint64(elfsym)<<32) |
| ctxt.Out.Write64(uint64(r.Xadd)) |
| ctxt.Out.Write64(uint64(sectoff + 4)) |
| ctxt.Out.Write64(uint64(elf.R_PPC64_ADDR16_LO_DS) | uint64(elfsym)<<32) |
| case objabi.R_ADDRPOWER_GOT: |
| ctxt.Out.Write64(uint64(elf.R_PPC64_GOT16_HA) | uint64(elfsym)<<32) |
| ctxt.Out.Write64(uint64(r.Xadd)) |
| ctxt.Out.Write64(uint64(sectoff + 4)) |
| ctxt.Out.Write64(uint64(elf.R_PPC64_GOT16_LO_DS) | uint64(elfsym)<<32) |
| case objabi.R_ADDRPOWER_PCREL: |
| ctxt.Out.Write64(uint64(elf.R_PPC64_REL16_HA) | uint64(elfsym)<<32) |
| ctxt.Out.Write64(uint64(r.Xadd)) |
| ctxt.Out.Write64(uint64(sectoff + 4)) |
| ctxt.Out.Write64(uint64(elf.R_PPC64_REL16_LO) | uint64(elfsym)<<32) |
| r.Xadd += 4 |
| case objabi.R_ADDRPOWER_TOCREL: |
| ctxt.Out.Write64(uint64(elf.R_PPC64_TOC16_HA) | uint64(elfsym)<<32) |
| ctxt.Out.Write64(uint64(r.Xadd)) |
| ctxt.Out.Write64(uint64(sectoff + 4)) |
| ctxt.Out.Write64(uint64(elf.R_PPC64_TOC16_LO) | uint64(elfsym)<<32) |
| case objabi.R_ADDRPOWER_TOCREL_DS: |
| ctxt.Out.Write64(uint64(elf.R_PPC64_TOC16_HA) | uint64(elfsym)<<32) |
| ctxt.Out.Write64(uint64(r.Xadd)) |
| ctxt.Out.Write64(uint64(sectoff + 4)) |
| ctxt.Out.Write64(uint64(elf.R_PPC64_TOC16_LO_DS) | uint64(elfsym)<<32) |
| case objabi.R_CALLPOWER: |
| if r.Siz != 4 { |
| return false |
| } |
| ctxt.Out.Write64(uint64(elf.R_PPC64_REL24) | uint64(elfsym)<<32) |
| |
| } |
| ctxt.Out.Write64(uint64(r.Xadd)) |
| |
| return true |
| } |
| |
| func elfsetupplt(ctxt *ld.Link) { |
| plt := ctxt.Syms.Lookup(".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 |
| } |
| } |
| |
| func machoreloc1(arch *sys.Arch, out *ld.OutBuf, s *sym.Symbol, r *sym.Reloc, sectoff int64) bool { |
| return false |
| } |
| |
| // Return the value of .TOC. for symbol s |
| func symtoc(ctxt *ld.Link, s *sym.Symbol) int64 { |
| var toc *sym.Symbol |
| |
| if s.Outer != nil { |
| toc = ctxt.Syms.ROLookup(".TOC.", int(s.Outer.Version)) |
| } else { |
| toc = ctxt.Syms.ROLookup(".TOC.", int(s.Version)) |
| } |
| |
| if toc == nil { |
| ld.Errorf(s, "TOC-relative relocation in object without .TOC.") |
| return 0 |
| } |
| |
| return toc.Value |
| } |
| |
| func archreloctoc(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, val int64) int64 { |
| var o1, o2 uint32 |
| |
| o1 = uint32(val >> 32) |
| o2 = uint32(val) |
| |
| t := ld.Symaddr(r.Sym) + r.Add - ctxt.Syms.ROLookup("TOC", 0).Value // sym addr |
| if t != int64(int32(t)) { |
| ld.Errorf(s, "TOC relocation for %s is too big to relocate %s: 0x%x", s.Name, r.Sym, t) |
| } |
| |
| if t&0x8000 != 0 { |
| t += 0x10000 |
| } |
| |
| o1 |= uint32((t >> 16) & 0xFFFF) |
| |
| switch r.Type { |
| case objabi.R_ADDRPOWER_TOCREL_DS: |
| if t&3 != 0 { |
| ld.Errorf(s, "bad DS reloc for %s: %d", s.Name, ld.Symaddr(r.Sym)) |
| } |
| o2 |= uint32(t) & 0xFFFC |
| default: |
| return -1 |
| } |
| |
| return int64(o1)<<32 | int64(o2) |
| } |
| |
| func archrelocaddr(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, val int64) int64 { |
| if ctxt.HeadType == objabi.Haix { |
| ld.Errorf(s, "archrelocaddr called for %s relocation\n", r.Sym.Name) |
| } |
| var o1, o2 uint32 |
| if ctxt.Arch.ByteOrder == binary.BigEndian { |
| o1 = uint32(val >> 32) |
| o2 = uint32(val) |
| } else { |
| o1 = uint32(val) |
| o2 = uint32(val >> 32) |
| } |
| |
| // We are spreading a 31-bit address across two instructions, putting the |
| // high (adjusted) part in the low 16 bits of the first instruction and the |
| // low part in the low 16 bits of the second instruction, or, in the DS case, |
| // bits 15-2 (inclusive) of the address into bits 15-2 of the second |
| // instruction (it is an error in this case if the low 2 bits of the address |
| // are non-zero). |
| |
| t := ld.Symaddr(r.Sym) + r.Add |
| if t < 0 || t >= 1<<31 { |
| ld.Errorf(s, "relocation for %s is too big (>=2G): 0x%x", s.Name, ld.Symaddr(r.Sym)) |
| } |
| if t&0x8000 != 0 { |
| t += 0x10000 |
| } |
| |
| switch r.Type { |
| case objabi.R_ADDRPOWER: |
| o1 |= (uint32(t) >> 16) & 0xffff |
| o2 |= uint32(t) & 0xffff |
| case objabi.R_ADDRPOWER_DS: |
| o1 |= (uint32(t) >> 16) & 0xffff |
| if t&3 != 0 { |
| ld.Errorf(s, "bad DS reloc for %s: %d", s.Name, ld.Symaddr(r.Sym)) |
| } |
| o2 |= uint32(t) & 0xfffc |
| default: |
| return -1 |
| } |
| |
| if ctxt.Arch.ByteOrder == binary.BigEndian { |
| return int64(o1)<<32 | int64(o2) |
| } |
| return int64(o2)<<32 | int64(o1) |
| } |
| |
| // resolve direct jump relocation r in s, and add trampoline if necessary |
| func trampoline(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol) { |
| |
| // Trampolines are created if the branch offset is too large and the linker cannot insert a call stub to handle it. |
| // For internal linking, trampolines are always created for long calls. |
| // For external linking, the linker can insert a call stub to handle a long call, but depends on having the TOC address in |
| // r2. For those build modes with external linking where the TOC address is not maintained in r2, trampolines must be created. |
| if ctxt.LinkMode == ld.LinkExternal && (ctxt.DynlinkingGo() || ctxt.BuildMode == ld.BuildModeCArchive || ctxt.BuildMode == ld.BuildModeCShared || ctxt.BuildMode == ld.BuildModePIE) { |
| // No trampolines needed since r2 contains the TOC |
| return |
| } |
| |
| t := ld.Symaddr(r.Sym) + r.Add - (s.Value + int64(r.Off)) |
| switch r.Type { |
| case objabi.R_CALLPOWER: |
| |
| // If branch offset is too far then create a trampoline. |
| |
| if (ctxt.LinkMode == ld.LinkExternal && s.Sect != r.Sym.Sect) || (ctxt.LinkMode == ld.LinkInternal && int64(int32(t<<6)>>6) != t) || (*ld.FlagDebugTramp > 1 && s.File != r.Sym.File) { |
| var tramp *sym.Symbol |
| for i := 0; ; i++ { |
| |
| // Using r.Add as part of the name is significant in functions like duffzero where the call |
| // target is at some offset within the function. Calls to duff+8 and duff+256 must appear as |
| // distinct trampolines. |
| |
| name := r.Sym.Name |
| if r.Add == 0 { |
| name = name + fmt.Sprintf("-tramp%d", i) |
| } else { |
| name = name + fmt.Sprintf("%+x-tramp%d", r.Add, i) |
| } |
| |
| // Look up the trampoline in case it already exists |
| |
| tramp = ctxt.Syms.Lookup(name, int(r.Sym.Version)) |
| if tramp.Value == 0 { |
| break |
| } |
| |
| t = ld.Symaddr(tramp) + r.Add - (s.Value + int64(r.Off)) |
| |
| // With internal linking, the trampoline can be used if it is not too far. |
| // With external linking, the trampoline must be in this section for it to be reused. |
| if (ctxt.LinkMode == ld.LinkInternal && int64(int32(t<<6)>>6) == t) || (ctxt.LinkMode == ld.LinkExternal && s.Sect == tramp.Sect) { |
| break |
| } |
| } |
| if tramp.Type == 0 { |
| if ctxt.DynlinkingGo() || ctxt.BuildMode == ld.BuildModeCArchive || ctxt.BuildMode == ld.BuildModeCShared || ctxt.BuildMode == ld.BuildModePIE { |
| // Should have returned for above cases |
| ld.Errorf(s, "unexpected trampoline for shared or dynamic linking\n") |
| } else { |
| ctxt.AddTramp(tramp) |
| gentramp(ctxt.Arch, ctxt.LinkMode, tramp, r.Sym, r.Add) |
| } |
| } |
| r.Sym = tramp |
| r.Add = 0 // This was folded into the trampoline target address |
| r.Done = false |
| } |
| default: |
| ld.Errorf(s, "trampoline called with non-jump reloc: %d (%s)", r.Type, sym.RelocName(ctxt.Arch, r.Type)) |
| } |
| } |
| |
| func gentramp(arch *sys.Arch, linkmode ld.LinkMode, tramp, target *sym.Symbol, offset int64) { |
| // Used for default build mode for an executable |
| // Address of the call target is generated using |
| // relocation and doesn't depend on r2 (TOC). |
| tramp.Size = 16 // 4 instructions |
| tramp.P = make([]byte, tramp.Size) |
| t := ld.Symaddr(target) + offset |
| o1 := uint32(0x3fe00000) // lis r31,targetaddr hi |
| o2 := uint32(0x3bff0000) // addi r31,targetaddr lo |
| // With external linking, the target address must be |
| // relocated using LO and HA |
| if linkmode == ld.LinkExternal { |
| tr := tramp.AddRel() |
| tr.Off = 0 |
| tr.Type = objabi.R_ADDRPOWER |
| tr.Siz = 8 // generates 2 relocations: HA + LO |
| tr.Sym = target |
| tr.Add = offset |
| } else { |
| // adjustment needed if lo has sign bit set |
| // when using addi to compute address |
| val := uint32((t & 0xffff0000) >> 16) |
| if t&0x8000 != 0 { |
| val += 1 |
| } |
| o1 |= val // hi part of addr |
| o2 |= uint32(t & 0xffff) // lo part of addr |
| } |
| o3 := uint32(0x7fe903a6) // mtctr r31 |
| o4 := uint32(0x4e800420) // bctr |
| arch.ByteOrder.PutUint32(tramp.P, o1) |
| arch.ByteOrder.PutUint32(tramp.P[4:], o2) |
| arch.ByteOrder.PutUint32(tramp.P[8:], o3) |
| arch.ByteOrder.PutUint32(tramp.P[12:], o4) |
| } |
| |
| func archreloc(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, val int64) (int64, bool) { |
| if ctxt.LinkMode == ld.LinkExternal { |
| switch r.Type { |
| default: |
| return val, false |
| case objabi.R_POWER_TLS, objabi.R_POWER_TLS_LE, objabi.R_POWER_TLS_IE: |
| r.Done = false |
| // check Outer is nil, Type is TLSBSS? |
| r.Xadd = r.Add |
| r.Xsym = r.Sym |
| return val, true |
| case objabi.R_ADDRPOWER, |
| objabi.R_ADDRPOWER_DS, |
| objabi.R_ADDRPOWER_TOCREL, |
| objabi.R_ADDRPOWER_TOCREL_DS, |
| objabi.R_ADDRPOWER_GOT, |
| objabi.R_ADDRPOWER_PCREL: |
| r.Done = false |
| |
| // 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 != sym.SHOSTOBJ && rs.Type != sym.SDYNIMPORT && rs.Sect == nil { |
| ld.Errorf(s, "missing section for %s", rs.Name) |
| } |
| r.Xsym = rs |
| |
| return val, true |
| case objabi.R_CALLPOWER: |
| r.Done = false |
| r.Xsym = r.Sym |
| r.Xadd = r.Add |
| return val, true |
| } |
| } |
| |
| switch r.Type { |
| case objabi.R_CONST: |
| return r.Add, true |
| case objabi.R_GOTOFF: |
| return ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ctxt.Syms.Lookup(".got", 0)), true |
| case objabi.R_ADDRPOWER_TOCREL, objabi.R_ADDRPOWER_TOCREL_DS: |
| return archreloctoc(ctxt, r, s, val), true |
| case objabi.R_ADDRPOWER, objabi.R_ADDRPOWER_DS: |
| return archrelocaddr(ctxt, r, s, val), true |
| case objabi.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.Errorf(s, "relocation for %s+%d is not aligned: %d", r.Sym.Name, r.Off, t) |
| } |
| // If branch offset is too far then create a trampoline. |
| |
| if int64(int32(t<<6)>>6) != t { |
| ld.Errorf(s, "direct call too far: %s %x", r.Sym.Name, t) |
| } |
| return val | int64(uint32(t)&^0xfc000003), true |
| case objabi.R_POWER_TOC: // S + A - .TOC. |
| return ld.Symaddr(r.Sym) + r.Add - symtoc(ctxt, s), true |
| |
| case objabi.R_POWER_TLS_LE: |
| // The thread pointer points 0x7000 bytes after the start of 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 ctxt.HeadType == objabi.Haix { |
| // On AIX, the thread pointer points 0x7800 bytes after |
| // the TLS. |
| v -= 0x800 |
| } |
| if int64(int16(v)) != v { |
| ld.Errorf(s, "TLS offset out of range %d", v) |
| } |
| return (val &^ 0xffff) | (v & 0xffff), true |
| } |
| |
| return val, false |
| } |
| |
| func archrelocvariant(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, t int64) int64 { |
| switch r.Variant & sym.RV_TYPE_MASK { |
| default: |
| ld.Errorf(s, "unexpected relocation variant %d", r.Variant) |
| fallthrough |
| |
| case sym.RV_NONE: |
| return t |
| |
| case sym.RV_POWER_LO: |
| if r.Variant&sym.RV_CHECK_OVERFLOW != 0 { |
| // Whether to check for signed or unsigned |
| // overflow depends on the instruction |
| var o1 uint32 |
| if ctxt.Arch.ByteOrder == binary.BigEndian { |
| o1 = binary.BigEndian.Uint32(s.P[r.Off-2:]) |
| } else { |
| o1 = binary.LittleEndian.Uint32(s.P[r.Off:]) |
| } |
| switch o1 >> 26 { |
| case 24, // ori |
| 26, // xori |
| 28: // andi |
| if t>>16 != 0 { |
| goto overflow |
| } |
| |
| default: |
| if int64(int16(t)) != t { |
| goto overflow |
| } |
| } |
| } |
| |
| return int64(int16(t)) |
| |
| case sym.RV_POWER_HA: |
| t += 0x8000 |
| fallthrough |
| |
| // Fallthrough |
| case sym.RV_POWER_HI: |
| t >>= 16 |
| |
| if r.Variant&sym.RV_CHECK_OVERFLOW != 0 { |
| // Whether to check for signed or unsigned |
| // overflow depends on the instruction |
| var o1 uint32 |
| if ctxt.Arch.ByteOrder == binary.BigEndian { |
| o1 = binary.BigEndian.Uint32(s.P[r.Off-2:]) |
| } else { |
| o1 = binary.LittleEndian.Uint32(s.P[r.Off:]) |
| } |
| switch o1 >> 26 { |
| case 25, // oris |
| 27, // xoris |
| 29: // andis |
| if t>>16 != 0 { |
| goto overflow |
| } |
| |
| default: |
| if int64(int16(t)) != t { |
| goto overflow |
| } |
| } |
| } |
| |
| return int64(int16(t)) |
| |
| case sym.RV_POWER_DS: |
| var o1 uint32 |
| if ctxt.Arch.ByteOrder == binary.BigEndian { |
| o1 = uint32(binary.BigEndian.Uint16(s.P[r.Off:])) |
| } else { |
| o1 = uint32(binary.LittleEndian.Uint16(s.P[r.Off:])) |
| } |
| if t&3 != 0 { |
| ld.Errorf(s, "relocation for %s+%d is not aligned: %d", r.Sym.Name, r.Off, t) |
| } |
| if (r.Variant&sym.RV_CHECK_OVERFLOW != 0) && int64(int16(t)) != t { |
| goto overflow |
| } |
| return int64(o1)&0x3 | int64(int16(t)) |
| } |
| |
| overflow: |
| ld.Errorf(s, "relocation for %s+%d is too big: %d", r.Sym.Name, r.Off, t) |
| return t |
| } |
| |
| func addpltsym(ctxt *ld.Link, s *sym.Symbol) { |
| if s.Plt() >= 0 { |
| return |
| } |
| |
| ld.Adddynsym(ctxt, s) |
| |
| if ctxt.IsELF { |
| plt := ctxt.Syms.Lookup(".plt", 0) |
| rela := ctxt.Syms.Lookup(".rela.plt", 0) |
| if plt.Size == 0 { |
| elfsetupplt(ctxt) |
| } |
| |
| // Create the glink resolver if necessary |
| glink := ensureglinkresolver(ctxt) |
| |
| // Write symbol resolver stub (just a branch to the |
| // glink resolver stub) |
| r := glink.AddRel() |
| |
| r.Sym = glink |
| r.Off = int32(glink.Size) |
| r.Siz = 4 |
| r.Type = objabi.R_CALLPOWER |
| glink.AddUint32(ctxt.Arch, 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.SetPlt(int32(plt.Size)) |
| |
| plt.Size += 8 |
| |
| rela.AddAddrPlus(ctxt.Arch, plt, int64(s.Plt())) |
| rela.AddUint64(ctxt.Arch, ld.ELF64_R_INFO(uint32(s.Dynid), uint32(elf.R_PPC64_JMP_SLOT))) |
| rela.AddUint64(ctxt.Arch, 0) |
| } else { |
| ld.Errorf(s, "addpltsym: unsupported binary format") |
| } |
| } |
| |
| // Generate the glink resolver stub if necessary and return the .glink section |
| func ensureglinkresolver(ctxt *ld.Link) *sym.Symbol { |
| glink := ctxt.Syms.Lookup(".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. |
| glink.AddUint32(ctxt.Arch, 0x7c0802a6) // mflr r0 |
| glink.AddUint32(ctxt.Arch, 0x429f0005) // bcl 20,31,1f |
| glink.AddUint32(ctxt.Arch, 0x7d6802a6) // 1: mflr r11 |
| glink.AddUint32(ctxt.Arch, 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 |
| glink.AddUint32(ctxt.Arch, 0x3800ffd0) // li r0,-(res_0-1b)=-48 |
| glink.AddUint32(ctxt.Arch, 0x7c006214) // add r0,r0,r12 |
| glink.AddUint32(ctxt.Arch, 0x7c0b0050) // sub r0,r0,r11 |
| glink.AddUint32(ctxt.Arch, 0x7800f082) // srdi r0,r0,2 |
| |
| // r11 = address of the first byte of the PLT |
| r := glink.AddRel() |
| |
| r.Off = int32(glink.Size) |
| r.Sym = ctxt.Syms.Lookup(".plt", 0) |
| r.Siz = 8 |
| r.Type = objabi.R_ADDRPOWER |
| |
| glink.AddUint32(ctxt.Arch, 0x3d600000) // addis r11,0,.plt@ha |
| glink.AddUint32(ctxt.Arch, 0x396b0000) // addi r11,r11,.plt@l |
| |
| // Load r12 = dynamic resolver address and r11 = DSO |
| // identifier from the first two doublewords of the PLT. |
| glink.AddUint32(ctxt.Arch, 0xe98b0000) // ld r12,0(r11) |
| glink.AddUint32(ctxt.Arch, 0xe96b0008) // ld r11,8(r11) |
| |
| // Jump to the dynamic resolver |
| glink.AddUint32(ctxt.Arch, 0x7d8903a6) // mtctr r12 |
| glink.AddUint32(ctxt.Arch, 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 := ctxt.Syms.Lookup(".dynamic", 0) |
| |
| ld.Elfwritedynentsymplus(ctxt, s, ld.DT_PPC64_GLINK, glink, glink.Size-32) |
| |
| return glink |
| } |
| |
| func asmb(ctxt *ld.Link) { |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("%5.2f asmb\n", ld.Cputime()) |
| } |
| |
| if ctxt.IsELF { |
| ld.Asmbelfsetup() |
| } |
| |
| for _, sect := range ld.Segtext.Sections { |
| ctxt.Out.SeekSet(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff)) |
| // Handle additional text sections with Codeblk |
| if sect.Name == ".text" { |
| ld.Codeblk(ctxt, int64(sect.Vaddr), int64(sect.Length)) |
| } else { |
| ld.Datblk(ctxt, int64(sect.Vaddr), int64(sect.Length)) |
| } |
| } |
| |
| if ld.Segrodata.Filelen > 0 { |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("%5.2f rodatblk\n", ld.Cputime()) |
| } |
| ctxt.Out.SeekSet(int64(ld.Segrodata.Fileoff)) |
| ld.Datblk(ctxt, int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen)) |
| } |
| if ld.Segrelrodata.Filelen > 0 { |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("%5.2f relrodatblk\n", ld.Cputime()) |
| } |
| ctxt.Out.SeekSet(int64(ld.Segrelrodata.Fileoff)) |
| ld.Datblk(ctxt, int64(ld.Segrelrodata.Vaddr), int64(ld.Segrelrodata.Filelen)) |
| } |
| |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("%5.2f datblk\n", ld.Cputime()) |
| } |
| |
| ctxt.Out.SeekSet(int64(ld.Segdata.Fileoff)) |
| ld.Datblk(ctxt, int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen)) |
| |
| ctxt.Out.SeekSet(int64(ld.Segdwarf.Fileoff)) |
| ld.Dwarfblk(ctxt, int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen)) |
| |
| /* output symbol table */ |
| ld.Symsize = 0 |
| |
| ld.Lcsize = 0 |
| symo := uint32(0) |
| if !*ld.FlagS { |
| // TODO: rationalize |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("%5.2f sym\n", ld.Cputime()) |
| } |
| switch ctxt.HeadType { |
| default: |
| if ctxt.IsELF { |
| symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen) |
| symo = uint32(ld.Rnd(int64(symo), int64(*ld.FlagRound))) |
| } |
| |
| case objabi.Hplan9: |
| symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen) |
| |
| case objabi.Haix: |
| // Nothing to do |
| } |
| |
| ctxt.Out.SeekSet(int64(symo)) |
| switch ctxt.HeadType { |
| default: |
| if ctxt.IsELF { |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("%5.2f elfsym\n", ld.Cputime()) |
| } |
| ld.Asmelfsym(ctxt) |
| ctxt.Out.Flush() |
| ctxt.Out.Write(ld.Elfstrdat) |
| |
| if ctxt.LinkMode == ld.LinkExternal { |
| ld.Elfemitreloc(ctxt) |
| } |
| } |
| |
| case objabi.Hplan9: |
| ld.Asmplan9sym(ctxt) |
| ctxt.Out.Flush() |
| |
| sym := ctxt.Syms.Lookup("pclntab", 0) |
| if sym != nil { |
| ld.Lcsize = int32(len(sym.P)) |
| ctxt.Out.Write(sym.P) |
| ctxt.Out.Flush() |
| } |
| |
| case objabi.Haix: |
| // symtab must be added once sections have been created in ld.Asmbxcoff |
| ctxt.Out.Flush() |
| } |
| } |
| |
| if ctxt.Debugvlog != 0 { |
| ctxt.Logf("%5.2f header\n", ld.Cputime()) |
| } |
| ctxt.Out.SeekSet(0) |
| switch ctxt.HeadType { |
| default: |
| case objabi.Hplan9: /* plan 9 */ |
| ctxt.Out.Write32(0x647) /* magic */ |
| ctxt.Out.Write32(uint32(ld.Segtext.Filelen)) /* sizes */ |
| ctxt.Out.Write32(uint32(ld.Segdata.Filelen)) |
| ctxt.Out.Write32(uint32(ld.Segdata.Length - ld.Segdata.Filelen)) |
| ctxt.Out.Write32(uint32(ld.Symsize)) /* nsyms */ |
| ctxt.Out.Write32(uint32(ld.Entryvalue(ctxt))) /* va of entry */ |
| ctxt.Out.Write32(0) |
| ctxt.Out.Write32(uint32(ld.Lcsize)) |
| |
| case objabi.Hlinux, |
| objabi.Hfreebsd, |
| objabi.Hnetbsd, |
| objabi.Hopenbsd, |
| objabi.Hnacl: |
| ld.Asmbelf(ctxt, int64(symo)) |
| |
| case objabi.Haix: |
| fileoff := uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen) |
| fileoff = uint32(ld.Rnd(int64(fileoff), int64(*ld.FlagRound))) |
| ld.Asmbxcoff(ctxt, int64(fileoff)) |
| } |
| |
| ctxt.Out.Flush() |
| if *ld.FlagC { |
| 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)) |
| } |
| } |
