// Inferno utils/5l/asm.c // https://bitbucket.org/inferno-os/inferno-os/src/master/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 mips64 import ( "cmd/internal/objabi" "cmd/internal/sys" "cmd/link/internal/ld" "cmd/link/internal/loader" "cmd/link/internal/sym" "debug/elf" ) var ( // dtOffsets contains offsets for entries within the .dynamic section. // These are used to fix up symbol values once they are known. dtOffsets map[elf.DynTag]int64 // dynSymCount contains the number of entries in the .dynsym section. // This is used to populate the DT_MIPS_SYMTABNO entry in the .dynamic // section. dynSymCount uint64 // gotLocalCount contains the number of local global offset table // entries. This is used to populate the DT_MIPS_LOCAL_GOTNO entry in // the .dynamic section. gotLocalCount uint64 // gotSymIndex contains the index of the first dynamic symbol table // entry that corresponds to an entry in the global offset table. // This is used to populate the DT_MIPS_GOTSYM entry in the .dynamic // section. gotSymIndex uint64 ) func gentext(ctxt *ld.Link, ldr *loader.Loader) { if *ld.FlagD || ctxt.Target.IsExternal() { return } dynamic := ldr.MakeSymbolUpdater(ctxt.ArchSyms.Dynamic) ld.Elfwritedynent(ctxt.Arch, dynamic, elf.DT_MIPS_RLD_VERSION, 1) ld.Elfwritedynent(ctxt.Arch, dynamic, elf.DT_MIPS_BASE_ADDRESS, 0) // elfsetupplt should have been called and gotLocalCount should now // have its correct value. if gotLocalCount == 0 { ctxt.Errorf(0, "internal error: elfsetupplt has not been called") } ld.Elfwritedynent(ctxt.Arch, dynamic, elf.DT_MIPS_LOCAL_GOTNO, gotLocalCount) // DT_* entries have to exist prior to elfdynhash(), which finalises the // table by adding DT_NULL. However, the values for the following entries // are not know until after dynreloc() has completed. Add the symbols now, // then update their values prior to code generation. dts := []elf.DynTag{ elf.DT_MIPS_SYMTABNO, elf.DT_MIPS_GOTSYM, } dtOffsets = make(map[elf.DynTag]int64) for _, dt := range dts { ld.Elfwritedynent(ctxt.Arch, dynamic, dt, 0) dtOffsets[dt] = dynamic.Size() - 8 } } 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) } if r.Type() >= objabi.ElfRelocOffset { ldr.Errorf(s, "unexpected relocation type %d (%s)", r.Type(), sym.RelocName(target.Arch, r.Type())) return false } switch r.Type() { case objabi.R_CALLMIPS, objabi.R_JMPMIPS: 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, build a PLT entry and change the relocation // target to that entry. if r.Add() != 0 { ldr.Errorf(s, "PLT call with non-zero addend (%v)", r.Add()) } addpltsym(target, ldr, syms, targ) su := ldr.MakeSymbolUpdater(s) su.SetRelocSym(rIdx, syms.PLT) su.SetRelocAdd(rIdx, int64(ldr.SymPlt(targ))) 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 { // mips64 ELF relocation (endian neutral) // offset uint64 // sym uint32 // ssym uint8 // type3 uint8 // type2 uint8 // type uint8 // addend int64 addend := r.Xadd out.Write64(uint64(sectoff)) elfsym := ld.ElfSymForReloc(ctxt, r.Xsym) out.Write32(uint32(elfsym)) out.Write8(0) out.Write8(0) out.Write8(0) switch r.Type { default: return false case objabi.R_ADDR, objabi.R_DWARFSECREF: switch r.Size { case 4: out.Write8(uint8(elf.R_MIPS_32)) case 8: out.Write8(uint8(elf.R_MIPS_64)) default: return false } case objabi.R_ADDRMIPS: out.Write8(uint8(elf.R_MIPS_LO16)) case objabi.R_ADDRMIPSU: out.Write8(uint8(elf.R_MIPS_HI16)) case objabi.R_ADDRMIPSTLS: out.Write8(uint8(elf.R_MIPS_TLS_TPREL_LO16)) if ctxt.Target.IsOpenbsd() { // OpenBSD mips64 does not currently offset TLS by 0x7000, // as such we need to add this back to get the correct offset // via the external linker. addend += 0x7000 } case objabi.R_CALLMIPS, objabi.R_JMPMIPS: out.Write8(uint8(elf.R_MIPS_26)) } out.Write64(uint64(addend)) return true } func elfsetupplt(ctxt *ld.Link, ldr *loader.Loader, plt, gotplt *loader.SymbolBuilder, dynamic loader.Sym) { if plt.Size() != 0 { return } // Load resolver address from got[0] into r25. plt.AddSymRef(ctxt.Arch, gotplt.Sym(), 0, objabi.R_ADDRMIPSU, 4) plt.SetUint32(ctxt.Arch, plt.Size()-4, 0x3c0e0000) // lui $14, %hi(&GOTPLT[0]) plt.AddSymRef(ctxt.Arch, gotplt.Sym(), 0, objabi.R_ADDRMIPS, 4) plt.SetUint32(ctxt.Arch, plt.Size()-4, 0xddd90000) // ld $25, %lo(&GOTPLT[0])($14) // Load return address into r15, the index of the got.plt entry into r24, then // JALR to the resolver. The address of the got.plt entry is currently in r24, // which we have to turn into an index. plt.AddSymRef(ctxt.Arch, gotplt.Sym(), 0, objabi.R_ADDRMIPS, 4) plt.SetUint32(ctxt.Arch, plt.Size()-4, 0x25ce0000) // addiu $14, $14, %lo(&GOTPLT[0]) plt.AddUint32(ctxt.Arch, 0x030ec023) // subu $24, $24, $14 plt.AddUint32(ctxt.Arch, 0x03e07825) // move $15, $31 plt.AddUint32(ctxt.Arch, 0x0018c0c2) // srl $24, $24, 3 plt.AddUint32(ctxt.Arch, 0x0320f809) // jalr $25 plt.AddUint32(ctxt.Arch, 0x2718fffe) // subu $24, $24, 2 if gotplt.Size() != 0 { ctxt.Errorf(gotplt.Sym(), "got.plt is not empty") } // Reserve got[0] for resolver address (populated by dynamic loader). gotplt.AddUint32(ctxt.Arch, 0) gotplt.AddUint32(ctxt.Arch, 0) gotLocalCount++ // Reserve got[1] for ELF object pointer (populated by dynamic loader). gotplt.AddUint32(ctxt.Arch, 0) gotplt.AddUint32(ctxt.Arch, 0) gotLocalCount++ } func addpltsym(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym) { if ldr.SymPlt(s) >= 0 { return } dynamic := ldr.MakeSymbolUpdater(syms.Dynamic) const dynSymEntrySize = 20 if gotSymIndex == 0 { // Compute and update GOT symbol index. gotSymIndex = uint64(ldr.SymSize(syms.DynSym) / dynSymEntrySize) dynamic.SetUint(target.Arch, dtOffsets[elf.DT_MIPS_GOTSYM], gotSymIndex) } if dynSymCount == 0 { dynSymCount = uint64(ldr.SymSize(syms.DynSym) / dynSymEntrySize) } ld.Adddynsym(ldr, target, syms, s) dynSymCount++ if !target.IsElf() { ldr.Errorf(s, "addpltsym: unsupported binary format") } plt := ldr.MakeSymbolUpdater(syms.PLT) gotplt := ldr.MakeSymbolUpdater(syms.GOTPLT) if plt.Size() == 0 { panic("plt is not set up") } // Load got.plt entry into r25. plt.AddSymRef(target.Arch, gotplt.Sym(), gotplt.Size(), objabi.R_ADDRMIPSU, 4) plt.SetUint32(target.Arch, plt.Size()-4, 0x3c0f0000) // lui $15, %hi(.got.plt entry) plt.AddSymRef(target.Arch, gotplt.Sym(), gotplt.Size(), objabi.R_ADDRMIPS, 4) plt.SetUint32(target.Arch, plt.Size()-4, 0xddf90000) // ld $25, %lo(.got.plt entry)($15) // Load address of got.plt entry into r24 and JALR to address in r25. plt.AddUint32(target.Arch, 0x03200008) // jr $25 plt.AddSymRef(target.Arch, gotplt.Sym(), gotplt.Size(), objabi.R_ADDRMIPS, 4) plt.SetUint32(target.Arch, plt.Size()-4, 0x65f80000) // daddiu $24, $15, %lo(.got.plt entry) // Add pointer to plt[0] to got.plt gotplt.AddAddrPlus(target.Arch, plt.Sym(), 0) ldr.SetPlt(s, int32(plt.Size()-16)) // Update dynamic symbol count. dynamic.SetUint(target.Arch, dtOffsets[elf.DT_MIPS_SYMTABNO], dynSymCount) } func machoreloc1(*sys.Arch, *ld.OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool { return false } func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loader.Reloc, s loader.Sym, val int64) (o int64, nExtReloc int, ok bool) { if target.IsExternal() { switch r.Type() { default: return val, 0, false case objabi.R_ADDRMIPS, objabi.R_ADDRMIPSU, objabi.R_ADDRMIPSTLS, objabi.R_CALLMIPS, objabi.R_JMPMIPS: return val, 1, true } } const isOk = true const noExtReloc = 0 rs := r.Sym() switch r.Type() { case objabi.R_ADDRMIPS, objabi.R_ADDRMIPSU: t := ldr.SymValue(rs) + r.Add() if r.Type() == objabi.R_ADDRMIPS { return int64(val&0xffff0000 | t&0xffff), noExtReloc, isOk } return int64(val&0xffff0000 | ((t+1<<15)>>16)&0xffff), noExtReloc, isOk case objabi.R_ADDRMIPSTLS: // thread pointer is at 0x7000 offset from the start of TLS data area t := ldr.SymValue(rs) + r.Add() - 0x7000 if target.IsOpenbsd() { // OpenBSD mips64 does not currently offset TLS by 0x7000, // as such we need to add this back to get the correct offset. t += 0x7000 } if t < -32768 || t >= 32678 { ldr.Errorf(s, "TLS offset out of range %d", t) } return int64(val&0xffff0000 | t&0xffff), noExtReloc, isOk case objabi.R_CALLMIPS, objabi.R_JMPMIPS: // Low 26 bits = (S + A) >> 2 t := ldr.SymValue(rs) + r.Add() return int64(val&0xfc000000 | (t>>2)&^0xfc000000), noExtReloc, isOk } return val, 0, false } func archrelocvariant(*ld.Target, *loader.Loader, loader.Reloc, sym.RelocVariant, loader.Sym, int64, []byte) int64 { return -1 } func extreloc(target *ld.Target, ldr *loader.Loader, r loader.Reloc, s loader.Sym) (loader.ExtReloc, bool) { switch r.Type() { case objabi.R_ADDRMIPS, objabi.R_ADDRMIPSU: return ld.ExtrelocViaOuterSym(ldr, r, s), true case objabi.R_ADDRMIPSTLS, objabi.R_CALLMIPS, objabi.R_JMPMIPS: return ld.ExtrelocSimple(ldr, r), true } return loader.ExtReloc{}, false }