asm.go

Documentation: cmd/link/internal/s390x

     1  // Inferno utils/5l/asm.c
     2  // https://bitbucket.org/inferno-os/inferno-os/src/master/utils/5l/asm.c
     3  //
     4  //	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
     5  //	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
     6  //	Portions Copyright © 1997-1999 Vita Nuova Limited
     7  //	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
     8  //	Portions Copyright © 2004,2006 Bruce Ellis
     9  //	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
    10  //	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
    11  //	Portions Copyright © 2009 The Go Authors. All rights reserved.
    12  //
    13  // Permission is hereby granted, free of charge, to any person obtaining a copy
    14  // of this software and associated documentation files (the "Software"), to deal
    15  // in the Software without restriction, including without limitation the rights
    16  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    17  // copies of the Software, and to permit persons to whom the Software is
    18  // furnished to do so, subject to the following conditions:
    19  //
    20  // The above copyright notice and this permission notice shall be included in
    21  // all copies or substantial portions of the Software.
    22  //
    23  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    24  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    25  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
    26  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    27  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    28  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    29  // THE SOFTWARE.
    30  
    31  package s390x
    32  
    33  import (
    34  	"cmd/internal/objabi"
    35  	"cmd/internal/sys"
    36  	"cmd/link/internal/ld"
    37  	"cmd/link/internal/loader"
    38  	"cmd/link/internal/sym"
    39  	"debug/elf"
    40  )
    41  
    42  // gentext generates assembly to append the local moduledata to the global
    43  // moduledata linked list at initialization time. This is only done if the runtime
    44  // is in a different module.
    45  //
    46  // <go.link.addmoduledata>:
    47  // 	larl  %r2, <local.moduledata>
    48  // 	jg    <runtime.addmoduledata@plt>
    49  //	undef
    50  //
    51  // The job of appending the moduledata is delegated to runtime.addmoduledata.
    52  func gentext(ctxt *ld.Link, ldr *loader.Loader) {
    53  	initfunc, addmoduledata := ld.PrepareAddmoduledata(ctxt)
    54  	if initfunc == nil {
    55  		return
    56  	}
    57  
    58  	// larl %r2, <local.moduledata>
    59  	initfunc.AddUint8(0xc0)
    60  	initfunc.AddUint8(0x20)
    61  	initfunc.AddSymRef(ctxt.Arch, ctxt.Moduledata, 6, objabi.R_PCREL, 4)
    62  	r1 := initfunc.Relocs()
    63  	ldr.SetRelocVariant(initfunc.Sym(), r1.Count()-1, sym.RV_390_DBL)
    64  
    65  	// jg <runtime.addmoduledata[@plt]>
    66  	initfunc.AddUint8(0xc0)
    67  	initfunc.AddUint8(0xf4)
    68  	initfunc.AddSymRef(ctxt.Arch, addmoduledata, 6, objabi.R_CALL, 4)
    69  	r2 := initfunc.Relocs()
    70  	ldr.SetRelocVariant(initfunc.Sym(), r2.Count()-1, sym.RV_390_DBL)
    71  
    72  	// undef (for debugging)
    73  	initfunc.AddUint32(ctxt.Arch, 0)
    74  }
    75  
    76  func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym, r loader.Reloc, rIdx int) bool {
    77  	targ := r.Sym()
    78  	var targType sym.SymKind
    79  	if targ != 0 {
    80  		targType = ldr.SymType(targ)
    81  	}
    82  
    83  	switch r.Type() {
    84  	default:
    85  		if r.Type() >= objabi.ElfRelocOffset {
    86  			ldr.Errorf(s, "unexpected relocation type %d", r.Type())
    87  			return false
    88  		}
    89  
    90  		// Handle relocations found in ELF object files.
    91  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_12),
    92  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOT12):
    93  		ldr.Errorf(s, "s390x 12-bit relocations have not been implemented (relocation type %d)", r.Type()-objabi.ElfRelocOffset)
    94  		return false
    95  
    96  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_8),
    97  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_16),
    98  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_32),
    99  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_64):
   100  		if targType == sym.SDYNIMPORT {
   101  			ldr.Errorf(s, "unexpected R_390_nn relocation for dynamic symbol %s", ldr.SymName(targ))
   102  		}
   103  
   104  		su := ldr.MakeSymbolUpdater(s)
   105  		su.SetRelocType(rIdx, objabi.R_ADDR)
   106  		return true
   107  
   108  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PC16),
   109  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PC32),
   110  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PC64):
   111  		if targType == sym.SDYNIMPORT {
   112  			ldr.Errorf(s, "unexpected R_390_PCnn relocation for dynamic symbol %s", ldr.SymName(targ))
   113  		}
   114  		// TODO(mwhudson): the test of VisibilityHidden here probably doesn't make
   115  		// sense and should be removed when someone has thought about it properly.
   116  		if (targType == 0 || targType == sym.SXREF) && !ldr.AttrVisibilityHidden(targ) {
   117  			ldr.Errorf(s, "unknown symbol %s in pcrel", ldr.SymName(targ))
   118  		}
   119  		su := ldr.MakeSymbolUpdater(s)
   120  		su.SetRelocType(rIdx, objabi.R_PCREL)
   121  		su.SetRelocAdd(rIdx, r.Add()+int64(r.Siz()))
   122  		return true
   123  
   124  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOT16),
   125  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOT32),
   126  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOT64):
   127  		ldr.Errorf(s, "unimplemented S390x relocation: %v", r.Type()-objabi.ElfRelocOffset)
   128  		return true
   129  
   130  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PLT16DBL),
   131  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PLT32DBL):
   132  		su := ldr.MakeSymbolUpdater(s)
   133  		su.SetRelocType(rIdx, objabi.R_PCREL)
   134  		ldr.SetRelocVariant(s, rIdx, sym.RV_390_DBL)
   135  		su.SetRelocAdd(rIdx, r.Add()+int64(r.Siz()))
   136  		if targType == sym.SDYNIMPORT {
   137  			addpltsym(target, ldr, syms, targ)
   138  			r.SetSym(syms.PLT)
   139  			su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymPlt(targ)))
   140  		}
   141  		return true
   142  
   143  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PLT32),
   144  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PLT64):
   145  		su := ldr.MakeSymbolUpdater(s)
   146  		su.SetRelocType(rIdx, objabi.R_PCREL)
   147  		su.SetRelocAdd(rIdx, r.Add()+int64(r.Siz()))
   148  		if targType == sym.SDYNIMPORT {
   149  			addpltsym(target, ldr, syms, targ)
   150  			r.SetSym(syms.PLT)
   151  			su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymPlt(targ)))
   152  		}
   153  		return true
   154  
   155  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_COPY):
   156  		ldr.Errorf(s, "unimplemented S390x relocation: %v", r.Type()-objabi.ElfRelocOffset)
   157  		return false
   158  
   159  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GLOB_DAT):
   160  		ldr.Errorf(s, "unimplemented S390x relocation: %v", r.Type()-objabi.ElfRelocOffset)
   161  		return false
   162  
   163  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_JMP_SLOT):
   164  		ldr.Errorf(s, "unimplemented S390x relocation: %v", r.Type()-objabi.ElfRelocOffset)
   165  		return false
   166  
   167  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_RELATIVE):
   168  		ldr.Errorf(s, "unimplemented S390x relocation: %v", r.Type()-objabi.ElfRelocOffset)
   169  		return false
   170  
   171  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOTOFF):
   172  		if targType == sym.SDYNIMPORT {
   173  			ldr.Errorf(s, "unexpected R_390_GOTOFF relocation for dynamic symbol %s", ldr.SymName(targ))
   174  		}
   175  		su := ldr.MakeSymbolUpdater(s)
   176  		su.SetRelocType(rIdx, objabi.R_GOTOFF)
   177  		return true
   178  
   179  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOTPC):
   180  		su := ldr.MakeSymbolUpdater(s)
   181  		su.SetRelocType(rIdx, objabi.R_PCREL)
   182  		r.SetSym(syms.GOT)
   183  		su.SetRelocAdd(rIdx, r.Add()+int64(r.Siz()))
   184  		return true
   185  
   186  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PC16DBL),
   187  		objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_PC32DBL):
   188  		su := ldr.MakeSymbolUpdater(s)
   189  		su.SetRelocType(rIdx, objabi.R_PCREL)
   190  		ldr.SetRelocVariant(s, rIdx, sym.RV_390_DBL)
   191  		su.SetRelocAdd(rIdx, r.Add()+int64(r.Siz()))
   192  		if targType == sym.SDYNIMPORT {
   193  			ldr.Errorf(s, "unexpected R_390_PCnnDBL relocation for dynamic symbol %s", ldr.SymName(targ))
   194  		}
   195  		return true
   196  
   197  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOTPCDBL):
   198  		su := ldr.MakeSymbolUpdater(s)
   199  		su.SetRelocType(rIdx, objabi.R_PCREL)
   200  		ldr.SetRelocVariant(s, rIdx, sym.RV_390_DBL)
   201  		r.SetSym(syms.GOT)
   202  		su.SetRelocAdd(rIdx, r.Add()+int64(r.Siz()))
   203  		return true
   204  
   205  	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_390_GOTENT):
   206  		ld.AddGotSym(target, ldr, syms, targ, uint32(elf.R_390_GLOB_DAT))
   207  		su := ldr.MakeSymbolUpdater(s)
   208  		su.SetRelocType(rIdx, objabi.R_PCREL)
   209  		ldr.SetRelocVariant(s, rIdx, sym.RV_390_DBL)
   210  		r.SetSym(syms.GOT)
   211  		su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymGot(targ))+int64(r.Siz()))
   212  		return true
   213  	}
   214  	// Handle references to ELF symbols from our own object files.
   215  	if targType != sym.SDYNIMPORT {
   216  		return true
   217  	}
   218  
   219  	return false
   220  }
   221  
   222  func elfreloc1(ctxt *ld.Link, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym, r loader.ExtReloc, ri int, sectoff int64) bool {
   223  	out.Write64(uint64(sectoff))
   224  
   225  	elfsym := ld.ElfSymForReloc(ctxt, r.Xsym)
   226  	siz := r.Size
   227  	switch r.Type {
   228  	default:
   229  		return false
   230  	case objabi.R_TLS_LE:
   231  		switch siz {
   232  		default:
   233  			return false
   234  		case 4:
   235  			// WARNING - silently ignored by linker in ELF64
   236  			out.Write64(uint64(elf.R_390_TLS_LE32) | uint64(elfsym)<<32)
   237  		case 8:
   238  			// WARNING - silently ignored by linker in ELF32
   239  			out.Write64(uint64(elf.R_390_TLS_LE64) | uint64(elfsym)<<32)
   240  		}
   241  	case objabi.R_TLS_IE:
   242  		switch siz {
   243  		default:
   244  			return false
   245  		case 4:
   246  			out.Write64(uint64(elf.R_390_TLS_IEENT) | uint64(elfsym)<<32)
   247  		}
   248  	case objabi.R_ADDR, objabi.R_DWARFSECREF:
   249  		switch siz {
   250  		default:
   251  			return false
   252  		case 4:
   253  			out.Write64(uint64(elf.R_390_32) | uint64(elfsym)<<32)
   254  		case 8:
   255  			out.Write64(uint64(elf.R_390_64) | uint64(elfsym)<<32)
   256  		}
   257  	case objabi.R_GOTPCREL:
   258  		if siz == 4 {
   259  			out.Write64(uint64(elf.R_390_GOTENT) | uint64(elfsym)<<32)
   260  		} else {
   261  			return false
   262  		}
   263  	case objabi.R_PCREL, objabi.R_PCRELDBL, objabi.R_CALL:
   264  		elfrel := elf.R_390_NONE
   265  		rVariant := ldr.RelocVariant(s, ri)
   266  		isdbl := rVariant&sym.RV_TYPE_MASK == sym.RV_390_DBL
   267  		// TODO(mundaym): all DBL style relocations should be
   268  		// signalled using the variant - see issue 14218.
   269  		switch r.Type {
   270  		case objabi.R_PCRELDBL, objabi.R_CALL:
   271  			isdbl = true
   272  		}
   273  		if ldr.SymType(r.Xsym) == sym.SDYNIMPORT && (ldr.SymElfType(r.Xsym) == elf.STT_FUNC || r.Type == objabi.R_CALL) {
   274  			if isdbl {
   275  				switch siz {
   276  				case 2:
   277  					elfrel = elf.R_390_PLT16DBL
   278  				case 4:
   279  					elfrel = elf.R_390_PLT32DBL
   280  				}
   281  			} else {
   282  				switch siz {
   283  				case 4:
   284  					elfrel = elf.R_390_PLT32
   285  				case 8:
   286  					elfrel = elf.R_390_PLT64
   287  				}
   288  			}
   289  		} else {
   290  			if isdbl {
   291  				switch siz {
   292  				case 2:
   293  					elfrel = elf.R_390_PC16DBL
   294  				case 4:
   295  					elfrel = elf.R_390_PC32DBL
   296  				}
   297  			} else {
   298  				switch siz {
   299  				case 2:
   300  					elfrel = elf.R_390_PC16
   301  				case 4:
   302  					elfrel = elf.R_390_PC32
   303  				case 8:
   304  					elfrel = elf.R_390_PC64
   305  				}
   306  			}
   307  		}
   308  		if elfrel == elf.R_390_NONE {
   309  			return false // unsupported size/dbl combination
   310  		}
   311  		out.Write64(uint64(elfrel) | uint64(elfsym)<<32)
   312  	}
   313  
   314  	out.Write64(uint64(r.Xadd))
   315  	return true
   316  }
   317  
   318  func elfsetupplt(ctxt *ld.Link, plt, got *loader.SymbolBuilder, dynamic loader.Sym) {
   319  	if plt.Size() == 0 {
   320  		// stg     %r1,56(%r15)
   321  		plt.AddUint8(0xe3)
   322  		plt.AddUint8(0x10)
   323  		plt.AddUint8(0xf0)
   324  		plt.AddUint8(0x38)
   325  		plt.AddUint8(0x00)
   326  		plt.AddUint8(0x24)
   327  		// larl    %r1,_GLOBAL_OFFSET_TABLE_
   328  		plt.AddUint8(0xc0)
   329  		plt.AddUint8(0x10)
   330  		plt.AddSymRef(ctxt.Arch, got.Sym(), 6, objabi.R_PCRELDBL, 4)
   331  		// mvc     48(8,%r15),8(%r1)
   332  		plt.AddUint8(0xd2)
   333  		plt.AddUint8(0x07)
   334  		plt.AddUint8(0xf0)
   335  		plt.AddUint8(0x30)
   336  		plt.AddUint8(0x10)
   337  		plt.AddUint8(0x08)
   338  		// lg      %r1,16(%r1)
   339  		plt.AddUint8(0xe3)
   340  		plt.AddUint8(0x10)
   341  		plt.AddUint8(0x10)
   342  		plt.AddUint8(0x10)
   343  		plt.AddUint8(0x00)
   344  		plt.AddUint8(0x04)
   345  		// br      %r1
   346  		plt.AddUint8(0x07)
   347  		plt.AddUint8(0xf1)
   348  		// nopr    %r0
   349  		plt.AddUint8(0x07)
   350  		plt.AddUint8(0x00)
   351  		// nopr    %r0
   352  		plt.AddUint8(0x07)
   353  		plt.AddUint8(0x00)
   354  		// nopr    %r0
   355  		plt.AddUint8(0x07)
   356  		plt.AddUint8(0x00)
   357  
   358  		// assume got->size == 0 too
   359  		got.AddAddrPlus(ctxt.Arch, dynamic, 0)
   360  
   361  		got.AddUint64(ctxt.Arch, 0)
   362  		got.AddUint64(ctxt.Arch, 0)
   363  	}
   364  }
   365  
   366  func machoreloc1(*sys.Arch, *ld.OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool {
   367  	return false
   368  }
   369  
   370  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) {
   371  	return val, 0, false
   372  }
   373  
   374  func archrelocvariant(target *ld.Target, ldr *loader.Loader, r loader.Reloc, rv sym.RelocVariant, s loader.Sym, t int64, p []byte) int64 {
   375  	switch rv & sym.RV_TYPE_MASK {
   376  	default:
   377  		ldr.Errorf(s, "unexpected relocation variant %d", rv)
   378  		return t
   379  
   380  	case sym.RV_NONE:
   381  		return t
   382  
   383  	case sym.RV_390_DBL:
   384  		if t&1 != 0 {
   385  			ldr.Errorf(s, "%s+%v is not 2-byte aligned", ldr.SymName(r.Sym()), ldr.SymValue(r.Sym()))
   386  		}
   387  		return t >> 1
   388  	}
   389  }
   390  
   391  func addpltsym(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym) {
   392  	if ldr.SymPlt(s) >= 0 {
   393  		return
   394  	}
   395  
   396  	ld.Adddynsym(ldr, target, syms, s)
   397  
   398  	if target.IsElf() {
   399  		plt := ldr.MakeSymbolUpdater(syms.PLT)
   400  		got := ldr.MakeSymbolUpdater(syms.GOT)
   401  		rela := ldr.MakeSymbolUpdater(syms.RelaPLT)
   402  		if plt.Size() == 0 {
   403  			panic("plt is not set up")
   404  		}
   405  		// larl    %r1,_GLOBAL_OFFSET_TABLE_+index
   406  
   407  		plt.AddUint8(0xc0)
   408  		plt.AddUint8(0x10)
   409  		plt.AddPCRelPlus(target.Arch, got.Sym(), got.Size()+6)
   410  		pltrelocs := plt.Relocs()
   411  		ldr.SetRelocVariant(plt.Sym(), pltrelocs.Count()-1, sym.RV_390_DBL)
   412  
   413  		// add to got: pointer to current pos in plt
   414  		got.AddAddrPlus(target.Arch, plt.Sym(), plt.Size()+8) // weird but correct
   415  		// lg      %r1,0(%r1)
   416  		plt.AddUint8(0xe3)
   417  		plt.AddUint8(0x10)
   418  		plt.AddUint8(0x10)
   419  		plt.AddUint8(0x00)
   420  		plt.AddUint8(0x00)
   421  		plt.AddUint8(0x04)
   422  		// br      %r1
   423  		plt.AddUint8(0x07)
   424  		plt.AddUint8(0xf1)
   425  		// basr    %r1,%r0
   426  		plt.AddUint8(0x0d)
   427  		plt.AddUint8(0x10)
   428  		// lgf     %r1,12(%r1)
   429  		plt.AddUint8(0xe3)
   430  		plt.AddUint8(0x10)
   431  		plt.AddUint8(0x10)
   432  		plt.AddUint8(0x0c)
   433  		plt.AddUint8(0x00)
   434  		plt.AddUint8(0x14)
   435  		// jg .plt
   436  		plt.AddUint8(0xc0)
   437  		plt.AddUint8(0xf4)
   438  
   439  		plt.AddUint32(target.Arch, uint32(-((plt.Size() - 2) >> 1))) // roll-your-own relocation
   440  		//.plt index
   441  		plt.AddUint32(target.Arch, uint32(rela.Size())) // rela size before current entry
   442  
   443  		// rela
   444  		rela.AddAddrPlus(target.Arch, got.Sym(), got.Size()-8)
   445  
   446  		sDynid := ldr.SymDynid(s)
   447  		rela.AddUint64(target.Arch, elf.R_INFO(uint32(sDynid), uint32(elf.R_390_JMP_SLOT)))
   448  		rela.AddUint64(target.Arch, 0)
   449  
   450  		ldr.SetPlt(s, int32(plt.Size()-32))
   451  
   452  	} else {
   453  		ldr.Errorf(s, "addpltsym: unsupported binary format")
   454  	}
   455  }
   456
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