cmd/internal/obj, runtime: implement IE model TLS on ppc64le

This requires changing the tls access code to match the patterns documented in
the ABI documentation or the system linker will "optimize" it into ridiculousness.

With this change, -buildmode=pie works, although as it is tested in testshared,
the tests are not run yet.

Change-Id: I1efa6687af0a5b8db3385b10f6542a49056b2eb3
Reviewed-on: https://go-review.googlesource.com/15971
Reviewed-by: Russ Cox <rsc@golang.org>

diff --git a/src/cmd/internal/obj/link.go b/src/cmd/internal/obj/link.go
index ab1de2447b76e85367d9df5f60d3b74993bf54f8..a7e0c2f863abb34e8e5b89e4d27b652d400511ac 100644 (file)
--- a/src/cmd/internal/obj/link.go
+++ b/src/cmd/internal/obj/link.go
@@ -480,6 +480,19 @@ const (
        // instruction word.
        R_POWER_TLS_LE
 
+       // R_POWER_TLS_IE is used to implement the "initial exec" model for tls access. It
+       // relocates a D-form, DS-form instruction sequence like R_ADDRPOWER_DS. It
+       // inserts to the offset of GOT slot for the thread-local symbol from the TOC (the
+       // GOT slot is filled by the dynamic linker with the offset of the thread-local
+       // symbol from the thread pointer (R13)).
+       R_POWER_TLS_IE
+
+       // R_POWER_TLS marks an X-form instruction such as "MOVD 0(R13)(R31*1), g" as
+       // accessing a particular thread-local symbol. It does not affect code generation
+       // but is used by the system linker when relaxing "initial exec" model code to
+       // "local exec" model code.
+       R_POWER_TLS
+
        // R_ADDRPOWER_DS is similar to R_ADDRPOWER above, but assumes the second
        // instruction is a "DS-form" instruction, which has an immediate field occupying
        // bits [15:2] of the instruction word. Bits [15:2] of the address of the

diff --git a/src/cmd/internal/obj/ppc64/a.out.go b/src/cmd/internal/obj/ppc64/a.out.go
index 3fd4685769fe8d880bbccc28ec4d3d1402fb3e36..d28e1e895e5a4ac7d5c0d689a34860fb2aa0344a 100644 (file)
--- a/src/cmd/internal/obj/ppc64/a.out.go
+++ b/src/cmd/internal/obj/ppc64/a.out.go
@@ -222,6 +222,7 @@ const (
        C_GOK
        C_ADDR
        C_TLS_LE
+       C_TLS_IE
        C_TEXTSIZE
 
        C_NCLASS /* must be the last */

diff --git a/src/cmd/internal/obj/ppc64/anames9.go b/src/cmd/internal/obj/ppc64/anames9.go
index 62125a4e5234843a4ada93772ef9820a08db1a37..1b5d564dfecf9fa31d007632ebef7e1e1c84ca91 100644 (file)
--- a/src/cmd/internal/obj/ppc64/anames9.go
+++ b/src/cmd/internal/obj/ppc64/anames9.go
@@ -36,6 +36,7 @@ var cnames9 = []string{
        "GOK",
        "ADDR",
        "TLS_LE",
+       "TLS_IE",
        "TEXTSIZE",
        "NCLASS",
 }

diff --git a/src/cmd/internal/obj/ppc64/asm9.go b/src/cmd/internal/obj/ppc64/asm9.go
index c226ed540db125312af6b844ba0f8b8be5717c4a..25b9aef83000c5e375ebda5372bed8e05b9799b3 100644 (file)
--- a/src/cmd/internal/obj/ppc64/asm9.go
+++ b/src/cmd/internal/obj/ppc64/asm9.go
@@ -246,6 +246,7 @@ var optab = []Optab{
        {AMOVB, C_ADDR, C_NONE, C_NONE, C_REG, 76, 12, 0},
 
        {AMOVD, C_TLS_LE, C_NONE, C_NONE, C_REG, 79, 4, 0},
+       {AMOVD, C_TLS_IE, C_NONE, C_NONE, C_REG, 80, 8, 0},
 
        /* load constant */
        {AMOVD, C_SECON, C_NONE, C_NONE, C_REG, 3, 4, REGSB},
@@ -587,7 +588,11 @@ func aclass(ctxt *obj.Link, a *obj.Addr) int {
                        ctxt.Instoffset = a.Offset
                        if a.Sym != nil { // use relocation
                                if a.Sym.Type == obj.STLSBSS {
-                                       return C_TLS_LE
+                                       if ctxt.Flag_shared != 0 {
+                                               return C_TLS_IE
+                                       } else {
+                                               return C_TLS_LE
+                                       }
                                }
                                return C_ADDR
                        }
@@ -1652,6 +1657,18 @@ func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {
                        if v != 0 {
                                ctxt.Diag("illegal indexed instruction\n%v", p)
                        }
+                       if ctxt.Flag_shared != 0 && r == REG_R13 {
+                               rel := obj.Addrel(ctxt.Cursym)
+                               rel.Off = int32(ctxt.Pc)
+                               rel.Siz = 4
+                               // This (and the matching part in the load case
+                               // below) are the only places in the ppc64 toolchain
+                               // that knows the name of the tls variable. Possibly
+                               // we could add some assembly syntax so that the name
+                               // of the variable does not have to be assumed.
+                               rel.Sym = obj.Linklookup(ctxt, "runtime.tls_g", 0)
+                               rel.Type = obj.R_POWER_TLS
+                       }
                        o1 = AOP_RRR(uint32(opstorex(ctxt, int(p.As))), uint32(p.From.Reg), uint32(p.To.Index), uint32(r))
                } else {
                        if int32(int16(v)) != v {
@@ -1671,6 +1688,13 @@ func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {
                        if v != 0 {
                                ctxt.Diag("illegal indexed instruction\n%v", p)
                        }
+                       if ctxt.Flag_shared != 0 && r == REG_R13 {
+                               rel := obj.Addrel(ctxt.Cursym)
+                               rel.Off = int32(ctxt.Pc)
+                               rel.Siz = 4
+                               rel.Sym = obj.Linklookup(ctxt, "runtime.tls_g", 0)
+                               rel.Type = obj.R_POWER_TLS
+                       }
                        o1 = AOP_RRR(uint32(oploadx(ctxt, int(p.As))), uint32(p.To.Reg), uint32(p.From.Index), uint32(r))
                } else {
                        if int32(int16(v)) != v {
@@ -2467,6 +2491,18 @@ func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {
                rel.Sym = p.From.Sym
                rel.Type = obj.R_POWER_TLS_LE
 
+       case 80:
+               if p.From.Offset != 0 {
+                       ctxt.Diag("invalid offset against tls var %v", p)
+               }
+               o1 = AOP_IRR(OP_ADDIS, uint32(p.To.Reg), REG_R2, 0)
+               o2 = AOP_IRR(uint32(opload(ctxt, AMOVD)), uint32(p.To.Reg), uint32(p.To.Reg), 0)
+               rel := obj.Addrel(ctxt.Cursym)
+               rel.Off = int32(ctxt.Pc)
+               rel.Siz = 8
+               rel.Sym = p.From.Sym
+               rel.Type = obj.R_POWER_TLS_IE
+
        }
 
        out[0] = o1

diff --git a/src/cmd/link/internal/ld/elf.go b/src/cmd/link/internal/ld/elf.go
index 51552e3c152f92b5b860d13f5092e9d9b9f54b2e..505cbcdbb1ab3d1bf39d7fd8f81ccdea4953682e 100644 (file)
--- a/src/cmd/link/internal/ld/elf.go
+++ b/src/cmd/link/internal/ld/elf.go
@@ -564,23 +564,28 @@ const (
        R_PPC_EMB_BIT_FLD     = 115
        R_PPC_EMB_RELSDA      = 116
 
-       R_PPC64_ADDR32       = R_PPC_ADDR32
-       R_PPC64_ADDR16_LO    = R_PPC_ADDR16_LO
-       R_PPC64_ADDR16_HA    = R_PPC_ADDR16_HA
-       R_PPC64_REL24        = R_PPC_REL24
-       R_PPC64_JMP_SLOT     = R_PPC_JMP_SLOT
-       R_PPC64_TPREL16      = R_PPC_TPREL16
-       R_PPC64_ADDR64       = 38
-       R_PPC64_TOC16        = 47
-       R_PPC64_TOC16_LO     = 48
-       R_PPC64_TOC16_HI     = 49
-       R_PPC64_TOC16_HA     = 50
-       R_PPC64_ADDR16_LO_DS = 57
-       R_PPC64_TOC16_DS     = 63
-       R_PPC64_TOC16_LO_DS  = 64
-       R_PPC64_REL16_LO     = 250
-       R_PPC64_REL16_HI     = 251
-       R_PPC64_REL16_HA     = 252
+       R_PPC64_ADDR32            = R_PPC_ADDR32
+       R_PPC64_ADDR16_LO         = R_PPC_ADDR16_LO
+       R_PPC64_ADDR16_HA         = R_PPC_ADDR16_HA
+       R_PPC64_REL24             = R_PPC_REL24
+       R_PPC64_GOT16_HA          = R_PPC_GOT16_HA
+       R_PPC64_JMP_SLOT          = R_PPC_JMP_SLOT
+       R_PPC64_TPREL16           = R_PPC_TPREL16
+       R_PPC64_ADDR64            = 38
+       R_PPC64_TOC16             = 47
+       R_PPC64_TOC16_LO          = 48
+       R_PPC64_TOC16_HI          = 49
+       R_PPC64_TOC16_HA          = 50
+       R_PPC64_ADDR16_LO_DS      = 57
+       R_PPC64_GOT16_LO_DS       = 59
+       R_PPC64_TOC16_DS          = 63
+       R_PPC64_TOC16_LO_DS       = 64
+       R_PPC64_TLS               = 67
+       R_PPC64_GOT_TPREL16_LO_DS = 88
+       R_PPC64_GOT_TPREL16_HA    = 90
+       R_PPC64_REL16_LO          = 250
+       R_PPC64_REL16_HI          = 251
+       R_PPC64_REL16_HA          = 252
 
        R_SPARC_NONE     = 0
        R_SPARC_8        = 1

diff --git a/src/cmd/link/internal/ppc64/asm.go b/src/cmd/link/internal/ppc64/asm.go
index 97efe7d354f06f0e6cecd425ba26e01e984ce11c..706160d0fb0340322164878aa94b037e4f9e104e 100644 (file)
--- a/src/cmd/link/internal/ppc64/asm.go
+++ b/src/cmd/link/internal/ppc64/asm.go
@@ -310,9 +310,18 @@ func elfreloc1(r *ld.Reloc, sectoff int64) int {
                        return -1
                }
 
+       case obj.R_POWER_TLS:
+               ld.Thearch.Vput(ld.R_PPC64_TLS | uint64(elfsym)<<32)
+
        case obj.R_POWER_TLS_LE:
                ld.Thearch.Vput(ld.R_PPC64_TPREL16 | uint64(elfsym)<<32)
 
+       case obj.R_POWER_TLS_IE:
+               ld.Thearch.Vput(ld.R_PPC64_GOT_TPREL16_HA | uint64(elfsym)<<32)
+               ld.Thearch.Vput(uint64(r.Xadd))
+               ld.Thearch.Vput(uint64(sectoff + 4))
+               ld.Thearch.Vput(ld.R_PPC64_GOT_TPREL16_LO_DS | uint64(elfsym)<<32)
+
        case obj.R_ADDRPOWER:
                ld.Thearch.Vput(ld.R_PPC64_ADDR16_HA | uint64(elfsym)<<32)
                ld.Thearch.Vput(uint64(r.Xadd))
@@ -444,7 +453,7 @@ func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
                default:
                        return -1
 
-               case obj.R_POWER_TLS_LE:
+               case obj.R_POWER_TLS, obj.R_POWER_TLS_LE, obj.R_POWER_TLS_IE:
                        r.Done = 0
                        // check Outer is nil, Type is TLSBSS?
                        r.Xadd = r.Add

diff --git a/src/runtime/tls_ppc64x.s b/src/runtime/tls_ppc64x.s
index 1b030fd36adec410c6708cc84b670eb01e02b805..c79c97dae3f5704259f314efab5fc5f85527afaf 100644 (file)
--- a/src/runtime/tls_ppc64x.s
+++ b/src/runtime/tls_ppc64x.s
@@ -27,8 +27,7 @@ TEXT runtime·save_g(SB),NOSPLIT|NOFRAME,$0-0
        CMP     R31, $0
        BEQ     nocgo
        MOVD    runtime·tls_g(SB), R31
-       ADD     R13, R31
-       MOVD    g, 0(R31)
+       MOVD    g, 0(R13)(R31*1)
 
 nocgo:
        RET
@@ -44,8 +43,7 @@ nocgo:
 // NOTE: _cgo_topofstack assumes this only clobbers g (R30), and R31.
 TEXT runtime·load_g(SB),NOSPLIT|NOFRAME,$0-0
        MOVD    runtime·tls_g(SB), R31
-       ADD     R13, R31
-       MOVD    0(R31), g
+       MOVD    0(R13)(R31*1), g
        RET
 
 GLOBL runtime·tls_g+0(SB), TLSBSS, $8