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

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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>
This commit is contained in:
Michael Hudson-Doyle 2015-10-16 21:15:18 +13:00
parent bd329d47d9
commit a35c85c0cc
7 changed files with 86 additions and 23 deletions
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13
src/cmd/internal/obj/link.go
View File

@ -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

1
src/cmd/internal/obj/ppc64/a.out.go
View File

@ -222,6 +222,7 @@ const (
C_GOK
C_ADDR
C_TLS_LE
C_TLS_IE
C_TEXTSIZE
C_NCLASS /* must be the last */

1
src/cmd/internal/obj/ppc64/anames9.go
View File

@ -36,6 +36,7 @@ var cnames9 = []string{
"GOK",
"ADDR",
"TLS_LE",
"TLS_IE",
"TEXTSIZE",
"NCLASS",
}

38
src/cmd/internal/obj/ppc64/asm9.go
View File

@ -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

39
src/cmd/link/internal/ld/elf.go
View File

@ -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

11
src/cmd/link/internal/ppc64/asm.go
View File

@ -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

6
src/runtime/tls_ppc64x.s
View File

@ -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