forked from OSchip/llvm-project
433 lines
14 KiB
C++
433 lines
14 KiB
C++
//===- PPC.cpp ------------------------------------------------------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "OutputSections.h"
|
|
#include "Symbols.h"
|
|
#include "SyntheticSections.h"
|
|
#include "Target.h"
|
|
#include "lld/Common/ErrorHandler.h"
|
|
#include "llvm/Support/Endian.h"
|
|
|
|
using namespace llvm;
|
|
using namespace llvm::support::endian;
|
|
using namespace llvm::ELF;
|
|
using namespace lld;
|
|
using namespace lld::elf;
|
|
|
|
namespace {
|
|
class PPC final : public TargetInfo {
|
|
public:
|
|
PPC();
|
|
RelExpr getRelExpr(RelType Type, const Symbol &S,
|
|
const uint8_t *Loc) const override;
|
|
RelType getDynRel(RelType Type) const override;
|
|
void writeGotHeader(uint8_t *Buf) const override;
|
|
void writePltHeader(uint8_t *Buf) const override {
|
|
llvm_unreachable("should call writePPC32GlinkSection() instead");
|
|
}
|
|
void writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr, uint64_t PltEntryAddr,
|
|
int32_t Index, unsigned RelOff) const override {
|
|
llvm_unreachable("should call writePPC32GlinkSection() instead");
|
|
}
|
|
void writeGotPlt(uint8_t *Buf, const Symbol &S) const override;
|
|
bool needsThunk(RelExpr Expr, RelType RelocType, const InputFile *File,
|
|
uint64_t BranchAddr, const Symbol &S) const override;
|
|
uint32_t getThunkSectionSpacing() const override;
|
|
bool inBranchRange(RelType Type, uint64_t Src, uint64_t Dst) const override;
|
|
void relocateOne(uint8_t *Loc, RelType Type, uint64_t Val) const override;
|
|
RelExpr adjustRelaxExpr(RelType Type, const uint8_t *Data,
|
|
RelExpr Expr) const override;
|
|
int getTlsGdRelaxSkip(RelType Type) const override;
|
|
void relaxTlsGdToIe(uint8_t *Loc, RelType Type, uint64_t Val) const override;
|
|
void relaxTlsGdToLe(uint8_t *Loc, RelType Type, uint64_t Val) const override;
|
|
void relaxTlsLdToLe(uint8_t *Loc, RelType Type, uint64_t Val) const override;
|
|
void relaxTlsIeToLe(uint8_t *Loc, RelType Type, uint64_t Val) const override;
|
|
};
|
|
} // namespace
|
|
|
|
static uint16_t lo(uint32_t V) { return V; }
|
|
static uint16_t ha(uint32_t V) { return (V + 0x8000) >> 16; }
|
|
|
|
static uint32_t readFromHalf16(const uint8_t *Loc) {
|
|
return read32(Config->IsLE ? Loc : Loc - 2);
|
|
}
|
|
|
|
static void writeFromHalf16(uint8_t *Loc, uint32_t Insn) {
|
|
write32(Config->IsLE ? Loc : Loc - 2, Insn);
|
|
}
|
|
|
|
void elf::writePPC32GlinkSection(uint8_t *Buf, size_t NumEntries) {
|
|
// On PPC Secure PLT ABI, bl foo@plt jumps to a call stub, which loads an
|
|
// absolute address from a specific .plt slot (usually called .got.plt on
|
|
// other targets) and jumps there.
|
|
//
|
|
// a) With immediate binding (BIND_NOW), the .plt entry is resolved at load
|
|
// time. The .glink section is not used.
|
|
// b) With lazy binding, the .plt entry points to a `b PLTresolve`
|
|
// instruction in .glink, filled in by PPC::writeGotPlt().
|
|
|
|
// Write N `b PLTresolve` first.
|
|
for (size_t I = 0; I != NumEntries; ++I)
|
|
write32(Buf + 4 * I, 0x48000000 | 4 * (NumEntries - I));
|
|
Buf += 4 * NumEntries;
|
|
|
|
// Then write PLTresolve(), which has two forms: PIC and non-PIC. PLTresolve()
|
|
// computes the PLT index (by computing the distance from the landing b to
|
|
// itself) and calls _dl_runtime_resolve() (in glibc).
|
|
uint32_t GOT = In.Got->getVA();
|
|
uint32_t Glink = In.Plt->getVA(); // VA of .glink
|
|
const uint8_t *End = Buf + 64;
|
|
if (Config->Pic) {
|
|
uint32_t AfterBcl = In.Plt->getSize() - Target->PltHeaderSize + 12;
|
|
uint32_t GotBcl = GOT + 4 - (Glink + AfterBcl);
|
|
write32(Buf + 0, 0x3d6b0000 | ha(AfterBcl)); // addis r11,r11,1f-glink@ha
|
|
write32(Buf + 4, 0x7c0802a6); // mflr r0
|
|
write32(Buf + 8, 0x429f0005); // bcl 20,30,.+4
|
|
write32(Buf + 12, 0x396b0000 | lo(AfterBcl)); // 1: addi r11,r11,1b-.glink@l
|
|
write32(Buf + 16, 0x7d8802a6); // mflr r12
|
|
write32(Buf + 20, 0x7c0803a6); // mtlr r0
|
|
write32(Buf + 24, 0x7d6c5850); // sub r11,r11,r12
|
|
write32(Buf + 28, 0x3d8c0000 | ha(GotBcl)); // addis 12,12,GOT+4-1b@ha
|
|
if (ha(GotBcl) == ha(GotBcl + 4)) {
|
|
write32(Buf + 32, 0x800c0000 | lo(GotBcl)); // lwz r0,r12,GOT+4-1b@l(r12)
|
|
write32(Buf + 36,
|
|
0x818c0000 | lo(GotBcl + 4)); // lwz r12,r12,GOT+8-1b@l(r12)
|
|
} else {
|
|
write32(Buf + 32, 0x840c0000 | lo(GotBcl)); // lwzu r0,r12,GOT+4-1b@l(r12)
|
|
write32(Buf + 36, 0x818c0000 | 4); // lwz r12,r12,4(r12)
|
|
}
|
|
write32(Buf + 40, 0x7c0903a6); // mtctr 0
|
|
write32(Buf + 44, 0x7c0b5a14); // add r0,11,11
|
|
write32(Buf + 48, 0x7d605a14); // add r11,0,11
|
|
write32(Buf + 52, 0x4e800420); // bctr
|
|
Buf += 56;
|
|
} else {
|
|
write32(Buf + 0, 0x3d800000 | ha(GOT + 4)); // lis r12,GOT+4@ha
|
|
write32(Buf + 4, 0x3d6b0000 | ha(-Glink)); // addis r11,r11,-Glink@ha
|
|
if (ha(GOT + 4) == ha(GOT + 8))
|
|
write32(Buf + 8, 0x800c0000 | lo(GOT + 4)); // lwz r0,GOT+4@l(r12)
|
|
else
|
|
write32(Buf + 8, 0x840c0000 | lo(GOT + 4)); // lwzu r0,GOT+4@l(r12)
|
|
write32(Buf + 12, 0x396b0000 | lo(-Glink)); // addi r11,r11,-Glink@l
|
|
write32(Buf + 16, 0x7c0903a6); // mtctr r0
|
|
write32(Buf + 20, 0x7c0b5a14); // add r0,r11,r11
|
|
if (ha(GOT + 4) == ha(GOT + 8))
|
|
write32(Buf + 24, 0x818c0000 | lo(GOT + 8)); // lwz r12,GOT+8@ha(r12)
|
|
else
|
|
write32(Buf + 24, 0x818c0000 | 4); // lwz r12,4(r12)
|
|
write32(Buf + 28, 0x7d605a14); // add r11,r0,r11
|
|
write32(Buf + 32, 0x4e800420); // bctr
|
|
Buf += 36;
|
|
}
|
|
|
|
// Pad with nop. They should not be executed.
|
|
for (; Buf < End; Buf += 4)
|
|
write32(Buf, 0x60000000);
|
|
}
|
|
|
|
PPC::PPC() {
|
|
GotRel = R_PPC_GLOB_DAT;
|
|
NoneRel = R_PPC_NONE;
|
|
PltRel = R_PPC_JMP_SLOT;
|
|
RelativeRel = R_PPC_RELATIVE;
|
|
IRelativeRel = R_PPC_IRELATIVE;
|
|
SymbolicRel = R_PPC_ADDR32;
|
|
GotBaseSymInGotPlt = false;
|
|
GotHeaderEntriesNum = 3;
|
|
GotPltHeaderEntriesNum = 0;
|
|
PltHeaderSize = 64; // size of PLTresolve in .glink
|
|
PltEntrySize = 4;
|
|
|
|
NeedsThunks = true;
|
|
|
|
TlsModuleIndexRel = R_PPC_DTPMOD32;
|
|
TlsOffsetRel = R_PPC_DTPREL32;
|
|
TlsGotRel = R_PPC_TPREL32;
|
|
|
|
DefaultMaxPageSize = 65536;
|
|
DefaultImageBase = 0x10000000;
|
|
|
|
write32(TrapInstr.data(), 0x7fe00008);
|
|
}
|
|
|
|
void PPC::writeGotHeader(uint8_t *Buf) const {
|
|
// _GLOBAL_OFFSET_TABLE_[0] = _DYNAMIC
|
|
// glibc stores _dl_runtime_resolve in _GLOBAL_OFFSET_TABLE_[1],
|
|
// link_map in _GLOBAL_OFFSET_TABLE_[2].
|
|
write32(Buf, Main->Dynamic->getVA());
|
|
}
|
|
|
|
void PPC::writeGotPlt(uint8_t *Buf, const Symbol &S) const {
|
|
// Address of the symbol resolver stub in .glink .
|
|
write32(Buf, In.Plt->getVA() + 4 * S.PltIndex);
|
|
}
|
|
|
|
bool PPC::needsThunk(RelExpr Expr, RelType Type, const InputFile *File,
|
|
uint64_t BranchAddr, const Symbol &S) const {
|
|
if (Type != R_PPC_REL24 && Type != R_PPC_PLTREL24)
|
|
return false;
|
|
if (S.isInPlt())
|
|
return true;
|
|
if (S.isUndefWeak())
|
|
return false;
|
|
return !(Expr == R_PC && PPC::inBranchRange(Type, BranchAddr, S.getVA()));
|
|
}
|
|
|
|
uint32_t PPC::getThunkSectionSpacing() const { return 0x2000000; }
|
|
|
|
bool PPC::inBranchRange(RelType Type, uint64_t Src, uint64_t Dst) const {
|
|
uint64_t Offset = Dst - Src;
|
|
if (Type == R_PPC_REL24 || Type == R_PPC_PLTREL24)
|
|
return isInt<26>(Offset);
|
|
llvm_unreachable("unsupported relocation type used in branch");
|
|
}
|
|
|
|
RelExpr PPC::getRelExpr(RelType Type, const Symbol &S,
|
|
const uint8_t *Loc) const {
|
|
switch (Type) {
|
|
case R_PPC_DTPREL16:
|
|
case R_PPC_DTPREL16_HA:
|
|
case R_PPC_DTPREL16_HI:
|
|
case R_PPC_DTPREL16_LO:
|
|
case R_PPC_DTPREL32:
|
|
return R_DTPREL;
|
|
case R_PPC_REL14:
|
|
case R_PPC_REL32:
|
|
case R_PPC_LOCAL24PC:
|
|
case R_PPC_REL16_LO:
|
|
case R_PPC_REL16_HI:
|
|
case R_PPC_REL16_HA:
|
|
return R_PC;
|
|
case R_PPC_GOT16:
|
|
return R_GOT_OFF;
|
|
case R_PPC_REL24:
|
|
return R_PLT_PC;
|
|
case R_PPC_PLTREL24:
|
|
return R_PPC32_PLTREL;
|
|
case R_PPC_GOT_TLSGD16:
|
|
return R_TLSGD_GOT;
|
|
case R_PPC_GOT_TLSLD16:
|
|
return R_TLSLD_GOT;
|
|
case R_PPC_GOT_TPREL16:
|
|
return R_GOT_OFF;
|
|
case R_PPC_TLS:
|
|
return R_TLSIE_HINT;
|
|
case R_PPC_TLSGD:
|
|
return R_TLSDESC_CALL;
|
|
case R_PPC_TLSLD:
|
|
return R_TLSLD_HINT;
|
|
case R_PPC_TPREL16:
|
|
case R_PPC_TPREL16_HA:
|
|
case R_PPC_TPREL16_LO:
|
|
case R_PPC_TPREL16_HI:
|
|
return R_TLS;
|
|
default:
|
|
return R_ABS;
|
|
}
|
|
}
|
|
|
|
RelType PPC::getDynRel(RelType Type) const {
|
|
if (Type == R_PPC_ADDR32)
|
|
return Type;
|
|
return R_PPC_NONE;
|
|
}
|
|
|
|
static std::pair<RelType, uint64_t> fromDTPREL(RelType Type, uint64_t Val) {
|
|
uint64_t DTPBiasedVal = Val - 0x8000;
|
|
switch (Type) {
|
|
case R_PPC_DTPREL16:
|
|
return {R_PPC64_ADDR16, DTPBiasedVal};
|
|
case R_PPC_DTPREL16_HA:
|
|
return {R_PPC_ADDR16_HA, DTPBiasedVal};
|
|
case R_PPC_DTPREL16_HI:
|
|
return {R_PPC_ADDR16_HI, DTPBiasedVal};
|
|
case R_PPC_DTPREL16_LO:
|
|
return {R_PPC_ADDR16_LO, DTPBiasedVal};
|
|
case R_PPC_DTPREL32:
|
|
return {R_PPC_ADDR32, DTPBiasedVal};
|
|
default:
|
|
return {Type, Val};
|
|
}
|
|
}
|
|
|
|
void PPC::relocateOne(uint8_t *Loc, RelType Type, uint64_t Val) const {
|
|
RelType NewType;
|
|
std::tie(NewType, Val) = fromDTPREL(Type, Val);
|
|
switch (NewType) {
|
|
case R_PPC_ADDR16:
|
|
checkIntUInt(Loc, Val, 16, Type);
|
|
write16(Loc, Val);
|
|
break;
|
|
case R_PPC_GOT16:
|
|
case R_PPC_GOT_TLSGD16:
|
|
case R_PPC_GOT_TLSLD16:
|
|
case R_PPC_GOT_TPREL16:
|
|
case R_PPC_TPREL16:
|
|
checkInt(Loc, Val, 16, Type);
|
|
write16(Loc, Val);
|
|
break;
|
|
case R_PPC_ADDR16_HA:
|
|
case R_PPC_DTPREL16_HA:
|
|
case R_PPC_GOT_TLSGD16_HA:
|
|
case R_PPC_GOT_TLSLD16_HA:
|
|
case R_PPC_GOT_TPREL16_HA:
|
|
case R_PPC_REL16_HA:
|
|
case R_PPC_TPREL16_HA:
|
|
write16(Loc, ha(Val));
|
|
break;
|
|
case R_PPC_ADDR16_HI:
|
|
case R_PPC_DTPREL16_HI:
|
|
case R_PPC_GOT_TLSGD16_HI:
|
|
case R_PPC_GOT_TLSLD16_HI:
|
|
case R_PPC_GOT_TPREL16_HI:
|
|
case R_PPC_REL16_HI:
|
|
case R_PPC_TPREL16_HI:
|
|
write16(Loc, Val >> 16);
|
|
break;
|
|
case R_PPC_ADDR16_LO:
|
|
case R_PPC_DTPREL16_LO:
|
|
case R_PPC_GOT_TLSGD16_LO:
|
|
case R_PPC_GOT_TLSLD16_LO:
|
|
case R_PPC_GOT_TPREL16_LO:
|
|
case R_PPC_REL16_LO:
|
|
case R_PPC_TPREL16_LO:
|
|
write16(Loc, Val);
|
|
break;
|
|
case R_PPC_ADDR32:
|
|
case R_PPC_REL32:
|
|
write32(Loc, Val);
|
|
break;
|
|
case R_PPC_REL14: {
|
|
uint32_t Mask = 0x0000FFFC;
|
|
checkInt(Loc, Val, 16, Type);
|
|
checkAlignment(Loc, Val, 4, Type);
|
|
write32(Loc, (read32(Loc) & ~Mask) | (Val & Mask));
|
|
break;
|
|
}
|
|
case R_PPC_REL24:
|
|
case R_PPC_LOCAL24PC:
|
|
case R_PPC_PLTREL24: {
|
|
uint32_t Mask = 0x03FFFFFC;
|
|
checkInt(Loc, Val, 26, Type);
|
|
checkAlignment(Loc, Val, 4, Type);
|
|
write32(Loc, (read32(Loc) & ~Mask) | (Val & Mask));
|
|
break;
|
|
}
|
|
default:
|
|
error(getErrorLocation(Loc) + "unrecognized relocation " + toString(Type));
|
|
}
|
|
}
|
|
|
|
RelExpr PPC::adjustRelaxExpr(RelType Type, const uint8_t *Data,
|
|
RelExpr Expr) const {
|
|
if (Expr == R_RELAX_TLS_GD_TO_IE)
|
|
return R_RELAX_TLS_GD_TO_IE_GOT_OFF;
|
|
if (Expr == R_RELAX_TLS_LD_TO_LE)
|
|
return R_RELAX_TLS_LD_TO_LE_ABS;
|
|
return Expr;
|
|
}
|
|
|
|
int PPC::getTlsGdRelaxSkip(RelType Type) const {
|
|
// A __tls_get_addr call instruction is marked with 2 relocations:
|
|
//
|
|
// R_PPC_TLSGD / R_PPC_TLSLD: marker relocation
|
|
// R_PPC_REL24: __tls_get_addr
|
|
//
|
|
// After the relaxation we no longer call __tls_get_addr and should skip both
|
|
// relocations to not create a false dependence on __tls_get_addr being
|
|
// defined.
|
|
if (Type == R_PPC_TLSGD || Type == R_PPC_TLSLD)
|
|
return 2;
|
|
return 1;
|
|
}
|
|
|
|
void PPC::relaxTlsGdToIe(uint8_t *Loc, RelType Type, uint64_t Val) const {
|
|
switch (Type) {
|
|
case R_PPC_GOT_TLSGD16: {
|
|
// addi rT, rA, x@got@tlsgd --> lwz rT, x@got@tprel(rA)
|
|
uint32_t Insn = readFromHalf16(Loc);
|
|
writeFromHalf16(Loc, 0x80000000 | (Insn & 0x03ff0000));
|
|
relocateOne(Loc, R_PPC_GOT_TPREL16, Val);
|
|
break;
|
|
}
|
|
case R_PPC_TLSGD:
|
|
// bl __tls_get_addr(x@tldgd) --> add r3, r3, r2
|
|
write32(Loc, 0x7c631214);
|
|
break;
|
|
default:
|
|
llvm_unreachable("unsupported relocation for TLS GD to IE relaxation");
|
|
}
|
|
}
|
|
|
|
void PPC::relaxTlsGdToLe(uint8_t *Loc, RelType Type, uint64_t Val) const {
|
|
switch (Type) {
|
|
case R_PPC_GOT_TLSGD16:
|
|
// addi r3, r31, x@got@tlsgd --> addis r3, r2, x@tprel@ha
|
|
writeFromHalf16(Loc, 0x3c620000 | ha(Val));
|
|
break;
|
|
case R_PPC_TLSGD:
|
|
// bl __tls_get_addr(x@tldgd) --> add r3, r3, x@tprel@l
|
|
write32(Loc, 0x38630000 | lo(Val));
|
|
break;
|
|
default:
|
|
llvm_unreachable("unsupported relocation for TLS GD to LE relaxation");
|
|
}
|
|
}
|
|
|
|
void PPC::relaxTlsLdToLe(uint8_t *Loc, RelType Type, uint64_t Val) const {
|
|
switch (Type) {
|
|
case R_PPC_GOT_TLSLD16:
|
|
// addi r3, rA, x@got@tlsgd --> addis r3, r2, 0
|
|
writeFromHalf16(Loc, 0x3c620000);
|
|
break;
|
|
case R_PPC_TLSLD:
|
|
// r3+x@dtprel computes r3+x-0x8000, while we want it to compute r3+x@tprel
|
|
// = r3+x-0x7000, so add 4096 to r3.
|
|
// bl __tls_get_addr(x@tlsld) --> addi r3, r3, 4096
|
|
write32(Loc, 0x38631000);
|
|
break;
|
|
case R_PPC_DTPREL16:
|
|
case R_PPC_DTPREL16_HA:
|
|
case R_PPC_DTPREL16_HI:
|
|
case R_PPC_DTPREL16_LO:
|
|
relocateOne(Loc, Type, Val);
|
|
break;
|
|
default:
|
|
llvm_unreachable("unsupported relocation for TLS LD to LE relaxation");
|
|
}
|
|
}
|
|
|
|
void PPC::relaxTlsIeToLe(uint8_t *Loc, RelType Type, uint64_t Val) const {
|
|
switch (Type) {
|
|
case R_PPC_GOT_TPREL16: {
|
|
// lwz rT, x@got@tprel(rA) --> addis rT, r2, x@tprel@ha
|
|
uint32_t RT = readFromHalf16(Loc) & 0x03e00000;
|
|
writeFromHalf16(Loc, 0x3c020000 | RT | ha(Val));
|
|
break;
|
|
}
|
|
case R_PPC_TLS: {
|
|
uint32_t Insn = read32(Loc);
|
|
if (Insn >> 26 != 31)
|
|
error("unrecognized instruction for IE to LE R_PPC_TLS");
|
|
// addi rT, rT, x@tls --> addi rT, rT, x@tprel@l
|
|
uint32_t DFormOp = getPPCDFormOp((read32(Loc) & 0x000007fe) >> 1);
|
|
if (DFormOp == 0)
|
|
error("unrecognized instruction for IE to LE R_PPC_TLS");
|
|
write32(Loc, (DFormOp << 26) | (Insn & 0x03ff0000) | lo(Val));
|
|
break;
|
|
}
|
|
default:
|
|
llvm_unreachable("unsupported relocation for TLS IE to LE relaxation");
|
|
}
|
|
}
|
|
|
|
TargetInfo *elf::getPPCTargetInfo() {
|
|
static PPC Target;
|
|
return &Target;
|
|
}
|