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[PAC][lld][AArch64][ELF] Support signed TLSDESC (#113817)

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Depends on #120010

Support `R_AARCH64_AUTH_TLSDESC_ADR_PAGE21`, `R_AARCH64_AUTH_TLSDESC_LD64_LO12`
and `R_AARCH64_AUTH_TLSDESC_LD64_LO12` static relocations and
`R_AARCH64_AUTH_TLSDESC` dynamic relocation. IE/LE optimization is not
currently supported for AUTH TLSDESC.
This commit is contained in:
Daniil Kovalev 2025-01-22 12:18:05 +03:00 committed by GitHub
parent 70f8040f09
commit 9178708c3b
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
8 changed files with 198 additions and 3 deletions
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8
lld/ELF/Arch/AArch64.cpp
View File

@ -157,9 +157,14 @@ RelExpr AArch64::getRelExpr(RelType type, const Symbol &s,
return RE_AARCH64_AUTH;
case R_AARCH64_TLSDESC_ADR_PAGE21:
return RE_AARCH64_TLSDESC_PAGE;
case R_AARCH64_AUTH_TLSDESC_ADR_PAGE21:
return RE_AARCH64_AUTH_TLSDESC_PAGE;
case R_AARCH64_TLSDESC_LD64_LO12:
case R_AARCH64_TLSDESC_ADD_LO12:
return R_TLSDESC;
case R_AARCH64_AUTH_TLSDESC_LD64_LO12:
case R_AARCH64_AUTH_TLSDESC_ADD_LO12:
return RE_AARCH64_AUTH_TLSDESC;
case R_AARCH64_TLSDESC_CALL:
return R_TLSDESC_CALL;
case R_AARCH64_TLSLE_ADD_TPREL_HI12:
@ -545,6 +550,7 @@ void AArch64::relocate(uint8_t *loc, const Relocation &rel,
case R_AARCH64_ADR_PREL_PG_HI21:
case R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21:
case R_AARCH64_TLSDESC_ADR_PAGE21:
case R_AARCH64_AUTH_TLSDESC_ADR_PAGE21:
checkInt(ctx, loc, val, 33, rel);
[[fallthrough]];
case R_AARCH64_ADR_PREL_PG_HI21_NC:
@ -597,6 +603,7 @@ void AArch64::relocate(uint8_t *loc, const Relocation &rel,
case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC:
case R_AARCH64_TLSLE_LDST64_TPREL_LO12_NC:
case R_AARCH64_TLSDESC_LD64_LO12:
case R_AARCH64_AUTH_TLSDESC_LD64_LO12:
checkAlignment(ctx, loc, val, 8, rel);
write32Imm12(loc, getBits(val, 3, 11));
break;
@ -671,6 +678,7 @@ void AArch64::relocate(uint8_t *loc, const Relocation &rel,
break;
case R_AARCH64_TLSLE_ADD_TPREL_LO12_NC:
case R_AARCH64_TLSDESC_ADD_LO12:
case R_AARCH64_AUTH_TLSDESC_ADD_LO12:
write32Imm12(loc, val);
break;
case R_AARCH64_TLSDESC:

2
lld/ELF/InputSection.cpp
View File

@ -966,12 +966,14 @@ uint64_t InputSectionBase::getRelocTargetVA(Ctx &ctx, const Relocation &r,
case R_SIZE:
return r.sym->getSize() + a;
case R_TLSDESC:
case RE_AARCH64_AUTH_TLSDESC:
return ctx.in.got->getTlsDescAddr(*r.sym) + a;
case R_TLSDESC_PC:
return ctx.in.got->getTlsDescAddr(*r.sym) + a - p;
case R_TLSDESC_GOTPLT:
return ctx.in.got->getTlsDescAddr(*r.sym) + a - ctx.in.gotPlt->getVA();
case RE_AARCH64_TLSDESC_PAGE:
case RE_AARCH64_AUTH_TLSDESC_PAGE:
return getAArch64Page(ctx.in.got->getTlsDescAddr(*r.sym) + a) -
getAArch64Page(p);
case RE_LOONGARCH_TLSDESC_PAGE_PC:

47
lld/ELF/Relocations.cpp
View File

@ -1292,6 +1292,27 @@ static unsigned handleMipsTlsRelocation(Ctx &ctx, RelType type, Symbol &sym,
return 0;
}
static unsigned handleAArch64PAuthTlsRelocation(InputSectionBase *sec,
RelExpr expr, RelType type,
uint64_t offset, Symbol &sym,
int64_t addend) {
// Do not optimize signed TLSDESC to LE/IE (as described in pauthabielf64).
// https://github.com/ARM-software/abi-aa/blob/main/pauthabielf64/pauthabielf64.rst#general-restrictions
// > PAUTHELF64 only supports the descriptor based TLS (TLSDESC).
if (oneof<RE_AARCH64_AUTH_TLSDESC_PAGE, RE_AARCH64_AUTH_TLSDESC>(expr)) {
sym.setFlags(NEEDS_TLSDESC | NEEDS_TLSDESC_AUTH);
sec->addReloc({expr, type, offset, addend, &sym});
return 1;
}
// TLSDESC_CALL hint relocation should not be emitted by compiler with signed
// TLSDESC enabled.
if (expr == R_TLSDESC_CALL)
sym.setFlags(NEEDS_TLSDESC_NONAUTH);
return 0;
}
// Notes about General Dynamic and Local Dynamic TLS models below. They may
// require the generation of a pair of GOT entries that have associated dynamic
// relocations. The pair of GOT entries created are of the form GOT[e0] Module
@ -1302,6 +1323,13 @@ static unsigned handleMipsTlsRelocation(Ctx &ctx, RelType type, Symbol &sym,
unsigned RelocationScanner::handleTlsRelocation(RelExpr expr, RelType type,
uint64_t offset, Symbol &sym,
int64_t addend) {
bool isAArch64 = ctx.arg.emachine == EM_AARCH64;
if (isAArch64)
if (unsigned processed = handleAArch64PAuthTlsRelocation(
sec, expr, type, offset, sym, addend))
return processed;
if (expr == R_TPREL || expr == R_TPREL_NEG) {
if (ctx.arg.shared) {
auto diag = Err(ctx);
@ -1336,7 +1364,9 @@ unsigned RelocationScanner::handleTlsRelocation(RelExpr expr, RelType type,
// R_RISCV_TLSDESC_{LOAD_LO12,ADD_LO12_I,CALL} reference a label. Do not
// set NEEDS_TLSDESC on the label.
if (expr != R_TLSDESC_CALL) {
if (!isRISCV || type == R_RISCV_TLSDESC_HI20)
if (isAArch64)
sym.setFlags(NEEDS_TLSDESC | NEEDS_TLSDESC_NONAUTH);
else if (!isRISCV || type == R_RISCV_TLSDESC_HI20)
sym.setFlags(NEEDS_TLSDESC);
sec->addReloc({expr, type, offset, addend, &sym});
}
@ -1847,10 +1877,21 @@ void elf::postScanRelocations(Ctx &ctx) {
GotSection *got = ctx.in.got.get();
if (flags & NEEDS_TLSDESC) {
if ((flags & NEEDS_TLSDESC_AUTH) && (flags & NEEDS_TLSDESC_NONAUTH)) {
Err(ctx)
<< "both AUTH and non-AUTH TLSDESC entries for '" << sym.getName()
<< "' requested, but only one type of TLSDESC entry per symbol is "
"supported";
return;
}
got->addTlsDescEntry(sym);
RelType tlsDescRel = ctx.target->tlsDescRel;
if (flags & NEEDS_TLSDESC_AUTH) {
got->addTlsDescAuthEntry();
tlsDescRel = ELF::R_AARCH64_AUTH_TLSDESC;
}
ctx.mainPart->relaDyn->addAddendOnlyRelocIfNonPreemptible(
ctx.target->tlsDescRel, *got, got->getTlsDescOffset(sym), sym,
ctx.target->tlsDescRel);
tlsDescRel, *got, got->getTlsDescOffset(sym), sym, tlsDescRel);
}
if (flags & NEEDS_TLSGD) {
got->addDynTlsEntry(sym);

2
lld/ELF/Relocations.h
View File

@ -99,6 +99,8 @@ enum RelExpr {
RE_AARCH64_PAGE_PC,
RE_AARCH64_RELAX_TLS_GD_TO_IE_PAGE_PC,
RE_AARCH64_TLSDESC_PAGE,
RE_AARCH64_AUTH_TLSDESC_PAGE,
RE_AARCH64_AUTH_TLSDESC,
RE_AARCH64_AUTH,
RE_ARM_PCA,
RE_ARM_SBREL,

2
lld/ELF/Symbols.h
View File

@ -53,6 +53,8 @@ enum {
NEEDS_TLSIE = 1 << 8,
NEEDS_GOT_AUTH = 1 << 9,
NEEDS_GOT_NONAUTH = 1 << 10,
NEEDS_TLSDESC_AUTH = 1 << 11,
NEEDS_TLSDESC_NONAUTH = 1 << 12,
};
// The base class for real symbol classes.

5
lld/ELF/SyntheticSections.cpp
View File

@ -681,6 +681,11 @@ bool GotSection::addTlsDescEntry(const Symbol &sym) {
return true;
}
void GotSection::addTlsDescAuthEntry() {
authEntries.push_back({(numEntries - 2) * ctx.arg.wordsize, true});
authEntries.push_back({(numEntries - 1) * ctx.arg.wordsize, false});
}
bool GotSection::addDynTlsEntry(const Symbol &sym) {
assert(sym.auxIdx == ctx.symAux.size() - 1);
ctx.symAux.back().tlsGdIdx = numEntries;

1
lld/ELF/SyntheticSections.h
View File

@ -114,6 +114,7 @@ public:
void addEntry(const Symbol &sym);
void addAuthEntry(const Symbol &sym);
bool addTlsDescEntry(const Symbol &sym);
void addTlsDescAuthEntry();
bool addDynTlsEntry(const Symbol &sym);
bool addTlsIndex();
uint32_t getTlsDescOffset(const Symbol &sym) const;

134
lld/test/ELF/aarch64-tlsdesc-pauth.s Normal file
View File

@ -0,0 +1,134 @@
// REQUIRES: aarch64
// RUN: rm -rf %t && split-file %s %t && cd %t
//--- a.s
.section .tbss,"awT",@nobits
.global a
a:
.xword 0
//--- ok.s
// RUN: llvm-mc -filetype=obj -triple=aarch64-pc-linux -mattr=+pauth ok.s -o ok.o
// RUN: ld.lld -shared ok.o -o ok.so
// RUN: llvm-objdump --no-print-imm-hex -d --no-show-raw-insn ok.so | \
// RUN: FileCheck -DP=20 -DA=896 -DB=912 -DC=928 %s
// RUN: llvm-readobj -r -x .got ok.so | FileCheck --check-prefix=REL \
// RUN: -DP1=20 -DA1=380 -DB1=390 -DC1=3A0 -DP2=020 -DA2=380 -DB2=390 -DC2=3a0 %s
// RUN: llvm-mc -filetype=obj -triple=aarch64-pc-linux -mattr=+pauth a.s -o a.so.o
// RUN: ld.lld -shared a.so.o -soname=so -o a.so
// RUN: ld.lld ok.o a.so -o ok
// RUN: llvm-objdump --no-print-imm-hex -d --no-show-raw-insn ok | \
// RUN: FileCheck -DP=220 -DA=936 -DB=952 -DC=968 %s
// RUN: llvm-readobj -r -x .got ok | FileCheck --check-prefix=REL \
// RUN: -DP1=220 -DA1=3A8 -DB1=3B8 -DC1=3C8 -DP2=220 -DA2=3a8 -DB2=3b8 -DC2=3c8 %s
.text
adrp x0, :tlsdesc_auth:a
ldr x16, [x0, :tlsdesc_auth_lo12:a]
add x0, x0, :tlsdesc_auth_lo12:a
blraa x16, x0
// CHECK: adrp x0, 0x[[P]]000
// CHECK-NEXT: ldr x16, [x0, #[[A]]]
// CHECK-NEXT: add x0, x0, #[[A]]
// CHECK-NEXT: blraa x16, x0
/// Create relocation against local TLS symbols where linker should
/// create target specific dynamic TLSDESC relocation where addend is
/// the symbol VMA in tls block.
adrp x0, :tlsdesc_auth:local1
ldr x16, [x0, :tlsdesc_auth_lo12:local1]
add x0, x0, :tlsdesc_auth_lo12:local1
blraa x16, x0
// CHECK: adrp x0, 0x[[P]]000
// CHECK-NEXT: ldr x16, [x0, #[[B]]]
// CHECK-NEXT: add x0, x0, #[[B]]
// CHECK-NEXT: blraa x16, x0
adrp x0, :tlsdesc_auth:local2
ldr x16, [x0, :tlsdesc_auth_lo12:local2]
add x0, x0, :tlsdesc_auth_lo12:local2
blraa x16, x0
// CHECK: adrp x0, 0x[[P]]000
// CHECK-NEXT: ldr x16, [x0, #[[C]]]
// CHECK-NEXT: add x0, x0, #[[C]]
// CHECK-NEXT: blraa x16, x0
.section .tbss,"awT",@nobits
.type local1,@object
.p2align 2
local1:
.word 0
.size local1, 4
.type local2,@object
.p2align 3
local2:
.xword 0
.size local2, 8
// R_AARCH64_AUTH_TLSDESC - 0x0 -> start of tls block
// R_AARCH64_AUTH_TLSDESC - 0x8 -> align (sizeof (local1), 8)
// REL: Relocations [
// REL-NEXT: Section (5) .rela.dyn {
// REL-NEXT: 0x[[P1]][[B1]] R_AARCH64_AUTH_TLSDESC - 0x0
// REL-NEXT: 0x[[P1]][[C1]] R_AARCH64_AUTH_TLSDESC - 0x8
// REL-NEXT: 0x[[P1]][[A1]] R_AARCH64_AUTH_TLSDESC a 0x0
// REL-NEXT: }
// REL-NEXT: ]
// REL: Hex dump of section '.got':
// REL-NEXT: 0x00[[P2]][[A2]] 00000000 00000080 00000000 000000a0
// REL-NEXT: 0x00[[P2]][[B2]] 00000000 00000080 00000000 000000a0
// REL-NEXT: 0x00[[P2]][[C2]] 00000000 00000080 00000000 000000a0
/// ^^
/// 0b10000000 bit 63 address diversity = true, bits 61..60 key = IA
/// ^^
/// 0b10100000 bit 63 address diversity = true, bits 61..60 key = DA
//--- err1.s
// RUN: llvm-mc -filetype=obj -triple=aarch64-pc-linux -mattr=+pauth err1.s -o err1.o
// RUN: not ld.lld -shared err1.o 2>&1 | FileCheck --check-prefix=ERR1 --implicit-check-not=error: %s
// ERR1: error: both AUTH and non-AUTH TLSDESC entries for 'a' requested, but only one type of TLSDESC entry per symbol is supported
.text
adrp x0, :tlsdesc_auth:a
ldr x16, [x0, :tlsdesc_auth_lo12:a]
add x0, x0, :tlsdesc_auth_lo12:a
blraa x16, x0
adrp x0, :tlsdesc:a
ldr x1, [x0, :tlsdesc_lo12:a]
add x0, x0, :tlsdesc_lo12:a
blr x1
//--- err2.s
// RUN: llvm-mc -filetype=obj -triple=aarch64-pc-linux -mattr=+pauth err2.s -o err2.o
// RUN: not ld.lld -shared err2.o 2>&1 | FileCheck --check-prefix=ERR2 --implicit-check-not=error: %s
// ERR2: error: both AUTH and non-AUTH TLSDESC entries for 'a' requested, but only one type of TLSDESC entry per symbol is supported
.text
adrp x0, :tlsdesc:a
ldr x1, [x0, :tlsdesc_lo12:a]
add x0, x0, :tlsdesc_lo12:a
blr x1
adrp x0, :tlsdesc_auth:a
ldr x16, [x0, :tlsdesc_auth_lo12:a]
add x0, x0, :tlsdesc_auth_lo12:a
blraa x16, x0
//--- err3.s
// RUN: llvm-mc -filetype=obj -triple=aarch64-pc-linux -mattr=+pauth err3.s -o err3.o
// RUN: not ld.lld -shared err3.o 2>&1 | FileCheck --check-prefix=ERR3 --implicit-check-not=error: %s
// ERR3: error: both AUTH and non-AUTH TLSDESC entries for 'a' requested, but only one type of TLSDESC entry per symbol is supported
.text
adrp x0, :tlsdesc_auth:a
ldr x16, [x0, :tlsdesc_auth_lo12:a]
add x0, x0, :tlsdesc_auth_lo12:a
.tlsdesccall a
blraa x16, x0