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[SPARC] Relax TLS GD/LD relocations
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@rui314
rui314 committed Aug 13, 2024
1 parent ed22d76 commit addb5f1
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Showing 3 changed files with 76 additions and 60 deletions.
113 changes: 75 additions & 38 deletions elf/arch-sparc64.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -359,27 +359,75 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
*(ub32 *)loc |= bits(S + A, 11, 0);
break;
case R_SPARC_TLS_GD_HI22:
*(ub32 *)loc |= bits(sym.get_tlsgd_addr(ctx) + A - GOT, 31, 10);
if (sym.has_tlsgd(ctx)) {
*(ub32 *)loc |= bits(sym.get_tlsgd_addr(ctx) + A - GOT, 31, 10);
} else if (sym.has_gottp(ctx)) {
*(ub32 *)loc |= bits(sym.get_gottp_addr(ctx) + A - GOT, 31, 10);
} else {
*(ub32 *)loc |= bits(~(S + A - ctx.tp_addr), 31, 10);
}
break;
case R_SPARC_TLS_GD_LO10:
*(ub32 *)loc |= bits(sym.get_tlsgd_addr(ctx) + A - GOT, 9, 0);
if (sym.has_tlsgd(ctx)) {
*(ub32 *)loc |= bits(sym.get_tlsgd_addr(ctx) + A - GOT, 9, 0);
} else if (sym.has_gottp(ctx)) {
u32 rd = bits(*(ub32 *)loc, 29, 25);
*(ub32 *)loc = 0x8010'2000 | (rd << 25) | (rd << 14); // or %reg, $0, %reg
*(ub32 *)loc |= bits(sym.get_gottp_addr(ctx) + A - GOT, 9, 0);
} else {
u32 rd = bits(*(ub32 *)loc, 29, 25);
*(ub32 *)loc = 0x8018'2000 | (rd << 25) | (rd << 14); // xor %reg, $0, %reg
*(ub32 *)loc |= bits(S + A - ctx.tp_addr, 9, 0) | 0b1'1100'0000'0000;
}
break;
case R_SPARC_TLS_GD_ADD:
if (sym.has_tlsgd(ctx)) {
// do nothing
} else if (sym.has_gottp(ctx)) {
u32 rs2 = bits(*(ub32 *)loc, 4, 0);
*(ub32 *)loc = 0xd05d'c000 | rs2; // ldx [ %l7 + %reg ], %o0
} else {
u32 rs2 = bits(*(ub32 *)loc, 4, 0);
*(ub32 *)loc = 0x9001'c000 | rs2; // add %g7, %reg, %o0
}
break;
case R_SPARC_TLS_GD_CALL:
case R_SPARC_TLS_LDM_CALL: {
u64 addr;
if (ctx.arg.static_)
addr = ctx.extra.tls_get_addr_sec->shdr.sh_addr;
else
addr = ctx.extra.tls_get_addr_sym->get_addr(ctx);

*(ub32 *)loc |= bits(addr + A - P, 31, 2);
if (sym.has_tlsgd(ctx)) {
u64 addr = ctx.extra.tls_get_addr_sym->get_addr(ctx);
*(ub32 *)loc |= bits(addr + A - P, 31, 2);
} else if (sym.has_gottp(ctx)) {
*(ub32 *)loc = 0x9001'c008; // add %g7, %o0, %o0
} else {
*(ub32 *)loc = 0x0100'0000; // nop
}
break;
}
case R_SPARC_TLS_LDM_HI22:
*(ub32 *)loc |= bits(ctx.got->get_tlsld_addr(ctx) + A - GOT, 31, 10);
if (ctx.got->has_tlsld(ctx))
*(ub32 *)loc |= bits(ctx.got->get_tlsld_addr(ctx) + A - GOT, 31, 10);
else
*(ub32 *)loc |= bits(ctx.tp_addr - ctx.tls_begin, 31, 10);
break;
case R_SPARC_TLS_LDM_LO10:
*(ub32 *)loc |= bits(ctx.got->get_tlsld_addr(ctx) + A - GOT, 9, 0);
if (ctx.got->has_tlsld(ctx))
*(ub32 *)loc |= bits(ctx.got->get_tlsld_addr(ctx) + A - GOT, 9, 0);
else
*(ub32 *)loc |= bits(ctx.tp_addr - ctx.tls_begin, 9, 0);
break;
case R_SPARC_TLS_LDM_ADD:
if (ctx.got->has_tlsld(ctx)) {
// do nothing
} else {
u32 rs2 = bits(*(ub32 *)loc, 4, 0);
*(ub32 *)loc = 0x9021'c000 | rs2; // sub %g7, %reg, %o0
}
break;
case R_SPARC_TLS_LDM_CALL:
if (ctx.got->has_tlsld(ctx)) {
u64 addr = ctx.extra.tls_get_addr_sym->get_addr(ctx);
*(ub32 *)loc |= bits(addr + A - P, 31, 2);
} else {
*(ub32 *)loc = 0x0100'0000; // nop
}
break;
case R_SPARC_TLS_LDO_HIX22:
*(ub32 *)loc |= bits(S + A - ctx.dtp_addr, 31, 10);
Expand All @@ -402,8 +450,6 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
case R_SPARC_SIZE32:
*(ub32 *)loc = sym.esym().st_size + A;
break;
case R_SPARC_TLS_GD_ADD:
case R_SPARC_TLS_LDM_ADD:
case R_SPARC_TLS_LDO_ADD:
case R_SPARC_TLS_IE_LD:
case R_SPARC_TLS_IE_LDX:
Expand Down Expand Up @@ -554,10 +600,22 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
scan_pcrel(ctx, sym, rel);
break;
case R_SPARC_TLS_GD_HI22:
sym.flags |= NEEDS_TLSGD;
if (ctx.arg.static_ || (ctx.arg.relax && sym.is_tprel_linktime_const(ctx))) {
// We always relax if -static because libc.a doesn't contain
// __tls_get_addr().
} else if (ctx.arg.relax && sym.is_tprel_runtime_const(ctx)) {
sym.flags |= NEEDS_GOTTP;
} else {
sym.flags |= NEEDS_TLSGD;
}
break;
case R_SPARC_TLS_LDM_HI22:
ctx.needs_tlsld = true;
if (ctx.arg.static_ || (ctx.arg.relax && !ctx.arg.shared)) {
// We always relax if -static because libc.a doesn't contain
// __tls_get_addr().
} else {
ctx.needs_tlsld = true;
}
break;
case R_SPARC_TLS_IE_HI22:
sym.flags |= NEEDS_GOTTP;
Expand Down Expand Up @@ -594,25 +652,4 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
}
}

// __tls_get_addr is not defined by libc.a, so we can't use that function
// in statically-linked executables. This section provides a replacement.
void SparcTlsGetAddrSection::copy_buf(Context<E> &ctx) {
ub32 *buf = (ub32 *)(ctx.buf + this->shdr.sh_offset);

constexpr ub32 insn[] = {
0x0300'0000, // sethi %hi(TP_SIZE), %g1
0x8210'6000, // or %g1, %lo(TP_SIZE), %g1
0x8221'c001, // sub %g7, %g1, %g1
0xd05a'2008, // ldx [ %o0 + 8 ], %o0
0x81c3'e008, // retl
0x9000'4008, // add %g1, %o0, %o0
};

assert(this->shdr.sh_size == sizeof(insn));
memcpy(buf, insn, sizeof(insn));

buf[0] |= bits(ctx.tp_addr - ctx.tls_begin, 31, 10);
buf[1] |= bits(ctx.tp_addr - ctx.tls_begin, 9, 0);
}

} // namespace mold::elf
18 changes: 0 additions & 18 deletions elf/mold.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1599,23 +1599,6 @@ class PPC64SaveRestoreSection : public Chunk<PPC64V2> {

template <> u64 get_eflags(Context<PPC64V2> &ctx);

//
// arch-sparc.cc
//

class SparcTlsGetAddrSection : public Chunk<SPARC64> {
public:
SparcTlsGetAddrSection() {
this->name = ".tls_get_addr";
this->shdr.sh_type = SHT_PROGBITS;
this->shdr.sh_flags = SHF_ALLOC | SHF_EXECINSTR;
this->shdr.sh_addralign = 4;
this->shdr.sh_size = 24;
}

void copy_buf(Context<SPARC64> &ctx) override;
};

//
// arch-alpha.cc
//
Expand Down Expand Up @@ -1747,7 +1730,6 @@ struct ContextExtras<PPC64V2> {

template <>
struct ContextExtras<SPARC64> {
SparcTlsGetAddrSection *tls_get_addr_sec = nullptr;
Symbol<SPARC64> *tls_get_addr_sym = nullptr;
};

Expand Down
5 changes: 1 addition & 4 deletions elf/passes.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -190,11 +190,8 @@ void create_synthetic_sections(Context<E> &ctx) {
if constexpr (is_ppc64v2<E>)
ctx.extra.save_restore = push(new PPC64SaveRestoreSection);

if constexpr (is_sparc<E>) {
if (ctx.arg.static_)
ctx.extra.tls_get_addr_sec = push(new SparcTlsGetAddrSection);
if constexpr (is_sparc<E>)
ctx.extra.tls_get_addr_sym = get_symbol(ctx, "__tls_get_addr");
}

if constexpr (is_alpha<E>)
ctx.extra.got = push(new AlphaGotSection);
Expand Down

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