Optimize erratum 843419 fix.
gold/ChangeLog: * aarch64.cc (AArch64_insn_utilities::is_adr): New method. (AArch64_insn_utilities::aarch64_adr_encode_imm): New method. (AArch64_insn_utilities::aarch64_adrp_decode_imm): New method. (E843419_stub): New sub-class of Erratum_stub. (AArch64_relobj::try_fix_erratum_843419_optimized): New method. (AArch64_relobj::section_needs_reloc_stub_scanning): Try optimized fix. (AArch64_relobj::create_erratum_stub): Add 1 argument. (Target_aarch64::scan_erratum_843419_span): Pass in adrp insn offset.
This commit is contained in:
Han Shen
parent
45972d0074
commit
0ef3814fe1
@ -1,3 +1,16 @@
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2015-07-20 Han Shen <shenhan@google.com>
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Optimize erratum 843419 fix.
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* aarch64.cc (AArch64_insn_utilities::is_adr): New method.
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(AArch64_insn_utilities::aarch64_adr_encode_imm): New method.
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(AArch64_insn_utilities::aarch64_adrp_decode_imm): New method.
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(E843419_stub): New sub-class of Erratum_stub.
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(AArch64_relobj::try_fix_erratum_843419_optimized): New method.
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(AArch64_relobj::section_needs_reloc_stub_scanning): Try optimized fix.
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(AArch64_relobj::create_erratum_stub): Add 1 argument.
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(Target_aarch64::scan_erratum_843419_span): Pass in adrp insn offset.
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2015-07-20 Han Shen <shenhan@google.com>
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Fix arm elf header flags wrt hardfp bit.
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165
gold/aarch64.cc
165
gold/aarch64.cc
@ -102,6 +102,10 @@ public:
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aarch64_ra(Insntype insn)
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{ return aarch64_bits(insn, 10, 5); }
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static bool
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is_adr(const Insntype insn)
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{ return (insn & 0x9F000000) == 0x10000000; }
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static bool
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is_adrp(const Insntype insn)
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{ return (insn & 0x9F000000) == 0x90000000; }
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@ -126,6 +130,39 @@ public:
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aarch64_rt2(const Insntype insn)
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{ return aarch64_bits(insn, 10, 5); }
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// Encode imm21 into adr. Signed imm21 is in the range of [-1M, 1M).
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static Insntype
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aarch64_adr_encode_imm(Insntype adr, int imm21)
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{
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gold_assert(is_adr(adr));
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gold_assert(-(1 << 20) <= imm21 && imm21 < (1 << 20));
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const int mask19 = (1 << 19) - 1;
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const int mask2 = 3;
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adr &= ~((mask19 << 5) | (mask2 << 29));
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adr |= ((imm21 & mask2) << 29) | (((imm21 >> 2) & mask19) << 5);
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return adr;
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}
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// Retrieve encoded adrp 33-bit signed imm value. This value is obtained by
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// 21-bit signed imm encoded in the insn multiplied by 4k (page size) and
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// 64-bit sign-extended, resulting in [-4G, 4G) with 12-lsb being 0.
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static int64_t
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aarch64_adrp_decode_imm(const Insntype adrp)
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{
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const int mask19 = (1 << 19) - 1;
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const int mask2 = 3;
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gold_assert(is_adrp(adrp));
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// 21-bit imm encoded in adrp.
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uint64_t imm = ((adrp >> 29) & mask2) | (((adrp >> 5) & mask19) << 2);
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// Retrieve msb of 21-bit-signed imm for sign extension.
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uint64_t msbt = (imm >> 20) & 1;
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// Real value is imm multipled by 4k. Value now has 33-bit information.
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int64_t value = imm << 12;
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// Sign extend to 64-bit by repeating msbt 31 (64-33) times and merge it
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// with value.
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return ((((uint64_t)(1) << 32) - msbt) << 33) | value;
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}
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static bool
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aarch64_b(const Insntype insn)
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{ return (insn & 0xFC000000) == 0x14000000; }
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@ -1019,6 +1056,35 @@ private:
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AArch64_address erratum_address_;
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}; // End of "Erratum_stub".
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// Erratum sub class to wrap additional info needed by 843419. In fixing this
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// erratum, we may choose to replace 'adrp' with 'adr', in this case, we need
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// adrp's code position (two or three insns before erratum insn itself).
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template<int size, bool big_endian>
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class E843419_stub : public Erratum_stub<size, big_endian>
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{
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public:
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typedef typename AArch64_insn_utilities<big_endian>::Insntype Insntype;
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E843419_stub(AArch64_relobj<size, big_endian>* relobj,
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unsigned int shndx, unsigned int sh_offset,
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unsigned int adrp_sh_offset)
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: Erratum_stub<size, big_endian>(relobj, ST_E_843419, shndx, sh_offset),
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adrp_sh_offset_(adrp_sh_offset)
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{}
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unsigned int
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adrp_sh_offset() const
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{ return this->adrp_sh_offset_; }
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private:
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// Section offset of "adrp". (We do not need a "adrp_shndx_" field, because we
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// can can obtain it from its parent.)
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const unsigned int adrp_sh_offset_;
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};
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template<int size, bool big_endian>
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const int Erratum_stub<size, big_endian>::STUB_ADDR_ALIGN = 4;
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@ -1754,6 +1820,13 @@ class AArch64_relobj : public Sized_relobj_file<size, big_endian>
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void
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fix_errata(typename Sized_relobj_file<size, big_endian>::Views* pviews);
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// Try to fix erratum 843419 in an optimized way. Return true if patch is
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// applied.
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bool
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try_fix_erratum_843419_optimized(
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The_erratum_stub*,
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typename Sized_relobj_file<size, big_endian>::View_size&);
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// Whether a section needs to be scanned for relocation stubs.
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bool
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section_needs_reloc_stub_scanning(const elfcpp::Shdr<size, big_endian>&,
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@ -1891,18 +1964,75 @@ AArch64_relobj<size, big_endian>::fix_errata(
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Insntype insn_to_fix = ip[0];
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stub->update_erratum_insn(insn_to_fix);
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// Replace the erratum insn with a branch-to-stub.
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AArch64_address stub_address =
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stub_table->erratum_stub_address(stub);
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unsigned int b_offset = stub_address - stub->erratum_address();
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AArch64_relocate_functions<size, big_endian>::construct_b(
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pview.view + stub->sh_offset(), b_offset & 0xfffffff);
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// First try to see if erratum is 843419 and if it can be fixed
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// without using branch-to-stub.
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if (!try_fix_erratum_843419_optimized(stub, pview))
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{
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// Replace the erratum insn with a branch-to-stub.
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AArch64_address stub_address =
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stub_table->erratum_stub_address(stub);
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unsigned int b_offset = stub_address - stub->erratum_address();
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AArch64_relocate_functions<size, big_endian>::construct_b(
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pview.view + stub->sh_offset(), b_offset & 0xfffffff);
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}
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++p;
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}
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}
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}
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// This is an optimization for 843419. This erratum requires the sequence begin
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// with 'adrp', when final value calculated by adrp fits in adr, we can just
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// replace 'adrp' with 'adr', so we save 2 jumps per occurrence. (Note, however,
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// in this case, we do not delete the erratum stub (too late to do so), it is
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// merely generated without ever being called.)
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template<int size, bool big_endian>
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bool
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AArch64_relobj<size, big_endian>::try_fix_erratum_843419_optimized(
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The_erratum_stub* stub,
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typename Sized_relobj_file<size, big_endian>::View_size& pview)
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{
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if (stub->type() != ST_E_843419)
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return false;
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typedef AArch64_insn_utilities<big_endian> Insn_utilities;
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typedef typename elfcpp::Swap<32,big_endian>::Valtype Insntype;
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E843419_stub<size, big_endian>* e843419_stub =
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reinterpret_cast<E843419_stub<size, big_endian>*>(stub);
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AArch64_address pc = pview.address + e843419_stub->adrp_sh_offset();
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Insntype* adrp_view = reinterpret_cast<Insntype*>(
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pview.view + e843419_stub->adrp_sh_offset());
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Insntype adrp_insn = adrp_view[0];
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gold_assert(Insn_utilities::is_adrp(adrp_insn));
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// Get adrp 33-bit signed imm value.
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int64_t adrp_imm = Insn_utilities::
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aarch64_adrp_decode_imm(adrp_insn);
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// adrp - final value transferred to target register is calculated as:
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// PC[11:0] = Zeros(12)
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// adrp_dest_value = PC + adrp_imm;
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int64_t adrp_dest_value = (pc & ~((1 << 12) - 1)) + adrp_imm;
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// adr -final value transferred to target register is calucalted as:
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// PC + adr_imm
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// So we have:
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// PC + adr_imm = adrp_dest_value
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// ==>
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// adr_imm = adrp_dest_value - PC
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int64_t adr_imm = adrp_dest_value - pc;
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// Check if imm fits in adr (21-bit signed).
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if (-(1 << 20) <= adr_imm && adr_imm < (1 << 20))
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{
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// Convert 'adrp' into 'adr'.
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Insntype adr_insn = adrp_insn & ((1 << 31) - 1);
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adr_insn = Insn_utilities::
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aarch64_adr_encode_imm(adr_insn, adr_imm);
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elfcpp::Swap<32, big_endian>::writeval(adrp_view, adr_insn);
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return true;
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}
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return false;
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}
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// Relocate sections.
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template<int size, bool big_endian>
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@ -3166,14 +3296,16 @@ class Target_aarch64 : public Sized_target<size, big_endian>
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return this->plt_;
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}
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// Helper method to create erratum stubs for ST_E_843419 and ST_E_835769.
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// Helper method to create erratum stubs for ST_E_843419 and ST_E_835769. For
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// ST_E_843419, we need an additional field for adrp offset.
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void create_erratum_stub(
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AArch64_relobj<size, big_endian>* relobj,
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unsigned int shndx,
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section_size_type erratum_insn_offset,
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Address erratum_address,
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typename Insn_utilities::Insntype erratum_insn,
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int erratum_type);
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int erratum_type,
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unsigned int e843419_adrp_offset=0);
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// Return whether this is a 3-insn erratum sequence.
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bool is_erratum_843419_sequence(
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@ -7871,7 +8003,8 @@ Target_aarch64<size, big_endian>::create_erratum_stub(
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section_size_type erratum_insn_offset,
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Address erratum_address,
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typename Insn_utilities::Insntype erratum_insn,
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int erratum_type)
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int erratum_type,
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unsigned int e843419_adrp_offset)
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{
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gold_assert(erratum_type == ST_E_843419 || erratum_type == ST_E_835769);
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The_stub_table* stub_table = relobj->stub_table(shndx);
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@ -7881,8 +8014,15 @@ Target_aarch64<size, big_endian>::create_erratum_stub(
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erratum_insn_offset) == NULL)
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{
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const int BPI = AArch64_insn_utilities<big_endian>::BYTES_PER_INSN;
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The_erratum_stub* stub = new The_erratum_stub(
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relobj, erratum_type, shndx, erratum_insn_offset);
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The_erratum_stub* stub;
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if (erratum_type == ST_E_835769)
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stub = new The_erratum_stub(relobj, erratum_type, shndx,
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erratum_insn_offset);
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else if (erratum_type == ST_E_843419)
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stub = new E843419_stub<size, big_endian>(
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relobj, shndx, erratum_insn_offset, e843419_adrp_offset);
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else
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gold_unreachable();
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stub->set_erratum_insn(erratum_insn);
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stub->set_erratum_address(erratum_address);
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// For erratum ST_E_843419 and ST_E_835769, the destination address is
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@ -8027,7 +8167,8 @@ Target_aarch64<size, big_endian>::scan_erratum_843419_span(
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output_address + offset + insn_offset;
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create_erratum_stub(relobj, shndx,
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erratum_insn_offset, erratum_address,
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erratum_insn, ST_E_843419);
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erratum_insn, ST_E_843419,
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span_start + offset);
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}
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}
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