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From: Richard Sandiford <richard.sandiford@arm.com>
To: Andrew Carlotti <andrew.carlotti@arm.com>
Cc: gcc-patches@gcc.gnu.org,  richard.earnshaw@arm.com
Subject: Re: [PATCH v2[1/5] aarch64: Add cpu feature detection to libgcc
Date: Mon, 20 Nov 2023 15:46:06 +0000	[thread overview]
Message-ID: <mptzfz8o2bl.fsf@arm.com> (raw)
In-Reply-To: <79cc2f22-4e89-a7ac-494c-0eb7de0cc9c8@e124511.cambridge.arm.com> (Andrew Carlotti's message of "Fri, 17 Nov 2023 02:51:31 +0000")

Andrew Carlotti <andrew.carlotti@arm.com> writes:
> This is added to enable function multiversioning, but can also be used
> directly.  The interface is chosen to match that used in LLVM's
> compiler-rt, to facilitate cross-compiler compatibility.
>
> The content of the patch is derived almost entirely from Pavel's prior
> contributions to compiler-rt/lib/builtins/cpu_model.c. I have made minor
> changes to align more closely with GCC coding style, and to exclude any code
> from other LLVM contributors, and am adding this to GCC with Pavel's approval.
>
> libgcc/ChangeLog:
>
> 	* config/aarch64/t-aarch64: Include cpuinfo.c
> 	* config/aarch64/cpuinfo.c: New file
> 	(__init_cpu_features_constructor) New.
> 	(__init_cpu_features_resolver) New.
> 	(__init_cpu_features) New.

OK on the basis that you mentioed in the covering note: we can deal
with fixes incrementally.  One question though...
>
> Co-authored-by: Pavel Iliin <Pavel.Iliin@arm.com>
>
>
> diff --git a/libgcc/config/aarch64/cpuinfo.c b/libgcc/config/aarch64/cpuinfo.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..0888ca4ed058430f524b99cb0e204bd996fa0e55
> --- /dev/null
> +++ b/libgcc/config/aarch64/cpuinfo.c
> @@ -0,0 +1,502 @@
> +/* CPU feature detection for AArch64 architecture.
> +   Copyright (C) 2023 Free Software Foundation, Inc.
> +
> +   This file is part of GCC.
> +
> +   This file is free software; you can redistribute it and/or modify it
> +   under the terms of the GNU General Public License as published by the
> +   Free Software Foundation; either version 3, or (at your option) any
> +   later version.
> +
> +   This file is distributed in the hope that it will be useful, but
> +   WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   General Public License for more details.
> +
> +   Under Section 7 of GPL version 3, you are granted additional
> +   permissions described in the GCC Runtime Library Exception, version
> +   3.1, as published by the Free Software Foundation.
> +  
> +   You should have received a copy of the GNU General Public License and
> +   a copy of the GCC Runtime Library Exception along with this program;
> +   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#if defined(__has_include)

Is this protecting against a known condition?  libgcc has to be built
with the associated version of GCC, so it might be better to drop the
#if and get a noisy failure if something unexpected happens.  That can
be part of 5/5 though.

Thanks,
Richard

> +#if __has_include(<sys/auxv.h>)
> +#include <sys/auxv.h>
> +
> +#if __has_include(<sys/ifunc.h>)
> +#include <sys/ifunc.h>
> +#else
> +typedef struct __ifunc_arg_t {
> +  unsigned long _size;
> +  unsigned long _hwcap;
> +  unsigned long _hwcap2;
> +} __ifunc_arg_t;
> +#endif
> +
> +#if __has_include(<asm/hwcap.h>)
> +#include <asm/hwcap.h>
> +
> +/* CPUFeatures must correspond to the same AArch64 features in aarch64.cc  */
> +enum CPUFeatures {
> +  FEAT_RNG,
> +  FEAT_FLAGM,
> +  FEAT_FLAGM2,
> +  FEAT_FP16FML,
> +  FEAT_DOTPROD,
> +  FEAT_SM4,
> +  FEAT_RDM,
> +  FEAT_LSE,
> +  FEAT_FP,
> +  FEAT_SIMD,
> +  FEAT_CRC,
> +  FEAT_SHA1,
> +  FEAT_SHA2,
> +  FEAT_SHA3,
> +  FEAT_AES,
> +  FEAT_PMULL,
> +  FEAT_FP16,
> +  FEAT_DIT,
> +  FEAT_DPB,
> +  FEAT_DPB2,
> +  FEAT_JSCVT,
> +  FEAT_FCMA,
> +  FEAT_RCPC,
> +  FEAT_RCPC2,
> +  FEAT_FRINTTS,
> +  FEAT_DGH,
> +  FEAT_I8MM,
> +  FEAT_BF16,
> +  FEAT_EBF16,
> +  FEAT_RPRES,
> +  FEAT_SVE,
> +  FEAT_SVE_BF16,
> +  FEAT_SVE_EBF16,
> +  FEAT_SVE_I8MM,
> +  FEAT_SVE_F32MM,
> +  FEAT_SVE_F64MM,
> +  FEAT_SVE2,
> +  FEAT_SVE_AES,
> +  FEAT_SVE_PMULL128,
> +  FEAT_SVE_BITPERM,
> +  FEAT_SVE_SHA3,
> +  FEAT_SVE_SM4,
> +  FEAT_SME,
> +  FEAT_MEMTAG,
> +  FEAT_MEMTAG2,
> +  FEAT_MEMTAG3,
> +  FEAT_SB,
> +  FEAT_PREDRES,
> +  FEAT_SSBS,
> +  FEAT_SSBS2,
> +  FEAT_BTI,
> +  FEAT_LS64,
> +  FEAT_LS64_V,
> +  FEAT_LS64_ACCDATA,
> +  FEAT_WFXT,
> +  FEAT_SME_F64,
> +  FEAT_SME_I64,
> +  FEAT_SME2,
> +  FEAT_RCPC3,
> +  FEAT_MAX,
> +  FEAT_EXT = 62, /* Reserved to indicate presence of additional features field
> +		    in __aarch64_cpu_features.  */
> +  FEAT_INIT      /* Used as flag of features initialization completion.  */
> +};
> +
> +/* Architecture features used in Function Multi Versioning.  */
> +struct {
> +  unsigned long long features;
> +  /* As features grows new fields could be added.  */
> +} __aarch64_cpu_features __attribute__((visibility("hidden"), nocommon));
> +
> +#ifndef _IFUNC_ARG_HWCAP
> +#define _IFUNC_ARG_HWCAP (1ULL << 62)
> +#endif
> +#ifndef AT_HWCAP
> +#define AT_HWCAP 16
> +#endif
> +#ifndef HWCAP_CPUID
> +#define HWCAP_CPUID (1 << 11)
> +#endif
> +#ifndef HWCAP_FP
> +#define HWCAP_FP (1 << 0)
> +#endif
> +#ifndef HWCAP_ASIMD
> +#define HWCAP_ASIMD (1 << 1)
> +#endif
> +#ifndef HWCAP_AES
> +#define HWCAP_AES (1 << 3)
> +#endif
> +#ifndef HWCAP_PMULL
> +#define HWCAP_PMULL (1 << 4)
> +#endif
> +#ifndef HWCAP_SHA1
> +#define HWCAP_SHA1 (1 << 5)
> +#endif
> +#ifndef HWCAP_SHA2
> +#define HWCAP_SHA2 (1 << 6)
> +#endif
> +#ifndef HWCAP_ATOMICS
> +#define HWCAP_ATOMICS (1 << 8)
> +#endif
> +#ifndef HWCAP_FPHP
> +#define HWCAP_FPHP (1 << 9)
> +#endif
> +#ifndef HWCAP_ASIMDHP
> +#define HWCAP_ASIMDHP (1 << 10)
> +#endif
> +#ifndef HWCAP_ASIMDRDM
> +#define HWCAP_ASIMDRDM (1 << 12)
> +#endif
> +#ifndef HWCAP_JSCVT
> +#define HWCAP_JSCVT (1 << 13)
> +#endif
> +#ifndef HWCAP_FCMA
> +#define HWCAP_FCMA (1 << 14)
> +#endif
> +#ifndef HWCAP_LRCPC
> +#define HWCAP_LRCPC (1 << 15)
> +#endif
> +#ifndef HWCAP_DCPOP
> +#define HWCAP_DCPOP (1 << 16)
> +#endif
> +#ifndef HWCAP_SHA3
> +#define HWCAP_SHA3 (1 << 17)
> +#endif
> +#ifndef HWCAP_SM3
> +#define HWCAP_SM3 (1 << 18)
> +#endif
> +#ifndef HWCAP_SM4
> +#define HWCAP_SM4 (1 << 19)
> +#endif
> +#ifndef HWCAP_ASIMDDP
> +#define HWCAP_ASIMDDP (1 << 20)
> +#endif
> +#ifndef HWCAP_SHA512
> +#define HWCAP_SHA512 (1 << 21)
> +#endif
> +#ifndef HWCAP_SVE
> +#define HWCAP_SVE (1 << 22)
> +#endif
> +#ifndef HWCAP_ASIMDFHM
> +#define HWCAP_ASIMDFHM (1 << 23)
> +#endif
> +#ifndef HWCAP_DIT
> +#define HWCAP_DIT (1 << 24)
> +#endif
> +#ifndef HWCAP_ILRCPC
> +#define HWCAP_ILRCPC (1 << 26)
> +#endif
> +#ifndef HWCAP_FLAGM
> +#define HWCAP_FLAGM (1 << 27)
> +#endif
> +#ifndef HWCAP_SSBS
> +#define HWCAP_SSBS (1 << 28)
> +#endif
> +#ifndef HWCAP_SB
> +#define HWCAP_SB (1 << 29)
> +#endif
> +
> +#ifndef HWCAP2_DCPODP
> +#define HWCAP2_DCPODP (1 << 0)
> +#endif
> +#ifndef HWCAP2_SVE2
> +#define HWCAP2_SVE2 (1 << 1)
> +#endif
> +#ifndef HWCAP2_SVEAES
> +#define HWCAP2_SVEAES (1 << 2)
> +#endif
> +#ifndef HWCAP2_SVEPMULL
> +#define HWCAP2_SVEPMULL (1 << 3)
> +#endif
> +#ifndef HWCAP2_SVEBITPERM
> +#define HWCAP2_SVEBITPERM (1 << 4)
> +#endif
> +#ifndef HWCAP2_SVESHA3
> +#define HWCAP2_SVESHA3 (1 << 5)
> +#endif
> +#ifndef HWCAP2_SVESM4
> +#define HWCAP2_SVESM4 (1 << 6)
> +#endif
> +#ifndef HWCAP2_FLAGM2
> +#define HWCAP2_FLAGM2 (1 << 7)
> +#endif
> +#ifndef HWCAP2_FRINT
> +#define HWCAP2_FRINT (1 << 8)
> +#endif
> +#ifndef HWCAP2_SVEI8MM
> +#define HWCAP2_SVEI8MM (1 << 9)
> +#endif
> +#ifndef HWCAP2_SVEF32MM
> +#define HWCAP2_SVEF32MM (1 << 10)
> +#endif
> +#ifndef HWCAP2_SVEF64MM
> +#define HWCAP2_SVEF64MM (1 << 11)
> +#endif
> +#ifndef HWCAP2_SVEBF16
> +#define HWCAP2_SVEBF16 (1 << 12)
> +#endif
> +#ifndef HWCAP2_I8MM
> +#define HWCAP2_I8MM (1 << 13)
> +#endif
> +#ifndef HWCAP2_BF16
> +#define HWCAP2_BF16 (1 << 14)
> +#endif
> +#ifndef HWCAP2_DGH
> +#define HWCAP2_DGH (1 << 15)
> +#endif
> +#ifndef HWCAP2_RNG
> +#define HWCAP2_RNG (1 << 16)
> +#endif
> +#ifndef HWCAP2_BTI
> +#define HWCAP2_BTI (1 << 17)
> +#endif
> +#ifndef HWCAP2_MTE
> +#define HWCAP2_MTE (1 << 18)
> +#endif
> +#ifndef HWCAP2_RPRES
> +#define HWCAP2_RPRES (1 << 21)
> +#endif
> +#ifndef HWCAP2_MTE3
> +#define HWCAP2_MTE3 (1 << 22)
> +#endif
> +#ifndef HWCAP2_SME
> +#define HWCAP2_SME (1 << 23)
> +#endif
> +#ifndef HWCAP2_SME_I16I64
> +#define HWCAP2_SME_I16I64 (1 << 24)
> +#endif
> +#ifndef HWCAP2_SME_F64F64
> +#define HWCAP2_SME_F64F64 (1 << 25)
> +#endif
> +#ifndef HWCAP2_WFXT
> +#define HWCAP2_WFXT (1UL << 31)
> +#endif
> +#ifndef HWCAP2_EBF16
> +#define HWCAP2_EBF16 (1UL << 32)
> +#endif
> +#ifndef HWCAP2_SVE_EBF16
> +#define HWCAP2_SVE_EBF16 (1UL << 33)
> +#endif
> +
> +static void
> +__init_cpu_features_constructor(unsigned long hwcap,
> +				const __ifunc_arg_t *arg) {
> +#define setCPUFeature(F) __aarch64_cpu_features.features |= 1ULL << F
> +#define getCPUFeature(id, ftr) __asm__("mrs %0, " #id : "=r"(ftr))
> +#define extractBits(val, start, number) \
> +  (val & ((1ULL << number) - 1ULL) << start) >> start
> +  unsigned long hwcap2 = 0;
> +  if (hwcap & _IFUNC_ARG_HWCAP)
> +    hwcap2 = arg->_hwcap2;
> +  if (hwcap & HWCAP_CRC32)
> +    setCPUFeature(FEAT_CRC);
> +  if (hwcap & HWCAP_PMULL)
> +    setCPUFeature(FEAT_PMULL);
> +  if (hwcap & HWCAP_FLAGM)
> +    setCPUFeature(FEAT_FLAGM);
> +  if (hwcap2 & HWCAP2_FLAGM2) {
> +    setCPUFeature(FEAT_FLAGM);
> +    setCPUFeature(FEAT_FLAGM2);
> +  }
> +  if (hwcap & HWCAP_SM3 && hwcap & HWCAP_SM4)
> +    setCPUFeature(FEAT_SM4);
> +  if (hwcap & HWCAP_ASIMDDP)
> +    setCPUFeature(FEAT_DOTPROD);
> +  if (hwcap & HWCAP_ASIMDFHM)
> +    setCPUFeature(FEAT_FP16FML);
> +  if (hwcap & HWCAP_FPHP) {
> +    setCPUFeature(FEAT_FP16);
> +    setCPUFeature(FEAT_FP);
> +  }
> +  if (hwcap & HWCAP_DIT)
> +    setCPUFeature(FEAT_DIT);
> +  if (hwcap & HWCAP_ASIMDRDM)
> +    setCPUFeature(FEAT_RDM);
> +  if (hwcap & HWCAP_ILRCPC)
> +    setCPUFeature(FEAT_RCPC2);
> +  if (hwcap & HWCAP_AES)
> +    setCPUFeature(FEAT_AES);
> +  if (hwcap & HWCAP_SHA1)
> +    setCPUFeature(FEAT_SHA1);
> +  if (hwcap & HWCAP_SHA2)
> +    setCPUFeature(FEAT_SHA2);
> +  if (hwcap & HWCAP_JSCVT)
> +    setCPUFeature(FEAT_JSCVT);
> +  if (hwcap & HWCAP_FCMA)
> +    setCPUFeature(FEAT_FCMA);
> +  if (hwcap & HWCAP_SB)
> +    setCPUFeature(FEAT_SB);
> +  if (hwcap & HWCAP_SSBS)
> +    setCPUFeature(FEAT_SSBS2);
> +  if (hwcap2 & HWCAP2_MTE) {
> +    setCPUFeature(FEAT_MEMTAG);
> +    setCPUFeature(FEAT_MEMTAG2);
> +  }
> +  if (hwcap2 & HWCAP2_MTE3) {
> +    setCPUFeature(FEAT_MEMTAG);
> +    setCPUFeature(FEAT_MEMTAG2);
> +    setCPUFeature(FEAT_MEMTAG3);
> +  }
> +  if (hwcap2 & HWCAP2_SVEAES)
> +    setCPUFeature(FEAT_SVE_AES);
> +  if (hwcap2 & HWCAP2_SVEPMULL) {
> +    setCPUFeature(FEAT_SVE_AES);
> +    setCPUFeature(FEAT_SVE_PMULL128);
> +  }
> +  if (hwcap2 & HWCAP2_SVEBITPERM)
> +    setCPUFeature(FEAT_SVE_BITPERM);
> +  if (hwcap2 & HWCAP2_SVESHA3)
> +    setCPUFeature(FEAT_SVE_SHA3);
> +  if (hwcap2 & HWCAP2_SVESM4)
> +    setCPUFeature(FEAT_SVE_SM4);
> +  if (hwcap2 & HWCAP2_DCPODP)
> +    setCPUFeature(FEAT_DPB2);
> +  if (hwcap & HWCAP_ATOMICS)
> +    setCPUFeature(FEAT_LSE);
> +  if (hwcap2 & HWCAP2_RNG)
> +    setCPUFeature(FEAT_RNG);
> +  if (hwcap2 & HWCAP2_I8MM)
> +    setCPUFeature(FEAT_I8MM);
> +  if (hwcap2 & HWCAP2_EBF16)
> +    setCPUFeature(FEAT_EBF16);
> +  if (hwcap2 & HWCAP2_SVE_EBF16)
> +    setCPUFeature(FEAT_SVE_EBF16);
> +  if (hwcap2 & HWCAP2_DGH)
> +    setCPUFeature(FEAT_DGH);
> +  if (hwcap2 & HWCAP2_FRINT)
> +    setCPUFeature(FEAT_FRINTTS);
> +  if (hwcap2 & HWCAP2_SVEI8MM)
> +    setCPUFeature(FEAT_SVE_I8MM);
> +  if (hwcap2 & HWCAP2_SVEF32MM)
> +    setCPUFeature(FEAT_SVE_F32MM);
> +  if (hwcap2 & HWCAP2_SVEF64MM)
> +    setCPUFeature(FEAT_SVE_F64MM);
> +  if (hwcap2 & HWCAP2_BTI)
> +    setCPUFeature(FEAT_BTI);
> +  if (hwcap2 & HWCAP2_RPRES)
> +    setCPUFeature(FEAT_RPRES);
> +  if (hwcap2 & HWCAP2_WFXT)
> +    setCPUFeature(FEAT_WFXT);
> +  if (hwcap2 & HWCAP2_SME)
> +    setCPUFeature(FEAT_SME);
> +  if (hwcap2 & HWCAP2_SME_I16I64)
> +    setCPUFeature(FEAT_SME_I64);
> +  if (hwcap2 & HWCAP2_SME_F64F64)
> +    setCPUFeature(FEAT_SME_F64);
> +  if (hwcap & HWCAP_CPUID) {
> +    unsigned long ftr;
> +    getCPUFeature(ID_AA64PFR1_EL1, ftr);
> +    /* ID_AA64PFR1_EL1.MTE >= 0b0001  */
> +    if (extractBits(ftr, 8, 4) >= 0x1)
> +      setCPUFeature(FEAT_MEMTAG);
> +    /* ID_AA64PFR1_EL1.SSBS == 0b0001  */
> +    if (extractBits(ftr, 4, 4) == 0x1)
> +      setCPUFeature(FEAT_SSBS);
> +    /* ID_AA64PFR1_EL1.SME == 0b0010  */
> +    if (extractBits(ftr, 24, 4) == 0x2)
> +      setCPUFeature(FEAT_SME2);
> +    getCPUFeature(ID_AA64PFR0_EL1, ftr);
> +    /* ID_AA64PFR0_EL1.FP != 0b1111  */
> +    if (extractBits(ftr, 16, 4) != 0xF) {
> +      setCPUFeature(FEAT_FP);
> +      /* ID_AA64PFR0_EL1.AdvSIMD has the same value as ID_AA64PFR0_EL1.FP  */
> +      setCPUFeature(FEAT_SIMD);
> +    }
> +    /* ID_AA64PFR0_EL1.SVE != 0b0000  */
> +    if (extractBits(ftr, 32, 4) != 0x0) {
> +      /* get ID_AA64ZFR0_EL1, that name supported if sve enabled only  */
> +      getCPUFeature(S3_0_C0_C4_4, ftr);
> +      /* ID_AA64ZFR0_EL1.SVEver == 0b0000  */
> +      if (extractBits(ftr, 0, 4) == 0x0)
> +	setCPUFeature(FEAT_SVE);
> +      /* ID_AA64ZFR0_EL1.SVEver == 0b0001  */
> +      if (extractBits(ftr, 0, 4) == 0x1)
> +	setCPUFeature(FEAT_SVE2);
> +      /* ID_AA64ZFR0_EL1.BF16 != 0b0000  */
> +      if (extractBits(ftr, 20, 4) != 0x0)
> +	setCPUFeature(FEAT_SVE_BF16);
> +    }
> +    getCPUFeature(ID_AA64ISAR0_EL1, ftr);
> +    /* ID_AA64ISAR0_EL1.SHA3 != 0b0000  */
> +    if (extractBits(ftr, 32, 4) != 0x0)
> +      setCPUFeature(FEAT_SHA3);
> +    getCPUFeature(ID_AA64ISAR1_EL1, ftr);
> +    /* ID_AA64ISAR1_EL1.DPB >= 0b0001  */
> +    if (extractBits(ftr, 0, 4) >= 0x1)
> +      setCPUFeature(FEAT_DPB);
> +    /* ID_AA64ISAR1_EL1.LRCPC != 0b0000  */
> +    if (extractBits(ftr, 20, 4) != 0x0)
> +      setCPUFeature(FEAT_RCPC);
> +    /* ID_AA64ISAR1_EL1.LRCPC == 0b0011  */
> +    if (extractBits(ftr, 20, 4) == 0x3)
> +      setCPUFeature(FEAT_RCPC3);
> +    /* ID_AA64ISAR1_EL1.SPECRES == 0b0001  */
> +    if (extractBits(ftr, 40, 4) == 0x2)
> +      setCPUFeature(FEAT_PREDRES);
> +    /* ID_AA64ISAR1_EL1.BF16 != 0b0000  */
> +    if (extractBits(ftr, 44, 4) != 0x0)
> +      setCPUFeature(FEAT_BF16);
> +    /* ID_AA64ISAR1_EL1.LS64 >= 0b0001  */
> +    if (extractBits(ftr, 60, 4) >= 0x1)
> +      setCPUFeature(FEAT_LS64);
> +    /* ID_AA64ISAR1_EL1.LS64 >= 0b0010  */
> +    if (extractBits(ftr, 60, 4) >= 0x2)
> +      setCPUFeature(FEAT_LS64_V);
> +    /* ID_AA64ISAR1_EL1.LS64 >= 0b0011  */
> +    if (extractBits(ftr, 60, 4) >= 0x3)
> +      setCPUFeature(FEAT_LS64_ACCDATA);
> +  } else {
> +    /* Set some features in case of no CPUID support.  */
> +    if (hwcap & (HWCAP_FP | HWCAP_FPHP)) {
> +      setCPUFeature(FEAT_FP);
> +      /* FP and AdvSIMD fields have the same value.  */
> +      setCPUFeature(FEAT_SIMD);
> +    }
> +    if (hwcap & HWCAP_DCPOP || hwcap2 & HWCAP2_DCPODP)
> +      setCPUFeature(FEAT_DPB);
> +    if (hwcap & HWCAP_LRCPC || hwcap & HWCAP_ILRCPC)
> +      setCPUFeature(FEAT_RCPC);
> +    if (hwcap2 & HWCAP2_BF16 || hwcap2 & HWCAP2_EBF16)
> +      setCPUFeature(FEAT_BF16);
> +    if (hwcap2 & HWCAP2_SVEBF16)
> +      setCPUFeature(FEAT_SVE_BF16);
> +    if (hwcap2 & HWCAP2_SVE2 && hwcap & HWCAP_SVE)
> +      setCPUFeature(FEAT_SVE2);
> +    if (hwcap & HWCAP_SHA3)
> +      setCPUFeature(FEAT_SHA3);
> +  }
> +  setCPUFeature(FEAT_INIT);
> +}
> +
> +void
> +__init_cpu_features_resolver(unsigned long hwcap, const __ifunc_arg_t *arg) {
> +  if (__aarch64_cpu_features.features)
> +    return;
> +  __init_cpu_features_constructor(hwcap, arg);
> +}
> +
> +void __attribute__ ((constructor))
> +__init_cpu_features(void) {
> +  unsigned long hwcap;
> +  unsigned long hwcap2;
> +  /* CPU features already initialized.  */
> +  if (__aarch64_cpu_features.features)
> +    return;
> +  hwcap = getauxval(AT_HWCAP);
> +  hwcap2 = getauxval(AT_HWCAP2);
> +  __ifunc_arg_t arg;
> +  arg._size = sizeof(__ifunc_arg_t);
> +  arg._hwcap = hwcap;
> +  arg._hwcap2 = hwcap2;
> +  __init_cpu_features_constructor(hwcap | _IFUNC_ARG_HWCAP, &arg);
> +#undef extractBits
> +#undef getCPUFeature
> +#undef setCPUFeature
> +}
> +#endif /* __has_include(<asm/hwcap.h>)  */
> +#endif /* __has_include(<sys/auxv.h>)  */
> +#endif /* defined(__has_include)  */
> diff --git a/libgcc/config/aarch64/t-aarch64 b/libgcc/config/aarch64/t-aarch64
> index a40b6241c86ecc4007b5cfd28aa989ee894aa410..8bc1a4ca0c2eb75c17e62a25aa45a875bfd472f8 100644
> --- a/libgcc/config/aarch64/t-aarch64
> +++ b/libgcc/config/aarch64/t-aarch64
> @@ -19,3 +19,4 @@
>  # <http://www.gnu.org/licenses/>.
>  
>  LIB2ADD += $(srcdir)/config/aarch64/sync-cache.c
> +LIB2ADD += $(srcdir)/config/aarch64/cpuinfo.c

  reply	other threads:[~2023-11-20 15:46 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-17  2:49 [PATCH v2 0/5] target_version and aarch64 function multiversioning Andrew Carlotti
2023-11-17  2:51 ` [PATCH v2[1/5] aarch64: Add cpu feature detection to libgcc Andrew Carlotti
2023-11-20 15:46   ` Richard Sandiford [this message]
2023-12-04 10:31     ` Andrew Carlotti
2023-11-17  2:53 ` [PATCH v2 2/5] c-family: Simplify attribute exclusion handling Andrew Carlotti
2023-11-19 21:45   ` Jeff Law
2023-11-17  2:54 ` [PATCH v2 3/5] ada: Improve " Andrew Carlotti
2023-11-17 10:45   ` Marc Poulhiès
2023-11-17 11:15     ` Andrew Carlotti
2023-11-20  8:26       ` Marc Poulhiès
2023-11-17  2:55 ` [PATCH v2 4/5] Add support for target_version attribute Andrew Carlotti
2023-11-29 17:53   ` Richard Sandiford
2023-12-04 11:14     ` Andrew Carlotti
2023-11-17  2:56 ` [PATCH v2 5/5] aarch64: Add function multiversioning support Andrew Carlotti
2023-11-24 16:22   ` Richard Sandiford
2023-12-04 13:23     ` Andrew Carlotti

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