Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) ================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) ARM64 ELF hwcaps
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3) ================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5) This document describes the usage and semantics of the arm64 ELF hwcaps.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) 1. Introduction
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) ---------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) Some hardware or software features are only available on some CPU
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) implementations, and/or with certain kernel configurations, but have no
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) architected discovery mechanism available to userspace code at EL0. The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) kernel exposes the presence of these features to userspace through a set
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) of flags called hwcaps, exposed in the auxilliary vector.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) Userspace software can test for features by acquiring the AT_HWCAP or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) AT_HWCAP2 entry of the auxiliary vector, and testing whether the relevant
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) flags are set, e.g.::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) 	bool floating_point_is_present(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) 	{
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) 		unsigned long hwcaps = getauxval(AT_HWCAP);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 		if (hwcaps & HWCAP_FP)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 			return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 		return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) Where software relies on a feature described by a hwcap, it should check
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) the relevant hwcap flag to verify that the feature is present before
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) attempting to make use of the feature.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) Features cannot be probed reliably through other means. When a feature
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) is not available, attempting to use it may result in unpredictable
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) behaviour, and is not guaranteed to result in any reliable indication
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) that the feature is unavailable, such as a SIGILL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 2. Interpretation of hwcaps
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) ---------------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) The majority of hwcaps are intended to indicate the presence of features
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) which are described by architected ID registers inaccessible to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) userspace code at EL0. These hwcaps are defined in terms of ID register
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) fields, and should be interpreted with reference to the definition of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) these fields in the ARM Architecture Reference Manual (ARM ARM).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) Such hwcaps are described below in the form::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51)     Functionality implied by idreg.field == val.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) Such hwcaps indicate the availability of functionality that the ARM ARM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) defines as being present when idreg.field has value val, but do not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) indicate that idreg.field is precisely equal to val, nor do they
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) indicate the absence of functionality implied by other values of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) idreg.field.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) Other hwcaps may indicate the presence of features which cannot be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) described by ID registers alone. These may be described without
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) reference to ID registers, and may refer to other documentation.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 3. The hwcaps exposed in AT_HWCAP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) ---------------------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) HWCAP_FP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68)     Functionality implied by ID_AA64PFR0_EL1.FP == 0b0000.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) HWCAP_ASIMD
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71)     Functionality implied by ID_AA64PFR0_EL1.AdvSIMD == 0b0000.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) HWCAP_EVTSTRM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74)     The generic timer is configured to generate events at a frequency of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75)     approximately 100KHz.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) HWCAP_AES
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78)     Functionality implied by ID_AA64ISAR0_EL1.AES == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) HWCAP_PMULL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81)     Functionality implied by ID_AA64ISAR0_EL1.AES == 0b0010.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) HWCAP_SHA1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84)     Functionality implied by ID_AA64ISAR0_EL1.SHA1 == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) HWCAP_SHA2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87)     Functionality implied by ID_AA64ISAR0_EL1.SHA2 == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) HWCAP_CRC32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90)     Functionality implied by ID_AA64ISAR0_EL1.CRC32 == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) HWCAP_ATOMICS
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93)     Functionality implied by ID_AA64ISAR0_EL1.Atomic == 0b0010.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) HWCAP_FPHP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96)     Functionality implied by ID_AA64PFR0_EL1.FP == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) HWCAP_ASIMDHP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99)     Functionality implied by ID_AA64PFR0_EL1.AdvSIMD == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) HWCAP_CPUID
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102)     EL0 access to certain ID registers is available, to the extent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)     described by Documentation/arm64/cpu-feature-registers.rst.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)     These ID registers may imply the availability of features.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) HWCAP_ASIMDRDM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108)     Functionality implied by ID_AA64ISAR0_EL1.RDM == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) HWCAP_JSCVT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111)     Functionality implied by ID_AA64ISAR1_EL1.JSCVT == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) HWCAP_FCMA
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114)     Functionality implied by ID_AA64ISAR1_EL1.FCMA == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) HWCAP_LRCPC
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117)     Functionality implied by ID_AA64ISAR1_EL1.LRCPC == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) HWCAP_DCPOP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120)     Functionality implied by ID_AA64ISAR1_EL1.DPB == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) HWCAP_SHA3
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123)     Functionality implied by ID_AA64ISAR0_EL1.SHA3 == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) HWCAP_SM3
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126)     Functionality implied by ID_AA64ISAR0_EL1.SM3 == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) HWCAP_SM4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)     Functionality implied by ID_AA64ISAR0_EL1.SM4 == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) HWCAP_ASIMDDP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132)     Functionality implied by ID_AA64ISAR0_EL1.DP == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) HWCAP_SHA512
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135)     Functionality implied by ID_AA64ISAR0_EL1.SHA2 == 0b0010.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) HWCAP_SVE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138)     Functionality implied by ID_AA64PFR0_EL1.SVE == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) HWCAP_ASIMDFHM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141)    Functionality implied by ID_AA64ISAR0_EL1.FHM == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) HWCAP_DIT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144)     Functionality implied by ID_AA64PFR0_EL1.DIT == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) HWCAP_USCAT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147)     Functionality implied by ID_AA64MMFR2_EL1.AT == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) HWCAP_ILRCPC
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150)     Functionality implied by ID_AA64ISAR1_EL1.LRCPC == 0b0010.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) HWCAP_FLAGM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153)     Functionality implied by ID_AA64ISAR0_EL1.TS == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) HWCAP_SSBS
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156)     Functionality implied by ID_AA64PFR1_EL1.SSBS == 0b0010.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) HWCAP_SB
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159)     Functionality implied by ID_AA64ISAR1_EL1.SB == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) HWCAP_PACA
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162)     Functionality implied by ID_AA64ISAR1_EL1.APA == 0b0001 or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163)     ID_AA64ISAR1_EL1.API == 0b0001, as described by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164)     Documentation/arm64/pointer-authentication.rst.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) HWCAP_PACG
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167)     Functionality implied by ID_AA64ISAR1_EL1.GPA == 0b0001 or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168)     ID_AA64ISAR1_EL1.GPI == 0b0001, as described by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169)     Documentation/arm64/pointer-authentication.rst.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) HWCAP2_DCPODP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173)     Functionality implied by ID_AA64ISAR1_EL1.DPB == 0b0010.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) HWCAP2_SVE2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177)     Functionality implied by ID_AA64ZFR0_EL1.SVEVer == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) HWCAP2_SVEAES
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181)     Functionality implied by ID_AA64ZFR0_EL1.AES == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) HWCAP2_SVEPMULL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185)     Functionality implied by ID_AA64ZFR0_EL1.AES == 0b0010.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) HWCAP2_SVEBITPERM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189)     Functionality implied by ID_AA64ZFR0_EL1.BitPerm == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) HWCAP2_SVESHA3
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193)     Functionality implied by ID_AA64ZFR0_EL1.SHA3 == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) HWCAP2_SVESM4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197)     Functionality implied by ID_AA64ZFR0_EL1.SM4 == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) HWCAP2_FLAGM2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201)     Functionality implied by ID_AA64ISAR0_EL1.TS == 0b0010.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) HWCAP2_FRINT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205)     Functionality implied by ID_AA64ISAR1_EL1.FRINTTS == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) HWCAP2_SVEI8MM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209)     Functionality implied by ID_AA64ZFR0_EL1.I8MM == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) HWCAP2_SVEF32MM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213)     Functionality implied by ID_AA64ZFR0_EL1.F32MM == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) HWCAP2_SVEF64MM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217)     Functionality implied by ID_AA64ZFR0_EL1.F64MM == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) HWCAP2_SVEBF16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221)     Functionality implied by ID_AA64ZFR0_EL1.BF16 == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) HWCAP2_I8MM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225)     Functionality implied by ID_AA64ISAR1_EL1.I8MM == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) HWCAP2_BF16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229)     Functionality implied by ID_AA64ISAR1_EL1.BF16 == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) HWCAP2_DGH
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233)     Functionality implied by ID_AA64ISAR1_EL1.DGH == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) HWCAP2_RNG
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237)     Functionality implied by ID_AA64ISAR0_EL1.RNDR == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) HWCAP2_BTI
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241)     Functionality implied by ID_AA64PFR0_EL1.BT == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) HWCAP2_MTE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245)     Functionality implied by ID_AA64PFR1_EL1.MTE == 0b0010, as described
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246)     by Documentation/arm64/memory-tagging-extension.rst.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) HWCAP2_ECV
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250)     Functionality implied by ID_AA64MMFR0_EL1.ECV == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) HWCAP2_AFP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254)     Functionality implied by ID_AA64MFR1_EL1.AFP == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) HWCAP2_RPRES
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258)     Functionality implied by ID_AA64ISAR2_EL1.RPRES == 0b0001.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 4. Unused AT_HWCAP bits
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) -----------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) For interoperation with userspace, the kernel guarantees that bits 62
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) and 63 of AT_HWCAP will always be returned as 0.