diff options
Diffstat (limited to 'Documentation/arm64/elf_hwcaps.txt')
| -rw-r--r-- | Documentation/arm64/elf_hwcaps.txt | 41 |
1 files changed, 38 insertions, 3 deletions
diff --git a/Documentation/arm64/elf_hwcaps.txt b/Documentation/arm64/elf_hwcaps.txt index 13d6691b37be..b73a2519ecf2 100644 --- a/Documentation/arm64/elf_hwcaps.txt +++ b/Documentation/arm64/elf_hwcaps.txt @@ -13,9 +13,9 @@ architected discovery mechanism available to userspace code at EL0. The kernel exposes the presence of these features to userspace through a set of flags called hwcaps, exposed in the auxilliary vector. -Userspace software can test for features by acquiring the AT_HWCAP entry -of the auxilliary vector, and testing whether the relevant flags are -set, e.g. +Userspace software can test for features by acquiring the AT_HWCAP or +AT_HWCAP2 entry of the auxiliary vector, and testing whether the relevant +flags are set, e.g. bool floating_point_is_present(void) { @@ -135,6 +135,10 @@ HWCAP_DCPOP Functionality implied by ID_AA64ISAR1_EL1.DPB == 0b0001. +HWCAP2_DCPODP + + Functionality implied by ID_AA64ISAR1_EL1.DPB == 0b0010. + HWCAP_SHA3 Functionality implied by ID_AA64ISAR0_EL1.SHA3 == 0b0001. @@ -159,6 +163,30 @@ HWCAP_SVE Functionality implied by ID_AA64PFR0_EL1.SVE == 0b0001. +HWCAP2_SVE2 + + Functionality implied by ID_AA64ZFR0_EL1.SVEVer == 0b0001. + +HWCAP2_SVEAES + + Functionality implied by ID_AA64ZFR0_EL1.AES == 0b0001. + +HWCAP2_SVEPMULL + + Functionality implied by ID_AA64ZFR0_EL1.AES == 0b0010. + +HWCAP2_SVEBITPERM + + Functionality implied by ID_AA64ZFR0_EL1.BitPerm == 0b0001. + +HWCAP2_SVESHA3 + + Functionality implied by ID_AA64ZFR0_EL1.SHA3 == 0b0001. + +HWCAP2_SVESM4 + + Functionality implied by ID_AA64ZFR0_EL1.SM4 == 0b0001. + HWCAP_ASIMDFHM Functionality implied by ID_AA64ISAR0_EL1.FHM == 0b0001. @@ -194,3 +222,10 @@ HWCAP_PACG Functionality implied by ID_AA64ISAR1_EL1.GPA == 0b0001 or ID_AA64ISAR1_EL1.GPI == 0b0001, as described by Documentation/arm64/pointer-authentication.txt. + + +4. Unused AT_HWCAP bits +----------------------- + +For interoperation with userspace, the kernel guarantees that bits 62 +and 63 of AT_HWCAP will always be returned as 0. |