Add a RISCV64 variable to cpu that indicates both the presence
of RISC-V extensions and performance information about the underlying
RISC-V cores. The variable is only populated with non false values on
Linux. The detection code first attempts to use the riscv_hwprobe
syscall introduced in Linux 6.4, falling back to HWCAP if riscv_hwprobe
is not supported. The patch can detect the C, V, Zba, Zbb and Zbs
extensions. V, Zba, Zbb and Zbs can only be detected on a 6.5 kernel
or later (without backports).
Updates golang/go#61416
Change-Id: I40f92724ee3d337c06bdc559ff0b18a8f6bfda9f
Reviewed-on: https://go-review.googlesource.com/c/sys/+/605815
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Joel Sing <joel@sing.id.au>
Reviewed-by: Meng Zhuo <mengzhuo1203@gmail.com>
The GODEBUG environment variable can be used to disable usage of
specific processor features of Go programs that use the sys/cpu package.
This is useful for testing and benchmarking different code paths that
are guarded by sys/cpu variable checks.
Use of processor features can not be enabled through GODEBUG.
To disable usage of AVX and SSE41 cpu features on GOARCH amd64 use:
GODEBUG=cpu.avx=off,cpu.sse41=off
The special "all" option can be used to disable all options:
GODEBUG=all=off
This aligns the support of GODEBUG for sys/cpu with existing support
for GODEBUG in the Go standard library package internal/cpu.
Fixesgolang/go#33963
Change-Id: I618b71af397bf06c57a49b2a300d032a16d05664
Reviewed-on: https://go-review.googlesource.com/c/sys/+/245237
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Add basic support for IBM Z (s390x) CPU feature (known as
'facilities') detection.
Note that some of these features are mandatory when using the Go
compiler (for example, ldisp and eimm) but aren't mandatory when
using gccgo.
Cryptographic function detection is not yet implemented for
gccgo.
Change-Id: Ic6494d0df0bc1c1ad1713c9ff11ae23fba03d215
Reviewed-on: https://go-review.googlesource.com/c/163003
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
On Android /proc/self/auxv is not readable, leading to a panic in init.
Instead of panic'ing in this case, introduce the Initialized global bool
to report whether the CPU features were initialized i.e. /proc/self/auxv
was successfullly read.
Fixesgolang/go#30413
Change-Id: Ib520f202990614a76bceb0bf9d19a88eadd13e10
Reviewed-on: https://go-review.googlesource.com/c/164057
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This CL introduces a new cpu package for CPU/platform feature detection.
The cpu package is basically a copy of `internal/cpu` of the standard library.
Revision: bf86aec25972f3a100c3aa58a6abcbcc35bdea49
This CL does not export ARM64 and PPC64 feature detection since at the moment
ARM64/PPC64 requires standard library support.
Updates golang/go#24843
Change-Id: I11bc1ca60b116e902c941b5887c00870dbb1f899
Reviewed-on: https://go-review.googlesource.com/107015
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
