GitHubMirror/sys
1
0
Fork 0
mirror of https://github.com/rwinkhart/sys.git synced 2026-09-03 07:37:34 -04:00
Code Issues Packages Projects Releases Wiki Activity

cpu: pretend AVX-512 is disabled on Darwin

Browse Source 
Darwin doesn't save/restore the AVX-512 mask registers when
processing a signal. Go generates lots of signals, which cause
the mask registers to randomly get clobbered. Better to pretend
that AVX-512 isn't supported.

Update golang/go#49233

Change-Id: I0dda77a6f205e10eefccd82e6f4f0f184dae42d9
Reviewed-on: https://go-review.googlesource.com/c/sys/+/361255
Trust: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Martin Möhrmann <martin@golang.org>
This commit is contained in:
Keith Randall
2021-11-03 23:57:46 +00:00
parent ae416a5f93
commit 7861aae155
2 changed files with 4 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files
cpu/cpu_x86.go
+4 -3
View File
@@ -90,9 +90,10 @@ func archInit() {
osSupportsAVX = isSet(1, eax) && isSet(2, eax)
if runtime.GOOS == "darwin" {
// Check darwin commpage for AVX512 support. Necessary because:
// https://github.com/apple/darwin-xnu/blob/0a798f6738bc1db01281fc08ae024145e84df927/osfmk/i386/fpu.c#L175-L201
osSupportsAVX512 = osSupportsAVX && darwinSupportsAVX512()
// Darwin doesn't save/restore AVX-512 mask registers correctly across signal handlers.
// Since users can't rely on mask register contents, let's not advertise AVX-512 support.
// See issue 49233.
osSupportsAVX512 = false
} else {
// Check if OPMASK and ZMM registers have OS support.
osSupportsAVX512 = osSupportsAVX && isSet(5, eax) && isSet(6, eax) && isSet(7, eax)