runtime, internal/cpu: CPU capabilities detection for ppc64x

This change replaces the current runtime capabilities check for ppc64x with the
new internal/cpu package. It also adds support for the new POWER9 ISA and
capabilities.

Updates #15403

Change-Id: I5b64a79e782f8da3603e5529600434f602986292
Reviewed-on: https://go-review.googlesource.com/53830
Reviewed-by: Martin Möhrmann <moehrmann@google.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/src/internal/cpu/cpu.go b/src/internal/cpu/cpu.go
index 2226b777e2..6a8e23d425 100644
--- a/src/internal/cpu/cpu.go
+++ b/src/internal/cpu/cpu.go
@@ -30,3 +30,28 @@ type x86 struct {
 	HasSSE42     bool
 	_            [CacheLineSize]byte
 }
+
+var PPC64 ppc64
+
+// For ppc64x, it is safe to check only for ISA level starting on ISA v3.00,
+// since there are no optional categories. There are some exceptions that also
+// require kernel support to work (darn, scv), so there are capability bits for
+// those as well. The minimum processor requirement is POWER8 (ISA 2.07), so we
+// maintain some of the old capability checks for optional categories for
+// safety.
+// The struct is padded to avoid false sharing.
+type ppc64 struct {
+	_          [CacheLineSize]byte
+	HasVMX     bool // Vector unit (Altivec)
+	HasDFP     bool // Decimal Floating Point unit
+	HasVSX     bool // Vector-scalar unit
+	HasHTM     bool // Hardware Transactional Memory
+	HasISEL    bool // Integer select
+	HasVCRYPTO bool // Vector cryptography
+	HasHTMNOSC bool // HTM: kernel-aborted transaction in syscalls
+	HasDARN    bool // Hardware random number generator (requires kernel enablement)
+	HasSCV     bool // Syscall vectored (requires kernel enablement)
+	IsPOWER8   bool // ISA v2.07 (POWER8)
+	IsPOWER9   bool // ISA v3.00 (POWER9)
+	_          [CacheLineSize]byte
+}