cpu: add CPU features for s390x
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>
diff --git a/cpu/cpu_linux_s390x.go b/cpu/cpu_linux_s390x.go
new file mode 100644
index 0000000..d579eae
--- /dev/null
+++ b/cpu/cpu_linux_s390x.go
@@ -0,0 +1,161 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cpu
+
+const cacheLineSize = 256
+
+const (
+ // bit mask values from /usr/include/bits/hwcap.h
+ hwcap_ZARCH = 2
+ hwcap_STFLE = 4
+ hwcap_MSA = 8
+ hwcap_LDISP = 16
+ hwcap_EIMM = 32
+ hwcap_DFP = 64
+ hwcap_ETF3EH = 256
+ hwcap_VX = 2048
+ hwcap_VXE = 8192
+)
+
+// bitIsSet reports whether the bit at index is set. The bit index
+// is in big endian order, so bit index 0 is the leftmost bit.
+func bitIsSet(bits []uint64, index uint) bool {
+ return bits[index/64]&((1<<63)>>(index%64)) != 0
+}
+
+// function is the code for the named cryptographic function.
+type function uint8
+
+const (
+ // KM{,A,C,CTR} function codes
+ aes128 function = 18 // AES-128
+ aes192 function = 19 // AES-192
+ aes256 function = 20 // AES-256
+
+ // K{I,L}MD function codes
+ sha1 function = 1 // SHA-1
+ sha256 function = 2 // SHA-256
+ sha512 function = 3 // SHA-512
+ sha3_224 function = 32 // SHA3-224
+ sha3_256 function = 33 // SHA3-256
+ sha3_384 function = 34 // SHA3-384
+ sha3_512 function = 35 // SHA3-512
+ shake128 function = 36 // SHAKE-128
+ shake256 function = 37 // SHAKE-256
+
+ // KLMD function codes
+ ghash function = 65 // GHASH
+)
+
+// queryResult contains the result of a Query function
+// call. Bits are numbered in big endian order so the
+// leftmost bit (the MSB) is at index 0.
+type queryResult struct {
+ bits [2]uint64
+}
+
+// Has reports whether the given functions are present.
+func (q *queryResult) Has(fns ...function) bool {
+ if len(fns) == 0 {
+ panic("no function codes provided")
+ }
+ for _, f := range fns {
+ if !bitIsSet(q.bits[:], uint(f)) {
+ return false
+ }
+ }
+ return true
+}
+
+// facility is a bit index for the named facility.
+type facility uint8
+
+const (
+ // cryptography facilities
+ msa4 facility = 77 // message-security-assist extension 4
+ msa8 facility = 146 // message-security-assist extension 8
+)
+
+// facilityList contains the result of an STFLE call.
+// Bits are numbered in big endian order so the
+// leftmost bit (the MSB) is at index 0.
+type facilityList struct {
+ bits [4]uint64
+}
+
+// Has reports whether the given facilities are present.
+func (s *facilityList) Has(fs ...facility) bool {
+ if len(fs) == 0 {
+ panic("no facility bits provided")
+ }
+ for _, f := range fs {
+ if !bitIsSet(s.bits[:], uint(f)) {
+ return false
+ }
+ }
+ return true
+}
+
+func doinit() {
+ // test HWCAP bit vector
+ has := func(featureMask uint) bool {
+ return hwCap&featureMask == featureMask
+ }
+
+ // mandatory
+ S390X.HasZARCH = has(hwcap_ZARCH)
+
+ // optional
+ S390X.HasSTFLE = has(hwcap_STFLE)
+ S390X.HasLDISP = has(hwcap_LDISP)
+ S390X.HasEIMM = has(hwcap_EIMM)
+ S390X.HasETF3EH = has(hwcap_ETF3EH)
+ S390X.HasDFP = has(hwcap_DFP)
+ S390X.HasMSA = has(hwcap_MSA)
+ S390X.HasVX = has(hwcap_VX)
+ if S390X.HasVX {
+ S390X.HasVXE = has(hwcap_VXE)
+ }
+
+ // We need implementations of stfle, km and so on
+ // to detect cryptographic features.
+ if !haveAsmFunctions() {
+ return
+ }
+
+ // optional cryptographic functions
+ if S390X.HasMSA {
+ aes := []function{aes128, aes192, aes256}
+
+ // cipher message
+ km, kmc := kmQuery(), kmcQuery()
+ S390X.HasAES = km.Has(aes...)
+ S390X.HasAESCBC = kmc.Has(aes...)
+ if S390X.HasSTFLE {
+ facilities := stfle()
+ if facilities.Has(msa4) {
+ kmctr := kmctrQuery()
+ S390X.HasAESCTR = kmctr.Has(aes...)
+ }
+ if facilities.Has(msa8) {
+ kma := kmaQuery()
+ S390X.HasAESGCM = kma.Has(aes...)
+ }
+ }
+
+ // compute message digest
+ kimd := kimdQuery() // intermediate (no padding)
+ klmd := klmdQuery() // last (padding)
+ S390X.HasSHA1 = kimd.Has(sha1) && klmd.Has(sha1)
+ S390X.HasSHA256 = kimd.Has(sha256) && klmd.Has(sha256)
+ S390X.HasSHA512 = kimd.Has(sha512) && klmd.Has(sha512)
+ S390X.HasGHASH = kimd.Has(ghash) // KLMD-GHASH does not exist
+ sha3 := []function{
+ sha3_224, sha3_256, sha3_384, sha3_512,
+ shake128, shake256,
+ }
+ S390X.HasSHA3 = kimd.Has(sha3...) && klmd.Has(sha3...)
+ }
+}
