internal/chacha20: use x/sys/cpu for s390x feature detection
Use the recently added CPU feature detection API rather than custom
assembly. This will need to be updated to use 'internal/cpu' when
the package is revendored into std.
Change-Id: Icf0f28236ca0c351c88035f36e5b9c29d4bc2ba7
Reviewed-on: https://go-review.googlesource.com/c/164383
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/internal/chacha20/chacha_s390x.go b/internal/chacha20/chacha_s390x.go
index 0c1c671..aad645b 100644
--- a/internal/chacha20/chacha_s390x.go
+++ b/internal/chacha20/chacha_s390x.go
@@ -6,15 +6,14 @@
package chacha20
-var haveAsm = hasVectorFacility()
+import (
+ "golang.org/x/sys/cpu"
+)
+
+var haveAsm = cpu.S390X.HasVX
const bufSize = 256
-// hasVectorFacility reports whether the machine supports the vector
-// facility (vx).
-// Implementation in asm_s390x.s.
-func hasVectorFacility() bool
-
// xorKeyStreamVX is an assembly implementation of XORKeyStream. It must only
// be called when the vector facility is available.
// Implementation in asm_s390x.s.
diff --git a/internal/chacha20/chacha_s390x.s b/internal/chacha20/chacha_s390x.s
index 98427c5..57df404 100644
--- a/internal/chacha20/chacha_s390x.s
+++ b/internal/chacha20/chacha_s390x.s
@@ -258,26 +258,3 @@
MOVD R8, R3
MOVD $0, R4
JMP continue
-
-// func hasVectorFacility() bool
-TEXT ·hasVectorFacility(SB), NOSPLIT, $24-1
- MOVD $x-24(SP), R1
- XC $24, 0(R1), 0(R1) // clear the storage
- MOVD $2, R0 // R0 is the number of double words stored -1
- WORD $0xB2B01000 // STFLE 0(R1)
- XOR R0, R0 // reset the value of R0
- MOVBZ z-8(SP), R1
- AND $0x40, R1
- BEQ novector
-
-vectorinstalled:
- // check if the vector instruction has been enabled
- VLEIB $0, $0xF, V16
- VLGVB $0, V16, R1
- CMPBNE R1, $0xF, novector
- MOVB $1, ret+0(FP) // have vx
- RET
-
-novector:
- MOVB $0, ret+0(FP) // no vx
- RET
