runtime: refactor cpu feature detection for 386 & amd64

Changes all cpu features to be detected and stored in bools in rt0_go.

Updates: #15403

Change-Id: I5a9961cdec789b331d09c44d86beb53833d5dc3e
Reviewed-on: https://go-review.googlesource.com/41950
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ilya Tocar <ilya.tocar@intel.com>
Reviewed-by: Keith Randall <khr@golang.org>

src/runtime/alg.go

@@ -283,9 +283,9 @@ func alginit() {
 	// Install aes hash algorithm if we have the instructions we need
 	if (GOARCH == "386" || GOARCH == "amd64") &&
 		GOOS != "nacl" &&
-		cpuid_ecx&(1<<25) != 0 && // aes (aesenc)
+		support_aes && // AESENC
-		cpuid_ecx&(1<<9) != 0 && // sse3 (pshufb)
+		support_ssse3 && // PSHUFB
-		cpuid_ecx&(1<<19) != 0 { // sse4.1 (pinsr{d,q})
+		support_sse41 { // PINSR{D,Q}
 		useAeshash = true
 		algarray[alg_MEM32].hash = aeshash32
 		algarray[alg_MEM64].hash = aeshash64

src/runtime/asm_386.s

@@ -75,7 +75,7 @@ notintel:
 	MOVL	$1, AX
 	CPUID
 	MOVL	CX, DI // Move to global variable clobbers CX when generating PIC
-	MOVL	AX, runtime·cpuid_eax(SB)
+	MOVL	AX, runtime·processorVersionInfo(SB)
 	MOVL	DI, runtime·cpuid_ecx(SB)
 	MOVL	DX, runtime·cpuid_edx(SB)
 
@@ -83,16 +83,73 @@ notintel:
 	TESTL	$(1<<23), DX // MMX
 	JZ	bad_proc
 
+	TESTL	$(1<<26), DX // SSE2
+	SETNE	runtime·support_sse2(SB)
+
+	TESTL	$(1<<9), DI // SSSE3
+	SETNE	runtime·support_ssse3(SB)
+
+	TESTL	$(1<<19), DI // SSE4.1
+	SETNE	runtime·support_sse41(SB)
+
+	TESTL	$(1<<20), DI // SSE4.2
+	SETNE	runtime·support_sse42(SB)
+
+	TESTL	$(1<<23), DI // POPCNT
+	SETNE	runtime·support_popcnt(SB)
+
+	TESTL	$(1<<25), DI // AES
+	SETNE	runtime·support_aes(SB)
+
+	TESTL	$(1<<27), DI // OSXSAVE
+	SETNE	runtime·support_osxsave(SB)
+
+	// If OS support for XMM and YMM is not present
+	// support_avx will be set back to false later.
+	TESTL	$(1<<28), DI // AVX
+	SETNE	runtime·support_avx(SB)
+
+eax7:
 	// Load EAX=7/ECX=0 cpuid flags
 	CMPL	SI, $7
-	JLT	nocpuinfo
+	JLT	osavx
 	MOVL	$7, AX
 	MOVL	$0, CX
 	CPUID
 	MOVL	BX, runtime·cpuid_ebx7(SB)
 
-nocpuinfo:	
+	TESTL	$(1<<3), BX // BMI1
+	SETNE	runtime·support_bmi1(SB)
 
+	// If OS support for XMM and YMM is not present
+	// support_avx2 will be set back to false later.
+	TESTL	$(1<<5), BX
+	SETNE	runtime·support_avx2(SB)
+
+	TESTL	$(1<<8), BX // BMI2
+	SETNE	runtime·support_bmi2(SB)
+
+	TESTL	$(1<<9), BX // ERMS
+	SETNE	runtime·support_erms(SB)
+
+osavx:
+	// nacl does not support XGETBV to test
+	// for XMM and YMM OS support.
+#ifndef GOOS_nacl
+	CMPB	runtime·support_osxsave(SB), $1
+	JNE	noavx
+	MOVL	$0, CX
+	// For XGETBV, OSXSAVE bit is required and sufficient
+	XGETBV
+	ANDL	$6, AX
+	CMPL	AX, $6 // Check for OS support of XMM and YMM registers.
+	JE nocpuinfo
+#endif
+noavx:
+	MOVB $0, runtime·support_avx(SB)
+	MOVB $0, runtime·support_avx2(SB)
+
+nocpuinfo:
 	// if there is an _cgo_init, call it to let it
 	// initialize and to set up GS.  if not,
 	// we set up GS ourselves.
@@ -803,8 +860,8 @@ TEXT runtime·getcallerpc(SB),NOSPLIT,$4-8
 
 // func cputicks() int64
 TEXT runtime·cputicks(SB),NOSPLIT,$0-8
-	TESTL	$0x4000000, runtime·cpuid_edx(SB) // no sse2, no mfence
+	CMPB	runtime·support_sse2(SB), $1
-	JEQ	done
+	JNE	done
 	CMPB	runtime·lfenceBeforeRdtsc(SB), $1
 	JNE	mfence
 	BYTE	$0x0f; BYTE $0xae; BYTE $0xe8 // LFENCE
@@ -1311,8 +1368,8 @@ TEXT runtime·memeqbody(SB),NOSPLIT,$0-0
 hugeloop:
 	CMPL	BX, $64
 	JB	bigloop
-	TESTL	$0x4000000, runtime·cpuid_edx(SB) // check for sse2
+	CMPB	runtime·support_sse2(SB), $1
-	JE	bigloop
+	JNE	bigloop
 	MOVOU	(SI), X0
 	MOVOU	(DI), X1
 	MOVOU	16(SI), X2
@@ -1455,8 +1512,8 @@ TEXT runtime·cmpbody(SB),NOSPLIT,$0-0
 	JEQ	allsame
 	CMPL	BP, $4
 	JB	small
-	TESTL	$0x4000000, runtime·cpuid_edx(SB) // check for sse2
+	CMPB	runtime·support_sse2(SB), $1
-	JE	mediumloop
+	JNE	mediumloop
 largeloop:
 	CMPL	BP, $16
 	JB	mediumloop

src/runtime/asm_amd64.s

@@ -26,10 +26,10 @@ TEXT runtime·rt0_go(SB),NOSPLIT,$0
 	MOVQ	SP, (g_stack+stack_hi)(DI)
 
 	// find out information about the processor we're on
-	MOVQ	$0, AX
+	MOVL	$0, AX
 	CPUID
-	MOVQ	AX, SI
+	MOVL	AX, SI
-	CMPQ	AX, $0
+	CMPL	AX, $0
 	JE	nocpuinfo
 
 	// Figure out how to serialize RDTSC.
@@ -46,62 +46,75 @@ TEXT runtime·rt0_go(SB),NOSPLIT,$0
 notintel:
 
 	// Load EAX=1 cpuid flags
-	MOVQ	$1, AX
+	MOVL	$1, AX
 	CPUID
-	MOVL	AX, runtime·cpuid_eax(SB)
+	MOVL	AX, runtime·processorVersionInfo(SB)
 	MOVL	CX, runtime·cpuid_ecx(SB)
 	MOVL	DX, runtime·cpuid_edx(SB)
 
+	TESTL	$(1<<26), DX // SSE2
+	SETNE	runtime·support_sse2(SB)
+
+	TESTL	$(1<<9), CX // SSSE3
+	SETNE	runtime·support_ssse3(SB)
+
+	TESTL	$(1<<19), CX // SSE4.1
+	SETNE	runtime·support_sse41(SB)
+
+	TESTL	$(1<<20), CX // SSE4.2
+	SETNE	runtime·support_sse42(SB)
+
+	TESTL	$(1<<23), CX // POPCNT
+	SETNE	runtime·support_popcnt(SB)
+
+	TESTL	$(1<<25), CX // AES
+	SETNE	runtime·support_aes(SB)
+
+	TESTL	$(1<<27), CX // OSXSAVE
+	SETNE	runtime·support_osxsave(SB)
+
+	// If OS support for XMM and YMM is not present
+	// support_avx will be set back to false later.
+	TESTL	$(1<<28), CX // AVX
+	SETNE	runtime·support_avx(SB)
+
+eax7:
 	// Load EAX=7/ECX=0 cpuid flags
-	CMPQ	SI, $7
+	CMPL	SI, $7
-	JLT	no7
+	JLT	osavx
 	MOVL	$7, AX
 	MOVL	$0, CX
 	CPUID
 	MOVL	BX, runtime·cpuid_ebx7(SB)
-no7:
+
-	// Detect AVX and AVX2 as per 14.7.1  Detection of AVX2 chapter of [1]
+	TESTL	$(1<<3), BX // BMI1
-	// [1] 64-ia-32-architectures-software-developer-manual-325462.pdf
+	SETNE	runtime·support_bmi1(SB)
-	// http://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-manual-325462.pdf
+
-	MOVL	runtime·cpuid_ecx(SB), CX
+	// If OS support for XMM and YMM is not present
-	ANDL    $0x18000000, CX // check for OSXSAVE and AVX bits
+	// support_avx2 will be set back to false later.
-	CMPL    CX, $0x18000000
+	TESTL	$(1<<5), BX
+	SETNE	runtime·support_avx2(SB)
+
+	TESTL	$(1<<8), BX // BMI2
+	SETNE	runtime·support_bmi2(SB)
+
+	TESTL	$(1<<9), BX // ERMS
+	SETNE	runtime·support_erms(SB)
+
+osavx:
+	CMPB	runtime·support_osxsave(SB), $1
 	JNE	noavx
 	MOVL	$0, CX
 	// For XGETBV, OSXSAVE bit is required and sufficient
 	XGETBV
 	ANDL	$6, AX
-	CMPL    AX, $6 // Check for OS support of YMM registers
+	CMPL	AX, $6 // Check for OS support of XMM and YMM registers.
-	JNE     noavx
+	JE nocpuinfo
-	MOVB    $1, runtime·support_avx(SB)
-	TESTL   $(1<<5), runtime·cpuid_ebx7(SB) // check for AVX2 bit
-	JEQ     noavx2
-	MOVB    $1, runtime·support_avx2(SB)
-	JMP     testbmi1
 noavx:
 	MOVB $0, runtime·support_avx(SB)
-noavx2:
 	MOVB $0, runtime·support_avx2(SB)
-testbmi1:
-	// Detect BMI1 and BMI2 extensions as per
-	// 5.1.16.1 Detection of VEX-encoded GPR Instructions,
-	//   LZCNT and TZCNT, PREFETCHW chapter of [1]
-	MOVB    $0, runtime·support_bmi1(SB)
-	TESTL   $(1<<3), runtime·cpuid_ebx7(SB) // check for BMI1 bit
-	JEQ     testbmi2
-	MOVB    $1, runtime·support_bmi1(SB)
-testbmi2:
-	MOVB    $0, runtime·support_bmi2(SB)
-	TESTL   $(1<<8), runtime·cpuid_ebx7(SB) // check for BMI2 bit
-	JEQ     testpopcnt
-	MOVB    $1, runtime·support_bmi2(SB)
-testpopcnt:
-	MOVB	$0, runtime·support_popcnt(SB)
-	TESTL	$(1<<23), runtime·cpuid_ecx(SB) // check for POPCNT bit
-	JEQ     nocpuinfo
-	MOVB    $1, runtime·support_popcnt(SB)
-nocpuinfo:	
 
+nocpuinfo:
 	// if there is an _cgo_init, call it.
 	MOVQ	_cgo_init(SB), AX
 	TESTQ	AX, AX
@@ -1942,9 +1955,8 @@ success_avx2:
 	VZEROUPPER
 	JMP success
 sse42:
-	MOVL runtime·cpuid_ecx(SB), CX
+	CMPB runtime·support_sse42(SB), $1
-	ANDL $0x100000, CX
+	JNE no_sse42
-	JZ no_sse42
 	CMPQ AX, $12
 	// PCMPESTRI is slower than normal compare,
 	// so using it makes sense only if we advance 4+ bytes per compare

src/runtime/asm_amd64p32.s

@@ -28,9 +28,9 @@ TEXT runtime·rt0_go(SB),NOSPLIT,$0
 	MOVL	SP, (g_stack+stack_hi)(DI)
 
 	// find out information about the processor we're on
-	MOVQ	$0, AX
+	MOVL	$0, AX
 	CPUID
-	CMPQ	AX, $0
+	CMPL	AX, $0
 	JE	nocpuinfo
 
 	CMPL	BX, $0x756E6547  // "Genu"
@@ -42,11 +42,79 @@ TEXT runtime·rt0_go(SB),NOSPLIT,$0
 	MOVB	$1, runtime·isIntel(SB)
 notintel:
 
-	MOVQ	$1, AX
+	// Load EAX=1 cpuid flags
+	MOVL	$1, AX
 	CPUID
-	MOVL	AX, runtime·cpuid_eax(SB)
+	MOVL	AX, runtime·processorVersionInfo(SB)
 	MOVL	CX, runtime·cpuid_ecx(SB)
 	MOVL	DX, runtime·cpuid_edx(SB)
+
+	TESTL	$(1<<26), DX // SSE2
+	SETNE	runtime·support_sse2(SB)
+
+	TESTL	$(1<<9), CX // SSSE3
+	SETNE	runtime·support_ssse3(SB)
+
+	TESTL	$(1<<19), CX // SSE4.1
+	SETNE	runtime·support_sse41(SB)
+
+	TESTL	$(1<<20), CX // SSE4.2
+	SETNE	runtime·support_sse42(SB)
+
+	TESTL	$(1<<23), CX // POPCNT
+	SETNE	runtime·support_popcnt(SB)
+
+	TESTL	$(1<<25), CX // AES
+	SETNE	runtime·support_aes(SB)
+
+	TESTL	$(1<<27), CX // OSXSAVE
+	SETNE	runtime·support_osxsave(SB)
+
+	// If OS support for XMM and YMM is not present
+	// support_avx will be set back to false later.
+	TESTL	$(1<<28), CX // AVX
+	SETNE	runtime·support_avx(SB)
+
+eax7:
+	// Load EAX=7/ECX=0 cpuid flags
+	CMPL	SI, $7
+	JLT	osavx
+	MOVL	$7, AX
+	MOVL	$0, CX
+	CPUID
+	MOVL	BX, runtime·cpuid_ebx7(SB)
+
+	TESTL	$(1<<3), BX // BMI1
+	SETNE	runtime·support_bmi1(SB)
+
+	// If OS support for XMM and YMM is not present
+	// support_avx2 will be set back to false later.
+	TESTL	$(1<<5), BX
+	SETNE	runtime·support_avx2(SB)
+
+	TESTL	$(1<<8), BX // BMI2
+	SETNE	runtime·support_bmi2(SB)
+
+	TESTL	$(1<<9), BX // ERMS
+	SETNE	runtime·support_erms(SB)
+
+osavx:
+	// nacl does not support XGETBV to test
+	// for XMM and YMM OS support.
+#ifndef GOOS_nacl
+	CMPB	runtime·support_osxsave(SB), $1
+	JNE	noavx
+	MOVL	$0, CX
+	// For XGETBV, OSXSAVE bit is required and sufficient
+	XGETBV
+	ANDL	$6, AX
+	CMPL	AX, $6 // Check for OS support of XMM and YMM registers.
+	JE nocpuinfo
+#endif
+noavx:
+	MOVB $0, runtime·support_avx(SB)
+	MOVB $0, runtime·support_avx2(SB)
+
 nocpuinfo:
 
 needtls:

src/runtime/cpuflags_amd64.go

@@ -8,13 +8,13 @@ var useAVXmemmove bool
 
 func init() {
 	// Let's remove stepping and reserved fields
-	processorVersionInfo := cpuid_eax & 0x0FFF3FF0
+	processor := processorVersionInfo & 0x0FFF3FF0
 
 	isIntelBridgeFamily := isIntel &&
-		(processorVersionInfo == 0x206A0 ||
+		processor == 0x206A0 ||
-			processorVersionInfo == 0x206D0 ||
+		processor == 0x206D0 ||
-			processorVersionInfo == 0x306A0 ||
+		processor == 0x306A0 ||
-			processorVersionInfo == 0x306E0)
+		processor == 0x306E0
 
 	useAVXmemmove = support_avx && !isIntelBridgeFamily
 }

src/runtime/memclr_386.s

@@ -27,8 +27,8 @@ tail:
 	JBE	_5through8
 	CMPL	BX, $16
 	JBE	_9through16
-	TESTL	$0x4000000, runtime·cpuid_edx(SB) // check for sse2
+	CMPB	runtime·support_sse2(SB), $1
-	JEQ	nosse2
+	JNE	nosse2
 	PXOR	X0, X0
 	CMPL	BX, $32
 	JBE	_17through32

src/runtime/memmove_386.s

@@ -49,8 +49,8 @@ tail:
 	JBE	move_5through8
 	CMPL	BX, $16
 	JBE	move_9through16
-	TESTL	$0x4000000, runtime·cpuid_edx(SB) // check for sse2
+	CMPB	runtime·support_sse2(SB), $1
-	JEQ	nosse2
+	JNE	nosse2
 	CMPL	BX, $32
 	JBE	move_17through32
 	CMPL	BX, $64
@@ -71,8 +71,8 @@ nosse2:
  */
 forward:
 	// If REP MOVSB isn't fast, don't use it
-	TESTL	$(1<<9), runtime·cpuid_ebx7(SB) // erms, aka enhanced REP MOVSB/STOSB
+	CMPB	runtime·support_erms(SB), $1 // enhanced REP MOVSB/STOSB
-	JEQ	fwdBy4
+	JNE	fwdBy4
 
 	// Check alignment
 	MOVL	SI, AX

src/runtime/memmove_amd64.s

@@ -81,8 +81,8 @@ forward:
 	JLS	move_256through2048
 
 	// If REP MOVSB isn't fast, don't use it
-	TESTL	$(1<<9), runtime·cpuid_ebx7(SB) // erms, aka enhanced REP MOVSB/STOSB
+	CMPB	runtime·support_erms(SB), $1 // enhanced REP MOVSB/STOSB
-	JEQ	fwdBy8
+	JNE	fwdBy8
 
 	// Check alignment
 	MOVL	SI, AX

src/runtime/runtime2.go

@@ -728,17 +728,29 @@ var (
 
 	// Information about what cpu features are available.
 	// Set on startup in asm_{386,amd64,amd64p32}.s.
-	cpuid_eax         uint32
+	// Packages outside the runtime should not use these
-	cpuid_ecx         uint32
+	// as they are not an external api.
-	cpuid_edx         uint32
+	processorVersionInfo uint32
-	cpuid_ebx7        uint32 // not set on amd64p32
 	isIntel              bool
 	lfenceBeforeRdtsc    bool
+	support_aes          bool
 	support_avx          bool
 	support_avx2         bool
 	support_bmi1         bool
 	support_bmi2         bool
+	support_erms         bool
+	support_osxsave      bool
 	support_popcnt       bool
+	support_sse2         bool
+	support_sse41        bool
+	support_sse42        bool
+	support_ssse3        bool
+
+	// TODO(moehrmann) delete below variables once external
+	// packages have their dependencies on these removed.
+	cpuid_ecx  uint32
+	cpuid_edx  uint32
+	cpuid_ebx7 uint32 // not set on amd64p32
 
 	goarm                uint8 // set by cmd/link on arm systems
 	framepointer_enabled bool  // set by cmd/link