From d2101e54908dc6899863be0772658dbd7e0bbc71 Mon Sep 17 00:00:00 2001
From: Austin Clements <austin@google.com>
Date: Wed, 23 Oct 2019 09:47:53 -0400
Subject: runtime/internal/atomic: add Store8

We already have Load8, And8, and Or8.

For #10958, #24543, but makes sense on its own.

Change-Id: I478529fc643edc57efdeccaae413c99edd19b2eb
Reviewed-on: https://go-review.googlesource.com/c/go/+/203283
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
---
 src/runtime/internal/atomic/asm_386.s          |  6 ++++++
 src/runtime/internal/atomic/asm_amd64.s        |  6 ++++++
 src/runtime/internal/atomic/asm_mips64x.s      |  8 ++++++++
 src/runtime/internal/atomic/asm_mipsx.s        |  8 ++++++++
 src/runtime/internal/atomic/asm_ppc64x.s       |  7 +++++++
 src/runtime/internal/atomic/asm_s390x.s        |  8 ++++++++
 src/runtime/internal/atomic/atomic_386.go      |  3 +++
 src/runtime/internal/atomic/atomic_amd64.go    |  3 +++
 src/runtime/internal/atomic/atomic_arm.go      |  3 +++
 src/runtime/internal/atomic/atomic_arm64.go    |  3 +++
 src/runtime/internal/atomic/atomic_arm64.s     |  6 ++++++
 src/runtime/internal/atomic/atomic_mips64x.go  |  3 +++
 src/runtime/internal/atomic/atomic_mipsx.go    |  3 +++
 src/runtime/internal/atomic/atomic_ppc64x.go   |  3 +++
 src/runtime/internal/atomic/atomic_s390x.go    |  3 +++
 src/runtime/internal/atomic/atomic_wasm.go     |  6 ++++++
 src/runtime/internal/atomic/sys_linux_arm.s    | 22 ++++++++++++++++++++++
 src/runtime/internal/atomic/sys_nonlinux_arm.s | 17 +++++++++++++++++
 18 files changed, 118 insertions(+)

(limited to 'src/runtime/internal/atomic')

diff --git a/src/runtime/internal/atomic/asm_386.s b/src/runtime/internal/atomic/asm_386.s
index 13289a88d0..9b9dc14a60 100644
--- a/src/runtime/internal/atomic/asm_386.s
+++ b/src/runtime/internal/atomic/asm_386.s
@@ -229,3 +229,9 @@ TEXT runtime∕internal∕atomic·And8(SB), NOSPLIT, $0-5
 	LOCK
 	ANDB	BX, (AX)
 	RET
+
+TEXT runtime∕internal∕atomic·Store8(SB), NOSPLIT, $0-5
+	MOVL	ptr+0(FP), BX
+	MOVB	val+4(FP), AX
+	XCHGB	AX, 0(BX)
+	RET
diff --git a/src/runtime/internal/atomic/asm_amd64.s b/src/runtime/internal/atomic/asm_amd64.s
index e18aee7d59..90c56424c9 100644
--- a/src/runtime/internal/atomic/asm_amd64.s
+++ b/src/runtime/internal/atomic/asm_amd64.s
@@ -136,6 +136,12 @@ TEXT runtime∕internal∕atomic·Store(SB), NOSPLIT, $0-12
 TEXT runtime∕internal∕atomic·StoreRel(SB), NOSPLIT, $0-12
 	JMP	runtime∕internal∕atomic·Store(SB)
 
+TEXT runtime∕internal∕atomic·Store8(SB), NOSPLIT, $0-9
+	MOVQ	ptr+0(FP), BX
+	MOVB	val+8(FP), AX
+	XCHGB	AX, 0(BX)
+	RET
+
 TEXT runtime∕internal∕atomic·Store64(SB), NOSPLIT, $0-16
 	MOVQ	ptr+0(FP), BX
 	MOVQ	val+8(FP), AX
diff --git a/src/runtime/internal/atomic/asm_mips64x.s b/src/runtime/internal/atomic/asm_mips64x.s
index 9cb10371b7..3290fb726a 100644
--- a/src/runtime/internal/atomic/asm_mips64x.s
+++ b/src/runtime/internal/atomic/asm_mips64x.s
@@ -166,6 +166,14 @@ TEXT ·Store(SB), NOSPLIT, $0-12
 	SYNC
 	RET
 
+TEXT ·Store8(SB), NOSPLIT, $0-9
+	MOVV	ptr+0(FP), R1
+	MOVB	val+8(FP), R2
+	SYNC
+	MOVB	R2, 0(R1)
+	SYNC
+	RET
+
 TEXT ·Store64(SB), NOSPLIT, $0-16
 	MOVV	ptr+0(FP), R1
 	MOVV	val+8(FP), R2
diff --git a/src/runtime/internal/atomic/asm_mipsx.s b/src/runtime/internal/atomic/asm_mipsx.s
index af6bce57d6..62811a6599 100644
--- a/src/runtime/internal/atomic/asm_mipsx.s
+++ b/src/runtime/internal/atomic/asm_mipsx.s
@@ -32,6 +32,14 @@ TEXT ·Store(SB),NOSPLIT,$0-8
 	SYNC
 	RET
 
+TEXT ·Store8(SB),NOSPLIT,$0-5
+	MOVW	ptr+0(FP), R1
+	MOVB	val+4(FP), R2
+	SYNC
+	MOVB	R2, 0(R1)
+	SYNC
+	RET
+
 TEXT ·Load(SB),NOSPLIT,$0-8
 	MOVW	ptr+0(FP), R1
 	SYNC
diff --git a/src/runtime/internal/atomic/asm_ppc64x.s b/src/runtime/internal/atomic/asm_ppc64x.s
index 052b031cfb..06dc931bf4 100644
--- a/src/runtime/internal/atomic/asm_ppc64x.s
+++ b/src/runtime/internal/atomic/asm_ppc64x.s
@@ -170,6 +170,13 @@ TEXT runtime∕internal∕atomic·Store(SB), NOSPLIT, $0-12
 	MOVW	R4, 0(R3)
 	RET
 
+TEXT runtime∕internal∕atomic·Store8(SB), NOSPLIT, $0-9
+	MOVD	ptr+0(FP), R3
+	MOVB	val+8(FP), R4
+	SYNC
+	MOVB	R4, 0(R3)
+	RET
+
 TEXT runtime∕internal∕atomic·Store64(SB), NOSPLIT, $0-16
 	MOVD	ptr+0(FP), R3
 	MOVD	val+8(FP), R4
diff --git a/src/runtime/internal/atomic/asm_s390x.s b/src/runtime/internal/atomic/asm_s390x.s
index 084f5b5163..78abd48afa 100644
--- a/src/runtime/internal/atomic/asm_s390x.s
+++ b/src/runtime/internal/atomic/asm_s390x.s
@@ -12,6 +12,14 @@ TEXT ·Store(SB), NOSPLIT, $0
 	SYNC
 	RET
 
+// func Store8(ptr *uint8, val uint8)
+TEXT ·Store8(SB), NOSPLIT, $0
+	MOVD	ptr+0(FP), R2
+	MOVB	val+8(FP), R3
+	MOVB	R3, 0(R2)
+	SYNC
+	RET
+
 // func Store64(ptr *uint64, val uint64)
 TEXT ·Store64(SB), NOSPLIT, $0
 	MOVD	ptr+0(FP), R2
diff --git a/src/runtime/internal/atomic/atomic_386.go b/src/runtime/internal/atomic/atomic_386.go
index d7f82cc752..8d002ebfe3 100644
--- a/src/runtime/internal/atomic/atomic_386.go
+++ b/src/runtime/internal/atomic/atomic_386.go
@@ -74,6 +74,9 @@ func CasRel(ptr *uint32, old, new uint32) bool
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 //go:noescape
 func Store64(ptr *uint64, val uint64)
 
diff --git a/src/runtime/internal/atomic/atomic_amd64.go b/src/runtime/internal/atomic/atomic_amd64.go
index fc865e892d..14b8101720 100644
--- a/src/runtime/internal/atomic/atomic_amd64.go
+++ b/src/runtime/internal/atomic/atomic_amd64.go
@@ -76,6 +76,9 @@ func CasRel(ptr *uint32, old, new uint32) bool
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 //go:noescape
 func Store64(ptr *uint64, val uint64)
 
diff --git a/src/runtime/internal/atomic/atomic_arm.go b/src/runtime/internal/atomic/atomic_arm.go
index c1fc1f727f..95713afcc1 100644
--- a/src/runtime/internal/atomic/atomic_arm.go
+++ b/src/runtime/internal/atomic/atomic_arm.go
@@ -209,5 +209,8 @@ func Xchg64(addr *uint64, v uint64) uint64
 //go:noescape
 func Load64(addr *uint64) uint64
 
+//go:noescape
+func Store8(addr *uint8, v uint8)
+
 //go:noescape
 func Store64(addr *uint64, v uint64)
diff --git a/src/runtime/internal/atomic/atomic_arm64.go b/src/runtime/internal/atomic/atomic_arm64.go
index 0182f309cc..26ca94d54c 100644
--- a/src/runtime/internal/atomic/atomic_arm64.go
+++ b/src/runtime/internal/atomic/atomic_arm64.go
@@ -56,6 +56,9 @@ func CasRel(ptr *uint32, old, new uint32) bool
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 //go:noescape
 func Store64(ptr *uint64, val uint64)
 
diff --git a/src/runtime/internal/atomic/atomic_arm64.s b/src/runtime/internal/atomic/atomic_arm64.s
index a7e8c35449..d95689fe2d 100644
--- a/src/runtime/internal/atomic/atomic_arm64.s
+++ b/src/runtime/internal/atomic/atomic_arm64.s
@@ -48,6 +48,12 @@ TEXT runtime∕internal∕atomic·Store(SB), NOSPLIT, $0-12
 	STLRW	R1, (R0)
 	RET
 
+TEXT runtime∕internal∕atomic·Store8(SB), NOSPLIT, $0-9
+	MOVD	ptr+0(FP), R0
+	MOVB	val+8(FP), R1
+	STLRB	R1, (R0)
+	RET
+
 TEXT runtime∕internal∕atomic·Store64(SB), NOSPLIT, $0-16
 	MOVD	ptr+0(FP), R0
 	MOVD	val+8(FP), R1
diff --git a/src/runtime/internal/atomic/atomic_mips64x.go b/src/runtime/internal/atomic/atomic_mips64x.go
index ce11e38a96..1d9977850b 100644
--- a/src/runtime/internal/atomic/atomic_mips64x.go
+++ b/src/runtime/internal/atomic/atomic_mips64x.go
@@ -58,6 +58,9 @@ func CasRel(ptr *uint32, old, new uint32) bool
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 //go:noescape
 func Store64(ptr *uint64, val uint64)
 
diff --git a/src/runtime/internal/atomic/atomic_mipsx.go b/src/runtime/internal/atomic/atomic_mipsx.go
index 6e39262c15..0e2d77ade1 100644
--- a/src/runtime/internal/atomic/atomic_mipsx.go
+++ b/src/runtime/internal/atomic/atomic_mipsx.go
@@ -141,6 +141,9 @@ func Or8(ptr *uint8, val uint8)
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 // NO go:noescape annotation; see atomic_pointer.go.
 func StorepNoWB(ptr unsafe.Pointer, val unsafe.Pointer)
 
diff --git a/src/runtime/internal/atomic/atomic_ppc64x.go b/src/runtime/internal/atomic/atomic_ppc64x.go
index 13805a5275..a48ecf5ee8 100644
--- a/src/runtime/internal/atomic/atomic_ppc64x.go
+++ b/src/runtime/internal/atomic/atomic_ppc64x.go
@@ -58,6 +58,9 @@ func CasRel(ptr *uint32, old, new uint32) bool
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 //go:noescape
 func Store64(ptr *uint64, val uint64)
 
diff --git a/src/runtime/internal/atomic/atomic_s390x.go b/src/runtime/internal/atomic/atomic_s390x.go
index 25fd890524..4d73b39baf 100644
--- a/src/runtime/internal/atomic/atomic_s390x.go
+++ b/src/runtime/internal/atomic/atomic_s390x.go
@@ -44,6 +44,9 @@ func LoadAcq(ptr *uint32) uint32 {
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 //go:noescape
 func Store64(ptr *uint64, val uint64)
 
diff --git a/src/runtime/internal/atomic/atomic_wasm.go b/src/runtime/internal/atomic/atomic_wasm.go
index 0731763ac1..9037c2f7c8 100644
--- a/src/runtime/internal/atomic/atomic_wasm.go
+++ b/src/runtime/internal/atomic/atomic_wasm.go
@@ -141,6 +141,12 @@ func StoreRel(ptr *uint32, val uint32) {
 	*ptr = val
 }
 
+//go:nosplit
+//go:noinline
+func Store8(ptr *uint8, val uint8) {
+	*ptr = val
+}
+
 //go:nosplit
 //go:noinline
 func Store64(ptr *uint64, val uint64) {
diff --git a/src/runtime/internal/atomic/sys_linux_arm.s b/src/runtime/internal/atomic/sys_linux_arm.s
index df62f6c8ad..0c1cc3dc86 100644
--- a/src/runtime/internal/atomic/sys_linux_arm.s
+++ b/src/runtime/internal/atomic/sys_linux_arm.s
@@ -120,3 +120,25 @@ end:
 	MOVB	R1, ret+4(FP)
 	RET
 
+TEXT	·Store8(SB),NOSPLIT,$0-5
+	MOVW	addr+0(FP), R1
+	MOVB	v+4(FP), R2
+
+	MOVB	runtime·goarm(SB), R8
+	CMP	$7, R8
+	BGE	native_barrier
+	BL	memory_barrier<>(SB)
+	B	store
+native_barrier:
+	DMB	MB_ISH
+
+store:
+	MOVB	R2, (R1)
+
+	CMP	$7, R8
+	BGE	native_barrier2
+	BL	memory_barrier<>(SB)
+	RET
+native_barrier2:
+	DMB	MB_ISH
+	RET
diff --git a/src/runtime/internal/atomic/sys_nonlinux_arm.s b/src/runtime/internal/atomic/sys_nonlinux_arm.s
index 9d81334791..57568b2238 100644
--- a/src/runtime/internal/atomic/sys_nonlinux_arm.s
+++ b/src/runtime/internal/atomic/sys_nonlinux_arm.s
@@ -60,3 +60,20 @@ TEXT	·Load8(SB),NOSPLIT|NOFRAME,$0-5
 
 	MOVB	R1, ret+4(FP)
 	RET
+
+TEXT	·Store8(SB),NOSPLIT,$0-5
+	MOVW	addr+0(FP), R1
+	MOVB	v+4(FP), R2
+
+	MOVB	runtime·goarm(SB), R8
+	CMP	$7, R8
+	BLT	2(PC)
+	DMB	MB_ISH
+
+	MOVB	R2, (R1)
+
+	CMP	$7, R8
+	BLT	2(PC)
+	DMB	MB_ISH
+	RET
+
-- 
cgit v1.3-5-g9baa


From 10855608bc9361aec0f17f22bf24313a3d07ec85 Mon Sep 17 00:00:00 2001
From: Michael Munday <mike.munday@ibm.com>
Date: Wed, 30 Oct 2019 12:45:33 +0000
Subject: runtime/internal/atomic: add tests for And8 and Or8

Add some simple unit tests for these atomic operations. These can't
catch all the bugs that are possible with these operations but at
least they provide some coverage.

Change-Id: I94b9f451fcc9fecdb2a1448c5357b019563ad275
Reviewed-on: https://go-review.googlesource.com/c/go/+/204317
Run-TryBot: Michael Munday <mike.munday@ibm.com>
Reviewed-by: Austin Clements <austin@google.com>
---
 src/runtime/internal/atomic/atomic_test.go | 117 +++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)

(limited to 'src/runtime/internal/atomic')

diff --git a/src/runtime/internal/atomic/atomic_test.go b/src/runtime/internal/atomic/atomic_test.go
index 9e4461ce38..0c1125c558 100644
--- a/src/runtime/internal/atomic/atomic_test.go
+++ b/src/runtime/internal/atomic/atomic_test.go
@@ -103,3 +103,120 @@ func TestUnaligned64(t *testing.T) {
 	shouldPanic(t, "Xchg64", func() { atomic.Xchg64(up64, 1) })
 	shouldPanic(t, "Cas64", func() { atomic.Cas64(up64, 1, 2) })
 }
+
+func TestAnd8(t *testing.T) {
+	// Basic sanity check.
+	x := uint8(0xff)
+	for i := uint8(0); i < 8; i++ {
+		atomic.And8(&x, ^(1 << i))
+		if r := uint8(0xff) << (i + 1); x != r {
+			t.Fatalf("clearing bit %#x: want %#x, got %#x", uint8(1<<i), r, x)
+		}
+	}
+
+	// Set every bit in array to 1.
+	a := make([]uint8, 1<<12)
+	for i := range a {
+		a[i] = 0xff
+	}
+
+	// Clear array bit-by-bit in different goroutines.
+	done := make(chan bool)
+	for i := 0; i < 8; i++ {
+		m := ^uint8(1 << i)
+		go func() {
+			for i := range a {
+				atomic.And8(&a[i], m)
+			}
+			done <- true
+		}()
+	}
+	for i := 0; i < 8; i++ {
+		<-done
+	}
+
+	// Check that the array has been totally cleared.
+	for i, v := range a {
+		if v != 0 {
+			t.Fatalf("a[%v] not cleared: want %#x, got %#x", i, uint8(0), v)
+		}
+	}
+}
+
+func TestOr8(t *testing.T) {
+	// Basic sanity check.
+	x := uint8(0)
+	for i := uint8(0); i < 8; i++ {
+		atomic.Or8(&x, 1<<i)
+		if r := (uint8(1) << (i + 1)) - 1; x != r {
+			t.Fatalf("setting bit %#x: want %#x, got %#x", uint8(1)<<i, r, x)
+		}
+	}
+
+	// Start with every bit in array set to 0.
+	a := make([]uint8, 1<<12)
+
+	// Set every bit in array bit-by-bit in different goroutines.
+	done := make(chan bool)
+	for i := 0; i < 8; i++ {
+		m := uint8(1 << i)
+		go func() {
+			for i := range a {
+				atomic.Or8(&a[i], m)
+			}
+			done <- true
+		}()
+	}
+	for i := 0; i < 8; i++ {
+		<-done
+	}
+
+	// Check that the array has been totally set.
+	for i, v := range a {
+		if v != 0xff {
+			t.Fatalf("a[%v] not fully set: want %#x, got %#x", i, uint8(0xff), v)
+		}
+	}
+}
+
+func TestBitwiseContended(t *testing.T) {
+	// Start with every bit in array set to 0.
+	a := make([]uint8, 16)
+
+	// Iterations to try.
+	N := 1 << 16
+	if testing.Short() {
+		N = 1 << 10
+	}
+
+	// Set and then clear every bit in the array bit-by-bit in different goroutines.
+	done := make(chan bool)
+	for i := 0; i < 8; i++ {
+		m := uint8(1 << i)
+		go func() {
+			for n := 0; n < N; n++ {
+				for i := range a {
+					atomic.Or8(&a[i], m)
+					if atomic.Load8(&a[i])&m != m {
+						t.Errorf("a[%v] bit %#x not set", i, m)
+					}
+					atomic.And8(&a[i], ^m)
+					if atomic.Load8(&a[i])&m != 0 {
+						t.Errorf("a[%v] bit %#x not clear", i, m)
+					}
+				}
+			}
+			done <- true
+		}()
+	}
+	for i := 0; i < 8; i++ {
+		<-done
+	}
+
+	// Check that the array has been totally cleared.
+	for i, v := range a {
+		if v != 0 {
+			t.Fatalf("a[%v] not cleared: want %#x, got %#x", i, uint8(0), v)
+		}
+	}
+}
-- 
cgit v1.3-5-g9baa