machine: add USBDevice.Attach and USBDevice.Detach

The USB device is attached to the bus automatically during startup,
before user code has a chance to finish its USB configuration (device
identifiers, extra HID interfaces, ...). Composite devices such as
keyboards may therefore be enumerated by the host with an incomplete
configuration.

Attach and Detach expose the soft-connect control (DP pull-up) so that
an application or library can detach in an init function, complete its
configuration, and attach again to let the host enumerate the finished
device. They can also be used to force re-enumeration without
replugging the cable.

Implemented for atsamd21, atsamd51, nrf52840, rp2040 and rp2350.

.github/workflows/build-macos.yml

@@ -40,7 +40,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.27.0-rc.3'
+          go-version: '1.27.0-rc.2'
           cache: true
       - name: Restore LLVM source cache
         uses: actions/cache/restore@v5
@@ -131,7 +131,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.27.0-rc.3'
+          go-version: '1.27.0-rc.2'
           cache: true
       - name: Build TinyGo (LLVM ${{ matrix.version }})
         run: go install -tags=llvm${{ matrix.version }}

.github/workflows/linux.yml

@@ -23,7 +23,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.27.0-rc.3'
+          go-version: '1.27.0-rc.2'
           cache: true
       - name: Run go mod tidy
         run: go mod tidy
@@ -36,7 +36,7 @@ jobs:
     # statically linked binary.
     runs-on: ubuntu-latest
     container:
-      image: golang:1.27rc3-alpine
+      image: golang:1.27rc2-alpine
     outputs:
       version: ${{ steps.version.outputs.version }}
     steps:
@@ -160,7 +160,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.27.0-rc.3'
+          go-version: '1.27.0-rc.2'
           cache: true
       - name: Install wasmtime
         uses: bytecodealliance/actions/wasmtime/setup@v1
@@ -204,7 +204,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.27.0-rc.3'
+          go-version: '1.27.0-rc.2'
           cache: true
       - name: Install Node.js
         uses: actions/setup-node@v6
@@ -323,7 +323,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.27.0-rc.3'
+          go-version: '1.27.0-rc.2'
           cache: true
       - name: Restore LLVM source cache
         uses: actions/cache/restore@v5

.github/workflows/windows.yml

@@ -34,7 +34,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.27.0-rc.3'
+          go-version: '1.27.0-rc.2'
           cache: true
       - name: Restore cached LLVM source
         uses: actions/cache/restore@v5
@@ -129,7 +129,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.27.0-rc.3'
+          go-version: '1.27.0-rc.2'
           cache: true
       - name: Download TinyGo build
         uses: actions/download-artifact@v8
@@ -150,7 +150,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.27.0-rc.3'
+          go-version: '1.27.0-rc.2'
           cache: true
       - name: Download TinyGo build
         uses: actions/download-artifact@v8
@@ -176,7 +176,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v6
         with:
-          go-version: '1.27.0-rc.3'
+          go-version: '1.27.0-rc.2'
           cache: true
       - name: Download TinyGo build
         uses: actions/download-artifact@v8

Dockerfile

@@ -1,5 +1,5 @@
 # tinygo-llvm stage obtains the llvm source for TinyGo
-FROM golang:1.27rc3 AS tinygo-llvm
+FROM golang:1.27rc2 AS tinygo-llvm
 
 RUN apt-get update && \
     apt-get install -y apt-utils make cmake clang-17 ninja-build && \
@@ -33,7 +33,7 @@ RUN cd /tinygo/ && \
 
 # tinygo-compiler copies the compiler build over to a base Go container (without
 # all the build tools etc).
-FROM golang:1.27rc3 AS tinygo-compiler
+FROM golang:1.27rc2 AS tinygo-compiler
 
 # Copy tinygo build.
 COPY --from=tinygo-compiler-build /tinygo/build/release/tinygo /tinygo

main.go

@@ -177,15 +177,8 @@ func Build(pkgName, outpath string, config *compileopts.Config) error {
 				// Pick a default output path based on the main directory.
 				outpath = filepath.Base(result.MainDir) + config.DefaultBinaryExtension()
 			}
-		} else if fi, statErr := os.Stat(outpath); statErr == nil && fi.IsDir() {
-			var name string
-			if strings.HasSuffix(pkgName, ".go") {
-				name = filepath.Base(pkgName[:len(pkgName)-3]) + config.DefaultBinaryExtension()
-			} else {
-				name = filepath.Base(result.MainDir) + config.DefaultBinaryExtension()
-			}
-			outpath = filepath.Join(outpath, name)
 		}
+
 		if err := os.Rename(result.Binary, outpath); err != nil {
 			// Moving failed. Do a file copy.
 			inf, err := os.Open(result.Binary)

src/machine/machine_atsamd21_usb.go

@@ -68,6 +68,20 @@ func (dev *USBDevice) Configure(config UARTConfig) {
 	dev.initcomplete = true
 }
 
+// Attach connects the device to the USB bus, allowing the host to detect and
+// enumerate it. It can be used together with Detach to delay enumeration
+// until the USB configuration (device identifiers, classes, ...) is complete.
+func (dev *USBDevice) Attach() {
+	sam.USB_DEVICE.CTRLB.ClearBits(sam.USB_DEVICE_CTRLB_DETACH)
+}
+
+// Detach disconnects the device from the USB bus. To the host this appears
+// as if the device was unplugged. A subsequent Attach makes the host
+// enumerate the device again.
+func (dev *USBDevice) Detach() {
+	sam.USB_DEVICE.CTRLB.SetBits(sam.USB_DEVICE_CTRLB_DETACH)
+}
+
 func handlePadCalibration() {
 	// Load Pad Calibration data from non-volatile memory
 	// This requires registers that are not included in the SVD file.

src/machine/machine_atsamd51_usb.go

@@ -71,6 +71,20 @@ func (dev *USBDevice) Configure(config UARTConfig) {
 	dev.initcomplete = true
 }
 
+// Attach connects the device to the USB bus, allowing the host to detect and
+// enumerate it. It can be used together with Detach to delay enumeration
+// until the USB configuration (device identifiers, classes, ...) is complete.
+func (dev *USBDevice) Attach() {
+	sam.USB_DEVICE.CTRLB.ClearBits(sam.USB_DEVICE_CTRLB_DETACH)
+}
+
+// Detach disconnects the device from the USB bus. To the host this appears
+// as if the device was unplugged. A subsequent Attach makes the host
+// enumerate the device again.
+func (dev *USBDevice) Detach() {
+	sam.USB_DEVICE.CTRLB.SetBits(sam.USB_DEVICE_CTRLB_DETACH)
+}
+
 func handlePadCalibration() {
 	// Load Pad Calibration data from non-volatile memory
 	// This requires registers that are not included in the SVD file.

src/machine/machine_nrf52840_usb.go

@@ -89,6 +89,21 @@ func (dev *USBDevice) Configure(config UARTConfig) {
 	dev.initcomplete = true
 }
 
+// Attach connects the device to the USB bus by enabling the DP pull-up,
+// allowing the host to detect and enumerate it. It can be used together with
+// Detach to delay enumeration until the USB configuration (device
+// identifiers, classes, ...) is complete.
+func (dev *USBDevice) Attach() {
+	nrf.USBD.USBPULLUP.Set(1)
+}
+
+// Detach disconnects the device from the USB bus by disabling the DP pull-up.
+// To the host this appears as if the device was unplugged. A subsequent
+// Attach makes the host enumerate the device again.
+func (dev *USBDevice) Detach() {
+	nrf.USBD.USBPULLUP.Set(0)
+}
+
 func handleUSBIRQ(interrupt.Interrupt) {
 	if nrf.USBD.EVENTS_SOF.Get() == 1 {
 		nrf.USBD.EVENTS_SOF.Set(0)

src/machine/machine_rp2040_usb.go

@@ -46,6 +46,21 @@ func (dev *USBDevice) Configure(config UARTConfig) {
 	rp.USBCTRL_REGS.SIE_CTRL.SetBits(rp.USBCTRL_REGS_SIE_CTRL_PULLUP_EN)
 }
 
+// Attach connects the device to the USB bus by enabling the DP pull-up,
+// allowing the host to detect and enumerate it. It can be used together with
+// Detach to delay enumeration until the USB configuration (device
+// identifiers, classes, ...) is complete.
+func (dev *USBDevice) Attach() {
+	rp.USBCTRL_REGS.SIE_CTRL.SetBits(rp.USBCTRL_REGS_SIE_CTRL_PULLUP_EN)
+}
+
+// Detach disconnects the device from the USB bus by disabling the DP pull-up.
+// To the host this appears as if the device was unplugged. A subsequent
+// Attach makes the host enumerate the device again.
+func (dev *USBDevice) Detach() {
+	rp.USBCTRL_REGS.SIE_CTRL.ClearBits(rp.USBCTRL_REGS_SIE_CTRL_PULLUP_EN)
+}
+
 func handleUSBIRQ(intr interrupt.Interrupt) {
 	status := rp.USBCTRL_REGS.INTS.Get()
 

src/machine/machine_rp2350_usb.go

@@ -49,6 +49,21 @@ func (dev *USBDevice) Configure(config UARTConfig) {
 	rp.USB.SetMAIN_CTRL_PHY_ISO(0x0)
 }
 
+// Attach connects the device to the USB bus by enabling the DP pull-up,
+// allowing the host to detect and enumerate it. It can be used together with
+// Detach to delay enumeration until the USB configuration (device
+// identifiers, classes, ...) is complete.
+func (dev *USBDevice) Attach() {
+	rp.USB.SIE_CTRL.SetBits(rp.USB_SIE_CTRL_PULLUP_EN)
+}
+
+// Detach disconnects the device from the USB bus by disabling the DP pull-up.
+// To the host this appears as if the device was unplugged. A subsequent
+// Attach makes the host enumerate the device again.
+func (dev *USBDevice) Detach() {
+	rp.USB.SIE_CTRL.ClearBits(rp.USB_SIE_CTRL_PULLUP_EN)
+}
+
 func handleUSBIRQ(intr interrupt.Interrupt) {
 	status := rp.USB.INTS.Get()
 

src/runtime/gc_blocks.go

@@ -510,7 +510,7 @@ func realloc(ptr unsafe.Pointer, size uintptr) unsafe.Pointer {
 	lastBlock := firstBlock.findHead()
 
 	// Calculate the size of the original allocation body.
-	oldSize := uintptr(lastBlock-firstBlock)*bytesPerBlock + (bytesPerBlock - unsafe.Sizeof(objHeader{}))
+	oldSize := uintptr(lastBlock-firstBlock)*blocksPerStateByte + (bytesPerBlock - unsafe.Sizeof(objHeader{}))
 
 	if size <= oldSize {
 		// The requested size is less than the old size.

src/runtime/gc_leaking.go

@@ -47,14 +47,8 @@ func alloc(size uintptr, layout unsafe.Pointer) unsafe.Pointer {
 	gcTotalAlloc += uint64(size)
 	gcMallocs++
 	heapptr += size
-	if heapptr < addr {
-		// The allocation size overflowed the heap pointer.
-		runtimePanic("out of memory")
-	}
-	for heapptr > heapEnd {
+	for heapptr >= heapEnd {
 		// Try to increase the heap and check again.
-		// Use > instead of >= because an allocation that exactly
-		// ends at heapEnd is still within heap boundaries.
 		if growHeap() {
 			continue
 		}

src/runtime/gc_stack_cores.go

@@ -43,12 +43,6 @@ func gcMarkReachable() {
 		gcPauseCore(i)
 	}
 
-	// Busy-wait until all the other cores are ready.
-	for gcScanState.Load() != numCPU {
-		spinLoopWait()
-	}
-	gcScanState.Store(0)
-
 	// Scan the stack(s) of the current core.
 	scanCurrentStack()
 	if !task.OnSystemStack() {
@@ -59,6 +53,13 @@ func gcMarkReachable() {
 	// Scan globals.
 	findGlobals(markRoots)
 
+	// Busy-wait until all the other cores are ready. They certainly should be,
+	// after the scanning we did above.
+	for gcScanState.Load() != numCPU {
+		spinLoopWait()
+	}
+	gcScanState.Store(0)
+
 	// Signal each core in turn that they can scan the stack.
 	for i := uint32(0); i < numCPU; i++ {
 		if i == core {

src/runtime/hashmap.go

@@ -807,13 +807,13 @@ func hashmapInterfaceHash(itf interface{}, seed uintptr) uint32 {
 	case reflectlite.Array:
 		var hash uint32
 		for i := 0; i < x.Len(); i++ {
-			hash = (hash * 31) ^ hashmapInterfaceHash(valueInterfaceUnsafe(x.Index(i)), seed)
+			hash ^= hashmapInterfaceHash(valueInterfaceUnsafe(x.Index(i)), seed)
 		}
 		return hash
 	case reflectlite.Struct:
 		var hash uint32
 		for i := 0; i < x.NumField(); i++ {
-			hash = (hash * 31) ^ hashmapInterfaceHash(valueInterfaceUnsafe(x.Field(i)), seed)
+			hash ^= hashmapInterfaceHash(valueInterfaceUnsafe(x.Field(i)), seed)
 		}
 		return hash
 	default:

targets/esp32.json

@@ -3,7 +3,7 @@
 	"inheritable-only": true,
 	"cpu": "esp32",
 	"features": "+atomctl,+bool,+clamps,+coprocessor,+debug,+density,+dfpaccel,+div32,+exception,+fp,+highpriinterrupts,+interrupt,+loop,+mac16,+memctl,+minmax,+miscsr,+mul32,+mul32high,+nsa,+prid,+regprotect,+rvector,+s32c1i,+sext,+threadptr,+timerint,+windowed",
-	"build-tags": ["esp32", "esp", "espradio"],
+	"build-tags": ["esp32", "esp"],
 	"scheduler": "tasks",
 	"serial": "uart",
 	"linker": "ld.lld",

targets/esp32c3.json

@@ -6,8 +6,7 @@
 	"features": "+32bit,+c,+m,+zmmul,-relax",
 	"build-tags": [
 		"esp32c3",
-		"esp",
-		"espradio"
+		"esp"
 	],
 	"serial": "usb",
 	"rtlib": "compiler-rt",

targets/esp32s3.json

@@ -3,7 +3,7 @@
 	"inheritable-only": true,
 	"cpu": "esp32s3",
 	"features": "+atomctl,+bool,+clamps,+coprocessor,+debug,+density,+div32,+esp32s3,+exception,+fp,+highpriinterrupts,+interrupt,+loop,+mac16,+memctl,+minmax,+miscsr,+mul32,+mul32high,+nsa,+prid,+regprotect,+rvector,+s32c1i,+sext,+threadptr,+timerint,+windowed",
-	"build-tags": ["esp32s3", "esp", "espradio"],
+	"build-tags": ["esp32s3", "esp"],
 	"scheduler": "tasks",
 	"serial": "usb",
 	"linker": "ld.lld",