runtime/interrupt: add cross-chip disable/restore interrupt support

This should cover all supported baremetal targets.

src/runtime/interrupt/interrupt_avr.go

@@ -0,0 +1,36 @@
+// +build avr
+
+package interrupt
+
+import "device"
+
+// State represents the previous global interrupt state.
+type State uint8
+
+// Disable disables all interrupts and returns the previous interrupt state. It
+// can be used in a critical section like this:
+//
+//     state := interrupt.Disable()
+//     // critical section
+//     interrupt.Restore(state)
+//
+// Critical sections can be nested. Make sure to call Restore in the same order
+// as you called Disable (this happens naturally with the pattern above).
+func Disable() (state State) {
+	// SREG is at I/O address 0x3f.
+	return State(device.AsmFull(`
+		in {}, 0x3f
+		cli
+	`, nil))
+}
+
+// Restore restores interrupts to what they were before. Give the previous state
+// returned by Disable as a parameter. If interrupts were disabled before
+// calling Disable, this will not re-enable interrupts, allowing for nested
+// cricital sections.
+func Restore(state State) {
+	// SREG is at I/O address 0x3f.
+	device.AsmFull("out 0x3f, {state}", map[string]interface{}{
+		"state": state,
+	})
+}

src/runtime/interrupt/interrupt_cortexm.go

@@ -21,3 +21,27 @@ func (irq Interrupt) Enable() {
 func (irq Interrupt) SetPriority(priority uint8) {
 	arm.SetPriority(uint32(irq.num), uint32(priority))
 }
+
+// State represents the previous global interrupt state.
+type State uintptr
+
+// Disable disables all interrupts and returns the previous interrupt state. It
+// can be used in a critical section like this:
+//
+//     state := interrupt.Disable()
+//     // critical section
+//     interrupt.Restore(state)
+//
+// Critical sections can be nested. Make sure to call Restore in the same order
+// as you called Disable (this happens naturally with the pattern above).
+func Disable() (state State) {
+	return State(arm.DisableInterrupts())
+}
+
+// Restore restores interrupts to what they were before. Give the previous state
+// returned by Disable as a parameter. If interrupts were disabled before
+// calling Disable, this will not re-enable interrupts, allowing for nested
+// cricital sections.
+func Restore(state State) {
+	arm.EnableInterrupts(uintptr(state))
+}

src/runtime/interrupt/interrupt_gameboyadvance.go

@@ -34,3 +34,32 @@ func handleInterrupt() {
 // appropriate interrupt handler for the given interrupt ID.
 //go:linkname callInterruptHandler runtime.callInterruptHandler
 func callInterruptHandler(id int)
+
+// State represents the previous global interrupt state.
+type State uint8
+
+// Disable disables all interrupts and returns the previous interrupt state. It
+// can be used in a critical section like this:
+//
+//     state := interrupt.Disable()
+//     // critical section
+//     interrupt.Restore(state)
+//
+// Critical sections can be nested. Make sure to call Restore in the same order
+// as you called Disable (this happens naturally with the pattern above).
+func Disable() (state State) {
+	// Save the previous interrupt state.
+	state = State(regInterruptMasterEnable.Get())
+	// Disable all interrupts.
+	regInterruptMasterEnable.Set(0)
+	return
+}
+
+// Restore restores interrupts to what they were before. Give the previous state
+// returned by Disable as a parameter. If interrupts were disabled before
+// calling Disable, this will not re-enable interrupts, allowing for nested
+// cricital sections.
+func Restore(state State) {
+	// Restore interrupts to the previous state.
+	regInterruptMasterEnable.Set(uint16(state))
+}

src/runtime/interrupt/interrupt_tinygoriscv.go

@@ -0,0 +1,29 @@
+// +build tinygo.riscv
+
+package interrupt
+
+import "device/riscv"
+
+// State represents the previous global interrupt state.
+type State uintptr
+
+// Disable disables all interrupts and returns the previous interrupt state. It
+// can be used in a critical section like this:
+//
+//     state := interrupt.Disable()
+//     // critical section
+//     interrupt.Restore(state)
+//
+// Critical sections can be nested. Make sure to call Restore in the same order
+// as you called Disable (this happens naturally with the pattern above).
+func Disable() (state State) {
+	return State(riscv.DisableInterrupts())
+}
+
+// Restore restores interrupts to what they were before. Give the previous state
+// returned by Disable as a parameter. If interrupts were disabled before
+// calling Disable, this will not re-enable interrupts, allowing for nested
+// cricital sections.
+func Restore(state State) {
+	riscv.EnableInterrupts(uintptr(state))
+}