runtime: add FIPS helper functions

Not entirely sure what they're for, but the Go runtime also stores this
information per goroutine so let's go with that.

Author: aykevl

src/internal/task/task.go

@@ -21,6 +21,9 @@ type Task struct {
 	// state is the underlying running state of the task.
 	state state
 
+	// This is needed for some crypto packages.
+	FipsIndicator uint8
+
 	// DeferFrame stores a pointer to the (stack allocated) defer frame of the
 	// goroutine that is used for the recover builtin.
 	DeferFrame unsafe.Pointer

src/runtime/panic.go

@@ -226,3 +226,8 @@ func divideByZeroPanic() {
 func blockingPanic() {
 	runtimePanicAt(returnAddress(0), "trying to do blocking operation in exported function")
 }
+
+//go:linkname fips_fatal crypto/internal/fips140.fatal
+func fips_fatal(msg string) {
+	runtimePanic(msg)
+}

src/runtime/scheduler.go

@@ -31,3 +31,14 @@ func scheduleLogChan(msg string, ch *channel, t *task.Task) {
 func Goexit() {
 	panicOrGoexit(nil, panicGoexit)
 }
+
+//go:linkname fips_getIndicator crypto/internal/fips140.getIndicator
+func fips_getIndicator() uint8 {
+	return task.Current().FipsIndicator
+}
+
+//go:linkname fips_setIndicator crypto/internal/fips140.setIndicator
+func fips_setIndicator(indicator uint8) {
+	// This indicator is stored per goroutine.
+	task.Current().FipsIndicator = indicator
+}