feat(verify): ABI checks on arm64, riscv64 and loong64

Assisted-by: GLM 5.3 Flash

verify/abi_riscv64.go

@@ -0,0 +1,33 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build riscv64
+
+package verify
+
+// leaveCheckedPtr is initialised by the linker from the GLOBL/DATA in
+// abi_riscv64.s: it holds the raw address of leaveJITCheckedRaw (which has
+// no ABIInternal wrapper, so the JIT function RETs directly into it).
+var leaveCheckedPtr uintptr
+
+// enterJITChecked sets a sentinel in X27 (the goroutine pointer; riscv64
+// keeps no hardware frame pointer), switches to the prepared stack and
+// jumps to fn.  The body lives in abi_riscv64.s and reads the parameters
+// from the frame by name, which GoLand cannot see.
+//
+// noinspection GoUnusedParameter
+//
+//go:nosplit
+func enterJITChecked(fn uintptr, stack uintptr)
+
+// leaveJITCheckedRaw is the raw return trampoline for ABI checks.  Its
+// address is obtained from the GLOBL in abi_riscv64.s (leaveCheckedPtr),
+// which points to the .abi0 code — NOT the ABIInternal wrapper that this
+// declaration would generate.  The declaration exists solely to satisfy
+// go vet's "missing Go declaration" check.
+//
+// noinspection GoUnusedFunction
+//
+//lint:ignore U1000 the assembly obtains this address through leaveCheckedPtr
+//go:nosplit
+func leaveJITCheckedRaw()