1 files changed, 90 insertions, 0 deletions
diff --git a/src/runtime/signal_darwin_arm64.go b/src/runtime/signal_darwin_arm64.go
new file mode 100644
index 0000000..690ffe4
--- /dev/null
+++ b/src/runtime/signal_darwin_arm64.go
@@ -0,0 +1,90 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime
+
+import "unsafe"
+
+type sigctxt struct {
+	info *siginfo
+	ctxt unsafe.Pointer
+}
+
+//go:nosplit
+//go:nowritebarrierrec
+func (c *sigctxt) regs() *regs64 { return &(*ucontext)(c.ctxt).uc_mcontext.ss }
+
+func (c *sigctxt) r0() uint64  { return c.regs().x[0] }
+func (c *sigctxt) r1() uint64  { return c.regs().x[1] }
+func (c *sigctxt) r2() uint64  { return c.regs().x[2] }
+func (c *sigctxt) r3() uint64  { return c.regs().x[3] }
+func (c *sigctxt) r4() uint64  { return c.regs().x[4] }
+func (c *sigctxt) r5() uint64  { return c.regs().x[5] }
+func (c *sigctxt) r6() uint64  { return c.regs().x[6] }
+func (c *sigctxt) r7() uint64  { return c.regs().x[7] }
+func (c *sigctxt) r8() uint64  { return c.regs().x[8] }
+func (c *sigctxt) r9() uint64  { return c.regs().x[9] }
+func (c *sigctxt) r10() uint64 { return c.regs().x[10] }
+func (c *sigctxt) r11() uint64 { return c.regs().x[11] }
+func (c *sigctxt) r12() uint64 { return c.regs().x[12] }
+func (c *sigctxt) r13() uint64 { return c.regs().x[13] }
+func (c *sigctxt) r14() uint64 { return c.regs().x[14] }
+func (c *sigctxt) r15() uint64 { return c.regs().x[15] }
+func (c *sigctxt) r16() uint64 { return c.regs().x[16] }
+func (c *sigctxt) r17() uint64 { return c.regs().x[17] }
+func (c *sigctxt) r18() uint64 { return c.regs().x[18] }
+func (c *sigctxt) r19() uint64 { return c.regs().x[19] }
+func (c *sigctxt) r20() uint64 { return c.regs().x[20] }
+func (c *sigctxt) r21() uint64 { return c.regs().x[21] }
+func (c *sigctxt) r22() uint64 { return c.regs().x[22] }
+func (c *sigctxt) r23() uint64 { return c.regs().x[23] }
+func (c *sigctxt) r24() uint64 { return c.regs().x[24] }
+func (c *sigctxt) r25() uint64 { return c.regs().x[25] }
+func (c *sigctxt) r26() uint64 { return c.regs().x[26] }
+func (c *sigctxt) r27() uint64 { return c.regs().x[27] }
+func (c *sigctxt) r28() uint64 { return c.regs().x[28] }
+func (c *sigctxt) r29() uint64 { return c.regs().fp }
+func (c *sigctxt) lr() uint64  { return c.regs().lr }
+func (c *sigctxt) sp() uint64  { return c.regs().sp }
+
+//go:nosplit
+//go:nowritebarrierrec
+func (c *sigctxt) pc() uint64 { return c.regs().pc }
+
+func (c *sigctxt) fault() uintptr { return uintptr(unsafe.Pointer(c.info.si_addr)) }
+
+func (c *sigctxt) sigcode() uint64 { return uint64(c.info.si_code) }
+func (c *sigctxt) sigaddr() uint64 { return uint64(uintptr(unsafe.Pointer(c.info.si_addr))) }
+
+func (c *sigctxt) set_pc(x uint64)  { c.regs().pc = x }
+func (c *sigctxt) set_sp(x uint64)  { c.regs().sp = x }
+func (c *sigctxt) set_lr(x uint64)  { c.regs().lr = x }
+func (c *sigctxt) set_r28(x uint64) { c.regs().x[28] = x }
+
+func (c *sigctxt) set_sigcode(x uint64) { c.info.si_code = int32(x) }
+func (c *sigctxt) set_sigaddr(x uint64) {
+	c.info.si_addr = (*byte)(unsafe.Pointer(uintptr(x)))
+}
+
+//go:nosplit
+func (c *sigctxt) fixsigcode(sig uint32) {
+	switch sig {
+	case _SIGTRAP:
+		// OS X sets c.sigcode() == TRAP_BRKPT unconditionally for all SIGTRAPs,
+		// leaving no way to distinguish a breakpoint-induced SIGTRAP
+		// from an asynchronous signal SIGTRAP.
+		// They all look breakpoint-induced by default.
+		// Try looking at the code to see if it's a breakpoint.
+		// The assumption is that we're very unlikely to get an
+		// asynchronous SIGTRAP at just the moment that the
+		// PC started to point at unmapped memory.
+		pc := uintptr(c.pc())
+		// OS X will leave the pc just after the instruction.
+		code := (*uint32)(unsafe.Pointer(pc - 4))
+		if *code != 0xd4200000 {
+			// SIGTRAP on something other than breakpoint.
+			c.set_sigcode(_SI_USER)
+		}
+	}
+}