all: add start of netbsd/arm64 support

This works well enough to run some code natively on arm64, but not well enough for more complicated code. I've been suggested to start a pull request anyway.

Updates #30824

Change-Id: Ib4f63e0e8a9edfc862cf65b5f1b0fbf9a8a1628e
GitHub-Last-Rev: b01b105e0446e349c8d9895d3ac6918fa0cdc48c
GitHub-Pull-Request: golang/go#29398
Reviewed-on: https://go-review.googlesource.com/c/go/+/155739
Run-TryBot: Benny Siegert <bsiegert@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/src/runtime/signal_netbsd_arm64.go b/src/runtime/signal_netbsd_arm64.go
new file mode 100644
index 0000000000..8dfdfeadd5
--- /dev/null
+++ b/src/runtime/signal_netbsd_arm64.go
@@ -0,0 +1,73 @@
+// Copyright 2019 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() *mcontextt {
+	return (*mcontextt)(unsafe.Pointer(&(*ucontextt)(c.ctxt).uc_mcontext))
+}
+
+func (c *sigctxt) r0() uint64  { return c.regs().__gregs[_REG_X0] }
+func (c *sigctxt) r1() uint64  { return c.regs().__gregs[_REG_X1] }
+func (c *sigctxt) r2() uint64  { return c.regs().__gregs[_REG_X2] }
+func (c *sigctxt) r3() uint64  { return c.regs().__gregs[_REG_X3] }
+func (c *sigctxt) r4() uint64  { return c.regs().__gregs[_REG_X4] }
+func (c *sigctxt) r5() uint64  { return c.regs().__gregs[_REG_X5] }
+func (c *sigctxt) r6() uint64  { return c.regs().__gregs[_REG_X6] }
+func (c *sigctxt) r7() uint64  { return c.regs().__gregs[_REG_X7] }
+func (c *sigctxt) r8() uint64  { return c.regs().__gregs[_REG_X8] }
+func (c *sigctxt) r9() uint64  { return c.regs().__gregs[_REG_X9] }
+func (c *sigctxt) r10() uint64 { return c.regs().__gregs[_REG_X10] }
+func (c *sigctxt) r11() uint64 { return c.regs().__gregs[_REG_X11] }
+func (c *sigctxt) r12() uint64 { return c.regs().__gregs[_REG_X12] }
+func (c *sigctxt) r13() uint64 { return c.regs().__gregs[_REG_X13] }
+func (c *sigctxt) r14() uint64 { return c.regs().__gregs[_REG_X14] }
+func (c *sigctxt) r15() uint64 { return c.regs().__gregs[_REG_X15] }
+func (c *sigctxt) r16() uint64 { return c.regs().__gregs[_REG_X16] }
+func (c *sigctxt) r17() uint64 { return c.regs().__gregs[_REG_X17] }
+func (c *sigctxt) r18() uint64 { return c.regs().__gregs[_REG_X18] }
+func (c *sigctxt) r19() uint64 { return c.regs().__gregs[_REG_X19] }
+func (c *sigctxt) r20() uint64 { return c.regs().__gregs[_REG_X20] }
+func (c *sigctxt) r21() uint64 { return c.regs().__gregs[_REG_X21] }
+func (c *sigctxt) r22() uint64 { return c.regs().__gregs[_REG_X22] }
+func (c *sigctxt) r23() uint64 { return c.regs().__gregs[_REG_X23] }
+func (c *sigctxt) r24() uint64 { return c.regs().__gregs[_REG_X24] }
+func (c *sigctxt) r25() uint64 { return c.regs().__gregs[_REG_X25] }
+func (c *sigctxt) r26() uint64 { return c.regs().__gregs[_REG_X26] }
+func (c *sigctxt) r27() uint64 { return c.regs().__gregs[_REG_X27] }
+func (c *sigctxt) r28() uint64 { return c.regs().__gregs[_REG_X28] }
+func (c *sigctxt) r29() uint64 { return c.regs().__gregs[_REG_X29] }
+func (c *sigctxt) lr() uint64  { return c.regs().__gregs[_REG_X30] }
+func (c *sigctxt) sp() uint64  { return c.regs().__gregs[_REG_X31] }
+
+//go:nosplit
+//go:nowritebarrierrec
+func (c *sigctxt) pc() uint64 { return c.regs().__gregs[_REG_ELR] }
+
+func (c *sigctxt) fault() uintptr  { return uintptr(c.info._reason) }
+func (c *sigctxt) trap() uint64    { return 0 }
+func (c *sigctxt) error() uint64   { return 0 }
+func (c *sigctxt) oldmask() uint64 { return 0 }
+
+func (c *sigctxt) sigcode() uint64 { return uint64(c.info._code) }
+func (c *sigctxt) sigaddr() uint64 { return uint64(c.info._reason) }
+
+func (c *sigctxt) set_pc(x uint64)  { c.regs().__gregs[_REG_ELR] = x }
+func (c *sigctxt) set_sp(x uint64)  { c.regs().__gregs[_REG_X31] = x }
+func (c *sigctxt) set_lr(x uint64)  { c.regs().__gregs[_REG_X30] = x }
+func (c *sigctxt) set_r28(x uint64) { c.regs().__gregs[_REG_X28] = x }
+
+func (c *sigctxt) set_sigcode(x uint64) { c.info._code = int32(x) }
+func (c *sigctxt) set_sigaddr(x uint64) {
+	c.info._reason = uintptr(x)
+}