Adding upstream version 1.16.10.upstream/1.16.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

81 files changed, 5251 insertions, 0 deletions

diff --git a/src/runtime/cgo/asm_386.s b/src/runtime/cgo/asm_386.s
new file mode 100644
index 0000000..2e7e951
--- /dev/null
+++ b/src/runtime/cgo/asm_386.s
@@ -0,0 +1,29 @@
+// Copyright 2009 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.
+
+#include "textflag.h"
+
+// Called by C code generated by cmd/cgo.
+// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
+// Saves C callee-saved registers and calls cgocallback with three arguments.
+// fn is the PC of a func(a unsafe.Pointer) function.
+TEXT crosscall2(SB),NOSPLIT,$28-16
+	MOVL BP, 24(SP)
+	MOVL BX, 20(SP)
+	MOVL SI, 16(SP)
+	MOVL DI, 12(SP)
+
+	MOVL	ctxt+12(FP), AX
+	MOVL	AX, 8(SP)
+	MOVL	a+4(FP), AX
+	MOVL	AX, 4(SP)
+	MOVL	fn+0(FP), AX
+	MOVL	AX, 0(SP)
+	CALL	runtime·cgocallback(SB)
+
+	MOVL 12(SP), DI
+	MOVL 16(SP), SI
+	MOVL 20(SP), BX
+	MOVL 24(SP), BP
+	RET
diff --git a/src/runtime/cgo/asm_amd64.s b/src/runtime/cgo/asm_amd64.s
new file mode 100644
index 0000000..5dc8e2d
--- /dev/null
+++ b/src/runtime/cgo/asm_amd64.s
@@ -0,0 +1,72 @@
+// Copyright 2009 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.
+
+#include "textflag.h"
+
+// Called by C code generated by cmd/cgo.
+// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
+// Saves C callee-saved registers and calls cgocallback with three arguments.
+// fn is the PC of a func(a unsafe.Pointer) function.
+// This signature is known to SWIG, so we can't change it.
+#ifndef GOOS_windows
+TEXT crosscall2(SB),NOSPLIT,$0x50-0 /* keeps stack pointer 32-byte aligned */
+#else
+TEXT crosscall2(SB),NOSPLIT,$0x110-0 /* also need to save xmm6 - xmm15 */
+#endif
+	MOVQ	BX, 0x18(SP)
+	MOVQ	R12, 0x28(SP)
+	MOVQ	R13, 0x30(SP)
+	MOVQ	R14, 0x38(SP)
+	MOVQ	R15, 0x40(SP)
+
+#ifdef GOOS_windows
+	// Win64 save RBX, RBP, RDI, RSI, RSP, R12, R13, R14, R15 and XMM6 -- XMM15.
+	MOVQ	DI, 0x48(SP)
+	MOVQ	SI, 0x50(SP)
+	MOVUPS	X6, 0x60(SP)
+	MOVUPS	X7, 0x70(SP)
+	MOVUPS	X8, 0x80(SP)
+	MOVUPS	X9, 0x90(SP)
+	MOVUPS	X10, 0xa0(SP)
+	MOVUPS	X11, 0xb0(SP)
+	MOVUPS	X12, 0xc0(SP)
+	MOVUPS	X13, 0xd0(SP)
+	MOVUPS	X14, 0xe0(SP)
+	MOVUPS	X15, 0xf0(SP)
+
+	MOVQ	CX, 0x0(SP)	/* fn */
+	MOVQ	DX, 0x8(SP)	/* arg */
+	// Skip n in R8.
+	MOVQ	R9, 0x10(SP)	/* ctxt */
+
+	CALL	runtime·cgocallback(SB)
+
+	MOVQ	0x48(SP), DI
+	MOVQ	0x50(SP), SI
+	MOVUPS	0x60(SP), X6
+	MOVUPS	0x70(SP), X7
+	MOVUPS	0x80(SP), X8
+	MOVUPS	0x90(SP), X9
+	MOVUPS	0xa0(SP), X10
+	MOVUPS	0xb0(SP), X11
+	MOVUPS	0xc0(SP), X12
+	MOVUPS	0xd0(SP), X13
+	MOVUPS	0xe0(SP), X14
+	MOVUPS	0xf0(SP), X15
+#else
+	MOVQ	DI, 0x0(SP)	/* fn */
+	MOVQ	SI, 0x8(SP)	/* arg */
+	// Skip n in DX.
+	MOVQ	CX, 0x10(SP)	/* ctxt */
+
+	CALL	runtime·cgocallback(SB)
+#endif
+
+	MOVQ	0x18(SP), BX
+	MOVQ	0x28(SP), R12
+	MOVQ	0x30(SP), R13
+	MOVQ	0x38(SP), R14
+	MOVQ	0x40(SP), R15
+
+	RET
diff --git a/src/runtime/cgo/asm_arm.s b/src/runtime/cgo/asm_arm.s
new file mode 100644
index 0000000..ea55e17
--- /dev/null
+++ b/src/runtime/cgo/asm_arm.s
@@ -0,0 +1,56 @@
+// Copyright 2012 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.
+
+#include "textflag.h"
+
+// Called by C code generated by cmd/cgo.
+// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
+// Saves C callee-saved registers and calls cgocallback with three arguments.
+// fn is the PC of a func(a unsafe.Pointer) function.
+TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
+	SUB	$(8*9), R13 // Reserve space for the floating point registers.
+	// The C arguments arrive in R0, R1, R2, and R3. We want to
+	// pass R0, R1, and R3 to Go, so we push those on the stack.
+	// Also, save C callee-save registers R4-R12.
+	MOVM.WP	[R0, R1, R3, R4, R5, R6, R7, R8, R9, g, R11, R12], (R13)
+	// Finally, save the link register R14. This also puts the
+	// arguments we pushed for cgocallback where they need to be,
+	// starting at 4(R13).
+	MOVW.W	R14, -4(R13)
+
+	// Skip floating point registers on GOARM < 6.
+	MOVB    runtime·goarm(SB), R11
+	CMP $6, R11
+	BLT skipfpsave
+	MOVD	F8, (13*4+8*1)(R13)
+	MOVD	F9, (13*4+8*2)(R13)
+	MOVD	F10, (13*4+8*3)(R13)
+	MOVD	F11, (13*4+8*4)(R13)
+	MOVD	F12, (13*4+8*5)(R13)
+	MOVD	F13, (13*4+8*6)(R13)
+	MOVD	F14, (13*4+8*7)(R13)
+	MOVD	F15, (13*4+8*8)(R13)
+
+skipfpsave:
+	BL	runtime·load_g(SB)
+	// We set up the arguments to cgocallback when saving registers above.
+	BL	runtime·cgocallback(SB)
+
+	MOVB    runtime·goarm(SB), R11
+	CMP $6, R11
+	BLT skipfprest
+	MOVD	(13*4+8*1)(R13), F8
+	MOVD	(13*4+8*2)(R13), F9
+	MOVD	(13*4+8*3)(R13), F10
+	MOVD	(13*4+8*4)(R13), F11
+	MOVD	(13*4+8*5)(R13), F12
+	MOVD	(13*4+8*6)(R13), F13
+	MOVD	(13*4+8*7)(R13), F14
+	MOVD	(13*4+8*8)(R13), F15
+
+skipfprest:
+	MOVW.P	4(R13), R14
+	MOVM.IAW	(R13), [R0, R1, R3, R4, R5, R6, R7, R8, R9, g, R11, R12]
+	ADD	$(8*9), R13
+	MOVW	R14, R15
diff --git a/src/runtime/cgo/asm_arm64.s b/src/runtime/cgo/asm_arm64.s
new file mode 100644
index 0000000..1cb25cf
--- /dev/null
+++ b/src/runtime/cgo/asm_arm64.s
@@ -0,0 +1,70 @@
+// 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.
+
+#include "textflag.h"
+
+// Called by C code generated by cmd/cgo.
+// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
+// Saves C callee-saved registers and calls cgocallback with three arguments.
+// fn is the PC of a func(a unsafe.Pointer) function.
+TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
+	/*
+	 * We still need to save all callee save register as before, and then
+	 *  push 3 args for fn (R0, R1, R3), skipping R2.
+	 * Also note that at procedure entry in gc world, 8(RSP) will be the
+	 *  first arg.
+	 * TODO(minux): use LDP/STP here if it matters.
+	 */
+	SUB	$(8*24), RSP
+	MOVD	R0, (8*1)(RSP)
+	MOVD	R1, (8*2)(RSP)
+	MOVD	R3, (8*3)(RSP)
+	MOVD	R19, (8*4)(RSP)
+	MOVD	R20, (8*5)(RSP)
+	MOVD	R21, (8*6)(RSP)
+	MOVD	R22, (8*7)(RSP)
+	MOVD	R23, (8*8)(RSP)
+	MOVD	R24, (8*9)(RSP)
+	MOVD	R25, (8*10)(RSP)
+	MOVD	R26, (8*11)(RSP)
+	MOVD	R27, (8*12)(RSP)
+	MOVD	g, (8*13)(RSP)
+	MOVD	R29, (8*14)(RSP)
+	MOVD	R30, (8*15)(RSP)
+	FMOVD	F8, (8*16)(RSP)
+	FMOVD	F9, (8*17)(RSP)
+	FMOVD	F10, (8*18)(RSP)
+	FMOVD	F11, (8*19)(RSP)
+	FMOVD	F12, (8*20)(RSP)
+	FMOVD	F13, (8*21)(RSP)
+	FMOVD	F14, (8*22)(RSP)
+	FMOVD	F15, (8*23)(RSP)
+
+	// Initialize Go ABI environment
+	BL	runtime·load_g(SB)
+
+	BL	runtime·cgocallback(SB)
+
+	MOVD	(8*4)(RSP), R19
+	MOVD	(8*5)(RSP), R20
+	MOVD	(8*6)(RSP), R21
+	MOVD	(8*7)(RSP), R22
+	MOVD	(8*8)(RSP), R23
+	MOVD	(8*9)(RSP), R24
+	MOVD	(8*10)(RSP), R25
+	MOVD	(8*11)(RSP), R26
+	MOVD	(8*12)(RSP), R27
+	MOVD	(8*13)(RSP), g
+	MOVD	(8*14)(RSP), R29
+	MOVD	(8*15)(RSP), R30
+	FMOVD	(8*16)(RSP), F8
+	FMOVD	(8*17)(RSP), F9
+	FMOVD	(8*18)(RSP), F10
+	FMOVD	(8*19)(RSP), F11
+	FMOVD	(8*20)(RSP), F12
+	FMOVD	(8*21)(RSP), F13
+	FMOVD	(8*22)(RSP), F14
+	FMOVD	(8*23)(RSP), F15
+	ADD	$(8*24), RSP
+	RET
diff --git a/src/runtime/cgo/asm_mips64x.s b/src/runtime/cgo/asm_mips64x.s
new file mode 100644
index 0000000..e51cdf3
--- /dev/null
+++ b/src/runtime/cgo/asm_mips64x.s
@@ -0,0 +1,82 @@
+// Copyright 2016 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.
+
+// +build mips64 mips64le
+
+#include "textflag.h"
+
+// Called by C code generated by cmd/cgo.
+// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
+// Saves C callee-saved registers and calls cgocallback with three arguments.
+// fn is the PC of a func(a unsafe.Pointer) function.
+TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
+	/*
+	 * We still need to save all callee save register as before, and then
+	 *  push 3 args for fn (R4, R5, R7), skipping R6.
+	 * Also note that at procedure entry in gc world, 8(R29) will be the
+	 *  first arg.
+	 */
+#ifndef GOMIPS64_softfloat
+	ADDV	$(-8*23), R29
+#else
+	ADDV	$(-8*15), R29
+#endif
+	MOVV	R4, (8*1)(R29) // fn unsafe.Pointer
+	MOVV	R5, (8*2)(R29) // a unsafe.Pointer
+	MOVV	R7, (8*3)(R29) // ctxt uintptr
+	MOVV	R16, (8*4)(R29)
+	MOVV	R17, (8*5)(R29)
+	MOVV	R18, (8*6)(R29)
+	MOVV	R19, (8*7)(R29)
+	MOVV	R20, (8*8)(R29)
+	MOVV	R21, (8*9)(R29)
+	MOVV	R22, (8*10)(R29)
+	MOVV	R23, (8*11)(R29)
+	MOVV	RSB, (8*12)(R29)
+	MOVV	g, (8*13)(R29)
+	MOVV	R31, (8*14)(R29)
+#ifndef GOMIPS64_softfloat
+	MOVD	F24, (8*15)(R29)
+	MOVD	F25, (8*16)(R29)
+	MOVD	F26, (8*17)(R29)
+	MOVD	F27, (8*18)(R29)
+	MOVD	F28, (8*19)(R29)
+	MOVD	F29, (8*20)(R29)
+	MOVD	F30, (8*21)(R29)
+	MOVD	F31, (8*22)(R29)
+#endif
+	// Initialize Go ABI environment
+	// prepare SB register = PC & 0xffffffff00000000
+	BGEZAL	R0, 1(PC)
+	SRLV	$32, R31, RSB
+	SLLV	$32, RSB
+	JAL	runtime·load_g(SB)
+
+	JAL	runtime·cgocallback(SB)
+
+	MOVV	(8*4)(R29), R16
+	MOVV	(8*5)(R29), R17
+	MOVV	(8*6)(R29), R18
+	MOVV	(8*7)(R29), R19
+	MOVV	(8*8)(R29), R20
+	MOVV	(8*9)(R29), R21
+	MOVV	(8*10)(R29), R22
+	MOVV	(8*11)(R29), R23
+	MOVV	(8*12)(R29), RSB
+	MOVV	(8*13)(R29), g
+	MOVV	(8*14)(R29), R31
+#ifndef GOMIPS64_softfloat
+	MOVD	(8*15)(R29), F24
+	MOVD	(8*16)(R29), F25
+	MOVD	(8*17)(R29), F26
+	MOVD	(8*18)(R29), F27
+	MOVD	(8*19)(R29), F28
+	MOVD	(8*20)(R29), F29
+	MOVD	(8*21)(R29), F30
+	MOVD	(8*22)(R29), F31
+	ADDV	$(8*23), R29
+#else
+	ADDV	$(8*15), R29
+#endif
+	RET
diff --git a/src/runtime/cgo/asm_mipsx.s b/src/runtime/cgo/asm_mipsx.s
new file mode 100644
index 0000000..1127c8b
--- /dev/null
+++ b/src/runtime/cgo/asm_mipsx.s
@@ -0,0 +1,75 @@
+// Copyright 2016 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.
+
+// +build mips mipsle
+
+#include "textflag.h"
+
+// Called by C code generated by cmd/cgo.
+// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
+// Saves C callee-saved registers and calls cgocallback with three arguments.
+// fn is the PC of a func(a unsafe.Pointer) function.
+TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
+	/*
+	 * We still need to save all callee save register as before, and then
+	 *  push 3 args for fn (R4, R5, R7), skipping R6.
+	 * Also note that at procedure entry in gc world, 4(R29) will be the
+	 *  first arg.
+	 */
+
+	// Space for 9 caller-saved GPR + LR + 6 caller-saved FPR.
+	// O32 ABI allows us to smash 16 bytes argument area of caller frame.
+#ifndef GOMIPS_softfloat
+	SUBU	$(4*14+8*6-16), R29
+#else
+	SUBU	$(4*14-16), R29	// For soft-float, no FPR.
+#endif
+	MOVW	R4, (4*1)(R29)	// fn unsafe.Pointer
+	MOVW	R5, (4*2)(R29)	// a unsafe.Pointer
+	MOVW	R7, (4*3)(R29)	// ctxt uintptr
+	MOVW	R16, (4*4)(R29)
+	MOVW	R17, (4*5)(R29)
+	MOVW	R18, (4*6)(R29)
+	MOVW	R19, (4*7)(R29)
+	MOVW	R20, (4*8)(R29)
+	MOVW	R21, (4*9)(R29)
+	MOVW	R22, (4*10)(R29)
+	MOVW	R23, (4*11)(R29)
+	MOVW	g, (4*12)(R29)
+	MOVW	R31, (4*13)(R29)
+#ifndef GOMIPS_softfloat
+	MOVD	F20, (4*14)(R29)
+	MOVD	F22, (4*14+8*1)(R29)
+	MOVD	F24, (4*14+8*2)(R29)
+	MOVD	F26, (4*14+8*3)(R29)
+	MOVD	F28, (4*14+8*4)(R29)
+	MOVD	F30, (4*14+8*5)(R29)
+#endif
+	JAL	runtime·load_g(SB)
+
+	JAL	runtime·cgocallback(SB)
+
+	MOVW	(4*4)(R29), R16
+	MOVW	(4*5)(R29), R17
+	MOVW	(4*6)(R29), R18
+	MOVW	(4*7)(R29), R19
+	MOVW	(4*8)(R29), R20
+	MOVW	(4*9)(R29), R21
+	MOVW	(4*10)(R29), R22
+	MOVW	(4*11)(R29), R23
+	MOVW	(4*12)(R29), g
+	MOVW	(4*13)(R29), R31
+#ifndef GOMIPS_softfloat
+	MOVD	(4*14)(R29), F20
+	MOVD	(4*14+8*1)(R29), F22
+	MOVD	(4*14+8*2)(R29), F24
+	MOVD	(4*14+8*3)(R29), F26
+	MOVD	(4*14+8*4)(R29), F28
+	MOVD	(4*14+8*5)(R29), F30
+
+	ADDU	$(4*14+8*6-16), R29
+#else
+	ADDU	$(4*14-16), R29
+#endif
+	RET
diff --git a/src/runtime/cgo/asm_ppc64x.s b/src/runtime/cgo/asm_ppc64x.s
new file mode 100644
index 0000000..f4efc1e
--- /dev/null
+++ b/src/runtime/cgo/asm_ppc64x.s
@@ -0,0 +1,134 @@
+// Copyright 2014 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.
+
+// +build ppc64 ppc64le
+
+#include "textflag.h"
+#include "asm_ppc64x.h"
+
+// Called by C code generated by cmd/cgo.
+// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
+// Saves C callee-saved registers and calls cgocallback with three arguments.
+// fn is the PC of a func(a unsafe.Pointer) function.
+TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
+	// Start with standard C stack frame layout and linkage
+	MOVD	LR, R0
+	MOVD	R0, 16(R1)	// Save LR in caller's frame
+	MOVW	CR, R0		// Save CR in caller's frame
+	MOVD	R0, 8(R1)
+	MOVD	R2, 24(R1)	// Save TOC in caller's frame
+
+	BL	saveregs2<>(SB)
+
+	MOVDU	R1, (-288-3*8-FIXED_FRAME)(R1)
+
+	// Initialize Go ABI environment
+	BL	runtime·reginit(SB)
+	BL	runtime·load_g(SB)
+
+#ifdef GOARCH_ppc64
+	// ppc64 use elf ABI v1. we must get the real entry address from
+	// first slot of the function descriptor before call.
+	// Same for AIX.
+	MOVD	8(R3), R2
+	MOVD	(R3), R3
+#endif
+	MOVD	R3, FIXED_FRAME+0(R1)	// fn unsafe.Pointer
+	MOVD	R4, FIXED_FRAME+8(R1)	// a unsafe.Pointer
+	// Skip R5 = n uint32
+	MOVD	R6, FIXED_FRAME+16(R1)	// ctxt uintptr
+	BL	runtime·cgocallback(SB)
+
+	ADD	$(288+3*8+FIXED_FRAME), R1
+
+	BL	restoreregs2<>(SB)
+
+	MOVD	24(R1), R2
+	MOVD	8(R1), R0
+	MOVFL	R0, $0xff
+	MOVD	16(R1), R0
+	MOVD	R0, LR
+	RET
+
+TEXT saveregs2<>(SB),NOSPLIT|NOFRAME,$0
+	// O=-288; for R in R{14..31}; do echo "\tMOVD\t$R, $O(R1)"|sed s/R30/g/; ((O+=8)); done; for F in F{14..31}; do echo "\tFMOVD\t$F, $O(R1)"; ((O+=8)); done
+	MOVD	R14, -288(R1)
+	MOVD	R15, -280(R1)
+	MOVD	R16, -272(R1)
+	MOVD	R17, -264(R1)
+	MOVD	R18, -256(R1)
+	MOVD	R19, -248(R1)
+	MOVD	R20, -240(R1)
+	MOVD	R21, -232(R1)
+	MOVD	R22, -224(R1)
+	MOVD	R23, -216(R1)
+	MOVD	R24, -208(R1)
+	MOVD	R25, -200(R1)
+	MOVD	R26, -192(R1)
+	MOVD	R27, -184(R1)
+	MOVD	R28, -176(R1)
+	MOVD	R29, -168(R1)
+	MOVD	g, -160(R1)
+	MOVD	R31, -152(R1)
+	FMOVD	F14, -144(R1)
+	FMOVD	F15, -136(R1)
+	FMOVD	F16, -128(R1)
+	FMOVD	F17, -120(R1)
+	FMOVD	F18, -112(R1)
+	FMOVD	F19, -104(R1)
+	FMOVD	F20, -96(R1)
+	FMOVD	F21, -88(R1)
+	FMOVD	F22, -80(R1)
+	FMOVD	F23, -72(R1)
+	FMOVD	F24, -64(R1)
+	FMOVD	F25, -56(R1)
+	FMOVD	F26, -48(R1)
+	FMOVD	F27, -40(R1)
+	FMOVD	F28, -32(R1)
+	FMOVD	F29, -24(R1)
+	FMOVD	F30, -16(R1)
+	FMOVD	F31, -8(R1)
+
+	RET
+
+TEXT restoreregs2<>(SB),NOSPLIT|NOFRAME,$0
+	// O=-288; for R in R{14..31}; do echo "\tMOVD\t$O(R1), $R"|sed s/R30/g/; ((O+=8)); done; for F in F{14..31}; do echo "\tFMOVD\t$O(R1), $F"; ((O+=8)); done
+	MOVD	-288(R1), R14
+	MOVD	-280(R1), R15
+	MOVD	-272(R1), R16
+	MOVD	-264(R1), R17
+	MOVD	-256(R1), R18
+	MOVD	-248(R1), R19
+	MOVD	-240(R1), R20
+	MOVD	-232(R1), R21
+	MOVD	-224(R1), R22
+	MOVD	-216(R1), R23
+	MOVD	-208(R1), R24
+	MOVD	-200(R1), R25
+	MOVD	-192(R1), R26
+	MOVD	-184(R1), R27
+	MOVD	-176(R1), R28
+	MOVD	-168(R1), R29
+	MOVD	-160(R1), g
+	MOVD	-152(R1), R31
+	FMOVD	-144(R1), F14
+	FMOVD	-136(R1), F15
+	FMOVD	-128(R1), F16
+	FMOVD	-120(R1), F17
+	FMOVD	-112(R1), F18
+	FMOVD	-104(R1), F19
+	FMOVD	-96(R1), F20
+	FMOVD	-88(R1), F21
+	FMOVD	-80(R1), F22
+	FMOVD	-72(R1), F23
+	FMOVD	-64(R1), F24
+	FMOVD	-56(R1), F25
+	FMOVD	-48(R1), F26
+	FMOVD	-40(R1), F27
+	FMOVD	-32(R1), F28
+	FMOVD	-24(R1), F29
+	FMOVD	-16(R1), F30
+	FMOVD	-8(R1), F31
+
+	RET
diff --git a/src/runtime/cgo/asm_riscv64.s b/src/runtime/cgo/asm_riscv64.s
new file mode 100644
index 0000000..b4ddbb0
--- /dev/null
+++ b/src/runtime/cgo/asm_riscv64.s
@@ -0,0 +1,84 @@
+// Copyright 2020 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.
+
+// +build riscv64
+
+#include "textflag.h"
+
+// Called by C code generated by cmd/cgo.
+// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
+// Saves C callee-saved registers and calls cgocallback with three arguments.
+// fn is the PC of a func(a unsafe.Pointer) function.
+TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
+	/*
+	 * Push arguments for fn (X10, X11, X13), along with all callee-save
+	 * registers. Note that at procedure entry the first argument is at
+	 * 8(X2).
+	 */
+	ADD	$(-8*31), X2
+	MOV	X10, (8*1)(X2) // fn unsafe.Pointer
+	MOV	X11, (8*2)(X2) // a unsafe.Pointer
+	MOV	X13, (8*3)(X2) // ctxt uintptr
+	MOV	X8, (8*4)(X2)
+	MOV	X9, (8*5)(X2)
+	MOV	X18, (8*6)(X2)
+	MOV	X19, (8*7)(X2)
+	MOV	X20, (8*8)(X2)
+	MOV	X21, (8*9)(X2)
+	MOV	X22, (8*10)(X2)
+	MOV	X23, (8*11)(X2)
+	MOV	X24, (8*12)(X2)
+	MOV	X25, (8*13)(X2)
+	MOV	X26, (8*14)(X2)
+	MOV	g, (8*15)(X2)
+	MOV	X3, (8*16)(X2)
+	MOV	X4, (8*17)(X2)
+	MOV	X1, (8*18)(X2)
+	MOVD	F8, (8*19)(X2)
+	MOVD	F9, (8*20)(X2)
+	MOVD	F18, (8*21)(X2)
+	MOVD	F19, (8*22)(X2)
+	MOVD	F20, (8*23)(X2)
+	MOVD	F21, (8*24)(X2)
+	MOVD	F22, (8*25)(X2)
+	MOVD	F23, (8*26)(X2)
+	MOVD	F24, (8*27)(X2)
+	MOVD	F25, (8*28)(X2)
+	MOVD	F26, (8*29)(X2)
+	MOVD	F27, (8*30)(X2)
+
+	// Initialize Go ABI environment
+	CALL	runtime·load_g(SB)
+	CALL	runtime·cgocallback(SB)
+
+	MOV	(8*4)(X2), X8
+	MOV	(8*5)(X2), X9
+	MOV	(8*6)(X2), X18
+	MOV	(8*7)(X2), X19
+	MOV	(8*8)(X2), X20
+	MOV	(8*9)(X2), X21
+	MOV	(8*10)(X2), X22
+	MOV	(8*11)(X2), X23
+	MOV	(8*12)(X2), X24
+	MOV	(8*13)(X2), X25
+	MOV	(8*14)(X2), X26
+	MOV	(8*15)(X2), g
+	MOV	(8*16)(X2), X3
+	MOV	(8*17)(X2), X4
+	MOV	(8*18)(X2), X1
+	MOVD	(8*19)(X2), F8
+	MOVD	(8*20)(X2), F9
+	MOVD	(8*21)(X2), F18
+	MOVD	(8*22)(X2), F19
+	MOVD	(8*23)(X2), F20
+	MOVD	(8*24)(X2), F21
+	MOVD	(8*25)(X2), F22
+	MOVD	(8*26)(X2), F23
+	MOVD	(8*27)(X2), F24
+	MOVD	(8*28)(X2), F25
+	MOVD	(8*29)(X2), F26
+	MOVD	(8*30)(X2), F27
+	ADD	$(8*31), X2
+
+	RET
diff --git a/src/runtime/cgo/asm_s390x.s b/src/runtime/cgo/asm_s390x.s
new file mode 100644
index 0000000..8bf16e7
--- /dev/null
+++ b/src/runtime/cgo/asm_s390x.s
@@ -0,0 +1,55 @@
+// Copyright 2016 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.
+
+#include "textflag.h"
+
+// Called by C code generated by cmd/cgo.
+// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
+// Saves C callee-saved registers and calls cgocallback with three arguments.
+// fn is the PC of a func(a unsafe.Pointer) function.
+TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
+	// Start with standard C stack frame layout and linkage.
+
+	// Save R6-R15 in the register save area of the calling function.
+	STMG	R6, R15, 48(R15)
+
+	// Allocate 96 bytes on the stack.
+	MOVD	$-96(R15), R15
+
+	// Save F8-F15 in our stack frame.
+	FMOVD	F8, 32(R15)
+	FMOVD	F9, 40(R15)
+	FMOVD	F10, 48(R15)
+	FMOVD	F11, 56(R15)
+	FMOVD	F12, 64(R15)
+	FMOVD	F13, 72(R15)
+	FMOVD	F14, 80(R15)
+	FMOVD	F15, 88(R15)
+
+	// Initialize Go ABI environment.
+	BL	runtime·load_g(SB)
+
+	MOVD	R2, 8(R15)	// fn unsafe.Pointer
+	MOVD	R3, 16(R15)	// a unsafe.Pointer
+	// Skip R4 = n uint32
+	MOVD	R5, 24(R15)	// ctxt uintptr
+	BL	runtime·cgocallback(SB)
+
+	FMOVD	32(R15), F8
+	FMOVD	40(R15), F9
+	FMOVD	48(R15), F10
+	FMOVD	56(R15), F11
+	FMOVD	64(R15), F12
+	FMOVD	72(R15), F13
+	FMOVD	80(R15), F14
+	FMOVD	88(R15), F15
+
+	// De-allocate stack frame.
+	MOVD	$96(R15), R15
+
+	// Restore R6-R15.
+	LMG	48(R15), R6, R15
+
+	RET
+
diff --git a/src/runtime/cgo/asm_wasm.s b/src/runtime/cgo/asm_wasm.s
new file mode 100644
index 0000000..cb140eb
--- /dev/null
+++ b/src/runtime/cgo/asm_wasm.s
@@ -0,0 +1,8 @@
+// Copyright 2018 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.
+
+#include "textflag.h"
+
+TEXT crosscall2(SB), NOSPLIT, $0
+	UNDEF
diff --git a/src/runtime/cgo/callbacks.go b/src/runtime/cgo/callbacks.go
new file mode 100644
index 0000000..cd8b795
--- /dev/null
+++ b/src/runtime/cgo/callbacks.go
@@ -0,0 +1,106 @@
+// Copyright 2011 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 cgo
+
+import "unsafe"
+
+// These utility functions are available to be called from code
+// compiled with gcc via crosscall2.
+
+// The declaration of crosscall2 is:
+//   void crosscall2(void (*fn)(void *), void *, int);
+//
+// We need to export the symbol crosscall2 in order to support
+// callbacks from shared libraries. This applies regardless of
+// linking mode.
+//
+// Compatibility note: SWIG uses crosscall2 in exactly one situation:
+// to call _cgo_panic using the pattern shown below. We need to keep
+// that pattern working. In particular, crosscall2 actually takes four
+// arguments, but it works to call it with three arguments when
+// calling _cgo_panic.
+//go:cgo_export_static crosscall2
+//go:cgo_export_dynamic crosscall2
+
+// Panic. The argument is converted into a Go string.
+
+// Call like this in code compiled with gcc:
+//   struct { const char *p; } a;
+//   a.p = /* string to pass to panic */;
+//   crosscall2(_cgo_panic, &a, sizeof a);
+//   /* The function call will not return.  */
+
+// TODO: We should export a regular C function to panic, change SWIG
+// to use that instead of the above pattern, and then we can drop
+// backwards-compatibility from crosscall2 and stop exporting it.
+
+//go:linkname _runtime_cgo_panic_internal runtime._cgo_panic_internal
+func _runtime_cgo_panic_internal(p *byte)
+
+//go:linkname _cgo_panic _cgo_panic
+//go:cgo_export_static _cgo_panic
+//go:cgo_export_dynamic _cgo_panic
+func _cgo_panic(a *struct{ cstr *byte }) {
+	_runtime_cgo_panic_internal(a.cstr)
+}
+
+//go:cgo_import_static x_cgo_init
+//go:linkname x_cgo_init x_cgo_init
+//go:linkname _cgo_init _cgo_init
+var x_cgo_init byte
+var _cgo_init = &x_cgo_init
+
+//go:cgo_import_static x_cgo_thread_start
+//go:linkname x_cgo_thread_start x_cgo_thread_start
+//go:linkname _cgo_thread_start _cgo_thread_start
+var x_cgo_thread_start byte
+var _cgo_thread_start = &x_cgo_thread_start
+
+// Creates a new system thread without updating any Go state.
+//
+// This method is invoked during shared library loading to create a new OS
+// thread to perform the runtime initialization. This method is similar to
+// _cgo_sys_thread_start except that it doesn't update any Go state.
+
+//go:cgo_import_static x_cgo_sys_thread_create
+//go:linkname x_cgo_sys_thread_create x_cgo_sys_thread_create
+//go:linkname _cgo_sys_thread_create _cgo_sys_thread_create
+var x_cgo_sys_thread_create byte
+var _cgo_sys_thread_create = &x_cgo_sys_thread_create
+
+// Notifies that the runtime has been initialized.
+//
+// We currently block at every CGO entry point (via _cgo_wait_runtime_init_done)
+// to ensure that the runtime has been initialized before the CGO call is
+// executed. This is necessary for shared libraries where we kickoff runtime
+// initialization in a separate thread and return without waiting for this
+// thread to complete the init.
+
+//go:cgo_import_static x_cgo_notify_runtime_init_done
+//go:linkname x_cgo_notify_runtime_init_done x_cgo_notify_runtime_init_done
+//go:linkname _cgo_notify_runtime_init_done _cgo_notify_runtime_init_done
+var x_cgo_notify_runtime_init_done byte
+var _cgo_notify_runtime_init_done = &x_cgo_notify_runtime_init_done
+
+// Sets the traceback context function. See runtime.SetCgoTraceback.
+
+//go:cgo_import_static x_cgo_set_context_function
+//go:linkname x_cgo_set_context_function x_cgo_set_context_function
+//go:linkname _cgo_set_context_function _cgo_set_context_function
+var x_cgo_set_context_function byte
+var _cgo_set_context_function = &x_cgo_set_context_function
+
+// Calls a libc function to execute background work injected via libc
+// interceptors, such as processing pending signals under the thread
+// sanitizer.
+//
+// Left as a nil pointer if no libc interceptors are expected.
+
+//go:cgo_import_static _cgo_yield
+//go:linkname _cgo_yield _cgo_yield
+var _cgo_yield unsafe.Pointer
+
+//go:cgo_export_static _cgo_topofstack
+//go:cgo_export_dynamic _cgo_topofstack
diff --git a/src/runtime/cgo/callbacks_aix.go b/src/runtime/cgo/callbacks_aix.go
new file mode 100644
index 0000000..f4b6fe2
--- /dev/null
+++ b/src/runtime/cgo/callbacks_aix.go
@@ -0,0 +1,11 @@
+// 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 cgo
+
+// These functions must be exported in order to perform
+// longcall on cgo programs (cf gcc_aix_ppc64.c).
+//go:cgo_export_static __cgo_topofstack
+//go:cgo_export_static runtime.rt0_go
+//go:cgo_export_static _rt0_ppc64_aix_lib
diff --git a/src/runtime/cgo/callbacks_traceback.go b/src/runtime/cgo/callbacks_traceback.go
new file mode 100644
index 0000000..cdadf9e
--- /dev/null
+++ b/src/runtime/cgo/callbacks_traceback.go
@@ -0,0 +1,17 @@
+// Copyright 2016 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.
+
+// +build darwin linux
+
+package cgo
+
+import _ "unsafe" // for go:linkname
+
+// Calls the traceback function passed to SetCgoTraceback.
+
+//go:cgo_import_static x_cgo_callers
+//go:linkname x_cgo_callers x_cgo_callers
+//go:linkname _cgo_callers _cgo_callers
+var x_cgo_callers byte
+var _cgo_callers = &x_cgo_callers
diff --git a/src/runtime/cgo/cgo.go b/src/runtime/cgo/cgo.go
new file mode 100644
index 0000000..4d2caf6
--- /dev/null
+++ b/src/runtime/cgo/cgo.go
@@ -0,0 +1,34 @@
+// Copyright 2010 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 cgo contains runtime support for code generated
+by the cgo tool.  See the documentation for the cgo command
+for details on using cgo.
+*/
+package cgo
+
+/*
+
+#cgo darwin,!arm64 LDFLAGS: -lpthread
+#cgo darwin,arm64 LDFLAGS: -framework CoreFoundation
+#cgo dragonfly LDFLAGS: -lpthread
+#cgo freebsd LDFLAGS: -lpthread
+#cgo android LDFLAGS: -llog
+#cgo !android,linux LDFLAGS: -lpthread
+#cgo netbsd LDFLAGS: -lpthread
+#cgo openbsd LDFLAGS: -lpthread
+#cgo aix LDFLAGS: -Wl,-berok
+#cgo solaris LDFLAGS: -lxnet
+#cgo illumos LDFLAGS: -lsocket
+
+// Issue 35247.
+#cgo darwin CFLAGS: -Wno-nullability-completeness
+
+#cgo CFLAGS: -Wall -Werror
+
+#cgo solaris CPPFLAGS: -D_POSIX_PTHREAD_SEMANTICS
+
+*/
+import "C"
diff --git a/src/runtime/cgo/dragonfly.go b/src/runtime/cgo/dragonfly.go
new file mode 100644
index 0000000..d6d6918
--- /dev/null
+++ b/src/runtime/cgo/dragonfly.go
@@ -0,0 +1,19 @@
+// Copyright 2010 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.
+
+// +build dragonfly
+
+package cgo
+
+import _ "unsafe" // for go:linkname
+
+// Supply environ and __progname, because we don't
+// link against the standard DragonFly crt0.o and the
+// libc dynamic library needs them.
+
+//go:linkname _environ environ
+//go:linkname _progname __progname
+
+var _environ uintptr
+var _progname uintptr
diff --git a/src/runtime/cgo/freebsd.go b/src/runtime/cgo/freebsd.go
new file mode 100644
index 0000000..5c9ddbd
--- /dev/null
+++ b/src/runtime/cgo/freebsd.go
@@ -0,0 +1,22 @@
+// Copyright 2010 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.
+
+// +build freebsd
+
+package cgo
+
+import _ "unsafe" // for go:linkname
+
+// Supply environ and __progname, because we don't
+// link against the standard FreeBSD crt0.o and the
+// libc dynamic library needs them.
+
+//go:linkname _environ environ
+//go:linkname _progname __progname
+
+//go:cgo_export_dynamic environ
+//go:cgo_export_dynamic __progname
+
+var _environ uintptr
+var _progname uintptr
diff --git a/src/runtime/cgo/gcc_386.S b/src/runtime/cgo/gcc_386.S
new file mode 100644
index 0000000..ff55b2c
--- /dev/null
+++ b/src/runtime/cgo/gcc_386.S
@@ -0,0 +1,40 @@
+// Copyright 2009 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.
+
+/*
+ * Apple still insists on underscore prefixes for C function names.
+ */
+#if defined(__APPLE__) || defined(_WIN32)
+#define EXT(s) _##s
+#else
+#define EXT(s) s
+#endif
+
+/*
+ * void crosscall_386(void (*fn)(void))
+ *
+ * Calling into the 8c tool chain, where all registers are caller save.
+ * Called from standard x86 ABI, where %ebp, %ebx, %esi,
+ * and %edi are callee-save, so they must be saved explicitly.
+ */
+.globl EXT(crosscall_386)
+EXT(crosscall_386):
+	pushl %ebp
+	movl %esp, %ebp
+	pushl %ebx
+	pushl %esi
+	pushl %edi
+
+	movl 8(%ebp), %eax	/* fn */
+	call *%eax
+
+	popl %edi
+	popl %esi
+	popl %ebx
+	popl %ebp
+	ret
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",@progbits
+#endif
diff --git a/src/runtime/cgo/gcc_aix_ppc64.S b/src/runtime/cgo/gcc_aix_ppc64.S
new file mode 100644
index 0000000..a00fae2
--- /dev/null
+++ b/src/runtime/cgo/gcc_aix_ppc64.S
@@ -0,0 +1,133 @@
+// 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.
+
+// +build ppc64
+// +build aix
+
+/*
+ * void crosscall_ppc64(void (*fn)(void), void *g)
+ *
+ * Calling into the gc tool chain, where all registers are caller save.
+ * Called from standard ppc64 C ABI, where r2, r14-r31, f14-f31 are
+ * callee-save, so they must be saved explicitly.
+ * AIX has a special assembly syntax and keywords that can be mixed with
+ * Linux assembly.
+ */
+  .toc
+  .csect .text[PR]
+  .globl crosscall_ppc64
+  .globl .crosscall_ppc64
+  .csect crosscall_ppc64[DS]
+crosscall_ppc64:
+  .llong .crosscall_ppc64, TOC[tc0], 0
+  .csect .text[PR]
+.crosscall_ppc64:
+	// Start with standard C stack frame layout and linkage
+	mflr	0
+	std	0, 16(1)	// Save LR in caller's frame
+	std	2, 40(1)	// Save TOC in caller's frame
+	bl	saveregs
+	stdu	1, -296(1)
+
+	// Set up Go ABI constant registers
+	// Must match _cgo_reginit in runtime package.
+	xor 0, 0, 0
+
+	// Restore g pointer (r30 in Go ABI, which may have been clobbered by C)
+	mr	30, 4
+
+	// Call fn
+	mr	12, 3
+	mtctr	12
+	bctrl
+
+	addi	1, 1, 296
+	bl	restoreregs
+	ld	2, 40(1)
+	ld	0, 16(1)
+	mtlr	0
+	blr
+
+saveregs:
+	// Save callee-save registers
+	// O=-288; for R in {14..31}; do echo "\tstd\t$R, $O(1)"; ((O+=8)); done; for F in f{14..31}; do echo "\tstfd\t$F, $O(1)"; ((O+=8)); done
+	std	14, -288(1)
+	std	15, -280(1)
+	std	16, -272(1)
+	std	17, -264(1)
+	std	18, -256(1)
+	std	19, -248(1)
+	std	20, -240(1)
+	std	21, -232(1)
+	std	22, -224(1)
+	std	23, -216(1)
+	std	24, -208(1)
+	std	25, -200(1)
+	std	26, -192(1)
+	std	27, -184(1)
+	std	28, -176(1)
+	std	29, -168(1)
+	std	30, -160(1)
+	std	31, -152(1)
+	stfd	14, -144(1)
+	stfd	15, -136(1)
+	stfd	16, -128(1)
+	stfd	17, -120(1)
+	stfd	18, -112(1)
+	stfd	19, -104(1)
+	stfd	20, -96(1)
+	stfd	21, -88(1)
+	stfd	22, -80(1)
+	stfd	23, -72(1)
+	stfd	24, -64(1)
+	stfd	25, -56(1)
+	stfd	26, -48(1)
+	stfd	27, -40(1)
+	stfd	28, -32(1)
+	stfd	29, -24(1)
+	stfd	30, -16(1)
+	stfd	31, -8(1)
+
+	blr
+
+restoreregs:
+	// O=-288; for R in {14..31}; do echo "\tld\t$R, $O(1)"; ((O+=8)); done; for F in {14..31}; do echo "\tlfd\t$F, $O(1)"; ((O+=8)); done
+	ld	14, -288(1)
+	ld	15, -280(1)
+	ld	16, -272(1)
+	ld	17, -264(1)
+	ld	18, -256(1)
+	ld	19, -248(1)
+	ld	20, -240(1)
+	ld	21, -232(1)
+	ld	22, -224(1)
+	ld	23, -216(1)
+	ld	24, -208(1)
+	ld	25, -200(1)
+	ld	26, -192(1)
+	ld	27, -184(1)
+	ld	28, -176(1)
+	ld	29, -168(1)
+	ld	30, -160(1)
+	ld	31, -152(1)
+	lfd	14, -144(1)
+	lfd	15, -136(1)
+	lfd	16, -128(1)
+	lfd	17, -120(1)
+	lfd	18, -112(1)
+	lfd	19, -104(1)
+	lfd	20, -96(1)
+	lfd	21, -88(1)
+	lfd	22, -80(1)
+	lfd	23, -72(1)
+	lfd	24, -64(1)
+	lfd	25, -56(1)
+	lfd	26, -48(1)
+	lfd	27, -40(1)
+	lfd	28, -32(1)
+	lfd	29, -24(1)
+	lfd	30, -16(1)
+	lfd	31, -8(1)
+
+	blr
diff --git a/src/runtime/cgo/gcc_aix_ppc64.c b/src/runtime/cgo/gcc_aix_ppc64.c
new file mode 100644
index 0000000..f4f50b8
--- /dev/null
+++ b/src/runtime/cgo/gcc_aix_ppc64.c
@@ -0,0 +1,38 @@
+// 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.
+
+// +build aix
+// +build ppc64 ppc64le
+
+/*
+ * On AIX, call to _cgo_topofstack and Go main are forced to be a longcall.
+ * Without it, ld might add trampolines in the middle of .text section
+ * to reach these functions which are normally declared in runtime package.
+ */
+extern int __attribute__((longcall)) __cgo_topofstack(void);
+extern int __attribute__((longcall)) runtime_rt0_go(int argc, char **argv);
+extern void __attribute__((longcall)) _rt0_ppc64_aix_lib(void);
+
+int _cgo_topofstack(void) {
+	return __cgo_topofstack();
+}
+
+int main(int argc, char **argv) {
+	return runtime_rt0_go(argc, argv);
+}
+
+static void libinit(void) __attribute__ ((constructor));
+
+/*
+ * libinit aims to replace .init_array section which isn't available on aix.
+ * Using __attribute__ ((constructor)) let gcc handles this instead of
+ * adding special code in cmd/link.
+ * However, it will be called for every Go programs which has cgo.
+ * Inside _rt0_ppc64_aix_lib(), runtime.isarchive is checked in order
+ * to know if this program is a c-archive or a simple cgo program.
+ * If it's not set, _rt0_ppc64_ax_lib() returns directly.
+ */
+static void libinit() {
+	_rt0_ppc64_aix_lib();
+}
diff --git a/src/runtime/cgo/gcc_amd64.S b/src/runtime/cgo/gcc_amd64.S
new file mode 100644
index 0000000..17d9d47
--- /dev/null
+++ b/src/runtime/cgo/gcc_amd64.S
@@ -0,0 +1,48 @@
+// Copyright 2009 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.
+
+/*
+ * Apple still insists on underscore prefixes for C function names.
+ */
+#if defined(__APPLE__)
+#define EXT(s) _##s
+#else
+#define EXT(s) s
+#endif
+
+/*
+ * void crosscall_amd64(void (*fn)(void))
+ *
+ * Calling into the 6c tool chain, where all registers are caller save.
+ * Called from standard x86-64 ABI, where %rbx, %rbp, %r12-%r15
+ * are callee-save so they must be saved explicitly.
+ * The standard x86-64 ABI passes the three arguments m, g, fn
+ * in %rdi, %rsi, %rdx.
+ */
+.globl EXT(crosscall_amd64)
+EXT(crosscall_amd64):
+	pushq %rbx
+	pushq %rbp
+	pushq %r12
+	pushq %r13
+	pushq %r14
+	pushq %r15
+
+#if defined(_WIN64)
+	call *%rcx	/* fn */
+#else
+	call *%rdi	/* fn */
+#endif
+
+	popq %r15
+	popq %r14
+	popq %r13
+	popq %r12
+	popq %rbp
+	popq %rbx
+	ret
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",@progbits
+#endif
diff --git a/src/runtime/cgo/gcc_android.c b/src/runtime/cgo/gcc_android.c
new file mode 100644
index 0000000..7ea2135
--- /dev/null
+++ b/src/runtime/cgo/gcc_android.c
@@ -0,0 +1,90 @@
+// Copyright 2014 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.
+
+#include <stdarg.h>
+#include <android/log.h>
+#include <pthread.h>
+#include <dlfcn.h>
+#include "libcgo.h"
+
+void
+fatalf(const char* format, ...)
+{
+	va_list ap;
+
+	// Write to both stderr and logcat.
+	//
+	// When running from an .apk, /dev/stderr and /dev/stdout
+	// redirect to /dev/null. And when running a test binary
+	// via adb shell, it's easy to miss logcat.
+
+	fprintf(stderr, "runtime/cgo: ");
+	va_start(ap, format);
+	vfprintf(stderr, format, ap);
+	va_end(ap);
+	fprintf(stderr, "\n");
+
+	va_start(ap, format);
+	__android_log_vprint(ANDROID_LOG_FATAL, "runtime/cgo", format, ap);
+	va_end(ap);
+
+	abort();
+}
+
+// Truncated to a different magic value on 32-bit; that's ok.
+#define magic1 (0x23581321345589ULL)
+
+// From https://android.googlesource.com/platform/bionic/+/refs/heads/android10-tests-release/libc/private/bionic_asm_tls.h#69.
+#define TLS_SLOT_APP 2
+
+// inittls allocates a thread-local storage slot for g.
+//
+// It finds the first available slot using pthread_key_create and uses
+// it as the offset value for runtime.tls_g.
+static void
+inittls(void **tlsg, void **tlsbase)
+{
+	pthread_key_t k;
+	int i, err;
+	void *handle, *get_ver, *off;
+
+	// Check for Android Q where we can use the free TLS_SLOT_APP slot.
+	handle = dlopen("libc.so", RTLD_LAZY);
+	if (handle == NULL) {
+		fatalf("inittls: failed to dlopen main program");
+		return;
+	}
+	// android_get_device_api_level is introduced in Android Q, so its mere presence
+	// is enough.
+	get_ver = dlsym(handle, "android_get_device_api_level");
+	dlclose(handle);
+	if (get_ver != NULL) {
+		off = (void *)(TLS_SLOT_APP*sizeof(void *));
+		// tlsg is initialized to Q's free TLS slot. Verify it while we're here.
+		if (*tlsg != off) {
+			fatalf("tlsg offset wrong, got %ld want %ld\n", *tlsg, off);
+		}
+		return;
+	}
+
+	err = pthread_key_create(&k, nil);
+	if(err != 0) {
+		fatalf("pthread_key_create failed: %d", err);
+	}
+	pthread_setspecific(k, (void*)magic1);
+	// If thread local slots are laid out as we expect, our magic word will
+	// be located at some low offset from tlsbase. However, just in case something went
+	// wrong, the search is limited to sensible offsets. PTHREAD_KEYS_MAX was the
+	// original limit, but issue 19472 made a higher limit necessary.
+	for (i=0; i<384; i++) {
+		if (*(tlsbase+i) == (void*)magic1) {
+			*tlsg = (void*)(i*sizeof(void *));
+			pthread_setspecific(k, 0);
+			return;
+		}
+	}
+	fatalf("inittls: could not find pthread key");
+}
+
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase) = inittls;
diff --git a/src/runtime/cgo/gcc_arm.S b/src/runtime/cgo/gcc_arm.S
new file mode 100644
index 0000000..fe1c48b
--- /dev/null
+++ b/src/runtime/cgo/gcc_arm.S
@@ -0,0 +1,42 @@
+// Copyright 2012 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.
+
+/*
+ * Apple still insists on underscore prefixes for C function names.
+ */
+#if defined(__APPLE__)
+#define EXT(s) _##s
+#else
+#define EXT(s) s
+#endif
+
+// Apple's ld64 wants 4-byte alignment for ARM code sections.
+// .align in both Apple as and GNU as treat n as aligning to 2**n bytes.
+.align	2
+
+/*
+ * void crosscall_arm1(void (*fn)(void), void (*setg_gcc)(void *g), void *g)
+ *
+ * Calling into the 5c tool chain, where all registers are caller save.
+ * Called from standard ARM EABI, where r4-r11 are callee-save, so they
+ * must be saved explicitly.
+ */
+.globl EXT(crosscall_arm1)
+EXT(crosscall_arm1):
+	push {r4, r5, r6, r7, r8, r9, r10, r11, ip, lr}
+	mov r4, r0
+	mov r5, r1
+	mov r0, r2
+
+	// Because the assembler might target an earlier revision of the ISA
+	// by default, we encode BLX as a .word.
+	.word 0xe12fff35 // blx r5 // setg(g)
+	.word 0xe12fff34 // blx r4 // fn()
+
+	pop {r4, r5, r6, r7, r8, r9, r10, r11, ip, pc}
+
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",%progbits
+#endif
diff --git a/src/runtime/cgo/gcc_arm64.S b/src/runtime/cgo/gcc_arm64.S
new file mode 100644
index 0000000..9154d2a
--- /dev/null
+++ b/src/runtime/cgo/gcc_arm64.S
@@ -0,0 +1,82 @@
+// 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.
+
+/*
+ * Apple still insists on underscore prefixes for C function names.
+ */
+#if defined(__APPLE__)
+#define EXT(s) _##s
+#else
+#define EXT(s) s
+#endif
+
+// Apple's ld64 wants 4-byte alignment for ARM code sections.
+// .align in both Apple as and GNU as treat n as aligning to 2**n bytes.
+.align	2
+
+/*
+ * void crosscall1(void (*fn)(void), void (*setg_gcc)(void *g), void *g)
+ *
+ * Calling into the gc tool chain, where all registers are caller save.
+ * Called from standard ARM EABI, where x19-x29 are callee-save, so they
+ * must be saved explicitly, along with x30 (LR).
+ */
+.globl EXT(crosscall1)
+EXT(crosscall1):
+	.cfi_startproc
+	stp x29, x30, [sp, #-96]!
+	.cfi_def_cfa_offset 96
+	.cfi_offset 29, -96
+	.cfi_offset 30, -88
+	mov x29, sp
+	.cfi_def_cfa_register 29
+	stp x19, x20, [sp, #80]
+	.cfi_offset 19, -16
+	.cfi_offset 20, -8
+	stp x21, x22, [sp, #64]
+	.cfi_offset 21, -32
+	.cfi_offset 22, -24
+	stp x23, x24, [sp, #48]
+	.cfi_offset 23, -48
+	.cfi_offset 24, -40
+	stp x25, x26, [sp, #32]
+	.cfi_offset 25, -64
+	.cfi_offset 26, -56
+	stp x27, x28, [sp, #16]
+	.cfi_offset 27, -80
+	.cfi_offset 28, -72
+
+	mov x19, x0
+	mov x20, x1
+	mov x0, x2
+
+	blr x20
+	blr x19
+
+	ldp x27, x28, [sp, #16]
+	.cfi_restore 27
+	.cfi_restore 28
+	ldp x25, x26, [sp, #32]
+	.cfi_restore 25
+	.cfi_restore 26
+	ldp x23, x24, [sp, #48]
+	.cfi_restore 23
+	.cfi_restore 24
+	ldp x21, x22, [sp, #64]
+	.cfi_restore 21
+	.cfi_restore 22
+	ldp x19, x20, [sp, #80]
+	.cfi_restore 19
+	.cfi_restore 20
+	ldp x29, x30, [sp], #96
+	.cfi_restore 29
+	.cfi_restore 30
+	.cfi_def_cfa 31, 0
+	ret
+	.cfi_endproc
+
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",%progbits
+#endif
diff --git a/src/runtime/cgo/gcc_context.c b/src/runtime/cgo/gcc_context.c
new file mode 100644
index 0000000..5fc0abb
--- /dev/null
+++ b/src/runtime/cgo/gcc_context.c
@@ -0,0 +1,21 @@
+// Copyright 2016 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.
+
+// +build cgo
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris windows
+
+#include "libcgo.h"
+
+// Releases the cgo traceback context.
+void _cgo_release_context(uintptr_t ctxt) {
+	void (*pfn)(struct context_arg*);
+
+	pfn = _cgo_get_context_function();
+	if (ctxt != 0 && pfn != nil) {
+		struct context_arg arg;
+
+		arg.Context = ctxt;
+		(*pfn)(&arg);
+	}
+}
diff --git a/src/runtime/cgo/gcc_darwin_amd64.c b/src/runtime/cgo/gcc_darwin_amd64.c
new file mode 100644
index 0000000..51410d5
--- /dev/null
+++ b/src/runtime/cgo/gcc_darwin_amd64.c
@@ -0,0 +1,66 @@
+// Copyright 2009 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.
+
+#include <string.h> /* for strerror */
+#include <pthread.h>
+#include <signal.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+
+void
+x_cgo_init(G *g)
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	// Move the g pointer into the slot reserved in thread local storage.
+	// Constant must match the one in cmd/link/internal/ld/sym.go.
+	asm volatile("movq %0, %%gs:0x30" :: "r"(ts.g));
+
+	crosscall_amd64(ts.fn);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_darwin_arm64.c b/src/runtime/cgo/gcc_darwin_arm64.c
new file mode 100644
index 0000000..a5f07f1
--- /dev/null
+++ b/src/runtime/cgo/gcc_darwin_arm64.c
@@ -0,0 +1,145 @@
+// Copyright 2014 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.
+
+#include <limits.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h> /* for strerror */
+#include <sys/param.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+#include <TargetConditionals.h>
+
+#if TARGET_OS_IPHONE
+#include <CoreFoundation/CFBundle.h>
+#include <CoreFoundation/CFString.h>
+#endif
+
+static void *threadentry(void*);
+static void (*setg_gcc)(void*);
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	//fprintf(stderr, "runtime/cgo: _cgo_sys_thread_start: fn=%p, g=%p\n", ts->fn, ts->g); // debug
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	size = 0;
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+#if TARGET_OS_IPHONE
+	darwin_arm_init_thread_exception_port();
+#endif
+
+	crosscall1(ts.fn, setg_gcc, (void*)ts.g);
+	return nil;
+}
+
+#if TARGET_OS_IPHONE
+
+// init_working_dir sets the current working directory to the app root.
+// By default ios/arm64 processes start in "/".
+static void
+init_working_dir()
+{
+	CFBundleRef bundle = CFBundleGetMainBundle();
+	if (bundle == NULL) {
+		fprintf(stderr, "runtime/cgo: no main bundle\n");
+		return;
+	}
+	CFURLRef url_ref = CFBundleCopyResourceURL(bundle, CFSTR("Info"), CFSTR("plist"), NULL);
+	if (url_ref == NULL) {
+		// No Info.plist found. It can happen on Corellium virtual devices.
+		return;
+	}
+	CFStringRef url_str_ref = CFURLGetString(url_ref);
+	char buf[MAXPATHLEN];
+	Boolean res = CFStringGetCString(url_str_ref, buf, sizeof(buf), kCFStringEncodingUTF8);
+	CFRelease(url_ref);
+	if (!res) {
+		fprintf(stderr, "runtime/cgo: cannot get URL string\n");
+		return;
+	}
+
+	// url is of the form "file:///path/to/Info.plist".
+	// strip it down to the working directory "/path/to".
+	int url_len = strlen(buf);
+	if (url_len < sizeof("file://")+sizeof("/Info.plist")) {
+		fprintf(stderr, "runtime/cgo: bad URL: %s\n", buf);
+		return;
+	}
+	buf[url_len-sizeof("/Info.plist")+1] = 0;
+	char *dir = &buf[0] + sizeof("file://")-1;
+
+	if (chdir(dir) != 0) {
+		fprintf(stderr, "runtime/cgo: chdir(%s) failed\n", dir);
+	}
+
+	// The test harness in go_ios_exec passes the relative working directory
+	// in the GoExecWrapperWorkingDirectory property of the app bundle.
+	CFStringRef wd_ref = CFBundleGetValueForInfoDictionaryKey(bundle, CFSTR("GoExecWrapperWorkingDirectory"));
+	if (wd_ref != NULL) {
+		if (!CFStringGetCString(wd_ref, buf, sizeof(buf), kCFStringEncodingUTF8)) {
+			fprintf(stderr, "runtime/cgo: cannot get GoExecWrapperWorkingDirectory string\n");
+			return;
+		}
+		if (chdir(buf) != 0) {
+			fprintf(stderr, "runtime/cgo: chdir(%s) failed\n", buf);
+		}
+	}
+}
+
+#endif // TARGET_OS_IPHONE
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	//fprintf(stderr, "x_cgo_init = %p\n", &x_cgo_init); // aid debugging in presence of ASLR
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+
+#if TARGET_OS_IPHONE
+	darwin_arm_init_mach_exception_handler();
+	darwin_arm_init_thread_exception_port();
+	init_working_dir();
+#endif
+}
diff --git a/src/runtime/cgo/gcc_dragonfly_amd64.c b/src/runtime/cgo/gcc_dragonfly_amd64.c
new file mode 100644
index 0000000..d25db91
--- /dev/null
+++ b/src/runtime/cgo/gcc_dragonfly_amd64.c
@@ -0,0 +1,71 @@
+// Copyright 2009 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.
+
+#include <sys/types.h>
+#include <sys/signalvar.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	SIGFILLSET(ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	/*
+	 * Set specific keys.
+	 */
+	setg_gcc((void*)ts.g);
+
+	crosscall_amd64(ts.fn);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_fatalf.c b/src/runtime/cgo/gcc_fatalf.c
new file mode 100644
index 0000000..597e750
--- /dev/null
+++ b/src/runtime/cgo/gcc_fatalf.c
@@ -0,0 +1,23 @@
+// Copyright 2014 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.
+
+// +build aix !android,linux freebsd
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "libcgo.h"
+
+void
+fatalf(const char* format, ...)
+{
+	va_list ap;
+
+	fprintf(stderr, "runtime/cgo: ");
+	va_start(ap, format);
+	vfprintf(stderr, format, ap);
+	va_end(ap);
+	fprintf(stderr, "\n");
+	abort();
+}
diff --git a/src/runtime/cgo/gcc_freebsd_386.c b/src/runtime/cgo/gcc_freebsd_386.c
new file mode 100644
index 0000000..9097a2a
--- /dev/null
+++ b/src/runtime/cgo/gcc_freebsd_386.c
@@ -0,0 +1,71 @@
+// Copyright 2009 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.
+
+#include <sys/types.h>
+#include <sys/signalvar.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	SIGFILLSET(ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	/*
+	 * Set specific keys.
+	 */
+	setg_gcc((void*)ts.g);
+
+	crosscall_386(ts.fn);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_freebsd_amd64.c b/src/runtime/cgo/gcc_freebsd_amd64.c
new file mode 100644
index 0000000..514a2f8
--- /dev/null
+++ b/src/runtime/cgo/gcc_freebsd_amd64.c
@@ -0,0 +1,79 @@
+// Copyright 2009 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.
+
+#include <sys/types.h>
+#include <errno.h>
+#include <sys/signalvar.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t *attr;
+	size_t size;
+
+	// Deal with memory sanitizer/clang interaction.
+	// See gcc_linux_amd64.c for details.
+	setg_gcc = setg;
+	attr = (pthread_attr_t*)malloc(sizeof *attr);
+	if (attr == NULL) {
+		fatalf("malloc failed: %s", strerror(errno));
+	}
+	pthread_attr_init(attr);
+	pthread_attr_getstacksize(attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(attr);
+	free(attr);
+}
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	SIGFILLSET(ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fatalf("pthread_create failed: %s", strerror(err));
+	}
+}
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	_cgo_tsan_acquire();
+	free(v);
+	_cgo_tsan_release();
+
+	/*
+	 * Set specific keys.
+	 */
+	setg_gcc((void*)ts.g);
+
+	crosscall_amd64(ts.fn);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_freebsd_arm.c b/src/runtime/cgo/gcc_freebsd_arm.c
new file mode 100644
index 0000000..74f2e0e
--- /dev/null
+++ b/src/runtime/cgo/gcc_freebsd_arm.c
@@ -0,0 +1,83 @@
+// Copyright 2012 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.
+
+#include <sys/types.h>
+#include <machine/sysarch.h>
+#include <sys/signalvar.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+#ifdef ARM_TP_ADDRESS
+// ARM_TP_ADDRESS is (ARM_VECTORS_HIGH + 0x1000) or 0xffff1000
+// and is known to runtime.read_tls_fallback. Verify it with
+// cpp.
+#if ARM_TP_ADDRESS != 0xffff1000
+#error Wrong ARM_TP_ADDRESS!
+#endif
+#endif
+
+static void *threadentry(void*);
+
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	SIGFILLSET(ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	// Not sure why the memset is necessary here,
+	// but without it, we get a bogus stack size
+	// out of pthread_attr_getstacksize. C'est la Linux.
+	memset(&attr, 0, sizeof attr);
+	pthread_attr_init(&attr);
+	size = 0;
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+extern void crosscall_arm1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	crosscall_arm1(ts.fn, setg_gcc, (void*)ts.g);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_freebsd_arm64.c b/src/runtime/cgo/gcc_freebsd_arm64.c
new file mode 100644
index 0000000..dd8f888
--- /dev/null
+++ b/src/runtime/cgo/gcc_freebsd_arm64.c
@@ -0,0 +1,68 @@
+// 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.
+
+#include <sys/types.h>
+#include <errno.h>
+#include <sys/signalvar.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	SIGFILLSET(ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	crosscall1(ts.fn, setg_gcc, (void*)ts.g);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_freebsd_sigaction.c b/src/runtime/cgo/gcc_freebsd_sigaction.c
new file mode 100644
index 0000000..98b122d
--- /dev/null
+++ b/src/runtime/cgo/gcc_freebsd_sigaction.c
@@ -0,0 +1,80 @@
+// Copyright 2018 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.
+
+// +build freebsd,amd64
+
+#include <errno.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include <signal.h>
+
+#include "libcgo.h"
+
+// go_sigaction_t is a C version of the sigactiont struct from
+// os_freebsd.go.  This definition — and its conversion to and from struct
+// sigaction — are specific to freebsd/amd64.
+typedef struct {
+        uint32_t __bits[_SIG_WORDS];
+} go_sigset_t;
+typedef struct {
+	uintptr_t handler;
+	int32_t flags;
+	go_sigset_t mask;
+} go_sigaction_t;
+
+int32_t
+x_cgo_sigaction(intptr_t signum, const go_sigaction_t *goact, go_sigaction_t *oldgoact) {
+	int32_t ret;
+	struct sigaction act;
+	struct sigaction oldact;
+	size_t i;
+
+	_cgo_tsan_acquire();
+
+	memset(&act, 0, sizeof act);
+	memset(&oldact, 0, sizeof oldact);
+
+	if (goact) {
+		if (goact->flags & SA_SIGINFO) {
+			act.sa_sigaction = (void(*)(int, siginfo_t*, void*))(goact->handler);
+		} else {
+			act.sa_handler = (void(*)(int))(goact->handler);
+		}
+		sigemptyset(&act.sa_mask);
+		for (i = 0; i < 8 * sizeof(goact->mask); i++) {
+			if (goact->mask.__bits[i/32] & ((uint32_t)(1)<<(i&31))) {
+				sigaddset(&act.sa_mask, i+1);
+			}
+		}
+		act.sa_flags = goact->flags;
+	}
+
+	ret = sigaction(signum, goact ? &act : NULL, oldgoact ? &oldact : NULL);
+	if (ret == -1) {
+		// runtime.sigaction expects _cgo_sigaction to return errno on error.
+		_cgo_tsan_release();
+		return errno;
+	}
+
+	if (oldgoact) {
+		if (oldact.sa_flags & SA_SIGINFO) {
+			oldgoact->handler = (uintptr_t)(oldact.sa_sigaction);
+		} else {
+			oldgoact->handler = (uintptr_t)(oldact.sa_handler);
+		}
+		for (i = 0 ; i < _SIG_WORDS; i++) {
+			oldgoact->mask.__bits[i] = 0;
+		}
+		for (i = 0; i < 8 * sizeof(oldgoact->mask); i++) {
+			if (sigismember(&oldact.sa_mask, i+1) == 1) {
+				oldgoact->mask.__bits[i/32] |= (uint32_t)(1)<<(i&31);
+			}
+		}
+		oldgoact->flags = oldact.sa_flags;
+	}
+
+	_cgo_tsan_release();
+	return ret;
+}
diff --git a/src/runtime/cgo/gcc_libinit.c b/src/runtime/cgo/gcc_libinit.c
new file mode 100644
index 0000000..3304d95
--- /dev/null
+++ b/src/runtime/cgo/gcc_libinit.c
@@ -0,0 +1,113 @@
+// 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.
+
+// +build cgo
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
+#include <pthread.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h> // strerror
+#include <time.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static pthread_cond_t runtime_init_cond = PTHREAD_COND_INITIALIZER;
+static pthread_mutex_t runtime_init_mu = PTHREAD_MUTEX_INITIALIZER;
+static int runtime_init_done;
+
+// The context function, used when tracing back C calls into Go.
+static void (*cgo_context_function)(struct context_arg*);
+
+void
+x_cgo_sys_thread_create(void* (*func)(void*), void* arg) {
+	pthread_t p;
+	int err = _cgo_try_pthread_create(&p, NULL, func, arg);
+	if (err != 0) {
+		fprintf(stderr, "pthread_create failed: %s", strerror(err));
+		abort();
+	}
+}
+
+uintptr_t
+_cgo_wait_runtime_init_done(void) {
+	void (*pfn)(struct context_arg*);
+
+	pthread_mutex_lock(&runtime_init_mu);
+	while (runtime_init_done == 0) {
+		pthread_cond_wait(&runtime_init_cond, &runtime_init_mu);
+	}
+
+	// TODO(iant): For the case of a new C thread calling into Go, such
+	// as when using -buildmode=c-archive, we know that Go runtime
+	// initialization is complete but we do not know that all Go init
+	// functions have been run. We should not fetch cgo_context_function
+	// until they have been, because that is where a call to
+	// SetCgoTraceback is likely to occur. We are going to wait for Go
+	// initialization to be complete anyhow, later, by waiting for
+	// main_init_done to be closed in cgocallbackg1. We should wait here
+	// instead. See also issue #15943.
+	pfn = cgo_context_function;
+
+	pthread_mutex_unlock(&runtime_init_mu);
+	if (pfn != nil) {
+		struct context_arg arg;
+
+		arg.Context = 0;
+		(*pfn)(&arg);
+		return arg.Context;
+	}
+	return 0;
+}
+
+void
+x_cgo_notify_runtime_init_done(void* dummy __attribute__ ((unused))) {
+	pthread_mutex_lock(&runtime_init_mu);
+	runtime_init_done = 1;
+	pthread_cond_broadcast(&runtime_init_cond);
+	pthread_mutex_unlock(&runtime_init_mu);
+}
+
+// Sets the context function to call to record the traceback context
+// when calling a Go function from C code. Called from runtime.SetCgoTraceback.
+void x_cgo_set_context_function(void (*context)(struct context_arg*)) {
+	pthread_mutex_lock(&runtime_init_mu);
+	cgo_context_function = context;
+	pthread_mutex_unlock(&runtime_init_mu);
+}
+
+// Gets the context function.
+void (*(_cgo_get_context_function(void)))(struct context_arg*) {
+	void (*ret)(struct context_arg*);
+
+	pthread_mutex_lock(&runtime_init_mu);
+	ret = cgo_context_function;
+	pthread_mutex_unlock(&runtime_init_mu);
+	return ret;
+}
+
+// _cgo_try_pthread_create retries pthread_create if it fails with
+// EAGAIN.
+int
+_cgo_try_pthread_create(pthread_t* thread, const pthread_attr_t* attr, void* (*pfn)(void*), void* arg) {
+	int tries;
+	int err;
+	struct timespec ts;
+
+	for (tries = 0; tries < 20; tries++) {
+		err = pthread_create(thread, attr, pfn, arg);
+		if (err == 0) {
+			pthread_detach(*thread);
+			return 0;
+		}
+		if (err != EAGAIN) {
+			return err;
+		}
+		ts.tv_sec = 0;
+		ts.tv_nsec = (tries + 1) * 1000 * 1000; // Milliseconds.
+		nanosleep(&ts, nil);
+	}
+	return EAGAIN;
+}
diff --git a/src/runtime/cgo/gcc_libinit_windows.c b/src/runtime/cgo/gcc_libinit_windows.c
new file mode 100644
index 0000000..2732248
--- /dev/null
+++ b/src/runtime/cgo/gcc_libinit_windows.c
@@ -0,0 +1,125 @@
+// 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.
+
+// +build cgo
+
+#define WIN64_LEAN_AND_MEAN
+#include <windows.h>
+#include <process.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
+#include "libcgo.h"
+
+static volatile LONG runtime_init_once_gate = 0;
+static volatile LONG runtime_init_once_done = 0;
+
+static CRITICAL_SECTION runtime_init_cs;
+
+static HANDLE runtime_init_wait;
+static int runtime_init_done;
+
+// Pre-initialize the runtime synchronization objects
+void
+_cgo_preinit_init() {
+	 runtime_init_wait = CreateEvent(NULL, TRUE, FALSE, NULL);
+	 if (runtime_init_wait == NULL) {
+		fprintf(stderr, "runtime: failed to create runtime initialization wait event.\n");
+		abort();
+	 }
+
+	 InitializeCriticalSection(&runtime_init_cs);
+}
+
+// Make sure that the preinit sequence has run.
+void
+_cgo_maybe_run_preinit() {
+	 if (!InterlockedExchangeAdd(&runtime_init_once_done, 0)) {
+			if (InterlockedIncrement(&runtime_init_once_gate) == 1) {
+				 _cgo_preinit_init();
+				 InterlockedIncrement(&runtime_init_once_done);
+			} else {
+				 // Decrement to avoid overflow.
+				 InterlockedDecrement(&runtime_init_once_gate);
+				 while(!InterlockedExchangeAdd(&runtime_init_once_done, 0)) {
+						Sleep(0);
+				 }
+			}
+	 }
+}
+
+void
+x_cgo_sys_thread_create(void (*func)(void*), void* arg) {
+	uintptr_t thandle;
+
+	thandle = _beginthread(func, 0, arg);
+	if(thandle == -1) {
+		fprintf(stderr, "runtime: failed to create new OS thread (%d)\n", errno);
+		abort();
+	}
+}
+
+int
+_cgo_is_runtime_initialized() {
+	 EnterCriticalSection(&runtime_init_cs);
+	 int status = runtime_init_done;
+	 LeaveCriticalSection(&runtime_init_cs);
+	 return status;
+}
+
+uintptr_t
+_cgo_wait_runtime_init_done(void) {
+	void (*pfn)(struct context_arg*);
+
+	 _cgo_maybe_run_preinit();
+	while (!_cgo_is_runtime_initialized()) {
+			WaitForSingleObject(runtime_init_wait, INFINITE);
+	}
+	pfn = _cgo_get_context_function();
+	if (pfn != nil) {
+		struct context_arg arg;
+
+		arg.Context = 0;
+		(*pfn)(&arg);
+		return arg.Context;
+	}
+	return 0;
+}
+
+void
+x_cgo_notify_runtime_init_done(void* dummy) {
+	 _cgo_maybe_run_preinit();
+
+	 EnterCriticalSection(&runtime_init_cs);
+	runtime_init_done = 1;
+	 LeaveCriticalSection(&runtime_init_cs);
+
+	 if (!SetEvent(runtime_init_wait)) {
+		fprintf(stderr, "runtime: failed to signal runtime initialization complete.\n");
+		abort();
+	}
+}
+
+// The context function, used when tracing back C calls into Go.
+static void (*cgo_context_function)(struct context_arg*);
+
+// Sets the context function to call to record the traceback context
+// when calling a Go function from C code. Called from runtime.SetCgoTraceback.
+void x_cgo_set_context_function(void (*context)(struct context_arg*)) {
+	EnterCriticalSection(&runtime_init_cs);
+	cgo_context_function = context;
+	LeaveCriticalSection(&runtime_init_cs);
+}
+
+// Gets the context function.
+void (*(_cgo_get_context_function(void)))(struct context_arg*) {
+	void (*ret)(struct context_arg*);
+
+	EnterCriticalSection(&runtime_init_cs);
+	ret = cgo_context_function;
+	LeaveCriticalSection(&runtime_init_cs);
+	return ret;
+}
diff --git a/src/runtime/cgo/gcc_linux_386.c b/src/runtime/cgo/gcc_linux_386.c
new file mode 100644
index 0000000..70c942a
--- /dev/null
+++ b/src/runtime/cgo/gcc_linux_386.c
@@ -0,0 +1,79 @@
+// Copyright 2009 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.
+
+#include <pthread.h>
+#include <string.h>
+#include <signal.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void *threadentry(void*);
+static void (*setg_gcc)(void*);
+
+// This will be set in gcc_android.c for android-specific customization.
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase) __attribute__((common));
+
+void
+x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+
+	if (x_cgo_inittls) {
+		x_cgo_inittls(tlsg, tlsbase);
+	}
+}
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	// Not sure why the memset is necessary here,
+	// but without it, we get a bogus stack size
+	// out of pthread_attr_getstacksize. C'est la Linux.
+	memset(&attr, 0, sizeof attr);
+	pthread_attr_init(&attr);
+	size = 0;
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fatalf("pthread_create failed: %s", strerror(err));
+	}
+}
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	/*
+	 * Set specific keys.
+	 */
+	setg_gcc((void*)ts.g);
+
+	crosscall_386(ts.fn);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_linux_amd64.c b/src/runtime/cgo/gcc_linux_amd64.c
new file mode 100644
index 0000000..f2bf648
--- /dev/null
+++ b/src/runtime/cgo/gcc_linux_amd64.c
@@ -0,0 +1,99 @@
+// Copyright 2009 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.
+
+#include <pthread.h>
+#include <errno.h>
+#include <string.h> // strerror
+#include <signal.h>
+#include <stdlib.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+static void (*setg_gcc)(void*);
+
+// This will be set in gcc_android.c for android-specific customization.
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase) __attribute__((common));
+
+void
+x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
+{
+	pthread_attr_t *attr;
+	size_t size;
+
+	/* The memory sanitizer distributed with versions of clang
+	   before 3.8 has a bug: if you call mmap before malloc, mmap
+	   may return an address that is later overwritten by the msan
+	   library.  Avoid this problem by forcing a call to malloc
+	   here, before we ever call malloc.
+
+	   This is only required for the memory sanitizer, so it's
+	   unfortunate that we always run it.  It should be possible
+	   to remove this when we no longer care about versions of
+	   clang before 3.8.  The test for this is
+	   misc/cgo/testsanitizers.
+
+	   GCC works hard to eliminate a seemingly unnecessary call to
+	   malloc, so we actually use the memory we allocate.  */
+
+	setg_gcc = setg;
+	attr = (pthread_attr_t*)malloc(sizeof *attr);
+	if (attr == NULL) {
+		fatalf("malloc failed: %s", strerror(errno));
+	}
+	pthread_attr_init(attr);
+	pthread_attr_getstacksize(attr, &size);
+	g->stacklo = (uintptr)&size - size + 4096;
+	pthread_attr_destroy(attr);
+	free(attr);
+
+	if (x_cgo_inittls) {
+		x_cgo_inittls(tlsg, tlsbase);
+	}
+}
+
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fatalf("pthread_create failed: %s", strerror(err));
+	}
+}
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	_cgo_tsan_acquire();
+	free(v);
+	_cgo_tsan_release();
+
+	/*
+	 * Set specific keys.
+	 */
+	setg_gcc((void*)ts.g);
+
+	crosscall_amd64(ts.fn);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_linux_arm.c b/src/runtime/cgo/gcc_linux_arm.c
new file mode 100644
index 0000000..5bc0fee
--- /dev/null
+++ b/src/runtime/cgo/gcc_linux_arm.c
@@ -0,0 +1,74 @@
+// Copyright 2010 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.
+
+#include <pthread.h>
+#include <string.h>
+#include <signal.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void *threadentry(void*);
+
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase) __attribute__((common));
+static void (*setg_gcc)(void*);
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	// Not sure why the memset is necessary here,
+	// but without it, we get a bogus stack size
+	// out of pthread_attr_getstacksize. C'est la Linux.
+	memset(&attr, 0, sizeof attr);
+	pthread_attr_init(&attr);
+	size = 0;
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fatalf("pthread_create failed: %s", strerror(err));
+	}
+}
+
+extern void crosscall_arm1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	crosscall_arm1(ts.fn, setg_gcc, (void*)ts.g);
+	return nil;
+}
+
+void
+x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+
+	if (x_cgo_inittls) {
+		x_cgo_inittls(tlsg, tlsbase);
+	}
+}
diff --git a/src/runtime/cgo/gcc_linux_arm64.c b/src/runtime/cgo/gcc_linux_arm64.c
new file mode 100644
index 0000000..17ff274
--- /dev/null
+++ b/src/runtime/cgo/gcc_linux_arm64.c
@@ -0,0 +1,96 @@
+// 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.
+
+#include <pthread.h>
+#include <errno.h>
+#include <string.h>
+#include <signal.h>
+#include <stdlib.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void *threadentry(void*);
+
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase) __attribute__((common));
+static void (*setg_gcc)(void*);
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	// Not sure why the memset is necessary here,
+	// but without it, we get a bogus stack size
+	// out of pthread_attr_getstacksize. C'est la Linux.
+	memset(&attr, 0, sizeof attr);
+	pthread_attr_init(&attr);
+	size = 0;
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fatalf("pthread_create failed: %s", strerror(err));
+	}
+}
+
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	crosscall1(ts.fn, setg_gcc, (void*)ts.g);
+	return nil;
+}
+
+void
+x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
+{
+	pthread_attr_t *attr;
+	size_t size;
+
+	/* The memory sanitizer distributed with versions of clang
+	   before 3.8 has a bug: if you call mmap before malloc, mmap
+	   may return an address that is later overwritten by the msan
+	   library.  Avoid this problem by forcing a call to malloc
+	   here, before we ever call malloc.
+
+	   This is only required for the memory sanitizer, so it's
+	   unfortunate that we always run it.  It should be possible
+	   to remove this when we no longer care about versions of
+	   clang before 3.8.  The test for this is
+	   misc/cgo/testsanitizers.
+
+	   GCC works hard to eliminate a seemingly unnecessary call to
+	   malloc, so we actually use the memory we allocate.  */
+
+	setg_gcc = setg;
+	attr = (pthread_attr_t*)malloc(sizeof *attr);
+	if (attr == NULL) {
+		fatalf("malloc failed: %s", strerror(errno));
+	}
+	pthread_attr_init(attr);
+	pthread_attr_getstacksize(attr, &size);
+	g->stacklo = (uintptr)&size - size + 4096;
+	pthread_attr_destroy(attr);
+	free(attr);
+
+	if (x_cgo_inittls) {
+		x_cgo_inittls(tlsg, tlsbase);
+	}
+}
diff --git a/src/runtime/cgo/gcc_linux_mips64x.c b/src/runtime/cgo/gcc_linux_mips64x.c
new file mode 100644
index 0000000..42837b1
--- /dev/null
+++ b/src/runtime/cgo/gcc_linux_mips64x.c
@@ -0,0 +1,78 @@
+// Copyright 2016 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.
+
+// +build cgo
+// +build linux
+// +build mips64 mips64le
+
+#include <pthread.h>
+#include <string.h>
+#include <signal.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void *threadentry(void*);
+
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase);
+static void (*setg_gcc)(void*);
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	// Not sure why the memset is necessary here,
+	// but without it, we get a bogus stack size
+	// out of pthread_attr_getstacksize.  C'est la Linux.
+	memset(&attr, 0, sizeof attr);
+	pthread_attr_init(&attr);
+	size = 0;
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fatalf("pthread_create failed: %s", strerror(err));
+	}
+}
+
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	crosscall1(ts.fn, setg_gcc, (void*)ts.g);
+	return nil;
+}
+
+void
+x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+
+	if (x_cgo_inittls) {
+		x_cgo_inittls(tlsg, tlsbase);
+	}
+}
diff --git a/src/runtime/cgo/gcc_linux_mipsx.c b/src/runtime/cgo/gcc_linux_mipsx.c
new file mode 100644
index 0000000..a44ea30
--- /dev/null
+++ b/src/runtime/cgo/gcc_linux_mipsx.c
@@ -0,0 +1,80 @@
+// Copyright 2016 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.
+
+// +build cgo
+// +build linux
+// +build mips mipsle
+
+#include <pthread.h>
+#include <string.h>
+#include <signal.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void *threadentry(void*);
+
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase);
+static void (*setg_gcc)(void*);
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	// Not sure why the memset is necessary here,
+	// but without it, we get a bogus stack size
+	// out of pthread_attr_getstacksize.  C'est la Linux.
+	memset(&attr, 0, sizeof attr);
+	pthread_attr_init(&attr);
+	size = 0;
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fatalf("pthread_create failed: %s", strerror(err));
+	}
+}
+
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	crosscall1(ts.fn, setg_gcc, (void*)ts.g);
+	return nil;
+}
+
+void
+x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+
+	memset(&attr, 0, sizeof attr);
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+
+	if (x_cgo_inittls) {
+		x_cgo_inittls(tlsg, tlsbase);
+	}
+}
diff --git a/src/runtime/cgo/gcc_linux_ppc64x.S b/src/runtime/cgo/gcc_linux_ppc64x.S
new file mode 100644
index 0000000..595eb38
--- /dev/null
+++ b/src/runtime/cgo/gcc_linux_ppc64x.S
@@ -0,0 +1,138 @@
+// Copyright 2014 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.
+
+// +build ppc64 ppc64le
+// +build linux
+
+/*
+ * Apple still insists on underscore prefixes for C function names.
+ */
+#if defined(__APPLE__)
+#define EXT(s) _##s
+#else
+#define EXT(s) s
+#endif
+
+/*
+ * void crosscall_ppc64(void (*fn)(void), void *g)
+ *
+ * Calling into the gc tool chain, where all registers are caller save.
+ * Called from standard ppc64 C ABI, where r2, r14-r31, f14-f31 are
+ * callee-save, so they must be saved explicitly.
+ */
+.globl EXT(crosscall_ppc64)
+EXT(crosscall_ppc64):
+	// Start with standard C stack frame layout and linkage
+	mflr	%r0
+	std	%r0, 16(%r1)	// Save LR in caller's frame
+	std	%r2, 24(%r1)	// Save TOC in caller's frame
+	bl	saveregs
+	stdu	%r1, -296(%r1)
+
+	// Set up Go ABI constant registers
+	bl	_cgo_reginit
+	nop
+
+	// Restore g pointer (r30 in Go ABI, which may have been clobbered by C)
+	mr	%r30, %r4
+
+	// Call fn
+	mr	%r12, %r3
+	mtctr	%r3
+	bctrl
+
+	addi	%r1, %r1, 296
+	bl	restoreregs
+	ld	%r2, 24(%r1)
+	ld	%r0, 16(%r1)
+	mtlr	%r0
+	blr
+
+saveregs:
+	// Save callee-save registers
+	// O=-288; for R in %r{14..31}; do echo "\tstd\t$R, $O(%r1)"; ((O+=8)); done; for F in f{14..31}; do echo "\tstfd\t$F, $O(%r1)"; ((O+=8)); done
+	std	%r14, -288(%r1)
+	std	%r15, -280(%r1)
+	std	%r16, -272(%r1)
+	std	%r17, -264(%r1)
+	std	%r18, -256(%r1)
+	std	%r19, -248(%r1)
+	std	%r20, -240(%r1)
+	std	%r21, -232(%r1)
+	std	%r22, -224(%r1)
+	std	%r23, -216(%r1)
+	std	%r24, -208(%r1)
+	std	%r25, -200(%r1)
+	std	%r26, -192(%r1)
+	std	%r27, -184(%r1)
+	std	%r28, -176(%r1)
+	std	%r29, -168(%r1)
+	std	%r30, -160(%r1)
+	std	%r31, -152(%r1)
+	stfd	%f14, -144(%r1)
+	stfd	%f15, -136(%r1)
+	stfd	%f16, -128(%r1)
+	stfd	%f17, -120(%r1)
+	stfd	%f18, -112(%r1)
+	stfd	%f19, -104(%r1)
+	stfd	%f20, -96(%r1)
+	stfd	%f21, -88(%r1)
+	stfd	%f22, -80(%r1)
+	stfd	%f23, -72(%r1)
+	stfd	%f24, -64(%r1)
+	stfd	%f25, -56(%r1)
+	stfd	%f26, -48(%r1)
+	stfd	%f27, -40(%r1)
+	stfd	%f28, -32(%r1)
+	stfd	%f29, -24(%r1)
+	stfd	%f30, -16(%r1)
+	stfd	%f31, -8(%r1)
+
+	blr
+
+restoreregs:
+	// O=-288; for R in %r{14..31}; do echo "\tld\t$R, $O(%r1)"; ((O+=8)); done; for F in %f{14..31}; do echo "\tlfd\t$F, $O(%r1)"; ((O+=8)); done
+	ld	%r14, -288(%r1)
+	ld	%r15, -280(%r1)
+	ld	%r16, -272(%r1)
+	ld	%r17, -264(%r1)
+	ld	%r18, -256(%r1)
+	ld	%r19, -248(%r1)
+	ld	%r20, -240(%r1)
+	ld	%r21, -232(%r1)
+	ld	%r22, -224(%r1)
+	ld	%r23, -216(%r1)
+	ld	%r24, -208(%r1)
+	ld	%r25, -200(%r1)
+	ld	%r26, -192(%r1)
+	ld	%r27, -184(%r1)
+	ld	%r28, -176(%r1)
+	ld	%r29, -168(%r1)
+	ld	%r30, -160(%r1)
+	ld	%r31, -152(%r1)
+	lfd	%f14, -144(%r1)
+	lfd	%f15, -136(%r1)
+	lfd	%f16, -128(%r1)
+	lfd	%f17, -120(%r1)
+	lfd	%f18, -112(%r1)
+	lfd	%f19, -104(%r1)
+	lfd	%f20, -96(%r1)
+	lfd	%f21, -88(%r1)
+	lfd	%f22, -80(%r1)
+	lfd	%f23, -72(%r1)
+	lfd	%f24, -64(%r1)
+	lfd	%f25, -56(%r1)
+	lfd	%f26, -48(%r1)
+	lfd	%f27, -40(%r1)
+	lfd	%f28, -32(%r1)
+	lfd	%f29, -24(%r1)
+	lfd	%f30, -16(%r1)
+	lfd	%f31, -8(%r1)
+
+	blr
+
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",%progbits
+#endif
diff --git a/src/runtime/cgo/gcc_linux_riscv64.c b/src/runtime/cgo/gcc_linux_riscv64.c
new file mode 100644
index 0000000..22b76c2
--- /dev/null
+++ b/src/runtime/cgo/gcc_linux_riscv64.c
@@ -0,0 +1,74 @@
+// Copyright 2020 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.
+
+#include <pthread.h>
+#include <string.h>
+#include <signal.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void *threadentry(void*);
+
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase);
+static void (*setg_gcc)(void*);
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	// Not sure why the memset is necessary here,
+	// but without it, we get a bogus stack size
+	// out of pthread_attr_getstacksize.  C'est la Linux.
+	memset(&attr, 0, sizeof attr);
+	pthread_attr_init(&attr);
+	size = 0;
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fatalf("pthread_create failed: %s", strerror(err));
+	}
+}
+
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	crosscall1(ts.fn, setg_gcc, (void*)ts.g);
+	return nil;
+}
+
+void
+x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+
+	if (x_cgo_inittls) {
+		x_cgo_inittls(tlsg, tlsbase);
+	}
+}
diff --git a/src/runtime/cgo/gcc_linux_s390x.c b/src/runtime/cgo/gcc_linux_s390x.c
new file mode 100644
index 0000000..bb60048
--- /dev/null
+++ b/src/runtime/cgo/gcc_linux_s390x.c
@@ -0,0 +1,69 @@
+// Copyright 2016 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.
+
+#include <pthread.h>
+#include <string.h>
+#include <signal.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void *threadentry(void*);
+
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*), void **tlsbase)
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fatalf("pthread_create failed: %s", strerror(err));
+	}
+}
+
+extern void crosscall_s390x(void (*fn)(void), void *g);
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	// Save g for this thread in C TLS
+	setg_gcc((void*)ts.g);
+
+	crosscall_s390x(ts.fn, (void*)ts.g);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_mips64x.S b/src/runtime/cgo/gcc_mips64x.S
new file mode 100644
index 0000000..908dd21
--- /dev/null
+++ b/src/runtime/cgo/gcc_mips64x.S
@@ -0,0 +1,87 @@
+// Copyright 2016 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.
+
+// +build mips64 mips64le
+
+/*
+ * void crosscall1(void (*fn)(void), void (*setg_gcc)(void *g), void *g)
+ *
+ * Calling into the gc tool chain, where all registers are caller save.
+ * Called from standard MIPS N64 ABI, where $16-$23, $28, $30, and $f24-$f31
+ * are callee-save, so they must be saved explicitly, along with $31 (LR).
+ */
+.globl crosscall1
+.set noat
+crosscall1:
+#ifndef __mips_soft_float
+	daddiu	$29, $29, -160
+#else
+	daddiu	$29, $29, -96 // For soft-float, no need to make room for FP registers
+#endif
+	sd	$31, 0($29)
+	sd	$16, 8($29)
+	sd	$17, 16($29)
+	sd	$18, 24($29)
+	sd	$19, 32($29)
+	sd	$20, 40($29)
+	sd	$21, 48($29)
+	sd	$22, 56($29)
+	sd	$23, 64($29)
+	sd	$28, 72($29)
+	sd	$30, 80($29)
+#ifndef __mips_soft_float
+	sdc1	$f24, 88($29)
+	sdc1	$f25, 96($29)
+	sdc1	$f26, 104($29)
+	sdc1	$f27, 112($29)
+	sdc1	$f28, 120($29)
+	sdc1	$f29, 128($29)
+	sdc1	$f30, 136($29)
+	sdc1	$f31, 144($29)
+#endif
+
+	// prepare SB register = pc & 0xffffffff00000000
+	bal	1f
+1:
+	dsrl	$28, $31, 32
+	dsll	$28, $28, 32
+
+	move	$20, $4 // save R4
+	move	$1, $6
+	jalr	$5	// call setg_gcc (clobbers R4)
+	jalr	$20	// call fn
+
+	ld	$16, 8($29)
+	ld	$17, 16($29)
+	ld	$18, 24($29)
+	ld	$19, 32($29)
+	ld	$20, 40($29)
+	ld	$21, 48($29)
+	ld	$22, 56($29)
+	ld	$23, 64($29)
+	ld	$28, 72($29)
+	ld	$30, 80($29)
+#ifndef __mips_soft_float
+	ldc1	$f24, 88($29)
+	ldc1	$f25, 96($29)
+	ldc1	$f26, 104($29)
+	ldc1	$f27, 112($29)
+	ldc1	$f28, 120($29)
+	ldc1	$f29, 128($29)
+	ldc1	$f30, 136($29)
+	ldc1	$f31, 144($29)
+#endif
+	ld	$31, 0($29)
+#ifndef __mips_soft_float
+	daddiu	$29, $29, 160
+#else
+	daddiu	$29, $29, 96
+#endif
+	jr	$31
+
+.set at
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",%progbits
+#endif
diff --git a/src/runtime/cgo/gcc_mipsx.S b/src/runtime/cgo/gcc_mipsx.S
new file mode 100644
index 0000000..54f4b82
--- /dev/null
+++ b/src/runtime/cgo/gcc_mipsx.S
@@ -0,0 +1,75 @@
+// Copyright 2016 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.
+
+// +build mips mipsle
+
+/*
+ * void crosscall1(void (*fn)(void), void (*setg_gcc)(void *g), void *g)
+ *
+ * Calling into the gc tool chain, where all registers are caller save.
+ * Called from standard MIPS O32 ABI, where $16-$23, $30, and $f20-$f31
+ * are callee-save, so they must be saved explicitly, along with $31 (LR).
+ */
+.globl crosscall1
+.set noat
+crosscall1:
+#ifndef __mips_soft_float
+	addiu	$29, $29, -88
+#else
+	addiu	$29, $29, -40 // For soft-float, no need to make room for FP registers
+#endif
+	sw	$31, 0($29)
+	sw	$16, 4($29)
+	sw	$17, 8($29)
+	sw	$18, 12($29)
+	sw	$19, 16($29)
+	sw	$20, 20($29)
+	sw	$21, 24($29)
+	sw	$22, 28($29)
+	sw	$23, 32($29)
+	sw	$30, 36($29)
+
+#ifndef __mips_soft_float
+	sdc1	$f20, 40($29)
+	sdc1	$f22, 48($29)
+	sdc1	$f24, 56($29)
+	sdc1	$f26, 64($29)
+	sdc1	$f28, 72($29)
+	sdc1	$f30, 80($29)
+#endif
+	move	$20, $4 // save R4
+	move	$4, $6
+	jalr	$5	// call setg_gcc
+	jalr	$20	// call fn
+
+	lw	$16, 4($29)
+	lw	$17, 8($29)
+	lw	$18, 12($29)
+	lw	$19, 16($29)
+	lw	$20, 20($29)
+	lw	$21, 24($29)
+	lw	$22, 28($29)
+	lw	$23, 32($29)
+	lw	$30, 36($29)
+#ifndef __mips_soft_float
+	ldc1	$f20, 40($29)
+	ldc1	$f22, 48($29)
+	ldc1	$f24, 56($29)
+	ldc1	$f26, 64($29)
+	ldc1	$f28, 72($29)
+	ldc1	$f30, 80($29)
+#endif
+	lw	$31, 0($29)
+#ifndef __mips_soft_float
+	addiu	$29, $29, 88
+#else
+	addiu	$29, $29, 40
+#endif
+	jr	$31
+
+.set at
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",%progbits
+#endif
diff --git a/src/runtime/cgo/gcc_mmap.c b/src/runtime/cgo/gcc_mmap.c
new file mode 100644
index 0000000..e6a621d
--- /dev/null
+++ b/src/runtime/cgo/gcc_mmap.c
@@ -0,0 +1,39 @@
+// 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.
+
+// +build linux,amd64 linux,arm64
+
+#include <errno.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+
+#include "libcgo.h"
+
+uintptr_t
+x_cgo_mmap(void *addr, uintptr_t length, int32_t prot, int32_t flags, int32_t fd, uint32_t offset) {
+	void *p;
+
+	_cgo_tsan_acquire();
+	p = mmap(addr, length, prot, flags, fd, offset);
+	_cgo_tsan_release();
+	if (p == MAP_FAILED) {
+		/* This is what the Go code expects on failure.  */
+		return (uintptr_t)errno;
+	}
+	return (uintptr_t)p;
+}
+
+void
+x_cgo_munmap(void *addr, uintptr_t length) {
+	int r;
+
+	_cgo_tsan_acquire();
+	r = munmap(addr, length);
+	_cgo_tsan_release();
+	if (r < 0) {
+		/* The Go runtime is not prepared for munmap to fail.  */
+		abort();
+	}
+}
diff --git a/src/runtime/cgo/gcc_netbsd_386.c b/src/runtime/cgo/gcc_netbsd_386.c
new file mode 100644
index 0000000..5495f0f
--- /dev/null
+++ b/src/runtime/cgo/gcc_netbsd_386.c
@@ -0,0 +1,82 @@
+// Copyright 2009 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.
+
+#include <sys/types.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+	stack_t ss;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	/*
+	 * Set specific keys.
+	 */
+	setg_gcc((void*)ts.g);
+
+	// On NetBSD, a new thread inherits the signal stack of the
+	// creating thread. That confuses minit, so we remove that
+	// signal stack here before calling the regular mstart. It's
+	// a bit baroque to remove a signal stack here only to add one
+	// in minit, but it's a simple change that keeps NetBSD
+	// working like other OS's. At this point all signals are
+	// blocked, so there is no race.
+	memset(&ss, 0, sizeof ss);
+	ss.ss_flags = SS_DISABLE;
+	sigaltstack(&ss, nil);
+
+	crosscall_386(ts.fn);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_netbsd_amd64.c b/src/runtime/cgo/gcc_netbsd_amd64.c
new file mode 100644
index 0000000..dc966fc
--- /dev/null
+++ b/src/runtime/cgo/gcc_netbsd_amd64.c
@@ -0,0 +1,83 @@
+// Copyright 2009 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.
+
+#include <sys/types.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+	stack_t ss;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	/*
+	 * Set specific keys.
+	 */
+	setg_gcc((void*)ts.g);
+
+	// On NetBSD, a new thread inherits the signal stack of the
+	// creating thread. That confuses minit, so we remove that
+	// signal stack here before calling the regular mstart. It's
+	// a bit baroque to remove a signal stack here only to add one
+	// in minit, but it's a simple change that keeps NetBSD
+	// working like other OS's. At this point all signals are
+	// blocked, so there is no race.
+	memset(&ss, 0, sizeof ss);
+	ss.ss_flags = SS_DISABLE;
+	sigaltstack(&ss, nil);
+
+	crosscall_amd64(ts.fn);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_netbsd_arm.c b/src/runtime/cgo/gcc_netbsd_arm.c
new file mode 100644
index 0000000..b0c80ea
--- /dev/null
+++ b/src/runtime/cgo/gcc_netbsd_arm.c
@@ -0,0 +1,79 @@
+// Copyright 2013 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.
+
+#include <sys/types.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void *threadentry(void*);
+
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+extern void crosscall_arm1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+	stack_t ss;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	// On NetBSD, a new thread inherits the signal stack of the
+	// creating thread. That confuses minit, so we remove that
+	// signal stack here before calling the regular mstart. It's
+	// a bit baroque to remove a signal stack here only to add one
+	// in minit, but it's a simple change that keeps NetBSD
+	// working like other OS's. At this point all signals are
+	// blocked, so there is no race.
+	memset(&ss, 0, sizeof ss);
+	ss.ss_flags = SS_DISABLE;
+	sigaltstack(&ss, nil);
+
+	crosscall_arm1(ts.fn, setg_gcc, (void*)ts.g);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_netbsd_arm64.c b/src/runtime/cgo/gcc_netbsd_arm64.c
new file mode 100644
index 0000000..694116c
--- /dev/null
+++ b/src/runtime/cgo/gcc_netbsd_arm64.c
@@ -0,0 +1,80 @@
+// 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.
+
+#include <sys/types.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void *threadentry(void*);
+
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+	stack_t ss;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	// On NetBSD, a new thread inherits the signal stack of the
+	// creating thread. That confuses minit, so we remove that
+	// signal stack here before calling the regular mstart. It's
+	// a bit baroque to remove a signal stack here only to add one
+	// in minit, but it's a simple change that keeps NetBSD
+	// working like other OS's. At this point all signals are
+	// blocked, so there is no race.
+	memset(&ss, 0, sizeof ss);
+	ss.ss_flags = SS_DISABLE;
+	sigaltstack(&ss, nil);
+
+	crosscall1(ts.fn, setg_gcc, (void*)ts.g);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_openbsd_386.c b/src/runtime/cgo/gcc_openbsd_386.c
new file mode 100644
index 0000000..127a1b6
--- /dev/null
+++ b/src/runtime/cgo/gcc_openbsd_386.c
@@ -0,0 +1,70 @@
+// Copyright 2009 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.
+
+#include <sys/types.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	/*
+	 * Set specific keys.
+	 */
+	setg_gcc((void*)ts.g);
+
+	crosscall_386(ts.fn);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_openbsd_amd64.c b/src/runtime/cgo/gcc_openbsd_amd64.c
new file mode 100644
index 0000000..34319fb
--- /dev/null
+++ b/src/runtime/cgo/gcc_openbsd_amd64.c
@@ -0,0 +1,70 @@
+// Copyright 2009 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.
+
+#include <sys/types.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	/*
+	 * Set specific keys.
+	 */
+	setg_gcc((void*)ts.g);
+
+	crosscall_amd64(ts.fn);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_openbsd_arm.c b/src/runtime/cgo/gcc_openbsd_arm.c
new file mode 100644
index 0000000..9a5757f
--- /dev/null
+++ b/src/runtime/cgo/gcc_openbsd_arm.c
@@ -0,0 +1,67 @@
+// Copyright 2018 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.
+
+#include <sys/types.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+extern void crosscall_arm1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	crosscall_arm1(ts.fn, setg_gcc, (void*)ts.g);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_openbsd_arm64.c b/src/runtime/cgo/gcc_openbsd_arm64.c
new file mode 100644
index 0000000..abf9f66
--- /dev/null
+++ b/src/runtime/cgo/gcc_openbsd_arm64.c
@@ -0,0 +1,67 @@
+// 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.
+
+#include <sys/types.h>
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	crosscall1(ts.fn, setg_gcc, (void*)ts.g);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_ppc64x.c b/src/runtime/cgo/gcc_ppc64x.c
new file mode 100644
index 0000000..9cb6e0c
--- /dev/null
+++ b/src/runtime/cgo/gcc_ppc64x.c
@@ -0,0 +1,71 @@
+// Copyright 2014 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.
+
+// +build ppc64 ppc64le
+
+#include <pthread.h>
+#include <string.h>
+#include <signal.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void *threadentry(void*);
+
+void (*x_cgo_inittls)(void **tlsg, void **tlsbase);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*), void **tlsbase)
+{
+	pthread_attr_t attr;
+	size_t size;
+
+	setg_gcc = setg;
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	g->stacklo = (uintptr)&attr - size + 4096;
+	pthread_attr_destroy(&attr);
+}
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
+	ts->g->stackhi = size;
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fatalf("pthread_create failed: %s", strerror(err));
+	}
+}
+
+extern void crosscall_ppc64(void (*fn)(void), void *g);
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	// Save g for this thread in C TLS
+	setg_gcc((void*)ts.g);
+
+	crosscall_ppc64(ts.fn, (void*)ts.g);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_riscv64.S b/src/runtime/cgo/gcc_riscv64.S
new file mode 100644
index 0000000..f429dc6
--- /dev/null
+++ b/src/runtime/cgo/gcc_riscv64.S
@@ -0,0 +1,80 @@
+// Copyright 2020 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.
+
+/*
+ * void crosscall1(void (*fn)(void), void (*setg_gcc)(void *g), void *g)
+ *
+ * Calling into the gc tool chain, where all registers are caller save.
+ * Called from standard RISCV ELF psABI, where x8-x9, x18-x27, f8-f9 and
+ * f18-f27 are callee-save, so they must be saved explicitly, along with
+ * x1 (LR).
+ */
+.globl crosscall1
+crosscall1:
+	sd	x1, -200(sp)
+	addi	sp, sp, -200
+	sd	x8, 8(sp)
+	sd	x9, 16(sp)
+	sd	x18, 24(sp)
+	sd	x19, 32(sp)
+	sd	x20, 40(sp)
+	sd	x21, 48(sp)
+	sd	x22, 56(sp)
+	sd	x23, 64(sp)
+	sd	x24, 72(sp)
+	sd	x25, 80(sp)
+	sd	x26, 88(sp)
+	sd	x27, 96(sp)
+	fsd	f8, 104(sp)
+	fsd	f9, 112(sp)
+	fsd	f18, 120(sp)
+	fsd	f19, 128(sp)
+	fsd	f20, 136(sp)
+	fsd	f21, 144(sp)
+	fsd	f22, 152(sp)
+	fsd	f23, 160(sp)
+	fsd	f24, 168(sp)
+	fsd	f25, 176(sp)
+	fsd	f26, 184(sp)
+	fsd	f27, 192(sp)
+
+	// a0 = *fn, a1 = *setg_gcc, a2 = *g
+	mv	s1, a0
+	mv	s0, a1
+	mv	a0, a2
+	jalr	ra, s0	// call setg_gcc (clobbers x30 aka g)
+	jalr	ra, s1	// call fn
+
+	ld	x1, 0(sp)
+	ld	x8, 8(sp)
+	ld	x9, 16(sp)
+	ld	x18, 24(sp)
+	ld	x19, 32(sp)
+	ld	x20, 40(sp)
+	ld	x21, 48(sp)
+	ld	x22, 56(sp)
+	ld	x23, 64(sp)
+	ld	x24, 72(sp)
+	ld	x25, 80(sp)
+	ld	x26, 88(sp)
+	ld	x27, 96(sp)
+	fld	f8, 104(sp)
+	fld	f9, 112(sp)
+	fld	f18, 120(sp)
+	fld	f19, 128(sp)
+	fld	f20, 136(sp)
+	fld	f21, 144(sp)
+	fld	f22, 152(sp)
+	fld	f23, 160(sp)
+	fld	f24, 168(sp)
+	fld	f25, 176(sp)
+	fld	f26, 184(sp)
+	fld	f27, 192(sp)
+	addi	sp, sp, 200
+
+	jr	ra
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",%progbits
+#endif
diff --git a/src/runtime/cgo/gcc_s390x.S b/src/runtime/cgo/gcc_s390x.S
new file mode 100644
index 0000000..614de4b
--- /dev/null
+++ b/src/runtime/cgo/gcc_s390x.S
@@ -0,0 +1,56 @@
+// Copyright 2016 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.
+
+/*
+ * void crosscall_s390x(void (*fn)(void), void *g)
+ *
+ * Calling into the go tool chain, where all registers are caller save.
+ * Called from standard s390x C ABI, where r6-r13, r15, and f8-f15 are
+ * callee-save, so they must be saved explicitly.
+ */
+.globl crosscall_s390x
+crosscall_s390x:
+	/* save r6-r15 in the register save area of the calling function */
+	stmg    %r6, %r15, 48(%r15)
+
+	/* allocate 64 bytes of stack space to save f8-f15 */
+	lay     %r15, -64(%r15)
+
+	/* save callee-saved floating point registers */
+	std     %f8, 0(%r15)
+	std     %f9, 8(%r15)
+	std     %f10, 16(%r15)
+	std     %f11, 24(%r15)
+	std     %f12, 32(%r15)
+	std     %f13, 40(%r15)
+	std     %f14, 48(%r15)
+	std     %f15, 56(%r15)
+
+	/* restore g pointer */
+	lgr     %r13, %r3
+
+	/* call fn */
+	basr    %r14, %r2
+
+	/* restore floating point registers */
+	ld      %f8, 0(%r15)
+	ld      %f9, 8(%r15)
+	ld      %f10, 16(%r15)
+	ld      %f11, 24(%r15)
+	ld      %f12, 32(%r15)
+	ld      %f13, 40(%r15)
+	ld      %f14, 48(%r15)
+	ld      %f15, 56(%r15)
+
+	/* de-allocate stack frame */
+	la      %r15, 64(%r15)
+
+	/* restore general purpose registers */
+	lmg     %r6, %r15, 48(%r15)
+
+	br      %r14 /* restored by lmg */
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",%progbits
+#endif
diff --git a/src/runtime/cgo/gcc_setenv.c b/src/runtime/cgo/gcc_setenv.c
new file mode 100644
index 0000000..d4f7983
--- /dev/null
+++ b/src/runtime/cgo/gcc_setenv.c
@@ -0,0 +1,28 @@
+// Copyright 2011 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.
+
+// +build cgo
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
+#include "libcgo.h"
+
+#include <stdlib.h>
+
+/* Stub for calling setenv */
+void
+x_cgo_setenv(char **arg)
+{
+	_cgo_tsan_acquire();
+	setenv(arg[0], arg[1], 1);
+	_cgo_tsan_release();
+}
+
+/* Stub for calling unsetenv */
+void
+x_cgo_unsetenv(char **arg)
+{
+	_cgo_tsan_acquire();
+	unsetenv(arg[0]);
+	_cgo_tsan_release();
+}
diff --git a/src/runtime/cgo/gcc_sigaction.c b/src/runtime/cgo/gcc_sigaction.c
new file mode 100644
index 0000000..e510e35
--- /dev/null
+++ b/src/runtime/cgo/gcc_sigaction.c
@@ -0,0 +1,82 @@
+// Copyright 2016 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.
+
+// +build linux,amd64 linux,arm64
+
+#include <errno.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include <signal.h>
+
+#include "libcgo.h"
+
+// go_sigaction_t is a C version of the sigactiont struct from
+// defs_linux_amd64.go.  This definition — and its conversion to and from struct
+// sigaction — are specific to linux/amd64.
+typedef struct {
+	uintptr_t handler;
+	uint64_t flags;
+	uintptr_t restorer;
+	uint64_t mask;
+} go_sigaction_t;
+
+// SA_RESTORER is part of the kernel interface.
+// This is GNU/Linux i386/amd64 specific.
+#ifndef SA_RESTORER
+#define SA_RESTORER 0x4000000
+#endif
+
+int32_t
+x_cgo_sigaction(intptr_t signum, const go_sigaction_t *goact, go_sigaction_t *oldgoact) {
+	int32_t ret;
+	struct sigaction act;
+	struct sigaction oldact;
+	size_t i;
+
+	_cgo_tsan_acquire();
+
+	memset(&act, 0, sizeof act);
+	memset(&oldact, 0, sizeof oldact);
+
+	if (goact) {
+		if (goact->flags & SA_SIGINFO) {
+			act.sa_sigaction = (void(*)(int, siginfo_t*, void*))(goact->handler);
+		} else {
+			act.sa_handler = (void(*)(int))(goact->handler);
+		}
+		sigemptyset(&act.sa_mask);
+		for (i = 0; i < 8 * sizeof(goact->mask); i++) {
+			if (goact->mask & ((uint64_t)(1)<<i)) {
+				sigaddset(&act.sa_mask, i+1);
+			}
+		}
+		act.sa_flags = goact->flags & ~SA_RESTORER;
+	}
+
+	ret = sigaction(signum, goact ? &act : NULL, oldgoact ? &oldact : NULL);
+	if (ret == -1) {
+		// runtime.rt_sigaction expects _cgo_sigaction to return errno on error.
+		_cgo_tsan_release();
+		return errno;
+	}
+
+	if (oldgoact) {
+		if (oldact.sa_flags & SA_SIGINFO) {
+			oldgoact->handler = (uintptr_t)(oldact.sa_sigaction);
+		} else {
+			oldgoact->handler = (uintptr_t)(oldact.sa_handler);
+		}
+		oldgoact->mask = 0;
+		for (i = 0; i < 8 * sizeof(oldgoact->mask); i++) {
+			if (sigismember(&oldact.sa_mask, i+1) == 1) {
+				oldgoact->mask |= (uint64_t)(1)<<i;
+			}
+		}
+		oldgoact->flags = oldact.sa_flags;
+	}
+
+	_cgo_tsan_release();
+	return ret;
+}
diff --git a/src/runtime/cgo/gcc_signal2_ios_arm64.c b/src/runtime/cgo/gcc_signal2_ios_arm64.c
new file mode 100644
index 0000000..5b8a18f
--- /dev/null
+++ b/src/runtime/cgo/gcc_signal2_ios_arm64.c
@@ -0,0 +1,11 @@
+// Copyright 2017 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.
+
+// +build lldb
+
+// Used by gcc_signal_darwin_arm64.c when doing the test build during cgo.
+// We hope that for real binaries the definition provided by Go will take precedence
+// and the linker will drop this .o file altogether, which is why this definition
+// is all by itself in its own file.
+void __attribute__((weak)) xx_cgo_panicmem(void) {}
diff --git a/src/runtime/cgo/gcc_signal_ios_arm64.c b/src/runtime/cgo/gcc_signal_ios_arm64.c
new file mode 100644
index 0000000..6519edd
--- /dev/null
+++ b/src/runtime/cgo/gcc_signal_ios_arm64.c
@@ -0,0 +1,213 @@
+// 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.
+
+// Emulation of the Unix signal SIGSEGV.
+//
+// On iOS, Go tests and apps under development are run by lldb.
+// The debugger uses a task-level exception handler to intercept signals.
+// Despite having a 'handle' mechanism like gdb, lldb will not allow a
+// SIGSEGV to pass to the running program. For Go, this means we cannot
+// generate a panic, which cannot be recovered, and so tests fail.
+//
+// We work around this by registering a thread-level mach exception handler
+// and intercepting EXC_BAD_ACCESS. The kernel offers thread handlers a
+// chance to resolve exceptions before the task handler, so we can generate
+// the panic and avoid lldb's SIGSEGV handler.
+//
+// The dist tool enables this by build flag when testing.
+
+// +build lldb
+
+#include <limits.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <mach/arm/thread_status.h>
+#include <mach/exception_types.h>
+#include <mach/mach.h>
+#include <mach/mach_init.h>
+#include <mach/mach_port.h>
+#include <mach/thread_act.h>
+#include <mach/thread_status.h>
+
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+void xx_cgo_panicmem(void);
+uintptr_t x_cgo_panicmem = (uintptr_t)xx_cgo_panicmem;
+
+static pthread_mutex_t mach_exception_handler_port_set_mu;
+static mach_port_t mach_exception_handler_port_set = MACH_PORT_NULL;
+
+kern_return_t
+catch_exception_raise(
+	mach_port_t exception_port,
+	mach_port_t thread,
+	mach_port_t task,
+	exception_type_t exception,
+	exception_data_t code_vector,
+	mach_msg_type_number_t code_count)
+{
+	kern_return_t ret;
+	arm_unified_thread_state_t thread_state;
+	mach_msg_type_number_t state_count = ARM_UNIFIED_THREAD_STATE_COUNT;
+
+	// Returning KERN_SUCCESS intercepts the exception.
+	//
+	// Returning KERN_FAILURE lets the exception fall through to the
+	// next handler, which is the standard signal emulation code
+	// registered on the task port.
+
+	if (exception != EXC_BAD_ACCESS) {
+		return KERN_FAILURE;
+	}
+
+	ret = thread_get_state(thread, ARM_UNIFIED_THREAD_STATE, (thread_state_t)&thread_state, &state_count);
+	if (ret) {
+		fprintf(stderr, "runtime/cgo: thread_get_state failed: %d\n", ret);
+		abort();
+	}
+
+	// Bounce call to sigpanic through asm that makes it look like
+	// we call sigpanic directly from the faulting code.
+#ifdef __arm64__
+	thread_state.ts_64.__x[1] = thread_state.ts_64.__lr;
+	thread_state.ts_64.__x[2] = thread_state.ts_64.__pc;
+	thread_state.ts_64.__pc = x_cgo_panicmem;
+#else
+	thread_state.ts_32.__r[1] = thread_state.ts_32.__lr;
+	thread_state.ts_32.__r[2] = thread_state.ts_32.__pc;
+	thread_state.ts_32.__pc = x_cgo_panicmem;
+#endif
+
+	if (0) {
+		// Useful debugging logic when panicmem is broken.
+		//
+		// Sends the first SIGSEGV and lets lldb catch the
+		// second one, avoiding a loop that locks up iOS
+		// devices requiring a hard reboot.
+		fprintf(stderr, "runtime/cgo: caught exc_bad_access\n");
+		fprintf(stderr, "__lr = %llx\n", thread_state.ts_64.__lr);
+		fprintf(stderr, "__pc = %llx\n", thread_state.ts_64.__pc);
+		static int pass1 = 0;
+		if (pass1) {
+			return KERN_FAILURE;
+		}
+		pass1 = 1;
+	}
+
+	ret = thread_set_state(thread, ARM_UNIFIED_THREAD_STATE, (thread_state_t)&thread_state, state_count);
+	if (ret) {
+		fprintf(stderr, "runtime/cgo: thread_set_state failed: %d\n", ret);
+		abort();
+	}
+
+	return KERN_SUCCESS;
+}
+
+void
+darwin_arm_init_thread_exception_port()
+{
+	// Called by each new OS thread to bind its EXC_BAD_ACCESS exception
+	// to mach_exception_handler_port_set.
+	int ret;
+	mach_port_t port = MACH_PORT_NULL;
+
+	ret = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &port);
+	if (ret) {
+		fprintf(stderr, "runtime/cgo: mach_port_allocate failed: %d\n", ret);
+		abort();
+	}
+	ret = mach_port_insert_right(
+		mach_task_self(),
+		port,
+		port,
+		MACH_MSG_TYPE_MAKE_SEND);
+	if (ret) {
+		fprintf(stderr, "runtime/cgo: mach_port_insert_right failed: %d\n", ret);
+		abort();
+	}
+
+	ret = thread_set_exception_ports(
+		mach_thread_self(),
+		EXC_MASK_BAD_ACCESS,
+		port,
+		EXCEPTION_DEFAULT,
+		THREAD_STATE_NONE);
+	if (ret) {
+		fprintf(stderr, "runtime/cgo: thread_set_exception_ports failed: %d\n", ret);
+		abort();
+	}
+
+	ret = pthread_mutex_lock(&mach_exception_handler_port_set_mu);
+	if (ret) {
+		fprintf(stderr, "runtime/cgo: pthread_mutex_lock failed: %d\n", ret);
+		abort();
+	}
+	ret = mach_port_move_member(
+		mach_task_self(),
+		port,
+		mach_exception_handler_port_set);
+	if (ret) {
+		fprintf(stderr, "runtime/cgo: mach_port_move_member failed: %d\n", ret);
+		abort();
+	}
+	ret = pthread_mutex_unlock(&mach_exception_handler_port_set_mu);
+	if (ret) {
+		fprintf(stderr, "runtime/cgo: pthread_mutex_unlock failed: %d\n", ret);
+		abort();
+	}
+}
+
+static void*
+mach_exception_handler(void *port)
+{
+	// Calls catch_exception_raise.
+	extern boolean_t exc_server();
+	mach_msg_server(exc_server, 2048, (mach_port_t)port, 0);
+	abort(); // never returns
+}
+
+void
+darwin_arm_init_mach_exception_handler()
+{
+	pthread_mutex_init(&mach_exception_handler_port_set_mu, NULL);
+
+	// Called once per process to initialize a mach port server, listening
+	// for EXC_BAD_ACCESS thread exceptions.
+	int ret;
+	pthread_t thr = NULL;
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+
+	ret = mach_port_allocate(
+		mach_task_self(),
+		MACH_PORT_RIGHT_PORT_SET,
+		&mach_exception_handler_port_set);
+	if (ret) {
+		fprintf(stderr, "runtime/cgo: mach_port_allocate failed for port_set: %d\n", ret);
+		abort();
+	}
+
+	// Block all signals to the exception handler thread
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	// Start a thread to handle exceptions.
+	uintptr_t port_set = (uintptr_t)mach_exception_handler_port_set;
+	pthread_attr_init(&attr);
+	pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+	ret = _cgo_try_pthread_create(&thr, &attr, mach_exception_handler, (void*)port_set);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (ret) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %d\n", ret);
+		abort();
+	}
+	pthread_attr_destroy(&attr);
+}
diff --git a/src/runtime/cgo/gcc_signal_ios_nolldb.c b/src/runtime/cgo/gcc_signal_ios_nolldb.c
new file mode 100644
index 0000000..cfa4025
--- /dev/null
+++ b/src/runtime/cgo/gcc_signal_ios_nolldb.c
@@ -0,0 +1,12 @@
+// 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.
+
+// +build !lldb
+// +build ios
+// +build arm64
+
+#include <stdint.h>
+
+void darwin_arm_init_thread_exception_port() {}
+void darwin_arm_init_mach_exception_handler() {}
diff --git a/src/runtime/cgo/gcc_solaris_amd64.c b/src/runtime/cgo/gcc_solaris_amd64.c
new file mode 100644
index 0000000..079bd12
--- /dev/null
+++ b/src/runtime/cgo/gcc_solaris_amd64.c
@@ -0,0 +1,82 @@
+// 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.
+
+#include <pthread.h>
+#include <string.h>
+#include <signal.h>
+#include <ucontext.h>
+#include "libcgo.h"
+#include "libcgo_unix.h"
+
+static void* threadentry(void*);
+static void (*setg_gcc)(void*);
+
+void
+x_cgo_init(G *g, void (*setg)(void*))
+{
+	ucontext_t ctx;
+
+	setg_gcc = setg;
+	if (getcontext(&ctx) != 0)
+		perror("runtime/cgo: getcontext failed");
+	g->stacklo = (uintptr_t)ctx.uc_stack.ss_sp;
+
+	// Solaris processes report a tiny stack when run with "ulimit -s unlimited".
+	// Correct that as best we can: assume it's at least 1 MB.
+	// See golang.org/issue/12210.
+	if(ctx.uc_stack.ss_size < 1024*1024)
+		g->stacklo -= 1024*1024 - ctx.uc_stack.ss_size;
+}
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	sigset_t ign, oset;
+	pthread_t p;
+	void *base;
+	size_t size;
+	int err;
+
+	sigfillset(&ign);
+	pthread_sigmask(SIG_SETMASK, &ign, &oset);
+
+	pthread_attr_init(&attr);
+
+	if (pthread_attr_getstack(&attr, &base, &size) != 0)
+		perror("runtime/cgo: pthread_attr_getstack failed");
+	if (size == 0) {
+		ts->g->stackhi = 2 << 20;
+		if (pthread_attr_setstack(&attr, NULL, ts->g->stackhi) != 0)
+			perror("runtime/cgo: pthread_attr_setstack failed");
+	} else {
+		ts->g->stackhi = size;
+	}
+	pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
+
+	pthread_sigmask(SIG_SETMASK, &oset, nil);
+
+	if (err != 0) {
+		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+		abort();
+	}
+}
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	/*
+	 * Set specific keys.
+	 */
+	setg_gcc((void*)ts.g);
+
+	crosscall_amd64(ts.fn);
+	return nil;
+}
diff --git a/src/runtime/cgo/gcc_traceback.c b/src/runtime/cgo/gcc_traceback.c
new file mode 100644
index 0000000..d86331c
--- /dev/null
+++ b/src/runtime/cgo/gcc_traceback.c
@@ -0,0 +1,24 @@
+// Copyright 2016 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.
+
+// +build cgo,darwin cgo,linux
+
+#include <stdint.h>
+#include "libcgo.h"
+
+// Call the user's traceback function and then call sigtramp.
+// The runtime signal handler will jump to this code.
+// We do it this way so that the user's traceback function will be called
+// by a C function with proper unwind info.
+void
+x_cgo_callers(uintptr_t sig, void *info, void *context, void (*cgoTraceback)(struct cgoTracebackArg*), uintptr_t* cgoCallers, void (*sigtramp)(uintptr_t, void*, void*)) {
+	struct cgoTracebackArg arg;
+
+	arg.Context = 0;
+	arg.SigContext = (uintptr_t)(context);
+	arg.Buf = cgoCallers;
+	arg.Max = 32; // must match len(runtime.cgoCallers)
+	(*cgoTraceback)(&arg);
+	sigtramp(sig, info, context);
+}
diff --git a/src/runtime/cgo/gcc_util.c b/src/runtime/cgo/gcc_util.c
new file mode 100644
index 0000000..3fcb48c
--- /dev/null
+++ b/src/runtime/cgo/gcc_util.c
@@ -0,0 +1,69 @@
+// Copyright 2009 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.
+
+#include "libcgo.h"
+
+/* Stub for creating a new thread */
+void
+x_cgo_thread_start(ThreadStart *arg)
+{
+	ThreadStart *ts;
+
+	/* Make our own copy that can persist after we return. */
+	_cgo_tsan_acquire();
+	ts = malloc(sizeof *ts);
+	_cgo_tsan_release();
+	if(ts == nil) {
+		fprintf(stderr, "runtime/cgo: out of memory in thread_start\n");
+		abort();
+	}
+	*ts = *arg;
+
+	_cgo_sys_thread_start(ts);	/* OS-dependent half */
+}
+
+#ifndef CGO_TSAN
+void(* const _cgo_yield)() = NULL;
+#else
+
+#include <string.h>
+
+char x_cgo_yield_strncpy_src = 0;
+char x_cgo_yield_strncpy_dst = 0;
+size_t x_cgo_yield_strncpy_n = 0;
+
+/*
+Stub for allowing libc interceptors to execute.
+
+_cgo_yield is set to NULL if we do not expect libc interceptors to exist.
+*/
+static void
+x_cgo_yield()
+{
+	/*
+	The libc function(s) we call here must form a no-op and include at least one
+	call that triggers TSAN to process pending asynchronous signals.
+
+	sleep(0) would be fine, but it's not portable C (so it would need more header
+	guards).
+	free(NULL) has a fast-path special case in TSAN, so it doesn't
+	trigger signal delivery.
+	free(malloc(0)) would work (triggering the interceptors in malloc), but
+	it also runs a bunch of user-supplied malloc hooks.
+
+	So we choose strncpy(_, _, 0): it requires an extra header,
+	but it's standard and should be very efficient.
+
+	GCC 7 has an unfortunate habit of optimizing out strncpy calls (see
+	https://golang.org/issue/21196), so the arguments here need to be global
+	variables with external linkage in order to ensure that the call traps all the
+	way down into libc.
+	*/
+	strncpy(&x_cgo_yield_strncpy_dst, &x_cgo_yield_strncpy_src,
+	        x_cgo_yield_strncpy_n);
+}
+
+void(* const _cgo_yield)() = &x_cgo_yield;
+
+#endif  /* GO_TSAN */
diff --git a/src/runtime/cgo/gcc_windows_386.c b/src/runtime/cgo/gcc_windows_386.c
new file mode 100644
index 0000000..60cb011
--- /dev/null
+++ b/src/runtime/cgo/gcc_windows_386.c
@@ -0,0 +1,55 @@
+// Copyright 2009 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.
+
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <process.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include "libcgo.h"
+#include "libcgo_windows.h"
+
+static void threadentry(void*);
+
+void
+x_cgo_init(G *g)
+{
+}
+
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	uintptr_t thandle;
+
+	thandle = _beginthread(threadentry, 0, ts);
+	if(thandle == -1) {
+		fprintf(stderr, "runtime: failed to create new OS thread (%d)\n", errno);
+		abort();
+	}
+}
+
+static void
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	// minit queries stack bounds from the OS.
+
+	/*
+	 * Set specific keys in thread local storage.
+	 */
+	asm volatile (
+		"movl %0, %%fs:0x14\n"	// MOVL tls0, 0x14(FS)
+		"movl %%fs:0x14, %%eax\n"	// MOVL 0x14(FS), tmp
+		"movl %1, 0(%%eax)\n"	// MOVL g, 0(FS)
+		:: "r"(ts.tls), "r"(ts.g) : "%eax"
+	);
+	
+	crosscall_386(ts.fn);
+}
diff --git a/src/runtime/cgo/gcc_windows_amd64.c b/src/runtime/cgo/gcc_windows_amd64.c
new file mode 100644
index 0000000..0f8c817
--- /dev/null
+++ b/src/runtime/cgo/gcc_windows_amd64.c
@@ -0,0 +1,55 @@
+// Copyright 2009 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.
+
+#define WIN64_LEAN_AND_MEAN
+#include <windows.h>
+#include <process.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include "libcgo.h"
+#include "libcgo_windows.h"
+
+static void threadentry(void*);
+
+void
+x_cgo_init(G *g)
+{
+}
+
+
+void
+_cgo_sys_thread_start(ThreadStart *ts)
+{
+	uintptr_t thandle;
+
+	thandle = _beginthread(threadentry, 0, ts);
+	if(thandle == -1) {
+		fprintf(stderr, "runtime: failed to create new OS thread (%d)\n", errno);
+		abort();
+	}
+}
+
+static void
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	// minit queries stack bounds from the OS.
+
+	/*
+	 * Set specific keys in thread local storage.
+	 */
+	asm volatile (
+	  "movq %0, %%gs:0x28\n"	// MOVL tls0, 0x28(GS)
+	  "movq %%gs:0x28, %%rax\n" // MOVQ 0x28(GS), tmp
+	  "movq %1, 0(%%rax)\n" // MOVQ g, 0(GS)
+	  :: "r"(ts.tls), "r"(ts.g) : "%rax"
+	);
+
+	crosscall_amd64(ts.fn);
+}
diff --git a/src/runtime/cgo/iscgo.go b/src/runtime/cgo/iscgo.go
new file mode 100644
index 0000000..e12d0f4
--- /dev/null
+++ b/src/runtime/cgo/iscgo.go
@@ -0,0 +1,17 @@
+// Copyright 2010 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.
+
+// The runtime package contains an uninitialized definition
+// for runtime·iscgo. Override it to tell the runtime we're here.
+// There are various function pointers that should be set too,
+// but those depend on dynamic linker magic to get initialized
+// correctly, and sometimes they break. This variable is a
+// backup: it depends only on old C style static linking rules.
+
+package cgo
+
+import _ "unsafe" // for go:linkname
+
+//go:linkname _iscgo runtime.iscgo
+var _iscgo bool = true
diff --git a/src/runtime/cgo/libcgo.h b/src/runtime/cgo/libcgo.h
new file mode 100644
index 0000000..aba500a
--- /dev/null
+++ b/src/runtime/cgo/libcgo.h
@@ -0,0 +1,151 @@
+// Copyright 2009 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.
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#undef nil
+#define nil ((void*)0)
+#define nelem(x) (sizeof(x)/sizeof((x)[0]))
+
+typedef uint32_t uint32;
+typedef uint64_t uint64;
+typedef uintptr_t uintptr;
+
+/*
+ * The beginning of the per-goroutine structure,
+ * as defined in ../pkg/runtime/runtime.h.
+ * Just enough to edit these two fields.
+ */
+typedef struct G G;
+struct G
+{
+	uintptr stacklo;
+	uintptr stackhi;
+};
+
+/*
+ * Arguments to the _cgo_thread_start call.
+ * Also known to ../pkg/runtime/runtime.h.
+ */
+typedef struct ThreadStart ThreadStart;
+struct ThreadStart
+{
+	G *g;
+	uintptr *tls;
+	void (*fn)(void);
+};
+
+/*
+ * Called by 5c/6c/8c world.
+ * Makes a local copy of the ThreadStart and
+ * calls _cgo_sys_thread_start(ts).
+ */
+extern void (*_cgo_thread_start)(ThreadStart *ts);
+
+/*
+ * Creates a new operating system thread without updating any Go state
+ * (OS dependent).
+ */
+extern void (*_cgo_sys_thread_create)(void* (*func)(void*), void* arg);
+
+/*
+ * Creates the new operating system thread (OS, arch dependent).
+ */
+void _cgo_sys_thread_start(ThreadStart *ts);
+
+/*
+ * Waits for the Go runtime to be initialized (OS dependent).
+ * If runtime.SetCgoTraceback is used to set a context function,
+ * calls the context function and returns the context value.
+ */
+uintptr_t _cgo_wait_runtime_init_done(void);
+
+/*
+ * Call fn in the 6c world.
+ */
+void crosscall_amd64(void (*fn)(void));
+
+/*
+ * Call fn in the 8c world.
+ */
+void crosscall_386(void (*fn)(void));
+
+/*
+ * Prints error then calls abort. For linux and android.
+ */
+void fatalf(const char* format, ...);
+
+/*
+ * Registers the current mach thread port for EXC_BAD_ACCESS processing.
+ */
+void darwin_arm_init_thread_exception_port(void);
+
+/*
+ * Starts a mach message server processing EXC_BAD_ACCESS.
+ */
+void darwin_arm_init_mach_exception_handler(void);
+
+/*
+ * The cgo context function. See runtime.SetCgoTraceback.
+ */
+struct context_arg {
+	uintptr_t Context;
+};
+extern void (*(_cgo_get_context_function(void)))(struct context_arg*);
+
+/*
+ * The argument for the cgo traceback callback. See runtime.SetCgoTraceback.
+ */
+struct cgoTracebackArg {
+	uintptr_t  Context;
+	uintptr_t  SigContext;
+	uintptr_t* Buf;
+	uintptr_t  Max;
+};
+
+/*
+ * TSAN support.  This is only useful when building with
+ *   CGO_CFLAGS="-fsanitize=thread" CGO_LDFLAGS="-fsanitize=thread" go install
+ */
+#undef CGO_TSAN
+#if defined(__has_feature)
+# if __has_feature(thread_sanitizer)
+#  define CGO_TSAN
+# endif
+#elif defined(__SANITIZE_THREAD__)
+# define CGO_TSAN
+#endif
+
+#ifdef CGO_TSAN
+
+// These must match the definitions in yesTsanProlog in cmd/cgo/out.go.
+// In general we should call _cgo_tsan_acquire when we enter C code,
+// and call _cgo_tsan_release when we return to Go code.
+// This is only necessary when calling code that might be instrumented
+// by TSAN, which mostly means system library calls that TSAN intercepts.
+// See the comment in cmd/cgo/out.go for more details.
+
+long long _cgo_sync __attribute__ ((common));
+
+extern void __tsan_acquire(void*);
+extern void __tsan_release(void*);
+
+__attribute__ ((unused))
+static void _cgo_tsan_acquire() {
+	__tsan_acquire(&_cgo_sync);
+}
+
+__attribute__ ((unused))
+static void _cgo_tsan_release() {
+	__tsan_release(&_cgo_sync);
+}
+
+#else // !defined(CGO_TSAN)
+
+#define _cgo_tsan_acquire()
+#define _cgo_tsan_release()
+
+#endif // !defined(CGO_TSAN)
diff --git a/src/runtime/cgo/libcgo_unix.h b/src/runtime/cgo/libcgo_unix.h
new file mode 100644
index 0000000..a56a366
--- /dev/null
+++ b/src/runtime/cgo/libcgo_unix.h
@@ -0,0 +1,15 @@
+// Copyright 2016 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.
+
+/*
+ * Call pthread_create, retrying on EAGAIN.
+ */
+extern int _cgo_try_pthread_create(pthread_t*, const pthread_attr_t*, void* (*)(void*), void*);
+
+/*
+ * Same as _cgo_try_pthread_create, but passing on the pthread_create function.
+ * Only defined on OpenBSD.
+ */
+extern int _cgo_openbsd_try_pthread_create(int (*)(pthread_t*, const pthread_attr_t*, void *(*pfn)(void*), void*),
+	pthread_t*, const pthread_attr_t*, void* (*)(void*), void* arg);
diff --git a/src/runtime/cgo/libcgo_windows.h b/src/runtime/cgo/libcgo_windows.h
new file mode 100644
index 0000000..0013f06
--- /dev/null
+++ b/src/runtime/cgo/libcgo_windows.h
@@ -0,0 +1,12 @@
+// Copyright 2020 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.
+
+// Ensure there's one symbol marked __declspec(dllexport).
+// If there are no exported symbols, the unfortunate behavior of
+// the binutils linker is to also strip the relocations table,
+// resulting in non-PIE binary. The other option is the
+// --export-all-symbols flag, but we don't need to export all symbols
+// and this may overflow the export table (#40795).
+// See https://sourceware.org/bugzilla/show_bug.cgi?id=19011
+__declspec(dllexport) int _cgo_dummy_export;
diff --git a/src/runtime/cgo/linux.go b/src/runtime/cgo/linux.go
new file mode 100644
index 0000000..76c0192
--- /dev/null
+++ b/src/runtime/cgo/linux.go
@@ -0,0 +1,74 @@
+// 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.
+
+// Linux system call wrappers that provide POSIX semantics through the
+// corresponding cgo->libc (nptl) wrappers for various system calls.
+
+// +build linux
+
+package cgo
+
+import "unsafe"
+
+// Each of the following entries is needed to ensure that the
+// syscall.syscall_linux code can conditionally call these
+// function pointers:
+//
+//  1. find the C-defined function start
+//  2. force the local byte alias to be mapped to that location
+//  3. map the Go pointer to the function to the syscall package
+
+//go:cgo_import_static _cgo_libc_setegid
+//go:linkname _cgo_libc_setegid _cgo_libc_setegid
+//go:linkname cgo_libc_setegid syscall.cgo_libc_setegid
+var _cgo_libc_setegid byte
+var cgo_libc_setegid = unsafe.Pointer(&_cgo_libc_setegid)
+
+//go:cgo_import_static _cgo_libc_seteuid
+//go:linkname _cgo_libc_seteuid _cgo_libc_seteuid
+//go:linkname cgo_libc_seteuid syscall.cgo_libc_seteuid
+var _cgo_libc_seteuid byte
+var cgo_libc_seteuid = unsafe.Pointer(&_cgo_libc_seteuid)
+
+//go:cgo_import_static _cgo_libc_setregid
+//go:linkname _cgo_libc_setregid _cgo_libc_setregid
+//go:linkname cgo_libc_setregid syscall.cgo_libc_setregid
+var _cgo_libc_setregid byte
+var cgo_libc_setregid = unsafe.Pointer(&_cgo_libc_setregid)
+
+//go:cgo_import_static _cgo_libc_setresgid
+//go:linkname _cgo_libc_setresgid _cgo_libc_setresgid
+//go:linkname cgo_libc_setresgid syscall.cgo_libc_setresgid
+var _cgo_libc_setresgid byte
+var cgo_libc_setresgid = unsafe.Pointer(&_cgo_libc_setresgid)
+
+//go:cgo_import_static _cgo_libc_setresuid
+//go:linkname _cgo_libc_setresuid _cgo_libc_setresuid
+//go:linkname cgo_libc_setresuid syscall.cgo_libc_setresuid
+var _cgo_libc_setresuid byte
+var cgo_libc_setresuid = unsafe.Pointer(&_cgo_libc_setresuid)
+
+//go:cgo_import_static _cgo_libc_setreuid
+//go:linkname _cgo_libc_setreuid _cgo_libc_setreuid
+//go:linkname cgo_libc_setreuid syscall.cgo_libc_setreuid
+var _cgo_libc_setreuid byte
+var cgo_libc_setreuid = unsafe.Pointer(&_cgo_libc_setreuid)
+
+//go:cgo_import_static _cgo_libc_setgroups
+//go:linkname _cgo_libc_setgroups _cgo_libc_setgroups
+//go:linkname cgo_libc_setgroups syscall.cgo_libc_setgroups
+var _cgo_libc_setgroups byte
+var cgo_libc_setgroups = unsafe.Pointer(&_cgo_libc_setgroups)
+
+//go:cgo_import_static _cgo_libc_setgid
+//go:linkname _cgo_libc_setgid _cgo_libc_setgid
+//go:linkname cgo_libc_setgid syscall.cgo_libc_setgid
+var _cgo_libc_setgid byte
+var cgo_libc_setgid = unsafe.Pointer(&_cgo_libc_setgid)
+
+//go:cgo_import_static _cgo_libc_setuid
+//go:linkname _cgo_libc_setuid _cgo_libc_setuid
+//go:linkname cgo_libc_setuid syscall.cgo_libc_setuid
+var _cgo_libc_setuid byte
+var cgo_libc_setuid = unsafe.Pointer(&_cgo_libc_setuid)
diff --git a/src/runtime/cgo/linux_syscall.c b/src/runtime/cgo/linux_syscall.c
new file mode 100644
index 0000000..59761c8
--- /dev/null
+++ b/src/runtime/cgo/linux_syscall.c
@@ -0,0 +1,85 @@
+// 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.
+
+// +build linux
+
+#ifndef _GNU_SOURCE // setres[ug]id() API.
+#define _GNU_SOURCE
+#endif
+
+#include <grp.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <errno.h>
+#include "libcgo.h"
+
+/*
+ * Assumed POSIX compliant libc system call wrappers. For linux, the
+ * glibc/nptl/setxid mechanism ensures that POSIX semantics are
+ * honored for all pthreads (by default), and this in turn with cgo
+ * ensures that all Go threads launched with cgo are kept in sync for
+ * these function calls.
+ */
+
+// argset_t matches runtime/cgocall.go:argset.
+typedef struct {
+	uintptr_t* args;
+	uintptr_t retval;
+} argset_t;
+
+// libc backed posix-compliant syscalls.
+
+#define SET_RETVAL(fn) \
+  uintptr_t ret = (uintptr_t) fn ; \
+  if (ret == (uintptr_t) -1) {	   \
+    x->retval = (uintptr_t) errno; \
+  } else                           \
+    x->retval = ret
+
+void
+_cgo_libc_setegid(argset_t* x) {
+	SET_RETVAL(setegid((gid_t) x->args[0]));
+}
+
+void
+_cgo_libc_seteuid(argset_t* x) {
+	SET_RETVAL(seteuid((uid_t) x->args[0]));
+}
+
+void
+_cgo_libc_setgid(argset_t* x) {
+	SET_RETVAL(setgid((gid_t) x->args[0]));
+}
+
+void
+_cgo_libc_setgroups(argset_t* x) {
+	SET_RETVAL(setgroups((size_t) x->args[0], (const gid_t *) x->args[1]));
+}
+
+void
+_cgo_libc_setregid(argset_t* x) {
+	SET_RETVAL(setregid((gid_t) x->args[0], (gid_t) x->args[1]));
+}
+
+void
+_cgo_libc_setresgid(argset_t* x) {
+	SET_RETVAL(setresgid((gid_t) x->args[0], (gid_t) x->args[1],
+			     (gid_t) x->args[2]));
+}
+
+void
+_cgo_libc_setresuid(argset_t* x) {
+	SET_RETVAL(setresuid((uid_t) x->args[0], (uid_t) x->args[1],
+			     (uid_t) x->args[2]));
+}
+
+void
+_cgo_libc_setreuid(argset_t* x) {
+	SET_RETVAL(setreuid((uid_t) x->args[0], (uid_t) x->args[1]));
+}
+
+void
+_cgo_libc_setuid(argset_t* x) {
+	SET_RETVAL(setuid((uid_t) x->args[0]));
+}
diff --git a/src/runtime/cgo/mmap.go b/src/runtime/cgo/mmap.go
new file mode 100644
index 0000000..00fb7fc
--- /dev/null
+++ b/src/runtime/cgo/mmap.go
@@ -0,0 +1,31 @@
+// 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.
+
+// +build linux,amd64 linux,arm64
+
+package cgo
+
+// Import "unsafe" because we use go:linkname.
+import _ "unsafe"
+
+// When using cgo, call the C library for mmap, so that we call into
+// any sanitizer interceptors. This supports using the memory
+// sanitizer with Go programs. The memory sanitizer only applies to
+// C/C++ code; this permits that code to see the Go code as normal
+// program addresses that have been initialized.
+
+// To support interceptors that look for both mmap and munmap,
+// also call the C library for munmap.
+
+//go:cgo_import_static x_cgo_mmap
+//go:linkname x_cgo_mmap x_cgo_mmap
+//go:linkname _cgo_mmap _cgo_mmap
+var x_cgo_mmap byte
+var _cgo_mmap = &x_cgo_mmap
+
+//go:cgo_import_static x_cgo_munmap
+//go:linkname x_cgo_munmap x_cgo_munmap
+//go:linkname _cgo_munmap _cgo_munmap
+var x_cgo_munmap byte
+var _cgo_munmap = &x_cgo_munmap
diff --git a/src/runtime/cgo/netbsd.go b/src/runtime/cgo/netbsd.go
new file mode 100644
index 0000000..74d0aed
--- /dev/null
+++ b/src/runtime/cgo/netbsd.go
@@ -0,0 +1,21 @@
+// Copyright 2010 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.
+
+// +build netbsd
+
+package cgo
+
+import _ "unsafe" // for go:linkname
+
+// Supply environ and __progname, because we don't
+// link against the standard NetBSD crt0.o and the
+// libc dynamic library needs them.
+
+//go:linkname _environ environ
+//go:linkname _progname __progname
+//go:linkname ___ps_strings __ps_strings
+
+var _environ uintptr
+var _progname uintptr
+var ___ps_strings uintptr
diff --git a/src/runtime/cgo/openbsd.go b/src/runtime/cgo/openbsd.go
new file mode 100644
index 0000000..81c73bf
--- /dev/null
+++ b/src/runtime/cgo/openbsd.go
@@ -0,0 +1,20 @@
+// Copyright 2010 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.
+
+// +build openbsd
+
+package cgo
+
+import _ "unsafe" // for go:linkname
+
+// Supply __guard_local because we don't link against the standard
+// OpenBSD crt0.o and the libc dynamic library needs it.
+
+//go:linkname _guard_local __guard_local
+
+var _guard_local uintptr
+
+// This is normally marked as hidden and placed in the
+// .openbsd.randomdata section.
+//go:cgo_export_dynamic __guard_local __guard_local
diff --git a/src/runtime/cgo/setenv.go b/src/runtime/cgo/setenv.go
new file mode 100644
index 0000000..6495fcb
--- /dev/null
+++ b/src/runtime/cgo/setenv.go
@@ -0,0 +1,21 @@
+// Copyright 2011 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.
+
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package cgo
+
+import _ "unsafe" // for go:linkname
+
+//go:cgo_import_static x_cgo_setenv
+//go:linkname x_cgo_setenv x_cgo_setenv
+//go:linkname _cgo_setenv runtime._cgo_setenv
+var x_cgo_setenv byte
+var _cgo_setenv = &x_cgo_setenv
+
+//go:cgo_import_static x_cgo_unsetenv
+//go:linkname x_cgo_unsetenv x_cgo_unsetenv
+//go:linkname _cgo_unsetenv runtime._cgo_unsetenv
+var x_cgo_unsetenv byte
+var _cgo_unsetenv = &x_cgo_unsetenv
diff --git a/src/runtime/cgo/sigaction.go b/src/runtime/cgo/sigaction.go
new file mode 100644
index 0000000..076fbc1
--- /dev/null
+++ b/src/runtime/cgo/sigaction.go
@@ -0,0 +1,22 @@
+// Copyright 2016 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.
+
+// +build linux,amd64 freebsd,amd64 linux,arm64
+
+package cgo
+
+// Import "unsafe" because we use go:linkname.
+import _ "unsafe"
+
+// When using cgo, call the C library for sigaction, so that we call into
+// any sanitizer interceptors. This supports using the memory
+// sanitizer with Go programs. The memory sanitizer only applies to
+// C/C++ code; this permits that code to see the Go runtime's existing signal
+// handlers when registering new signal handlers for the process.
+
+//go:cgo_import_static x_cgo_sigaction
+//go:linkname x_cgo_sigaction x_cgo_sigaction
+//go:linkname _cgo_sigaction _cgo_sigaction
+var x_cgo_sigaction byte
+var _cgo_sigaction = &x_cgo_sigaction
diff --git a/src/runtime/cgo/signal_ios_arm64.go b/src/runtime/cgo/signal_ios_arm64.go
new file mode 100644
index 0000000..3425c44
--- /dev/null
+++ b/src/runtime/cgo/signal_ios_arm64.go
@@ -0,0 +1,10 @@
+// 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 cgo
+
+import _ "unsafe"
+
+//go:cgo_export_static xx_cgo_panicmem xx_cgo_panicmem
+func xx_cgo_panicmem()
diff --git a/src/runtime/cgo/signal_ios_arm64.s b/src/runtime/cgo/signal_ios_arm64.s
new file mode 100644
index 0000000..1ae00d1
--- /dev/null
+++ b/src/runtime/cgo/signal_ios_arm64.s
@@ -0,0 +1,56 @@
+// 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.
+
+#include "textflag.h"
+
+// xx_cgo_panicmem is the entrypoint for SIGSEGV as intercepted via a
+// mach thread port as EXC_BAD_ACCESS. As the segfault may have happened
+// in C code, we first need to load_g then call xx_cgo_panicmem.
+//
+//	R1 - LR at moment of fault
+//	R2 - PC at moment of fault
+TEXT xx_cgo_panicmem(SB),NOSPLIT|NOFRAME,$0
+	// If in external C code, we need to load the g register.
+	BL  runtime·load_g(SB)
+	CMP $0, g
+	BNE ongothread
+
+	// On a foreign thread.
+	// TODO(crawshaw): call badsignal
+	MOVD.W $0, -16(RSP)
+	MOVW $139, R1
+	MOVW R1, 8(RSP)
+	B    runtime·exit(SB)
+
+ongothread:
+	// Trigger a SIGSEGV panic.
+	//
+	// The goal is to arrange the stack so it looks like the runtime
+	// function sigpanic was called from the PC that faulted. It has
+	// to be sigpanic, as the stack unwinding code in traceback.go
+	// looks explicitly for it.
+	//
+	// To do this we call into runtime·setsigsegv, which sets the
+	// appropriate state inside the g object. We give it the faulting
+	// PC on the stack, then put it in the LR before calling sigpanic.
+
+	// Build a 32-byte stack frame for us for this call.
+	// Saved LR (none available) is at the bottom,
+	// then the PC argument for setsigsegv,
+	// then a copy of the LR for us to restore.
+	MOVD.W $0, -32(RSP)
+	MOVD R1, 8(RSP)
+	MOVD R2, 16(RSP)
+	BL runtime·setsigsegv(SB)
+	MOVD 8(RSP), R1
+	MOVD 16(RSP), R2
+
+	// Build a 16-byte stack frame for the simulated
+	// call to sigpanic, by taking 16 bytes away from the
+	// 32-byte stack frame above.
+	// The saved LR in this frame is the LR at time of fault,
+	// and the LR on entry to sigpanic is the PC at time of fault.
+	MOVD.W R1, 16(RSP)
+	MOVD R2, R30
+	B runtime·sigpanic(SB)