1 files changed, 787 insertions, 0 deletions
diff --git a/src/runtime/sys_linux_arm64.s b/src/runtime/sys_linux_arm64.s
new file mode 100644
index 0000000..51c87be
--- /dev/null
+++ b/src/runtime/sys_linux_arm64.s
@@ -0,0 +1,787 @@
+// 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.
+
+//
+// System calls and other sys.stuff for arm64, Linux
+//
+
+#include "go_asm.h"
+#include "go_tls.h"
+#include "textflag.h"
+#include "cgo/abi_arm64.h"
+
+#define AT_FDCWD -100
+
+#define CLOCK_REALTIME 0
+#define CLOCK_MONOTONIC 1
+
+#define SYS_exit		93
+#define SYS_read		63
+#define SYS_write		64
+#define SYS_openat		56
+#define SYS_close		57
+#define SYS_pipe2		59
+#define SYS_nanosleep		101
+#define SYS_mmap		222
+#define SYS_munmap		215
+#define SYS_setitimer		103
+#define SYS_clone		220
+#define SYS_sched_yield		124
+#define SYS_rt_sigreturn	139
+#define SYS_rt_sigaction	134
+#define SYS_rt_sigprocmask	135
+#define SYS_sigaltstack		132
+#define SYS_madvise		233
+#define SYS_mincore		232
+#define SYS_getpid		172
+#define SYS_gettid		178
+#define SYS_kill		129
+#define SYS_tgkill		131
+#define SYS_futex		98
+#define SYS_sched_getaffinity	123
+#define SYS_exit_group		94
+#define SYS_clock_gettime	113
+#define SYS_faccessat		48
+#define SYS_socket		198
+#define SYS_connect		203
+#define SYS_brk			214
+#define SYS_timer_create	107
+#define SYS_timer_settime	110
+#define SYS_timer_delete	111
+
+TEXT runtime·exit(SB),NOSPLIT|NOFRAME,$0-4
+	MOVW	code+0(FP), R0
+	MOVD	$SYS_exit_group, R8
+	SVC
+	RET
+
+// func exitThread(wait *atomic.Uint32)
+TEXT runtime·exitThread(SB),NOSPLIT|NOFRAME,$0-8
+	MOVD	wait+0(FP), R0
+	// We're done using the stack.
+	MOVW	$0, R1
+	STLRW	R1, (R0)
+	MOVW	$0, R0	// exit code
+	MOVD	$SYS_exit, R8
+	SVC
+	JMP	0(PC)
+
+TEXT runtime·open(SB),NOSPLIT|NOFRAME,$0-20
+	MOVD	$AT_FDCWD, R0
+	MOVD	name+0(FP), R1
+	MOVW	mode+8(FP), R2
+	MOVW	perm+12(FP), R3
+	MOVD	$SYS_openat, R8
+	SVC
+	CMN	$4095, R0
+	BCC	done
+	MOVW	$-1, R0
+done:
+	MOVW	R0, ret+16(FP)
+	RET
+
+TEXT runtime·closefd(SB),NOSPLIT|NOFRAME,$0-12
+	MOVW	fd+0(FP), R0
+	MOVD	$SYS_close, R8
+	SVC
+	CMN	$4095, R0
+	BCC	done
+	MOVW	$-1, R0
+done:
+	MOVW	R0, ret+8(FP)
+	RET
+
+TEXT runtime·write1(SB),NOSPLIT|NOFRAME,$0-28
+	MOVD	fd+0(FP), R0
+	MOVD	p+8(FP), R1
+	MOVW	n+16(FP), R2
+	MOVD	$SYS_write, R8
+	SVC
+	MOVW	R0, ret+24(FP)
+	RET
+
+TEXT runtime·read(SB),NOSPLIT|NOFRAME,$0-28
+	MOVW	fd+0(FP), R0
+	MOVD	p+8(FP), R1
+	MOVW	n+16(FP), R2
+	MOVD	$SYS_read, R8
+	SVC
+	MOVW	R0, ret+24(FP)
+	RET
+
+// func pipe2(flags int32) (r, w int32, errno int32)
+TEXT runtime·pipe2(SB),NOSPLIT|NOFRAME,$0-20
+	MOVD	$r+8(FP), R0
+	MOVW	flags+0(FP), R1
+	MOVW	$SYS_pipe2, R8
+	SVC
+	MOVW	R0, errno+16(FP)
+	RET
+
+TEXT runtime·usleep(SB),NOSPLIT,$24-4
+	MOVWU	usec+0(FP), R3
+	MOVD	R3, R5
+	MOVW	$1000000, R4
+	UDIV	R4, R3
+	MOVD	R3, 8(RSP)
+	MUL	R3, R4
+	SUB	R4, R5
+	MOVW	$1000, R4
+	MUL	R4, R5
+	MOVD	R5, 16(RSP)
+
+	// nanosleep(&ts, 0)
+	ADD	$8, RSP, R0
+	MOVD	$0, R1
+	MOVD	$SYS_nanosleep, R8
+	SVC
+	RET
+
+TEXT runtime·gettid(SB),NOSPLIT,$0-4
+	MOVD	$SYS_gettid, R8
+	SVC
+	MOVW	R0, ret+0(FP)
+	RET
+
+TEXT runtime·raise(SB),NOSPLIT|NOFRAME,$0
+	MOVD	$SYS_getpid, R8
+	SVC
+	MOVW	R0, R19
+	MOVD	$SYS_gettid, R8
+	SVC
+	MOVW	R0, R1	// arg 2 tid
+	MOVW	R19, R0	// arg 1 pid
+	MOVW	sig+0(FP), R2	// arg 3
+	MOVD	$SYS_tgkill, R8
+	SVC
+	RET
+
+TEXT runtime·raiseproc(SB),NOSPLIT|NOFRAME,$0
+	MOVD	$SYS_getpid, R8
+	SVC
+	MOVW	R0, R0		// arg 1 pid
+	MOVW	sig+0(FP), R1	// arg 2
+	MOVD	$SYS_kill, R8
+	SVC
+	RET
+
+TEXT ·getpid(SB),NOSPLIT|NOFRAME,$0-8
+	MOVD	$SYS_getpid, R8
+	SVC
+	MOVD	R0, ret+0(FP)
+	RET
+
+TEXT ·tgkill(SB),NOSPLIT,$0-24
+	MOVD	tgid+0(FP), R0
+	MOVD	tid+8(FP), R1
+	MOVD	sig+16(FP), R2
+	MOVD	$SYS_tgkill, R8
+	SVC
+	RET
+
+TEXT runtime·setitimer(SB),NOSPLIT|NOFRAME,$0-24
+	MOVW	mode+0(FP), R0
+	MOVD	new+8(FP), R1
+	MOVD	old+16(FP), R2
+	MOVD	$SYS_setitimer, R8
+	SVC
+	RET
+
+TEXT runtime·timer_create(SB),NOSPLIT,$0-28
+	MOVW	clockid+0(FP), R0
+	MOVD	sevp+8(FP), R1
+	MOVD	timerid+16(FP), R2
+	MOVD	$SYS_timer_create, R8
+	SVC
+	MOVW	R0, ret+24(FP)
+	RET
+
+TEXT runtime·timer_settime(SB),NOSPLIT,$0-28
+	MOVW	timerid+0(FP), R0
+	MOVW	flags+4(FP), R1
+	MOVD	new+8(FP), R2
+	MOVD	old+16(FP), R3
+	MOVD	$SYS_timer_settime, R8
+	SVC
+	MOVW	R0, ret+24(FP)
+	RET
+
+TEXT runtime·timer_delete(SB),NOSPLIT,$0-12
+	MOVW	timerid+0(FP), R0
+	MOVD	$SYS_timer_delete, R8
+	SVC
+	MOVW	R0, ret+8(FP)
+	RET
+
+TEXT runtime·mincore(SB),NOSPLIT|NOFRAME,$0-28
+	MOVD	addr+0(FP), R0
+	MOVD	n+8(FP), R1
+	MOVD	dst+16(FP), R2
+	MOVD	$SYS_mincore, R8
+	SVC
+	MOVW	R0, ret+24(FP)
+	RET
+
+// func walltime() (sec int64, nsec int32)
+TEXT runtime·walltime(SB),NOSPLIT,$24-12
+	MOVD	RSP, R20	// R20 is unchanged by C code
+	MOVD	RSP, R1
+
+	MOVD	g_m(g), R21	// R21 = m
+
+	// Set vdsoPC and vdsoSP for SIGPROF traceback.
+	// Save the old values on stack and restore them on exit,
+	// so this function is reentrant.
+	MOVD	m_vdsoPC(R21), R2
+	MOVD	m_vdsoSP(R21), R3
+	MOVD	R2, 8(RSP)
+	MOVD	R3, 16(RSP)
+
+	MOVD	$ret-8(FP), R2 // caller's SP
+	MOVD	LR, m_vdsoPC(R21)
+	MOVD	R2, m_vdsoSP(R21)
+
+	MOVD	m_curg(R21), R0
+	CMP	g, R0
+	BNE	noswitch
+
+	MOVD	m_g0(R21), R3
+	MOVD	(g_sched+gobuf_sp)(R3), R1	// Set RSP to g0 stack
+
+noswitch:
+	SUB	$16, R1
+	BIC	$15, R1	// Align for C code
+	MOVD	R1, RSP
+
+	MOVW	$CLOCK_REALTIME, R0
+	MOVD	runtime·vdsoClockgettimeSym(SB), R2
+	CBZ	R2, fallback
+
+	// Store g on gsignal's stack, so if we receive a signal
+	// during VDSO code we can find the g.
+	// If we don't have a signal stack, we won't receive signal,
+	// so don't bother saving g.
+	// When using cgo, we already saved g on TLS, also don't save
+	// g here.
+	// Also don't save g if we are already on the signal stack.
+	// We won't get a nested signal.
+	MOVBU	runtime·iscgo(SB), R22
+	CBNZ	R22, nosaveg
+	MOVD	m_gsignal(R21), R22          // g.m.gsignal
+	CBZ	R22, nosaveg
+	CMP	g, R22
+	BEQ	nosaveg
+	MOVD	(g_stack+stack_lo)(R22), R22 // g.m.gsignal.stack.lo
+	MOVD	g, (R22)
+
+	BL	(R2)
+
+	MOVD	ZR, (R22)  // clear g slot, R22 is unchanged by C code
+
+	B	finish
+
+nosaveg:
+	BL	(R2)
+	B	finish
+
+fallback:
+	MOVD	$SYS_clock_gettime, R8
+	SVC
+
+finish:
+	MOVD	0(RSP), R3	// sec
+	MOVD	8(RSP), R5	// nsec
+
+	MOVD	R20, RSP	// restore SP
+	// Restore vdsoPC, vdsoSP
+	// We don't worry about being signaled between the two stores.
+	// If we are not in a signal handler, we'll restore vdsoSP to 0,
+	// and no one will care about vdsoPC. If we are in a signal handler,
+	// we cannot receive another signal.
+	MOVD	16(RSP), R1
+	MOVD	R1, m_vdsoSP(R21)
+	MOVD	8(RSP), R1
+	MOVD	R1, m_vdsoPC(R21)
+
+	MOVD	R3, sec+0(FP)
+	MOVW	R5, nsec+8(FP)
+	RET
+
+TEXT runtime·nanotime1(SB),NOSPLIT,$24-8
+	MOVD	RSP, R20	// R20 is unchanged by C code
+	MOVD	RSP, R1
+
+	MOVD	g_m(g), R21	// R21 = m
+
+	// Set vdsoPC and vdsoSP for SIGPROF traceback.
+	// Save the old values on stack and restore them on exit,
+	// so this function is reentrant.
+	MOVD	m_vdsoPC(R21), R2
+	MOVD	m_vdsoSP(R21), R3
+	MOVD	R2, 8(RSP)
+	MOVD	R3, 16(RSP)
+
+	MOVD	$ret-8(FP), R2 // caller's SP
+	MOVD	LR, m_vdsoPC(R21)
+	MOVD	R2, m_vdsoSP(R21)
+
+	MOVD	m_curg(R21), R0
+	CMP	g, R0
+	BNE	noswitch
+
+	MOVD	m_g0(R21), R3
+	MOVD	(g_sched+gobuf_sp)(R3), R1	// Set RSP to g0 stack
+
+noswitch:
+	SUB	$32, R1
+	BIC	$15, R1
+	MOVD	R1, RSP
+
+	MOVW	$CLOCK_MONOTONIC, R0
+	MOVD	runtime·vdsoClockgettimeSym(SB), R2
+	CBZ	R2, fallback
+
+	// Store g on gsignal's stack, so if we receive a signal
+	// during VDSO code we can find the g.
+	// If we don't have a signal stack, we won't receive signal,
+	// so don't bother saving g.
+	// When using cgo, we already saved g on TLS, also don't save
+	// g here.
+	// Also don't save g if we are already on the signal stack.
+	// We won't get a nested signal.
+	MOVBU	runtime·iscgo(SB), R22
+	CBNZ	R22, nosaveg
+	MOVD	m_gsignal(R21), R22          // g.m.gsignal
+	CBZ	R22, nosaveg
+	CMP	g, R22
+	BEQ	nosaveg
+	MOVD	(g_stack+stack_lo)(R22), R22 // g.m.gsignal.stack.lo
+	MOVD	g, (R22)
+
+	BL	(R2)
+
+	MOVD	ZR, (R22)  // clear g slot, R22 is unchanged by C code
+
+	B	finish
+
+nosaveg:
+	BL	(R2)
+	B	finish
+
+fallback:
+	MOVD	$SYS_clock_gettime, R8
+	SVC
+
+finish:
+	MOVD	0(RSP), R3	// sec
+	MOVD	8(RSP), R5	// nsec
+
+	MOVD	R20, RSP	// restore SP
+	// Restore vdsoPC, vdsoSP
+	// We don't worry about being signaled between the two stores.
+	// If we are not in a signal handler, we'll restore vdsoSP to 0,
+	// and no one will care about vdsoPC. If we are in a signal handler,
+	// we cannot receive another signal.
+	MOVD	16(RSP), R1
+	MOVD	R1, m_vdsoSP(R21)
+	MOVD	8(RSP), R1
+	MOVD	R1, m_vdsoPC(R21)
+
+	// sec is in R3, nsec in R5
+	// return nsec in R3
+	MOVD	$1000000000, R4
+	MUL	R4, R3
+	ADD	R5, R3
+	MOVD	R3, ret+0(FP)
+	RET
+
+TEXT runtime·rtsigprocmask(SB),NOSPLIT|NOFRAME,$0-28
+	MOVW	how+0(FP), R0
+	MOVD	new+8(FP), R1
+	MOVD	old+16(FP), R2
+	MOVW	size+24(FP), R3
+	MOVD	$SYS_rt_sigprocmask, R8
+	SVC
+	CMN	$4095, R0
+	BCC	done
+	MOVD	$0, R0
+	MOVD	R0, (R0)	// crash
+done:
+	RET
+
+TEXT runtime·rt_sigaction(SB),NOSPLIT|NOFRAME,$0-36
+	MOVD	sig+0(FP), R0
+	MOVD	new+8(FP), R1
+	MOVD	old+16(FP), R2
+	MOVD	size+24(FP), R3
+	MOVD	$SYS_rt_sigaction, R8
+	SVC
+	MOVW	R0, ret+32(FP)
+	RET
+
+// Call the function stored in _cgo_sigaction using the GCC calling convention.
+TEXT runtime·callCgoSigaction(SB),NOSPLIT,$0
+	MOVD	sig+0(FP), R0
+	MOVD	new+8(FP), R1
+	MOVD	old+16(FP), R2
+	MOVD	 _cgo_sigaction(SB), R3
+	SUB	$16, RSP		// reserve 16 bytes for sp-8 where fp may be saved.
+	BL	R3
+	ADD	$16, RSP
+	MOVW	R0, ret+24(FP)
+	RET
+
+TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
+	MOVW	sig+8(FP), R0
+	MOVD	info+16(FP), R1
+	MOVD	ctx+24(FP), R2
+	MOVD	fn+0(FP), R11
+	BL	(R11)
+	RET
+
+// Called from c-abi, R0: sig, R1: info, R2: cxt
+TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$176
+	// Save callee-save registers in the case of signal forwarding.
+	// Please refer to https://golang.org/issue/31827 .
+	SAVE_R19_TO_R28(8*4)
+	SAVE_F8_TO_F15(8*14)
+
+	// this might be called in external code context,
+	// where g is not set.
+	// first save R0, because runtime·load_g will clobber it
+	MOVW	R0, 8(RSP)
+	MOVBU	runtime·iscgo(SB), R0
+	CBZ	R0, 2(PC)
+	BL	runtime·load_g(SB)
+
+	// Restore signum to R0.
+	MOVW	8(RSP), R0
+	// R1 and R2 already contain info and ctx, respectively.
+	MOVD	$runtime·sigtrampgo<ABIInternal>(SB), R3
+	BL	(R3)
+
+	// Restore callee-save registers.
+	RESTORE_R19_TO_R28(8*4)
+	RESTORE_F8_TO_F15(8*14)
+
+	RET
+
+// Called from c-abi, R0: sig, R1: info, R2: cxt
+TEXT runtime·sigprofNonGoWrapper<>(SB),NOSPLIT,$176
+	// Save callee-save registers because it's a callback from c code.
+	SAVE_R19_TO_R28(8*4)
+	SAVE_F8_TO_F15(8*14)
+
+	// R0, R1 and R2 already contain sig, info and ctx, respectively.
+	CALL	runtime·sigprofNonGo<ABIInternal>(SB)
+
+	// Restore callee-save registers.
+	RESTORE_R19_TO_R28(8*4)
+	RESTORE_F8_TO_F15(8*14)
+	RET
+
+// Called from c-abi, R0: sig, R1: info, R2: cxt
+TEXT runtime·cgoSigtramp(SB),NOSPLIT|NOFRAME,$0
+	// The stack unwinder, presumably written in C, may not be able to
+	// handle Go frame correctly. So, this function is NOFRAME, and we
+	// save/restore LR manually.
+	MOVD	LR, R10
+	// Save R27, g because they will be clobbered,
+	// we need to restore them before jump to sigtramp.
+	MOVD	R27, R11
+	MOVD	g, R12
+
+	// If no traceback function, do usual sigtramp.
+	MOVD	runtime·cgoTraceback(SB), R6
+	CBZ	R6, sigtramp
+
+	// If no traceback support function, which means that
+	// runtime/cgo was not linked in, do usual sigtramp.
+	MOVD	_cgo_callers(SB), R7
+	CBZ	R7, sigtramp
+
+	// Figure out if we are currently in a cgo call.
+	// If not, just do usual sigtramp.
+	// first save R0, because runtime·load_g will clobber it.
+	MOVD	R0, R8
+	// Set up g register.
+	CALL	runtime·load_g(SB)
+	MOVD	R8, R0
+
+	CBZ	g, sigtrampnog // g == nil
+	MOVD	g_m(g), R6
+	CBZ	R6, sigtramp    // g.m == nil
+	MOVW	m_ncgo(R6), R7
+	CBZW	R7, sigtramp    // g.m.ncgo = 0
+	MOVD	m_curg(R6), R8
+	CBZ	R8, sigtramp    // g.m.curg == nil
+	MOVD	g_syscallsp(R8), R7
+	CBZ	R7,	sigtramp    // g.m.curg.syscallsp == 0
+	MOVD	m_cgoCallers(R6), R4 // R4 is the fifth arg in C calling convention.
+	CBZ	R4,	sigtramp    // g.m.cgoCallers == nil
+	MOVW	m_cgoCallersUse(R6), R8
+	CBNZW	R8, sigtramp    // g.m.cgoCallersUse != 0
+
+	// Jump to a function in runtime/cgo.
+	// That function, written in C, will call the user's traceback
+	// function with proper unwind info, and will then call back here.
+	// The first three arguments, and the fifth, are already in registers.
+	// Set the two remaining arguments now.
+	MOVD	runtime·cgoTraceback(SB), R3
+	MOVD	$runtime·sigtramp(SB), R5
+	MOVD	_cgo_callers(SB), R13
+	MOVD	R10, LR // restore
+	MOVD	R11, R27
+	MOVD	R12, g
+	B	(R13)
+
+sigtramp:
+	MOVD	R10, LR // restore
+	MOVD	R11, R27
+	MOVD	R12, g
+	B	runtime·sigtramp(SB)
+
+sigtrampnog:
+	// Signal arrived on a non-Go thread. If this is SIGPROF, get a
+	// stack trace.
+	CMPW	$27, R0 // 27 == SIGPROF
+	BNE	sigtramp
+
+	// Lock sigprofCallersUse (cas from 0 to 1).
+	MOVW	$1, R7
+	MOVD	$runtime·sigprofCallersUse(SB), R8
+load_store_loop:
+	LDAXRW	(R8), R9
+	CBNZW	R9, sigtramp // Skip stack trace if already locked.
+	STLXRW	R7, (R8), R9
+	CBNZ	R9, load_store_loop
+
+	// Jump to the traceback function in runtime/cgo.
+	// It will call back to sigprofNonGo, which will ignore the
+	// arguments passed in registers.
+	// First three arguments to traceback function are in registers already.
+	MOVD	runtime·cgoTraceback(SB), R3
+	MOVD	$runtime·sigprofCallers(SB), R4
+	MOVD	$runtime·sigprofNonGoWrapper<>(SB), R5
+	MOVD	_cgo_callers(SB), R13
+	MOVD	R10, LR // restore
+	MOVD	R11, R27
+	MOVD	R12, g
+	B	(R13)
+
+TEXT runtime·sysMmap(SB),NOSPLIT|NOFRAME,$0
+	MOVD	addr+0(FP), R0
+	MOVD	n+8(FP), R1
+	MOVW	prot+16(FP), R2
+	MOVW	flags+20(FP), R3
+	MOVW	fd+24(FP), R4
+	MOVW	off+28(FP), R5
+
+	MOVD	$SYS_mmap, R8
+	SVC
+	CMN	$4095, R0
+	BCC	ok
+	NEG	R0,R0
+	MOVD	$0, p+32(FP)
+	MOVD	R0, err+40(FP)
+	RET
+ok:
+	MOVD	R0, p+32(FP)
+	MOVD	$0, err+40(FP)
+	RET
+
+// Call the function stored in _cgo_mmap using the GCC calling convention.
+// This must be called on the system stack.
+TEXT runtime·callCgoMmap(SB),NOSPLIT,$0
+	MOVD	addr+0(FP), R0
+	MOVD	n+8(FP), R1
+	MOVW	prot+16(FP), R2
+	MOVW	flags+20(FP), R3
+	MOVW	fd+24(FP), R4
+	MOVW	off+28(FP), R5
+	MOVD	_cgo_mmap(SB), R9
+	SUB	$16, RSP		// reserve 16 bytes for sp-8 where fp may be saved.
+	BL	R9
+	ADD	$16, RSP
+	MOVD	R0, ret+32(FP)
+	RET
+
+TEXT runtime·sysMunmap(SB),NOSPLIT|NOFRAME,$0
+	MOVD	addr+0(FP), R0
+	MOVD	n+8(FP), R1
+	MOVD	$SYS_munmap, R8
+	SVC
+	CMN	$4095, R0
+	BCC	cool
+	MOVD	R0, 0xf0(R0)
+cool:
+	RET
+
+// Call the function stored in _cgo_munmap using the GCC calling convention.
+// This must be called on the system stack.
+TEXT runtime·callCgoMunmap(SB),NOSPLIT,$0
+	MOVD	addr+0(FP), R0
+	MOVD	n+8(FP), R1
+	MOVD	_cgo_munmap(SB), R9
+	SUB	$16, RSP		// reserve 16 bytes for sp-8 where fp may be saved.
+	BL	R9
+	ADD	$16, RSP
+	RET
+
+TEXT runtime·madvise(SB),NOSPLIT|NOFRAME,$0
+	MOVD	addr+0(FP), R0
+	MOVD	n+8(FP), R1
+	MOVW	flags+16(FP), R2
+	MOVD	$SYS_madvise, R8
+	SVC
+	MOVW	R0, ret+24(FP)
+	RET
+
+// int64 futex(int32 *uaddr, int32 op, int32 val,
+//	struct timespec *timeout, int32 *uaddr2, int32 val2);
+TEXT runtime·futex(SB),NOSPLIT|NOFRAME,$0
+	MOVD	addr+0(FP), R0
+	MOVW	op+8(FP), R1
+	MOVW	val+12(FP), R2
+	MOVD	ts+16(FP), R3
+	MOVD	addr2+24(FP), R4
+	MOVW	val3+32(FP), R5
+	MOVD	$SYS_futex, R8
+	SVC
+	MOVW	R0, ret+40(FP)
+	RET
+
+// int64 clone(int32 flags, void *stk, M *mp, G *gp, void (*fn)(void));
+TEXT runtime·clone(SB),NOSPLIT|NOFRAME,$0
+	MOVW	flags+0(FP), R0
+	MOVD	stk+8(FP), R1
+
+	// Copy mp, gp, fn off parent stack for use by child.
+	MOVD	mp+16(FP), R10
+	MOVD	gp+24(FP), R11
+	MOVD	fn+32(FP), R12
+
+	MOVD	R10, -8(R1)
+	MOVD	R11, -16(R1)
+	MOVD	R12, -24(R1)
+	MOVD	$1234, R10
+	MOVD	R10, -32(R1)
+
+	MOVD	$SYS_clone, R8
+	SVC
+
+	// In parent, return.
+	CMP	ZR, R0
+	BEQ	child
+	MOVW	R0, ret+40(FP)
+	RET
+child:
+
+	// In child, on new stack.
+	MOVD	-32(RSP), R10
+	MOVD	$1234, R0
+	CMP	R0, R10
+	BEQ	good
+	MOVD	$0, R0
+	MOVD	R0, (R0)	// crash
+
+good:
+	// Initialize m->procid to Linux tid
+	MOVD	$SYS_gettid, R8
+	SVC
+
+	MOVD	-24(RSP), R12     // fn
+	MOVD	-16(RSP), R11     // g
+	MOVD	-8(RSP), R10      // m
+
+	CMP	$0, R10
+	BEQ	nog
+	CMP	$0, R11
+	BEQ	nog
+
+	MOVD	R0, m_procid(R10)
+
+	// TODO: setup TLS.
+
+	// In child, set up new stack
+	MOVD	R10, g_m(R11)
+	MOVD	R11, g
+	//CALL	runtime·stackcheck(SB)
+
+nog:
+	// Call fn
+	MOVD	R12, R0
+	BL	(R0)
+
+	// It shouldn't return.	 If it does, exit that thread.
+	MOVW	$111, R0
+again:
+	MOVD	$SYS_exit, R8
+	SVC
+	B	again	// keep exiting
+
+TEXT runtime·sigaltstack(SB),NOSPLIT|NOFRAME,$0
+	MOVD	new+0(FP), R0
+	MOVD	old+8(FP), R1
+	MOVD	$SYS_sigaltstack, R8
+	SVC
+	CMN	$4095, R0
+	BCC	ok
+	MOVD	$0, R0
+	MOVD	R0, (R0)	// crash
+ok:
+	RET
+
+TEXT runtime·osyield(SB),NOSPLIT|NOFRAME,$0
+	MOVD	$SYS_sched_yield, R8
+	SVC
+	RET
+
+TEXT runtime·sched_getaffinity(SB),NOSPLIT|NOFRAME,$0
+	MOVD	pid+0(FP), R0
+	MOVD	len+8(FP), R1
+	MOVD	buf+16(FP), R2
+	MOVD	$SYS_sched_getaffinity, R8
+	SVC
+	MOVW	R0, ret+24(FP)
+	RET
+
+// int access(const char *name, int mode)
+TEXT runtime·access(SB),NOSPLIT,$0-20
+	MOVD	$AT_FDCWD, R0
+	MOVD	name+0(FP), R1
+	MOVW	mode+8(FP), R2
+	MOVD	$SYS_faccessat, R8
+	SVC
+	MOVW	R0, ret+16(FP)
+	RET
+
+// int connect(int fd, const struct sockaddr *addr, socklen_t len)
+TEXT runtime·connect(SB),NOSPLIT,$0-28
+	MOVW	fd+0(FP), R0
+	MOVD	addr+8(FP), R1
+	MOVW	len+16(FP), R2
+	MOVD	$SYS_connect, R8
+	SVC
+	MOVW	R0, ret+24(FP)
+	RET
+
+// int socket(int domain, int typ, int prot)
+TEXT runtime·socket(SB),NOSPLIT,$0-20
+	MOVW	domain+0(FP), R0
+	MOVW	typ+4(FP), R1
+	MOVW	prot+8(FP), R2
+	MOVD	$SYS_socket, R8
+	SVC
+	MOVW	R0, ret+16(FP)
+	RET
+
+// func sbrk0() uintptr
+TEXT runtime·sbrk0(SB),NOSPLIT,$0-8
+	// Implemented as brk(NULL).
+	MOVD	$0, R0
+	MOVD	$SYS_brk, R8
+	SVC
+	MOVD	R0, ret+0(FP)
+	RET