src/runtime/sys_linux_riscv64.s

// 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.

//
// System calls and other sys.stuff for riscv64, Linux
//

#include "textflag.h"
#include "go_asm.h"

#define AT_FDCWD -100
#define CLOCK_REALTIME 0
#define CLOCK_MONOTONIC 1

#define SYS_brk			214
#define SYS_clock_gettime	113
#define SYS_clone		220
#define SYS_close		57
#define SYS_connect		203
#define SYS_exit		93
#define SYS_exit_group		94
#define SYS_faccessat		48
#define SYS_futex		98
#define SYS_getpid		172
#define SYS_gettid		178
#define SYS_gettimeofday	169
#define SYS_kill		129
#define SYS_madvise		233
#define SYS_mincore		232
#define SYS_mmap		222
#define SYS_munmap		215
#define SYS_nanosleep		101
#define SYS_openat		56
#define SYS_pipe2		59
#define SYS_pselect6		72
#define SYS_read		63
#define SYS_rt_sigaction	134
#define SYS_rt_sigprocmask	135
#define SYS_rt_sigreturn	139
#define SYS_sched_getaffinity	123
#define SYS_sched_yield		124
#define SYS_setitimer		103
#define SYS_sigaltstack		132
#define SYS_socket		198
#define SYS_tgkill		131
#define SYS_timer_create	107
#define SYS_timer_delete	111
#define SYS_timer_settime	110
#define SYS_tkill		130
#define SYS_write		64

// func exit(code int32)
TEXT runtime·exit<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_exit_group, A7
	ECALL
	RET

// func exitThread(wait *atomic.Uint32)
TEXT runtime·exitThread(SB),NOSPLIT|NOFRAME,$0-8
	MOV	wait+0(FP), A0
	// We're done using the stack.
	FENCE	RW, W
	MOVW	ZERO, (A0)
	FENCE	RW, RW
	MOV	$0, A0	// exit code
	MOV	$SYS_exit, A7
	ECALL
	JMP	0(PC)

// func open(name *byte, mode, perm int32) int32
TEXT runtime·open(SB),NOSPLIT|NOFRAME,$0-20
	MOV	$AT_FDCWD, A0
	MOV	name+0(FP), A1
	MOVW	mode+8(FP), A2
	MOVW	perm+12(FP), A3
	MOV	$SYS_openat, A7
	ECALL
	MOV	$-4096, T0
	BGEU	T0, A0, 2(PC)
	MOV	$-1, A0
	MOVW	A0, ret+16(FP)
	RET

// func closefd(fd int32) int32
TEXT runtime·closefd(SB),NOSPLIT|NOFRAME,$0-12
	MOVW	fd+0(FP), A0
	MOV	$SYS_close, A7
	ECALL
	MOV	$-4096, T0
	BGEU	T0, A0, 2(PC)
	MOV	$-1, A0
	MOVW	A0, ret+8(FP)
	RET

// func write1(fd uintptr, p unsafe.Pointer, n int32) int32
TEXT runtime·write1<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_write, A7
	ECALL
	RET

// func read(fd int32, p unsafe.Pointer, n int32) int32
TEXT runtime·read<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_read, A7
	ECALL
	RET

// func pipe2(flags int32) (r, w int32, errno int32)
TEXT runtime·pipe2(SB),NOSPLIT|NOFRAME,$0-20
	MOV	$r+8(FP), A0
	MOVW	flags+0(FP), A1
	MOV	$SYS_pipe2, A7
	ECALL
	MOVW	A0, errno+16(FP)
	RET

// func usleep(usec uint32)
TEXT runtime·usleep(SB),NOSPLIT,$24-4
	MOVWU	usec+0(FP), A0
	MOV	$1000, A1
	MUL	A1, A0, A0
	MOV	$1000000000, A1
	DIV	A1, A0, A2
	MOV	A2, 8(X2)
	REM	A1, A0, A3
	MOV	A3, 16(X2)
	ADD	$8, X2, A0
	MOV	ZERO, A1
	MOV	$SYS_nanosleep, A7
	ECALL
	RET

// func gettid() uint32
TEXT runtime·gettid<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_gettid, A7
	ECALL
	RET

// func raise(sig uint32)
TEXT runtime·raise(SB),NOSPLIT|NOFRAME,$0
	MOV	$SYS_gettid, A7
	ECALL
	// arg 1 tid - already in A0
	MOVW	sig+0(FP), A1	// arg 2
	MOV	$SYS_tkill, A7
	ECALL
	RET

// func raiseproc(sig uint32)
TEXT runtime·raiseproc(SB),NOSPLIT|NOFRAME,$0
	MOV	$SYS_getpid, A7
	ECALL
	// arg 1 pid - already in A0
	MOVW	sig+0(FP), A1	// arg 2
	MOV	$SYS_kill, A7
	ECALL
	RET

// func getpid() int
TEXT ·getpid<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_getpid, A7
	ECALL
	RET

// func tgkill(tgid, tid, sig int)
TEXT ·tgkill<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_tgkill, A7
	ECALL
	RET

// func setitimer(mode int32, new, old *itimerval)
TEXT runtime·setitimer<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_setitimer, A7
	ECALL
	RET

// func timer_create(clockid int32, sevp *sigevent, timerid *int32) int32
TEXT runtime·timer_create<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_timer_create, A7
	ECALL
	RET

// func timer_settime(timerid int32, flags int32, new, old *itimerspec) int32
TEXT runtime·timer_settime<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_timer_settime, A7
	ECALL
	RET

// func timer_delete(timerid int32) int32
TEXT runtime·timer_delete<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_timer_delete, A7
	ECALL
	RET

// func mincore(addr unsafe.Pointer, n uintptr, dst *byte) int32
TEXT runtime·mincore<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_mincore, A7
	ECALL
	RET

// func walltime() (sec int64, nsec int32)
TEXT runtime·walltime(SB),NOSPLIT,$40-12
	MOV	$CLOCK_REALTIME, A0

	MOV	runtime·vdsoClockgettimeSym(SB), A7
	BEQZ	A7, fallback
	MOV	X2, S2 // S2,S3,S4 is unchanged by C code
	MOV	g_m(g), S3 // S3 = m

	// Save the old values on stack for reentrant
	MOV	m_vdsoPC(S3), T0
	MOV	T0, 24(X2)
	MOV	m_vdsoSP(S3), T0
	MOV	T0, 32(X2)

	MOV	RA, m_vdsoPC(S3)
	MOV	$ret-8(FP), T1 // caller's SP
	MOV	T1, m_vdsoSP(S3)

	MOV	m_curg(S3), T1
	BNE	g, T1, noswitch

	MOV	m_g0(S3), T1
	MOV	(g_sched+gobuf_sp)(T1), X2

noswitch:
	SUB	$24, X2 // Space for result
	ANDI	$~7, X2 // Align for C code
	MOV	$8(X2), A1

	// Store g on gsignal's stack, see sys_linux_arm64.s for detail
	MOVBU	runtime·iscgo(SB), S4
	BNEZ	S4, nosaveg
	MOV	m_gsignal(S3), S4 // g.m.gsignal
	BEQZ	S4, nosaveg
	BEQ	g, S4, nosaveg
	MOV	(g_stack+stack_lo)(S4), S4 // g.m.gsignal.stack.lo
	MOV	g, (S4)

	JALR	RA, A7

	MOV	ZERO, (S4)
	JMP	finish

nosaveg:
	JALR	RA, A7

finish:
	MOV	8(X2), T0	// sec
	MOV	16(X2), T1	// nsec

	MOV	S2, X2	// restore stack
	MOV	24(X2), A2
	MOV	A2, m_vdsoPC(S3)

	MOV	32(X2), A3
	MOV	A3, m_vdsoSP(S3)

	MOV	T0, sec+0(FP)
	MOVW	T1, nsec+8(FP)
	RET

fallback:
	MOV	$8(X2), A1
	MOV	$SYS_clock_gettime, A7
	ECALL
	MOV	8(X2), T0	// sec
	MOV	16(X2), T1	// nsec
	MOV	T0, sec+0(FP)
	MOVW	T1, nsec+8(FP)
	RET

// func nanotime1() int64
TEXT runtime·nanotime1(SB),NOSPLIT,$40-8
	MOV	$CLOCK_MONOTONIC, A0

	MOV	runtime·vdsoClockgettimeSym(SB), A7
	BEQZ	A7, fallback

	MOV	X2, S2 // S2 = RSP, S2 is unchanged by C code
	MOV	g_m(g), S3 // S3 = m
	// Save the old values on stack for reentrant
	MOV	m_vdsoPC(S3), T0
	MOV	T0, 24(X2)
	MOV	m_vdsoSP(S3), T0
	MOV	T0, 32(X2)

	MOV	RA, m_vdsoPC(S3)
	MOV	$ret-8(FP), T0 // caller's SP
	MOV	T0, m_vdsoSP(S3)

	MOV	m_curg(S3), T1
	BNE	g, T1, noswitch

	MOV	m_g0(S3), T1
	MOV	(g_sched+gobuf_sp)(T1), X2

noswitch:
	SUB	$24, X2 // Space for result
	ANDI	$~7, X2 // Align for C code
	MOV	$8(X2), A1

	// Store g on gsignal's stack, see sys_linux_arm64.s for detail
	MOVBU	runtime·iscgo(SB), S4
	BNEZ	S4, nosaveg
	MOV	m_gsignal(S3), S4 // g.m.gsignal
	BEQZ	S4, nosaveg
	BEQ	g, S4, nosaveg
	MOV	(g_stack+stack_lo)(S4), S4 // g.m.gsignal.stack.lo
	MOV	g, (S4)

	JALR	RA, A7

	MOV	ZERO, (S4)
	JMP	finish

nosaveg:
	JALR	RA, A7

finish:
	MOV	8(X2), T0	// sec
	MOV	16(X2), T1	// nsec
	// restore stack
	MOV	S2, X2
	MOV	24(X2), T2
	MOV	T2, m_vdsoPC(S3)

	MOV	32(X2), T2
	MOV	T2, m_vdsoSP(S3)
	// sec is in T0, nsec in T1
	// return nsec in T0
	MOV	$1000000000, T2
	MUL	T2, T0
	ADD	T1, T0
	MOV	T0, ret+0(FP)
	RET

fallback:
	MOV	$8(X2), A1
	MOV	$SYS_clock_gettime, A7
	ECALL
	MOV	8(X2), T0	// sec
	MOV	16(X2), T1	// nsec
	MOV	$1000000000, T2
	MUL	T2, T0
	ADD	T1, T0
	MOV	T0, ret+0(FP)
	RET

// func rtsigprocmask(how int32, new, old *sigset, size int32)
TEXT runtime·rtsigprocmask(SB),NOSPLIT|NOFRAME,$0-28
	MOVW	how+0(FP), A0
	MOV	new+8(FP), A1
	MOV	old+16(FP), A2
	MOVW	size+24(FP), A3
	MOV	$SYS_rt_sigprocmask, A7
	ECALL
	MOV	$-4096, T0
	BLTU	A0, T0, 2(PC)
	WORD	$0	// crash
	RET

// func rt_sigaction(sig uintptr, new, old *sigactiont, size uintptr) int32
TEXT runtime·rt_sigaction<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_rt_sigaction, A7
	ECALL
	RET

// func sigfwd(fn uintptr, sig uint32, info *siginfo, ctx unsafe.Pointer)
TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
	MOVW	sig+8(FP), A0
	MOV	info+16(FP), A1
	MOV	ctx+24(FP), A2
	MOV	fn+0(FP), T1
	JALR	RA, T1
	RET

// func sigtramp(signo, ureg, ctxt unsafe.Pointer)
TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$64
	MOVW	A0, 8(X2)
	MOV	A1, 16(X2)
	MOV	A2, 24(X2)

	// this might be called in external code context,
	// where g is not set.
	MOVBU	runtime·iscgo(SB), A0
	BEQ	A0, ZERO, 2(PC)
	CALL	runtime·load_g(SB)

	MOV	$runtime·sigtrampgo(SB), A0
	JALR	RA, A0
	RET

// func cgoSigtramp()
TEXT runtime·cgoSigtramp(SB),NOSPLIT,$0
	MOV	$runtime·sigtramp(SB), T1
	JALR	ZERO, T1

// func mmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uint32) (p unsafe.Pointer, err int)
TEXT runtime·mmap(SB),NOSPLIT|NOFRAME,$0
	MOV	addr+0(FP), A0
	MOV	n+8(FP), A1
	MOVW	prot+16(FP), A2
	MOVW	flags+20(FP), A3
	MOVW	fd+24(FP), A4
	MOVW	off+28(FP), A5
	MOV	$SYS_mmap, A7
	ECALL
	MOV	$-4096, T0
	BGEU	T0, A0, 5(PC)
	SUB	A0, ZERO, A0
	MOV	ZERO, p+32(FP)
	MOV	A0, err+40(FP)
	RET
ok:
	MOV	A0, p+32(FP)
	MOV	ZERO, err+40(FP)
	RET

// func munmap(addr unsafe.Pointer, n uintptr)
TEXT runtime·munmap(SB),NOSPLIT|NOFRAME,$0
	MOV	addr+0(FP), A0
	MOV	n+8(FP), A1
	MOV	$SYS_munmap, A7
	ECALL
	MOV	$-4096, T0
	BLTU	A0, T0, 2(PC)
	WORD	$0	// crash
	RET

// func madvise(addr unsafe.Pointer, n uintptr, flags int32)
TEXT runtime·madvise<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_madvise, A7
	ECALL
	RET

// func futex(addr unsafe.Pointer, op int32, val uint32, ts, addr2 unsafe.Pointer, val3 uint32) int32
TEXT runtime·futex<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_futex, A7
	ECALL
	RET

// func clone(flags int32, stk, mp, gp, fn unsafe.Pointer) int32
TEXT runtime·clone(SB),NOSPLIT|NOFRAME,$0
	MOVW	flags+0(FP), A0
	MOV	stk+8(FP), A1

	// Copy mp, gp, fn off parent stack for use by child.
	MOV	mp+16(FP), T0
	MOV	gp+24(FP), T1
	MOV	fn+32(FP), T2

	MOV	T0, -8(A1)
	MOV	T1, -16(A1)
	MOV	T2, -24(A1)
	MOV	$1234, T0
	MOV	T0, -32(A1)

	MOV	$SYS_clone, A7
	ECALL

	// In parent, return.
	BEQ	ZERO, A0, child
	MOVW	ZERO, ret+40(FP)
	RET

child:
	// In child, on new stack.
	MOV	-32(X2), T0
	MOV	$1234, A0
	BEQ	A0, T0, good
	WORD	$0	// crash

good:
	// Initialize m->procid to Linux tid
	MOV	$SYS_gettid, A7
	ECALL

	MOV	-24(X2), T2	// fn
	MOV	-16(X2), T1	// g
	MOV	-8(X2), T0	// m

	BEQ	ZERO, T0, nog
	BEQ	ZERO, T1, nog

	MOV	A0, m_procid(T0)

	// In child, set up new stack
	MOV	T0, g_m(T1)
	MOV	T1, g

nog:
	// Call fn
	JALR	RA, T2

	// It shouldn't return.  If it does, exit this thread.
	MOV	$111, A0
	MOV	$SYS_exit, A7
	ECALL
	JMP	-3(PC)	// keep exiting

// func sigaltstack(new, old *stackt)
TEXT runtime·sigaltstack(SB),NOSPLIT|NOFRAME,$0
	MOV	new+0(FP), A0
	MOV	old+8(FP), A1
	MOV	$SYS_sigaltstack, A7
	ECALL
	MOV	$-4096, T0
	BLTU	A0, T0, 2(PC)
	WORD	$0	// crash
	RET

// func osyield()
TEXT runtime·osyield<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_sched_yield, A7
	ECALL
	RET

// func sched_getaffinity(pid, len uintptr, buf *uintptr) int32
TEXT runtime·sched_getaffinity<ABIInternal>(SB),NOSPLIT,$0
	MOV	$SYS_sched_getaffinity, A7
	ECALL
	RET

// func sbrk0() uintptr
TEXT runtime·sbrk0<ABIInternal>(SB),NOSPLIT,$0
	// Implemented as brk(NULL).
	MOV	ZERO, A0
	MOV	$SYS_brk, A7
	ECALL
	RET