runtime: add support for openbsd/mips64
Update #40995
Change-Id: Ie028dfd87ef8731804567a0501f1f7758e8dd203
Reviewed-on: https://go-review.googlesource.com/c/go/+/250580
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Joel Sing <joel@sing.id.au>
diff --git a/src/runtime/os_openbsd.go b/src/runtime/os_openbsd.go
index cd3565d..d7960f4 100644
--- a/src/runtime/os_openbsd.go
+++ b/src/runtime/os_openbsd.go
@@ -236,7 +236,11 @@
// Called to initialize a new m (including the bootstrap m).
// Called on the parent thread (main thread in case of bootstrap), can allocate memory.
func mpreinit(mp *m) {
- mp.gsignal = malg(32 * 1024)
+ gsignalSize := int32(32 * 1024)
+ if GOARCH == "mips64" {
+ gsignalSize = int32(64 * 1024)
+ }
+ mp.gsignal = malg(gsignalSize)
mp.gsignal.m = mp
}
diff --git a/src/runtime/os_openbsd_mips64.go b/src/runtime/os_openbsd_mips64.go
new file mode 100644
index 0000000..ae220cd
--- /dev/null
+++ b/src/runtime/os_openbsd_mips64.go
@@ -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.
+
+package runtime
+
+//go:nosplit
+func cputicks() int64 {
+ // Currently cputicks() is used in blocking profiler and to seed runtime·fastrand().
+ // runtime·nanotime() is a poor approximation of CPU ticks that is enough for the profiler.
+ return nanotime()
+}
diff --git a/src/runtime/rt0_openbsd_mips64.s b/src/runtime/rt0_openbsd_mips64.s
new file mode 100644
index 0000000..82a8dfa
--- /dev/null
+++ b/src/runtime/rt0_openbsd_mips64.s
@@ -0,0 +1,36 @@
+// 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 "textflag.h"
+
+TEXT _rt0_mips64_openbsd(SB),NOSPLIT,$0
+ JMP _main<>(SB)
+
+TEXT _rt0_mips64le_openbsd(SB),NOSPLIT,$0
+ JMP _main<>(SB)
+
+TEXT _main<>(SB),NOSPLIT|NOFRAME,$0
+ // In a statically linked binary, the stack contains argc,
+ // argv as argc string pointers followed by a NULL, envv as a
+ // sequence of string pointers followed by a NULL, and auxv.
+ // There is no TLS base pointer.
+#ifdef GOARCH_mips64
+ MOVW 4(R29), R4 // argc, big-endian ABI places int32 at offset 4
+#else
+ MOVW 0(R29), R4 // argc
+#endif
+ ADDV $8, R29, R5 // argv
+ JMP main(SB)
+
+TEXT main(SB),NOSPLIT|NOFRAME,$0
+ // in external linking, glibc jumps to main with argc in R4
+ // and argv in R5
+
+ // initialize REGSB = PC&0xffffffff00000000
+ BGEZAL R0, 1(PC)
+ SRLV $32, R31, RSB
+ SLLV $32, RSB
+
+ MOVV $runtime·rt0_go(SB), R1
+ JMP (R1)
diff --git a/src/runtime/signal_mips64x.go b/src/runtime/signal_mips64x.go
index 040c959..2a347ff 100644
--- a/src/runtime/signal_mips64x.go
+++ b/src/runtime/signal_mips64x.go
@@ -2,7 +2,7 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
-// +build linux
+// +build linux openbsd
// +build mips64 mips64le
package runtime
diff --git a/src/runtime/signal_openbsd_mips64.go b/src/runtime/signal_openbsd_mips64.go
new file mode 100644
index 0000000..54ed523
--- /dev/null
+++ b/src/runtime/signal_openbsd_mips64.go
@@ -0,0 +1,78 @@
+// 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.
+
+package runtime
+
+import (
+ "unsafe"
+)
+
+type sigctxt struct {
+ info *siginfo
+ ctxt unsafe.Pointer
+}
+
+//go:nosplit
+//go:nowritebarrierrec
+func (c *sigctxt) regs() *sigcontext {
+ return (*sigcontext)(c.ctxt)
+}
+
+func (c *sigctxt) r0() uint64 { return c.regs().sc_regs[0] }
+func (c *sigctxt) r1() uint64 { return c.regs().sc_regs[1] }
+func (c *sigctxt) r2() uint64 { return c.regs().sc_regs[2] }
+func (c *sigctxt) r3() uint64 { return c.regs().sc_regs[3] }
+func (c *sigctxt) r4() uint64 { return c.regs().sc_regs[4] }
+func (c *sigctxt) r5() uint64 { return c.regs().sc_regs[5] }
+func (c *sigctxt) r6() uint64 { return c.regs().sc_regs[6] }
+func (c *sigctxt) r7() uint64 { return c.regs().sc_regs[7] }
+func (c *sigctxt) r8() uint64 { return c.regs().sc_regs[8] }
+func (c *sigctxt) r9() uint64 { return c.regs().sc_regs[9] }
+func (c *sigctxt) r10() uint64 { return c.regs().sc_regs[10] }
+func (c *sigctxt) r11() uint64 { return c.regs().sc_regs[11] }
+func (c *sigctxt) r12() uint64 { return c.regs().sc_regs[12] }
+func (c *sigctxt) r13() uint64 { return c.regs().sc_regs[13] }
+func (c *sigctxt) r14() uint64 { return c.regs().sc_regs[14] }
+func (c *sigctxt) r15() uint64 { return c.regs().sc_regs[15] }
+func (c *sigctxt) r16() uint64 { return c.regs().sc_regs[16] }
+func (c *sigctxt) r17() uint64 { return c.regs().sc_regs[17] }
+func (c *sigctxt) r18() uint64 { return c.regs().sc_regs[18] }
+func (c *sigctxt) r19() uint64 { return c.regs().sc_regs[19] }
+func (c *sigctxt) r20() uint64 { return c.regs().sc_regs[20] }
+func (c *sigctxt) r21() uint64 { return c.regs().sc_regs[21] }
+func (c *sigctxt) r22() uint64 { return c.regs().sc_regs[22] }
+func (c *sigctxt) r23() uint64 { return c.regs().sc_regs[23] }
+func (c *sigctxt) r24() uint64 { return c.regs().sc_regs[24] }
+func (c *sigctxt) r25() uint64 { return c.regs().sc_regs[25] }
+func (c *sigctxt) r26() uint64 { return c.regs().sc_regs[26] }
+func (c *sigctxt) r27() uint64 { return c.regs().sc_regs[27] }
+func (c *sigctxt) r28() uint64 { return c.regs().sc_regs[28] }
+func (c *sigctxt) r29() uint64 { return c.regs().sc_regs[29] }
+func (c *sigctxt) r30() uint64 { return c.regs().sc_regs[30] }
+func (c *sigctxt) r31() uint64 { return c.regs().sc_regs[31] }
+func (c *sigctxt) sp() uint64 { return c.regs().sc_regs[29] }
+
+//go:nosplit
+//go:nowritebarrierrec
+func (c *sigctxt) pc() uint64 { return c.regs().sc_pc }
+
+func (c *sigctxt) link() uint64 { return c.regs().sc_regs[31] }
+func (c *sigctxt) lo() uint64 { return c.regs().mullo }
+func (c *sigctxt) hi() uint64 { return c.regs().mulhi }
+
+func (c *sigctxt) sigcode() uint32 { return uint32(c.info.si_code) }
+func (c *sigctxt) sigaddr() uint64 {
+ return *(*uint64)(add(unsafe.Pointer(c.info), 16))
+}
+
+func (c *sigctxt) set_r28(x uint64) { c.regs().sc_regs[28] = x }
+func (c *sigctxt) set_r30(x uint64) { c.regs().sc_regs[30] = x }
+func (c *sigctxt) set_pc(x uint64) { c.regs().sc_pc = x }
+func (c *sigctxt) set_sp(x uint64) { c.regs().sc_regs[29] = x }
+func (c *sigctxt) set_link(x uint64) { c.regs().sc_regs[31] = x }
+
+func (c *sigctxt) set_sigcode(x uint32) { c.info.si_code = int32(x) }
+func (c *sigctxt) set_sigaddr(x uint64) {
+ *(*uint64)(add(unsafe.Pointer(c.info), 16)) = x
+}
diff --git a/src/runtime/sys_openbsd_mips64.s b/src/runtime/sys_openbsd_mips64.s
new file mode 100644
index 0000000..57a5dbd
--- /dev/null
+++ b/src/runtime/sys_openbsd_mips64.s
@@ -0,0 +1,400 @@
+// 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.
+
+//
+// System calls and other sys.stuff for mips64, OpenBSD
+// /usr/src/sys/kern/syscalls.master for syscall numbers.
+//
+
+#include "go_asm.h"
+#include "go_tls.h"
+#include "textflag.h"
+
+#define CLOCK_REALTIME $0
+#define CLOCK_MONOTONIC $3
+
+// Exit the entire program (like C exit)
+TEXT runtime·exit(SB),NOSPLIT|NOFRAME,$0
+ MOVW code+0(FP), R4 // arg 1 - status
+ MOVV $1, R2 // sys_exit
+ SYSCALL
+ BEQ R7, 3(PC)
+ MOVV $0, R2 // crash on syscall failure
+ MOVV R2, (R2)
+ RET
+
+// func exitThread(wait *uint32)
+TEXT runtime·exitThread(SB),NOSPLIT,$0
+ MOVV wait+0(FP), R4 // arg 1 - notdead
+ MOVV $302, R2 // sys___threxit
+ SYSCALL
+ MOVV $0, R2 // crash on syscall failure
+ MOVV R2, (R2)
+ JMP 0(PC)
+
+TEXT runtime·open(SB),NOSPLIT|NOFRAME,$0
+ MOVV name+0(FP), R4 // arg 1 - path
+ MOVW mode+8(FP), R5 // arg 2 - mode
+ MOVW perm+12(FP), R6 // arg 3 - perm
+ MOVV $5, R2 // sys_open
+ SYSCALL
+ BEQ R7, 2(PC)
+ MOVW $-1, R2
+ MOVW R2, ret+16(FP)
+ RET
+
+TEXT runtime·closefd(SB),NOSPLIT|NOFRAME,$0
+ MOVW fd+0(FP), R4 // arg 1 - fd
+ MOVV $6, R2 // sys_close
+ SYSCALL
+ BEQ R7, 2(PC)
+ MOVW $-1, R2
+ MOVW R2, ret+8(FP)
+ RET
+
+TEXT runtime·read(SB),NOSPLIT|NOFRAME,$0
+ MOVW fd+0(FP), R4 // arg 1 - fd
+ MOVV p+8(FP), R5 // arg 2 - buf
+ MOVW n+16(FP), R6 // arg 3 - nbyte
+ MOVV $3, R2 // sys_read
+ SYSCALL
+ BEQ R7, 2(PC)
+ SUBVU R2, R0, R2 // caller expects negative errno
+ MOVW R2, ret+24(FP)
+ RET
+
+// func pipe() (r, w int32, errno int32)
+TEXT runtime·pipe(SB),NOSPLIT|NOFRAME,$0-12
+ MOVV $r+0(FP), R4
+ MOVW $0, R5
+ MOVV $101, R2 // sys_pipe2
+ SYSCALL
+ BEQ R7, 2(PC)
+ SUBVU R2, R0, R2 // caller expects negative errno
+ MOVW R2, errno+8(FP)
+ RET
+
+// func pipe2(flags int32) (r, w int32, errno int32)
+TEXT runtime·pipe2(SB),NOSPLIT|NOFRAME,$0-20
+ MOVV $r+8(FP), R4
+ MOVW flags+0(FP), R5
+ MOVV $101, R2 // sys_pipe2
+ SYSCALL
+ BEQ R7, 2(PC)
+ SUBVU R2, R0, R2 // caller expects negative errno
+ MOVW R2, errno+16(FP)
+ RET
+
+TEXT runtime·write1(SB),NOSPLIT|NOFRAME,$0
+ MOVV fd+0(FP), R4 // arg 1 - fd
+ MOVV p+8(FP), R5 // arg 2 - buf
+ MOVW n+16(FP), R6 // arg 3 - nbyte
+ MOVV $4, R2 // sys_write
+ SYSCALL
+ BEQ R7, 2(PC)
+ SUBVU R2, R0, R2 // caller expects negative errno
+ MOVW R2, ret+24(FP)
+ RET
+
+TEXT runtime·usleep(SB),NOSPLIT,$24-4
+ MOVWU usec+0(FP), R3
+ MOVV R3, R5
+ MOVW $1000000, R4
+ DIVVU R4, R3
+ MOVV LO, R3
+ MOVV R3, 8(R29) // tv_sec
+ MOVW $1000, R4
+ MULVU R3, R4
+ MOVV LO, R4
+ SUBVU R4, R5
+ MOVV R5, 16(R29) // tv_nsec
+
+ ADDV $8, R29, R4 // arg 1 - rqtp
+ MOVV $0, R5 // arg 2 - rmtp
+ MOVV $91, R2 // sys_nanosleep
+ SYSCALL
+ RET
+
+TEXT runtime·getthrid(SB),NOSPLIT,$0-4
+ MOVV $299, R2 // sys_getthrid
+ SYSCALL
+ MOVW R2, ret+0(FP)
+ RET
+
+TEXT runtime·thrkill(SB),NOSPLIT,$0-16
+ MOVW tid+0(FP), R4 // arg 1 - tid
+ MOVV sig+8(FP), R5 // arg 2 - signum
+ MOVW $0, R6 // arg 3 - tcb
+ MOVV $119, R2 // sys_thrkill
+ SYSCALL
+ RET
+
+TEXT runtime·raiseproc(SB),NOSPLIT,$0
+ MOVV $20, R4 // sys_getpid
+ SYSCALL
+ MOVV R2, R4 // arg 1 - pid
+ MOVW sig+0(FP), R5 // arg 2 - signum
+ MOVV $122, R2 // sys_kill
+ SYSCALL
+ RET
+
+TEXT runtime·mmap(SB),NOSPLIT,$0
+ MOVV addr+0(FP), R4 // arg 1 - addr
+ MOVV n+8(FP), R5 // arg 2 - len
+ MOVW prot+16(FP), R6 // arg 3 - prot
+ MOVW flags+20(FP), R7 // arg 4 - flags
+ MOVW fd+24(FP), R8 // arg 5 - fd
+ MOVW $0, R9 // arg 6 - pad
+ MOVW off+28(FP), R10 // arg 7 - offset
+ MOVV $197, R2 // sys_mmap
+ SYSCALL
+ MOVV $0, R4
+ BEQ R7, 3(PC)
+ MOVV R2, R4 // if error, move to R4
+ MOVV $0, R2
+ MOVV R2, p+32(FP)
+ MOVV R4, err+40(FP)
+ RET
+
+TEXT runtime·munmap(SB),NOSPLIT,$0
+ MOVV addr+0(FP), R4 // arg 1 - addr
+ MOVV n+8(FP), R5 // arg 2 - len
+ MOVV $73, R2 // sys_munmap
+ SYSCALL
+ BEQ R7, 3(PC)
+ MOVV $0, R2 // crash on syscall failure
+ MOVV R2, (R2)
+ RET
+
+TEXT runtime·madvise(SB),NOSPLIT,$0
+ MOVV addr+0(FP), R4 // arg 1 - addr
+ MOVV n+8(FP), R5 // arg 2 - len
+ MOVW flags+16(FP), R6 // arg 2 - flags
+ MOVV $75, R2 // sys_madvise
+ SYSCALL
+ BEQ R7, 2(PC)
+ MOVW $-1, R2
+ MOVW R2, ret+24(FP)
+ RET
+
+TEXT runtime·setitimer(SB),NOSPLIT,$0
+ MOVW mode+0(FP), R4 // arg 1 - mode
+ MOVV new+8(FP), R5 // arg 2 - new value
+ MOVV old+16(FP), R6 // arg 3 - old value
+ MOVV $69, R2 // sys_setitimer
+ SYSCALL
+ RET
+
+// func walltime1() (sec int64, nsec int32)
+TEXT runtime·walltime1(SB), NOSPLIT, $32
+ MOVW CLOCK_REALTIME, R4 // arg 1 - clock_id
+ MOVV $8(R29), R5 // arg 2 - tp
+ MOVV $87, R2 // sys_clock_gettime
+ SYSCALL
+
+ MOVV 8(R29), R4 // sec
+ MOVV 16(R29), R5 // nsec
+ MOVV R4, sec+0(FP)
+ MOVW R5, nsec+8(FP)
+
+ RET
+
+// int64 nanotime1(void) so really
+// void nanotime1(int64 *nsec)
+TEXT runtime·nanotime1(SB),NOSPLIT,$32
+ MOVW CLOCK_MONOTONIC, R4 // arg 1 - clock_id
+ MOVV $8(R29), R5 // arg 2 - tp
+ MOVV $87, R2 // sys_clock_gettime
+ SYSCALL
+
+ MOVV 8(R29), R3 // sec
+ MOVV 16(R29), R5 // nsec
+
+ MOVV $1000000000, R4
+ MULVU R4, R3
+ MOVV LO, R3
+ ADDVU R5, R3
+ MOVV R3, ret+0(FP)
+ RET
+
+TEXT runtime·sigaction(SB),NOSPLIT,$0
+ MOVW sig+0(FP), R4 // arg 1 - signum
+ MOVV new+8(FP), R5 // arg 2 - new sigaction
+ MOVV old+16(FP), R6 // arg 3 - old sigaction
+ MOVV $46, R2 // sys_sigaction
+ SYSCALL
+ BEQ R7, 3(PC)
+ MOVV $3, R2 // crash on syscall failure
+ MOVV R2, (R2)
+ RET
+
+TEXT runtime·obsdsigprocmask(SB),NOSPLIT,$0
+ MOVW how+0(FP), R4 // arg 1 - mode
+ MOVW new+4(FP), R5 // arg 2 - new
+ MOVV $48, R2 // sys_sigprocmask
+ SYSCALL
+ BEQ R7, 3(PC)
+ MOVV $3, R2 // crash on syscall failure
+ MOVV R2, (R2)
+ MOVW R2, ret+8(FP)
+ RET
+
+TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
+ MOVW sig+8(FP), R4
+ MOVV info+16(FP), R5
+ MOVV ctx+24(FP), R6
+ MOVV fn+0(FP), R7
+ CALL (R7) // Alignment for ELF ABI?
+ RET
+
+TEXT runtime·sigtramp(SB),NOSPLIT,$192
+ // initialize REGSB = PC&0xffffffff00000000
+ BGEZAL R0, 1(PC)
+ SRLV $32, R31, RSB
+ SLLV $32, RSB
+
+ // this might be called in external code context,
+ // where g is not set.
+ MOVB runtime·iscgo(SB), R1
+ BEQ R1, 2(PC)
+ JAL runtime·load_g(SB)
+
+ MOVW R4, 8(R29)
+ MOVV R5, 16(R29)
+ MOVV R6, 24(R29)
+ MOVV $runtime·sigtrampgo(SB), R1
+ JAL (R1)
+ RET
+
+// int32 tfork(void *param, uintptr psize, M *mp, G *gp, void (*fn)(void));
+TEXT runtime·tfork(SB),NOSPLIT,$0
+
+ // Copy mp, gp and fn off parent stack for use by child.
+ MOVV mm+16(FP), R16
+ MOVV gg+24(FP), R17
+ MOVV fn+32(FP), R18
+
+ MOVV param+0(FP), R4 // arg 1 - param
+ MOVV psize+8(FP), R5 // arg 2 - psize
+ MOVV $8, R2 // sys___tfork
+ SYSCALL
+
+ // Return if syscall failed.
+ BEQ R7, 4(PC)
+ SUBVU R2, R0, R2 // caller expects negative errno
+ MOVW R2, ret+40(FP)
+ RET
+
+ // In parent, return.
+ BEQ R2, 3(PC)
+ MOVW R2, ret+40(FP)
+ RET
+
+ // Initialise m, g.
+ MOVV R17, g
+ MOVV R16, g_m(g)
+
+ // Call fn.
+ CALL (R18)
+
+ // fn should never return.
+ MOVV $2, R8 // crash if reached
+ MOVV R8, (R8)
+ RET
+
+TEXT runtime·sigaltstack(SB),NOSPLIT,$0
+ MOVV new+0(FP), R4 // arg 1 - new sigaltstack
+ MOVV old+8(FP), R5 // arg 2 - old sigaltstack
+ MOVV $288, R2 // sys_sigaltstack
+ SYSCALL
+ BEQ R7, 3(PC)
+ MOVV $0, R8 // crash on syscall failure
+ MOVV R8, (R8)
+ RET
+
+TEXT runtime·osyield(SB),NOSPLIT,$0
+ MOVV $298, R2 // sys_sched_yield
+ SYSCALL
+ RET
+
+TEXT runtime·thrsleep(SB),NOSPLIT,$0
+ MOVV ident+0(FP), R4 // arg 1 - ident
+ MOVW clock_id+8(FP), R5 // arg 2 - clock_id
+ MOVV tsp+16(FP), R6 // arg 3 - tsp
+ MOVV lock+24(FP), R7 // arg 4 - lock
+ MOVV abort+32(FP), R8 // arg 5 - abort
+ MOVV $94, R2 // sys___thrsleep
+ SYSCALL
+ MOVW R2, ret+40(FP)
+ RET
+
+TEXT runtime·thrwakeup(SB),NOSPLIT,$0
+ MOVV ident+0(FP), R4 // arg 1 - ident
+ MOVW n+8(FP), R5 // arg 2 - n
+ MOVV $301, R2 // sys___thrwakeup
+ SYSCALL
+ MOVW R2, ret+16(FP)
+ RET
+
+TEXT runtime·sysctl(SB),NOSPLIT,$0
+ MOVV mib+0(FP), R4 // arg 1 - mib
+ MOVW miblen+8(FP), R5 // arg 2 - miblen
+ MOVV out+16(FP), R6 // arg 3 - out
+ MOVV size+24(FP), R7 // arg 4 - size
+ MOVV dst+32(FP), R8 // arg 5 - dest
+ MOVV ndst+40(FP), R9 // arg 6 - newlen
+ MOVV $202, R2 // sys___sysctl
+ SYSCALL
+ BEQ R7, 2(PC)
+ SUBVU R2, R0, R2 // caller expects negative errno
+ MOVW R2, ret+48(FP)
+ RET
+
+// int32 runtime·kqueue(void);
+TEXT runtime·kqueue(SB),NOSPLIT,$0
+ MOVV $269, R2 // sys_kqueue
+ SYSCALL
+ BEQ R7, 2(PC)
+ SUBVU R2, R0, R2 // caller expects negative errno
+ MOVW R2, ret+0(FP)
+ RET
+
+// int32 runtime·kevent(int kq, Kevent *changelist, int nchanges, Kevent *eventlist, int nevents, Timespec *timeout);
+TEXT runtime·kevent(SB),NOSPLIT,$0
+ MOVW kq+0(FP), R4 // arg 1 - kq
+ MOVV ch+8(FP), R5 // arg 2 - changelist
+ MOVW nch+16(FP), R6 // arg 3 - nchanges
+ MOVV ev+24(FP), R7 // arg 4 - eventlist
+ MOVW nev+32(FP), R8 // arg 5 - nevents
+ MOVV ts+40(FP), R9 // arg 6 - timeout
+ MOVV $72, R2 // sys_kevent
+ SYSCALL
+ BEQ R7, 2(PC)
+ SUBVU R2, R0, R2 // caller expects negative errno
+ MOVW R2, ret+48(FP)
+ RET
+
+// func closeonexec(fd int32)
+TEXT runtime·closeonexec(SB),NOSPLIT,$0
+ MOVW fd+0(FP), R4 // arg 1 - fd
+ MOVV $2, R5 // arg 2 - cmd (F_SETFD)
+ MOVV $1, R6 // arg 3 - arg (FD_CLOEXEC)
+ MOVV $92, R2 // sys_fcntl
+ SYSCALL
+ RET
+
+// func runtime·setNonblock(int32 fd)
+TEXT runtime·setNonblock(SB),NOSPLIT|NOFRAME,$0-4
+ MOVW fd+0(FP), R4 // arg 1 - fd
+ MOVV $3, R5 // arg 2 - cmd (F_GETFL)
+ MOVV $0, R6 // arg 3
+ MOVV $92, R2 // sys_fcntl
+ SYSCALL
+ MOVV $4, R6 // O_NONBLOCK
+ OR R2, R6 // arg 3 - flags
+ MOVW fd+0(FP), R4 // arg 1 - fd
+ MOVV $4, R5 // arg 2 - cmd (F_SETFL)
+ MOVV $92, R2 // sys_fcntl
+ SYSCALL
+ RET
