runtime: inline calls to notok

When a very low-level system call that should never fail
does fail, we call notok, which crashes the program.
Often, we are then left with only the program counter as
information about the crash, and it is in notok.
Instead, inline calls to notok (it is just one instruction
on most systems) so that the program counter will
tell us which system call is unhappy.

R=golang-dev, gri, minux.ma, bradfitz
CC=golang-dev
https://golang.org/cl/5792048

src/pkg/runtime/asm_amd64.s

@@ -73,7 +73,7 @@ ok:
 	// start this M
 	CALL	runtime·mstart(SB)
 
-	CALL	runtime·notok(SB)		// never returns
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·breakpoint(SB),7,$0

src/pkg/runtime/sys_darwin_386.s

@@ -8,15 +8,11 @@
 
 #include "zasm_GOOS_GOARCH.h"
 
-TEXT runtime·notok(SB),7,$0
-	MOVL	$0xf1, 0xf1
-	RET
-
 // Exit the entire program (like C exit)
 TEXT runtime·exit(SB),7,$0
 	MOVL	$1, AX
 	INT	$0x80
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 // Exit this OS thread (like pthread_exit, which eventually
@@ -25,7 +21,7 @@ TEXT runtime·exit1(SB),7,$0
 	MOVL	$361, AX
 	INT	$0x80
 	JAE 2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·write(SB),7,$0
@@ -52,14 +48,14 @@ TEXT runtime·madvise(SB),7,$0
 	MOVL	$75, AX
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·munmap(SB),7,$0
 	MOVL	$73, AX
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·setitimer(SB),7,$0
@@ -110,14 +106,14 @@ TEXT runtime·sigprocmask(SB),7,$0
 	MOVL	$329, AX  // pthread_sigmask (on OS X, sigprocmask==entire process)
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigaction(SB),7,$0
 	MOVL	$46, AX
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 // Sigtramp's job is to call the actual signal handler.
@@ -165,14 +161,14 @@ TEXT runtime·sigtramp(SB),7,$40
 	MOVL	BX, 8(SP)
 	MOVL	$184, AX	// sigreturn(ucontext, infostyle)
 	INT	$0x80
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigaltstack(SB),7,$0
 	MOVL	$53, AX
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·usleep(SB),7,$32
@@ -268,7 +264,7 @@ TEXT runtime·bsdthread_register(SB),7,$40
 	MOVL	$0, 24(SP)	// dispatchqueue_offset
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 // Invoke Mach system call.

src/pkg/runtime/sys_darwin_amd64.s

@@ -18,7 +18,7 @@ TEXT runtime·exit(SB),7,$0
 	MOVL	8(SP), DI		// arg 1 exit status
 	MOVL	$(0x2000000+1), AX	// syscall entry
 	SYSCALL
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 // Exit this OS thread (like pthread_exit, which eventually
@@ -27,7 +27,7 @@ TEXT runtime·exit1(SB),7,$0
 	MOVL	8(SP), DI		// arg 1 exit status
 	MOVL	$(0x2000000+361), AX	// syscall entry
 	SYSCALL
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·write(SB),7,$0
@@ -62,7 +62,7 @@ TEXT runtime·madvise(SB), 7, $0
 	MOVL	$(0x2000000+75), AX	// syscall entry madvise
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 // func now() (sec int64, nsec int32)
@@ -99,7 +99,7 @@ TEXT runtime·sigprocmask(SB),7,$0
 	MOVL	$(0x2000000+329), AX  // pthread_sigmask (on OS X, sigprocmask==entire process)
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigaction(SB),7,$0
@@ -111,7 +111,7 @@ TEXT runtime·sigaction(SB),7,$0
 	MOVL	$(0x2000000+46), AX	// syscall entry
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigtramp(SB),7,$64
@@ -164,12 +164,7 @@ TEXT runtime·munmap(SB),7,$0
 	MOVL	$(0x2000000+73), AX	// syscall entry
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
-	RET
-
-TEXT runtime·notok(SB),7,$0
-	MOVL	$0xf1, BP
-	MOVQ	BP, (BP)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigaltstack(SB),7,$0
@@ -178,7 +173,7 @@ TEXT runtime·sigaltstack(SB),7,$0
 	MOVQ	$(0x2000000+53), AX
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·usleep(SB),7,$16
@@ -266,7 +261,7 @@ TEXT runtime·bsdthread_register(SB),7,$0
 	MOVQ	$(0x2000000+366), AX	// bsdthread_register
 	SYSCALL
 	JCC 2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 // Mach system calls use 0x1000000 instead of the BSD's 0x2000000.

src/pkg/runtime/sys_freebsd_386.s

@@ -45,14 +45,14 @@ TEXT runtime·thr_start(SB),7,$0
 TEXT runtime·exit(SB),7,$-4
 	MOVL	$1, AX
 	INT	$0x80
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·exit1(SB),7,$-4
 	MOVL	$431, AX
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·write(SB),7,$-4
@@ -79,10 +79,6 @@ TEXT runtime·raisesigpipe(SB),7,$12
 	INT	$0x80
 	RET
 
-TEXT runtime·notok(SB),7,$0
-	MOVL	$0xf1, 0xf1
-	RET
-
 TEXT runtime·mmap(SB),7,$32
 	LEAL arg0+0(FP), SI
 	LEAL	4(SP), DI
@@ -103,7 +99,7 @@ TEXT runtime·munmap(SB),7,$-4
 	MOVL	$73, AX
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·setitimer(SB), 7, $-4
@@ -157,7 +153,7 @@ TEXT runtime·sigaction(SB),7,$-4
 	MOVL	$416, AX
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigtramp(SB),7,$44
@@ -194,14 +190,14 @@ TEXT runtime·sigtramp(SB),7,$44
 	MOVL	AX, 4(SP)
 	MOVL	$417, AX	// sigreturn(ucontext)
 	INT	$0x80
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigaltstack(SB),7,$0
 	MOVL	$53, AX
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·usleep(SB),7,$20
@@ -317,7 +313,7 @@ TEXT runtime·sigprocmask(SB),7,$16
 	MOVL	$340, AX		// sys_sigprocmask
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 GLOBL runtime·tlsoffset(SB),$4

src/pkg/runtime/sys_freebsd_amd64.s

@@ -47,14 +47,14 @@ TEXT runtime·exit(SB),7,$-8
 	MOVL	8(SP), DI		// arg 1 exit status
 	MOVL	$1, AX
 	SYSCALL
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·exit1(SB),7,$-8
 	MOVQ	8(SP), DI		// arg 1 exit status
 	MOVL	$431, AX
 	SYSCALL
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·write(SB),7,$-8
@@ -129,7 +129,7 @@ TEXT runtime·sigaction(SB),7,$-8
 	MOVL	$416, AX
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigtramp(SB),7,$64
@@ -174,12 +174,7 @@ TEXT runtime·munmap(SB),7,$0
 	MOVL	$73, AX
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
-	RET
-
-TEXT runtime·notok(SB),7,$-8
-	MOVL	$0xf1, BP
-	MOVQ	BP, (BP)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigaltstack(SB),7,$-8
@@ -188,7 +183,7 @@ TEXT runtime·sigaltstack(SB),7,$-8
 	MOVQ	$53, AX
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·usleep(SB),7,$16
@@ -216,7 +211,7 @@ TEXT runtime·settls(SB),7,$8
 	MOVQ	$165, AX	// sysarch
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sysctl(SB),7,$0
@@ -246,5 +241,5 @@ TEXT runtime·sigprocmask(SB),7,$0
 	MOVL	$340, AX		// sys_sigprocmask
 	SYSCALL
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET

src/pkg/runtime/sys_linux_amd64.s

@@ -139,7 +139,7 @@ TEXT runtime·rtsigprocmask(SB),7,$0-32
 	SYSCALL
 	CMPQ	AX, $0xfffffffffffff001
 	JLS	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·rt_sigaction(SB),7,$0-32
@@ -205,7 +205,7 @@ TEXT runtime·munmap(SB),7,$0
 	SYSCALL
 	CMPQ	AX, $0xfffffffffffff001
 	JLS	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·madvise(SB),7,$0
@@ -216,12 +216,7 @@ TEXT runtime·madvise(SB),7,$0
 	SYSCALL
 	CMPQ	AX, $0xfffffffffffff001
 	JLS	2(PC)
-	CALL	runtime·notok(SB)
-	RET
-
-TEXT runtime·notok(SB),7,$0
-	MOVQ	$0xf1, BP
-	MOVQ	BP, (BP)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 // int64 futex(int32 *uaddr, int32 op, int32 val,
@@ -290,7 +285,7 @@ TEXT runtime·sigaltstack(SB),7,$-8
 	SYSCALL
 	CMPQ	AX, $0xfffffffffffff001
 	JLS	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 // set tls base to DI
@@ -303,7 +298,7 @@ TEXT runtime·settls(SB),7,$32
 	SYSCALL
 	CMPQ	AX, $0xfffffffffffff001
 	JLS	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·osyield(SB),7,$0

src/pkg/runtime/sys_linux_arm.s

@@ -38,11 +38,6 @@
 #define ARM_BASE (SYS_BASE + 0x0f0000)
 #define SYS_ARM_cacheflush (ARM_BASE + 2)
 
-TEXT notok<>(SB),7,$0
-	MOVW	$0, R9
-	MOVW	R9, (R9)
-	B   	0(PC)
-
 TEXT runtime·open(SB),7,$0
 	MOVW	0(FP), R0
 	MOVW	4(FP), R1
@@ -126,7 +121,8 @@ TEXT runtime·munmap(SB),7,$0
 	SWI	$0
 	MOVW	$0xfffff001, R6
 	CMP 	R6, R0
-	BL.HI	notok<>(SB)
+	MOVW.HI	$0, R9  // crash on syscall failure
+	MOVW.HI	R9, (R9)
 	RET
 
 TEXT runtime·madvise(SB),7,$0
@@ -137,7 +133,8 @@ TEXT runtime·madvise(SB),7,$0
 	SWI	$0
 	MOVW	$0xfffff001, R6
 	CMP 	R6, R0
-	BL.HI	notok<>(SB)
+	MOVW.HI	$0, R9  // crash on syscall failure
+	MOVW.HI	R9, (R9)
 	RET
 
 TEXT runtime·setitimer(SB),7,$0
@@ -291,7 +288,8 @@ TEXT runtime·sigaltstack(SB),7,$0
 	SWI	$0
 	MOVW	$0xfffff001, R6
 	CMP 	R6, R0
-	BL.HI	notok<>(SB)
+	MOVW.HI	$0, R9  // crash on syscall failure
+	MOVW.HI	R9, (R9)
 	RET
 
 TEXT runtime·sigtramp(SB),7,$24

src/pkg/runtime/sys_netbsd_386.s

@@ -12,14 +12,14 @@
 TEXT runtime·exit(SB),7,$-4
 	MOVL	$1, AX
 	INT	$0x80
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·exit1(SB),7,$-4
 	MOVL	$302, AX		// sys_threxit
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·write(SB),7,$-4
@@ -55,10 +55,6 @@ TEXT runtime·raisesigpipe(SB),7,$12
 	INT	$0x80
 	RET
 
-TEXT runtime·notok(SB),7,$0
-	MOVL	$0xf1, 0xf1
-	RET
-
 TEXT runtime·mmap(SB),7,$36
 	LEAL	arg0+0(FP), SI
 	LEAL	4(SP), DI
@@ -83,7 +79,7 @@ TEXT runtime·munmap(SB),7,$-4
 	MOVL	$73, AX			// sys_munmap
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·setitimer(SB),7,$-4
@@ -136,7 +132,7 @@ TEXT runtime·sigaction(SB),7,$-4
 	MOVL	$46, AX			// sys_sigaction
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigtramp(SB),7,$44
@@ -173,7 +169,7 @@ TEXT runtime·sigtramp(SB),7,$44
 	MOVL	AX, 4(SP)		// arg 1 - sigcontext
 	MOVL	$103, AX		// sys_sigreturn
 	INT	$0x80
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 // int32 rfork_thread(int32 flags, void *stack, M *m, G *g, void (*fn)(void));
@@ -285,7 +281,7 @@ TEXT runtime·settls(SB),7,$16
 	MOVL	$165, AX		// sys_sysarch
 	INT	$0x80
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·osyield(SB),7,$-4

src/pkg/runtime/sys_netbsd_amd64.s

@@ -83,13 +83,13 @@ TEXT runtime·exit(SB),7,$-8
 	MOVL	8(SP), DI		// arg 1 - exit status
 	MOVL	$1, AX			// sys_exit
 	SYSCALL
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·exit1(SB),7,$-8
 	MOVL	$302, AX		// sys_threxit
 	SYSCALL
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·write(SB),7,$-8
@@ -170,7 +170,7 @@ TEXT runtime·sigaction(SB),7,$-8
 	MOVL	$46, AX
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigtramp(SB),7,$64
@@ -221,12 +221,7 @@ TEXT runtime·munmap(SB),7,$0
 	MOVL	$73, AX			// sys_munmap
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
-	RET
-
-TEXT runtime·notok(SB),7,$-8
-	MOVL	$0xf1, BP
-	MOVQ	BP, (BP)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigaltstack(SB),7,$-8
@@ -235,7 +230,7 @@ TEXT runtime·sigaltstack(SB),7,$-8
 	MOVQ	$288, AX		// sys_sigaltstack
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 // set tls base to DI
@@ -248,7 +243,7 @@ TEXT runtime·settls(SB),7,$8
 	MOVQ	$165, AX		// sys_sysarch
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sysctl(SB),7,$0

src/pkg/runtime/sys_openbsd_386.s

@@ -12,14 +12,14 @@
 TEXT runtime·exit(SB),7,$-4
 	MOVL	$1, AX
 	INT	$0x80
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·exit1(SB),7,$-4
 	MOVL	$302, AX		// sys_threxit
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·write(SB),7,$-4
@@ -55,10 +55,6 @@ TEXT runtime·raisesigpipe(SB),7,$12
 	INT	$0x80
 	RET
 
-TEXT runtime·notok(SB),7,$0
-	MOVL	$0xf1, 0xf1
-	RET
-
 TEXT runtime·mmap(SB),7,$36
 	LEAL	arg0+0(FP), SI
 	LEAL	4(SP), DI
@@ -83,7 +79,7 @@ TEXT runtime·munmap(SB),7,$-4
 	MOVL	$73, AX			// sys_munmap
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·setitimer(SB),7,$-4
@@ -136,7 +132,7 @@ TEXT runtime·sigaction(SB),7,$-4
 	MOVL	$46, AX			// sys_sigaction
 	INT	$0x80
 	JAE	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigtramp(SB),7,$44
@@ -173,7 +169,7 @@ TEXT runtime·sigtramp(SB),7,$44
 	MOVL	AX, 4(SP)		// arg 1 - sigcontext
 	MOVL	$103, AX		// sys_sigreturn
 	INT	$0x80
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 // int32 rfork_thread(int32 flags, void *stack, M *m, G *g, void (*fn)(void));
@@ -285,7 +281,7 @@ TEXT runtime·settls(SB),7,$16
 	MOVL	$165, AX		// sys_sysarch
 	INT	$0x80
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·osyield(SB),7,$-4

src/pkg/runtime/sys_openbsd_amd64.s

@@ -83,13 +83,13 @@ TEXT runtime·exit(SB),7,$-8
 	MOVL	8(SP), DI		// arg 1 - exit status
 	MOVL	$1, AX			// sys_exit
 	SYSCALL
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·exit1(SB),7,$-8
 	MOVL	$302, AX		// sys_threxit
 	SYSCALL
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·write(SB),7,$-8
@@ -170,7 +170,7 @@ TEXT runtime·sigaction(SB),7,$-8
 	MOVL	$46, AX
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigtramp(SB),7,$64
@@ -221,12 +221,7 @@ TEXT runtime·munmap(SB),7,$0
 	MOVL	$73, AX			// sys_munmap
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
-	RET
-
-TEXT runtime·notok(SB),7,$-8
-	MOVL	$0xf1, BP
-	MOVQ	BP, (BP)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sigaltstack(SB),7,$-8
@@ -235,7 +230,7 @@ TEXT runtime·sigaltstack(SB),7,$-8
 	MOVQ	$288, AX		// sys_sigaltstack
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 // set tls base to DI
@@ -248,7 +243,7 @@ TEXT runtime·settls(SB),7,$8
 	MOVQ	$165, AX		// sys_sysarch
 	SYSCALL
 	JCC	2(PC)
-	CALL	runtime·notok(SB)
+	MOVL	$0xf1, 0xf1  // crash
 	RET
 
 TEXT runtime·sysctl(SB),7,$0

src/pkg/runtime/sys_windows_amd64.s

@@ -268,11 +268,6 @@ TEXT runtime·tstart_stdcall(SB),7,$0
 	XORL	AX, AX			// return 0 == success
 	RET
 
-TEXT runtime·notok(SB),7,$0
-	MOVQ	$0xf1, BP
-	MOVQ	BP, (BP)
-	RET
-
 // set tls base to DI
 TEXT runtime·settls(SB),7,$0
 	CALL	runtime·setstacklimits(SB)