// from other sources are always considered valid.
//
//go:nosplit
func validSIGPROF(mp *m, c *sigctxt) bool {
	code := int32(c.sigcode())
	setitimer := code == _SI_KERNEL
	timer_create := code == _SI_TIMER

	if !(setitimer || timer_create) {
		// The signal doesn't correspond to a profiling mechanism that the
		// runtime enables itself. There's no reason to process it, but there's
		// no reason to ignore it either.

	// (Other calls to add or addNonGo should be blocked out
	// by the fact that only one SIGPROF can be handled by the
	// process at a time. If not, this lock will serialize those too.
	// The use of timer_create(2) on Linux to request process-targeted
	// signals may have changed this.)
	for !prof.signalLock.CompareAndSwap(0, 1) {
		// TODO: Is it safe to osyield here? https://go.dev/issue/52672
		osyield()
	}

TEXT runtime·setitimer(SB),NOSPLIT|NOFRAME,$0-24
	MOVW	mode+0(FP), A0
	MOV	new+8(FP), A1
	MOV	old+16(FP), A2
	MOV	$SYS_setitimer, A7
	ECALL
	RET

// func timer_create(clockid int32, sevp *sigevent, timerid *int32) int32
TEXT runtime·timer_create(SB),NOSPLIT,$0-28
	MOVW	clockid+0(FP), A0
	MOV	sevp+8(FP), A1
	MOV	timerid+16(FP), A2
	MOV	$SYS_timer_create, A7
	ECALL

TEXT runtime·setitimer(SB),NOSPLIT|NOFRAME,$0-24
	MOVW	mode+0(FP), R4
	MOVV	new+8(FP), R5
	MOVV	old+16(FP), R6
	MOVV	$SYS_setitimer, R11
	SYSCALL
	RET

// func timer_create(clockid int32, sevp *sigevent, timerid *int32) int32
TEXT runtime·timer_create(SB),NOSPLIT,$0-28
	MOVW	clockid+0(FP), R4
	MOVV	sevp+8(FP), R5
	MOVV	timerid+16(FP), R6
	MOVV	$SYS_timer_create, R11
	SYSCALL

	SYS_SHMDT                = 230 // { int|sys||shmdt(const void *shmaddr); }
	SYS_SHMGET               = 231 // { int|sys||shmget(key_t key, size_t size, int shmflg); }
	SYS_TIMER_CREATE         = 235 // { int|sys||timer_create(clockid_t clock_id, struct sigevent *evp, timer_t *timerid); }
	SYS_TIMER_DELETE         = 236 // { int|sys||timer_delete(timer_t timerid); }
	SYS_TIMER_GETOVERRUN     = 239 // { int|sys||timer_getoverrun(timer_t timerid); }

	SYS_SHMDT                = 230 // { int|sys||shmdt(const void *shmaddr); }
	SYS_SHMGET               = 231 // { int|sys||shmget(key_t key, size_t size, int shmflg); }
	SYS_TIMER_CREATE         = 235 // { int|sys||timer_create(clockid_t clock_id, struct sigevent *evp, timer_t *timerid); }
	SYS_TIMER_DELETE         = 236 // { int|sys||timer_delete(timer_t timerid); }
	SYS_TIMER_GETOVERRUN     = 239 // { int|sys||timer_getoverrun(timer_t timerid); }

	SYS_SHMDT                = 230 // { int|sys||shmdt(const void *shmaddr); }
	SYS_SHMGET               = 231 // { int|sys||shmget(key_t key, size_t size, int shmflg); }
	SYS_TIMER_CREATE         = 235 // { int|sys||timer_create(clockid_t clock_id, struct sigevent *evp, timer_t *timerid); }
	SYS_TIMER_DELETE         = 236 // { int|sys||timer_delete(timer_t timerid); }
	SYS_TIMER_GETOVERRUN     = 239 // { int|sys||timer_getoverrun(timer_t timerid); }

	SYS_SHMDT                = 230 // { int|sys||shmdt(const void *shmaddr); }
	SYS_SHMGET               = 231 // { int|sys||shmget(key_t key, size_t size, int shmflg); }
	SYS_TIMER_CREATE         = 235 // { int|sys||timer_create(clockid_t clock_id, struct sigevent *evp, timer_t *timerid); }
	SYS_TIMER_DELETE         = 236 // { int|sys||timer_delete(timer_t timerid); }
	SYS_TIMER_GETOVERRUN     = 239 // { int|sys||timer_getoverrun(timer_t timerid); }

	SYS_SHMDT                = 230 // { int|sys||shmdt(const void *shmaddr); }
	SYS_SHMGET               = 231 // { int|sys||shmget(key_t key, size_t size, int shmflg); }
	SYS_TIMER_CREATE         = 235 // { int|sys||timer_create(clockid_t clock_id, struct sigevent *evp, timer_t *timerid); }
	SYS_TIMER_DELETE         = 236 // { int|sys||timer_delete(timer_t timerid); }
	SYS_TIMER_GETOVERRUN     = 239 // { int|sys||timer_getoverrun(timer_t timerid); }

	SYS_SHMDT                = 230 // { int|sys||shmdt(const void *shmaddr); }
	SYS_SHMGET               = 231 // { int|sys||shmget(key_t key, size_t size, int shmflg); }
	SYS_TIMER_CREATE         = 235 // { int|sys||timer_create(clockid_t clock_id, struct sigevent *evp, timer_t *timerid); }
	SYS_TIMER_DELETE         = 236 // { int|sys||timer_delete(timer_t timerid); }
	SYS_TIMER_GETOVERRUN     = 239 // { int|sys||timer_getoverrun(timer_t timerid); }