Function fpu_kern_enter

freebsd/arm64/arm64/vfp.c:270–315

}

void
fpu_kern_enter(struct thread *td, struct fpu_kern_ctx *ctx, u_int flags)
{
	struct pcb *pcb;

	pcb = td->td_pcb;
	KASSERT((flags & FPU_KERN_NOCTX) != 0 || ctx != NULL,
	    ("ctx is required when !FPU_KERN_NOCTX"));
	KASSERT(ctx == NULL || (ctx->flags & FPU_KERN_CTX_INUSE) == 0,
	    ("using inuse ctx"));
	KASSERT((pcb->pcb_fpflags & PCB_FP_NOSAVE) == 0,
	    ("recursive fpu_kern_enter while in PCB_FP_NOSAVE state"));

	if ((flags & FPU_KERN_NOCTX) != 0) {
		critical_enter();
		if (curthread == PCPU_GET(fpcurthread)) {
			vfp_save_state(curthread, pcb);
		}
		PCPU_SET(fpcurthread, NULL);

		vfp_enable();
		pcb->pcb_fpflags |= PCB_FP_KERN | PCB_FP_NOSAVE |
		    PCB_FP_STARTED;
		return;
	}

	if ((flags & FPU_KERN_KTHR) != 0 && is_fpu_kern_thread(0)) {
		ctx->flags = FPU_KERN_CTX_DUMMY | FPU_KERN_CTX_INUSE;
		return;
	}
	/*
	 * Check either we are already using the VFP in the kernel, or
	 * the the saved state points to the default user space.
	 */
	KASSERT((pcb->pcb_fpflags & PCB_FP_KERN) != 0 ||
	    pcb->pcb_fpusaved == &pcb->pcb_fpustate,
	    ("Mangled pcb_fpusaved %x %p %p", pcb->pcb_fpflags, pcb->pcb_fpusaved, &pcb->pcb_fpustate));
	ctx->flags = FPU_KERN_CTX_INUSE;
	vfp_save_state(curthread, pcb);
	ctx->prev = pcb->pcb_fpusaved;
	pcb->pcb_fpusaved = &ctx->state;
	pcb->pcb_fpflags |= PCB_FP_KERN;
	pcb->pcb_fpflags &= ~PCB_FP_STARTED;

	return;
}

int
fpu_kern_leave(struct thread *td, struct fpu_kern_ctx *ctx)