| /* |
| * Copyright (C) 2009 Imagination Technologies |
| * |
| * This file is subject to the terms and conditions of the GNU General Public |
| * License. See the file COPYING in the main directory of this archive |
| * for more details. |
| * |
| * The Meta KICK interrupt mechanism is generally a useful feature, so |
| * we provide an interface for registering multiple interrupt |
| * handlers. All the registered interrupt handlers are "chained". When |
| * a KICK interrupt is received the first function in the list is |
| * called. If that interrupt handler cannot handle the KICK the next |
| * one is called, then the next until someone handles it (or we run |
| * out of functions). As soon as one function handles the interrupt no |
| * other handlers are called. |
| * |
| * The only downside of chaining interrupt handlers is that each |
| * handler must be able to detect whether the KICK was intended for it |
| * or not. For example, when the IPI handler runs and it sees that |
| * there are no IPI messages it must not signal that the KICK was |
| * handled, thereby giving the other handlers a chance to run. |
| * |
| * The reason that we provide our own interface for calling KICK |
| * handlers instead of using the generic kernel infrastructure is that |
| * the KICK handlers require access to a CPU's pTBI structure. So we |
| * pass it as an argument. |
| */ |
| #include <linux/export.h> |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/types.h> |
| |
| #include <asm/traps.h> |
| |
| /* |
| * All accesses/manipulations of kick_handlers_list should be |
| * performed while holding kick_handlers_lock. |
| */ |
| static DEFINE_SPINLOCK(kick_handlers_lock); |
| static LIST_HEAD(kick_handlers_list); |
| |
| void kick_register_func(struct kick_irq_handler *kh) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&kick_handlers_lock, flags); |
| |
| list_add_tail(&kh->list, &kick_handlers_list); |
| |
| spin_unlock_irqrestore(&kick_handlers_lock, flags); |
| } |
| EXPORT_SYMBOL(kick_register_func); |
| |
| void kick_unregister_func(struct kick_irq_handler *kh) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&kick_handlers_lock, flags); |
| |
| list_del(&kh->list); |
| |
| spin_unlock_irqrestore(&kick_handlers_lock, flags); |
| } |
| EXPORT_SYMBOL(kick_unregister_func); |
| |
| TBIRES |
| kick_handler(TBIRES State, int SigNum, int Triggers, int Inst, PTBI pTBI) |
| { |
| struct kick_irq_handler *kh; |
| struct list_head *lh; |
| int handled = 0; |
| TBIRES ret; |
| |
| head_end(State, ~INTS_OFF_MASK); |
| |
| /* If we interrupted user code handle any critical sections. */ |
| if (State.Sig.SaveMask & TBICTX_PRIV_BIT) |
| restart_critical_section(State); |
| |
| trace_hardirqs_off(); |
| |
| /* |
| * There is no need to disable interrupts here because we |
| * can't nest KICK interrupts in a KICK interrupt handler. |
| */ |
| spin_lock(&kick_handlers_lock); |
| |
| list_for_each(lh, &kick_handlers_list) { |
| kh = list_entry(lh, struct kick_irq_handler, list); |
| |
| ret = kh->func(State, SigNum, Triggers, Inst, pTBI, &handled); |
| if (handled) |
| break; |
| } |
| |
| spin_unlock(&kick_handlers_lock); |
| |
| WARN_ON(!handled); |
| |
| return tail_end(ret); |
| } |