path: root/arch/powerpc/kernel/irq.c

/*
 *  Derived from arch/i386/kernel/irq.c
 *    Copyright (C) 1992 Linus Torvalds
 *  Adapted from arch/i386 by Gary Thomas
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *  Updated and modified by Cort Dougan <cort@fsmlabs.com>
 *    Copyright (C) 1996-2001 Cort Dougan
 *  Adapted for Power Macintosh by Paul Mackerras
 *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * This file contains the code used by various IRQ handling routines:
 * asking for different IRQ's should be done through these routines
 * instead of just grabbing them. Thus setups with different IRQ numbers
 * shouldn't result in any weird surprises, and installing new handlers
 * should be easier.
 *
 * The MPC8xx has an interrupt mask in the SIU.  If a bit is set, the
 * interrupt is _enabled_.  As expected, IRQ0 is bit 0 in the 32-bit
 * mask register (of which only 16 are defined), hence the weird shifting
 * and complement of the cached_irq_mask.  I want to be able to stuff
 * this right into the SIU SMASK register.
 * Many of the prep/chrp functions are conditional compiled on CONFIG_8xx
 * to reduce code space and undefined function references.
 */

#undef DEBUG

#include <linux/module.h>
#include <linux/threads.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/timex.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/seq_file.h>
#include <linux/cpumask.h>
#include <linux/profile.h>
#include <linux/bitops.h>
#include <linux/list.h>
#include <linux/radix-tree.h>
#include <linux/mutex.h>
#include <linux/bootmem.h>
#include <linux/pci.h>
#include <linux/debugfs.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/irq.h>
#include <asm/cache.h>
#include <asm/prom.h>
#include <asm/ptrace.h>
#include <asm/machdep.h>
#include <asm/udbg.h>
#ifdef CONFIG_PPC64
#include <asm/paca.h>
#include <asm/firmware.h>
#include <asm/lv1call.h>
#endif

int __irq_offset_value;
static int ppc_spurious_interrupts;

#ifdef CONFIG_PPC32
EXPORT_SYMBOL(__irq_offset_value);
atomic_t ppc_n_lost_interrupts;

#ifdef CONFIG_TAU_INT
extern int tau_initialized;
extern int tau_interrupts(int);
#endif
#endif /* CONFIG_PPC32 */

#ifdef CONFIG_PPC64
EXPORT_SYMBOL(irq_desc);

int distribute_irqs = 1;

static inline notrace unsigned long get_hard_enabled(void)
{
	unsigned long enabled;

	__asm__ __volatile__("lbz %0,%1(13)"
	: "=r" (enabled) : "i" (offsetof(struct paca_struct, hard_enabled)));

	return enabled;
}

static inline notrace void set_soft_enabled(unsigned long enable)
{
	__asm__ __volatile__("stb %0,%1(13)"
	: : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
}

notrace void raw_local_irq_restore(unsigned long en)
{
	/*
	 * get_paca()->soft_enabled = en;
	 * Is it ever valid to use local_irq_restore(0) when soft_enabled is 1?
	 * That was allowed before, and in such a case we do need to take care
	 * that gcc will set soft_enabled directly via r13, not choose to use
	 * an intermediate register, lest we're preempted to a different cpu.
	 */
	set_soft_enabled(en);
	if (!en)
		return;

	if (firmware_has_feature(FW_FEATURE_ISERIES)) {
		/*
		 * Do we need to disable preemption here?  Not really: in the
		 * unlikely event that we're preempted to a different cpu in
		 * between getting r13, loading its lppaca_ptr, and loading
		 * its any_int, we might call iseries_handle_interrupts without
		 * an interrupt pending on the new cpu, but that's no disaster,
		 * is it?  And the business of preempting us off the old cpu
		 * would itself involve a local_irq_restore which handles the
		 * interrupt to that cpu.
		 *
		 * But use "local_paca->lppaca_ptr" instead of "get_lppaca()"
		 * to avoid any preemption checking added into get_paca().
		 */
		if (local_paca->lppaca_ptr->int_dword.any_int)
			iseries_handle_interrupts();
	}

	/*
	 * if (get_paca()->hard_enabled) return;
	 * But again we need to take care that gcc gets hard_enabled directly
	 * via r13, not choose to use an intermediate register, lest we're
	 * preempted to a different cpu in between the two instructions.
	 */
	if (get_hard_enabled())
		return;

	/*
	 * Need to hard-enable interrupts here.  Since currently disabled,
	 * no need to take further asm precautions against preemption; but
	 * use local_paca instead of get_paca() to avoid preemption checking.
	 */
	local_paca->hard_enabled = en;
	if ((int)mfspr(SPRN_DEC) < 0)
		mtspr(SPRN_DEC, 1);

	/*
	 * Force the delivery of pending soft-disabled interrupts on PS3.
	 * Any HV call will have this side effect.
	 */
	if (firmware_has_feature(FW_FEATURE_PS3_LV1)) {
		u64 tmp;
		lv1_get_version_info(&tmp);
	}

	__hard_irq_enable();
}
EXPORT_SYMBOL(raw_local_irq_restore);
#endif /* CONFIG_PPC64 */

int show_interrupts(struct seq_file *p, void *v)
{
	int i = *(loff_t *)v, j;
	struct irqaction *action;
	irq_desc_t *desc;
	unsigned long flags;

	if (i == 0) {
		seq_puts(p, "           ");
		for_each_online_cpu(j)
			seq_printf(p, "CPU%d       ", j);
		seq_putc(p, '\n');
	}

	i