mca.c

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	old_sw->ar_fpsr = old_regs->ar_fpsr;
	copy_reg(&ms->pmsa_gr[4-1], ms->pmsa_nat_bits, &old_sw->r4, &old_unat);
	copy_reg(&ms->pmsa_gr[5-1], ms->pmsa_nat_bits, &old_sw->r5, &old_unat);
	copy_reg(&ms->pmsa_gr[6-1], ms->pmsa_nat_bits, &old_sw->r6, &old_unat);
	copy_reg(&ms->pmsa_gr[7-1], ms->pmsa_nat_bits, &old_sw->r7, &old_unat);
	old_sw->b0 = (u64)ia64_leave_kernel;
	old_sw->b1 = ms->pmsa_br1;
	old_sw->ar_pfs = 0;
	old_sw->ar_unat = old_unat;
	old_sw->pr = old_regs->pr | (1UL << PRED_NON_SYSCALL);
	previous_current->thread.ksp = (u64)p - 16;

	/* Finally copy the original stack's registers back to its RBS.
	 * Registers from ar.bspstore through ar.bsp at the time of the event
	 * are in the current RBS, copy them back to the original stack.  The
	 * copy must be done register by register because the original bspstore
	 * and the current one have different alignments, so the saved RNAT
	 * data occurs at different places.
	 *
	 * mca_asm does cover, so the old_bsp already includes all registers at
	 * the time of MCA/INIT.  It also does flushrs, so all registers before
	 * this function have been written to backing store on the MCA/INIT
	 * stack.
	 */
	new_rnat = ia64_get_rnat(ia64_rse_rnat_addr(new_bspstore));
	old_rnat = regs->ar_rnat;
	while (slots--) {
		if (ia64_rse_is_rnat_slot(new_bspstore)) {
			new_rnat = ia64_get_rnat(new_bspstore++);
		}
		if (ia64_rse_is_rnat_slot(old_bspstore)) {
			*old_bspstore++ = old_rnat;
			old_rnat = 0;
		}
		nat = (new_rnat >> ia64_rse_slot_num(new_bspstore)) & 1UL;
		old_rnat &= ~(1UL << ia64_rse_slot_num(old_bspstore));
		old_rnat |= (nat << ia64_rse_slot_num(old_bspstore));
		*old_bspstore++ = *new_bspstore++;
	}
	old_sw->ar_bspstore = (unsigned long)old_bspstore;
	old_sw->ar_rnat = old_rnat;

	sos->prev_task = previous_current;
	return previous_current;

no_mod:
	printk(KERN_INFO "cpu %d, %s %s, original stack not modified\n",
			smp_processor_id(), type, msg);
	return previous_current;
}

/* The monarch/slave interaction is based on monarch_cpu and requires that all
 * slaves have entered rendezvous before the monarch leaves.  If any cpu has
 * not entered rendezvous yet then wait a bit.  The assumption is that any
 * slave that has not rendezvoused after a reasonable time is never going to do
 * so.  In this context, slave includes cpus that respond to the MCA rendezvous
 * interrupt, as well as cpus that receive the INIT slave event.
 */

static void
ia64_wait_for_slaves(int monarch)
{
	int c, wait = 0;
	for_each_online_cpu(c) {
		if (c == monarch)
			continue;
		if (ia64_mc_info.imi_rendez_checkin[c] == IA64_MCA_RENDEZ_CHECKIN_NOTDONE) {
			udelay(1000);		/* short wait first */
			wait = 1;
			break;
		}
	}
	if (!wait)
		return;
	for_each_online_cpu(c) {
		if (c == monarch)
			continue;
		if (ia64_mc_info.imi_rendez_checkin[c] == IA64_MCA_RENDEZ_CHECKIN_NOTDONE) {
			udelay(5*1000000);	/* wait 5 seconds for slaves (arbitrary) */
			break;
		}
	}
}

/*
 * ia64_mca_handler
 *
 *	This is uncorrectable machine check handler called from OS_MCA
 *	dispatch code which is in turn called from SAL_CHECK().
 *	This is the place where the core of OS MCA handling is done.
 *	Right now the logs are extracted and displayed in a well-defined
 *	format. This handler code is supposed to be run only on the
 *	monarch processor. Once the monarch is done with MCA handling
 *	further MCA logging is enabled by clearing logs.
 *	Monarch also has the duty of sending wakeup-IPIs to pull the
 *	slave processors out of rendezvous spinloop.
 */
void
ia64_mca_handler(struct pt_regs *regs, struct switch_stack *sw,
		 struct ia64_sal_os_state *sos)
{
	pal_processor_state_info_t *psp = (pal_processor_state_info_t *)
		&sos->proc_state_param;
	int recover, cpu = smp_processor_id();
	task_t *previous_current;

	oops_in_progress = 1;	/* FIXME: make printk NMI/MCA/INIT safe */
	previous_current = ia64_mca_modify_original_stack(regs, sw, sos, "MCA");
	monarch_cpu = cpu;
	ia64_wait_for_slaves(cpu);

	/* Wakeup all the processors which are spinning in the rendezvous loop.
	 * They will leave SAL, then spin in the OS with interrupts disabled
	 * until this monarch cpu leaves the MCA handler.  That gets control
	 * back to the OS so we can backtrace the other cpus, backtrace when
	 * spinning in SAL does not work.
	 */
	ia64_mca_wakeup_all();

	/* Get the MCA error record and log it */
	ia64_mca_log_sal_error_record(SAL_INFO_TYPE_MCA);

	/* TLB error is only exist in this SAL error record */
	recover = (psp->tc && !(psp->cc || psp->bc || psp->rc || psp->uc))
	/* other error recovery */
	   || (ia64_mca_ucmc_extension
		&& ia64_mca_ucmc_extension(
			IA64_LOG_CURR_BUFFER(SAL_INFO_TYPE_MCA),
			sos));

	if (recover) {
		sal_log_record_header_t *rh = IA64_LOG_CURR_BUFFER(SAL_INFO_TYPE_MCA);
		rh->severity = sal_log_severity_corrected;
		ia64_sal_clear_state_info(SAL_INFO_TYPE_MCA);
		sos->os_status = IA64_MCA_CORRECTED;
	}

	set_curr_task(cpu, previous_current);
	monarch_cpu = -1;
}

static DECLARE_WORK(cmc_disable_work, ia64_mca_cmc_vector_disable_keventd, NULL);
static DECLARE_WORK(cmc_enable_work, ia64_mca_cmc_vector_enable_keventd, NULL);

/*
 * ia64_mca_cmc_int_handler
 *
 *  This is corrected machine check interrupt handler.
 *	Right now the logs are extracted and displayed in a well-defined
 *	format.
 *
 * Inputs
 *      interrupt number
 *      client data arg ptr
 *      saved registers ptr
 *
 * Outputs
 *	None
 */
static irqreturn_t
ia64_mca_cmc_int_handler(int cmc_irq, void *arg, struct pt_regs *ptregs)
{
	static unsigned long	cmc_history[CMC_HISTORY_LENGTH];
	static int		index;
	static DEFINE_SPINLOCK(cmc_history_lock);

	IA64_MCA_DEBUG("%s: received interrupt vector = %#x on CPU %d\n",
		       __FUNCTION__, cmc_irq, smp_processor_id());

	/* SAL spec states this should run w/ interrupts enabled */
	local_irq_enable();

	/* Get the CMC error record and log it */
	ia64_mca_log_sal_error_record(SAL_INFO_TYPE_CMC);

	spin_lock(&cmc_history_lock);
	if (!cmc_polling_enabled) {
		int i, count = 1; /* we know 1 happened now */
		unsigned long now = jiffies;

		for (i = 0; i < CMC_HISTORY_LENGTH; i++) {
			if (now - cmc_history[i] <= HZ)
				count++;
		}

		IA64_MCA_DEBUG(KERN_INFO "CMC threshold %d/%d\n", count, CMC_HISTORY_LENGTH);
		if (count >= CMC_HISTORY_LENGTH) {

			cmc_polling_enabled = 1;
			spin_unlock(&cmc_history_lock);
			/* If we're being hit with CMC interrupts, we won't
			 * ever execute the schedule_work() below.  Need to
			 * disable CMC interrupts on this processor now.
			 */
			ia64_mca_cmc_vector_disable(NULL);
			schedule_work(&cmc_disable_work);

			/*
			 * Corrected errors will still be corrected, but
			 * make sure there's a log somewhere that indicates
			 * something is generating more than we can handle.
			 */
			printk(KERN_WARNING "WARNING: Switching to polling CMC handler; error records may be lost\n");

			mod_timer(&cmc_poll_timer, jiffies + CMC_POLL_INTERVAL);

			/* lock already released, get out now */
			return IRQ_HANDLED;
		} else {
			cmc_history[index++] = now;
			if (index == CMC_HISTORY_LENGTH)
				index = 0;
		}
	}
	spin_unlock(&cmc_history_lock);
	return IRQ_HANDLED;
}

/*
 *  ia64_mca_cmc_int_caller
 *
 * 	Triggered by sw interrupt from CMC polling routine.  Calls
 * 	real interrupt handler and either triggers a sw interrupt
 * 	on the next cpu or does cleanup at the end.
 *
 * Inputs
 *	interrupt number
 *	client data arg ptr
 *	saved registers ptr
 * Outputs
 * 	handled
 */
static irqreturn_t
ia64_mca_cmc_int_caller(int cmc_irq, void *arg, struct pt_regs *ptregs)
{
	static int start_count = -1;
	unsigned int cpuid;

	cpuid = smp_processor_id();

	/* If first cpu, update count */
	if (start_count == -1)
		start_count = IA64_LOG_COUNT(SAL_INFO_TYPE_CMC);

	ia64_mca_cmc_int_handler(cmc_irq, arg, ptregs);

	for (++cpuid ; cpuid < NR_CPUS && !cpu_online(cpuid) ; cpuid++);

	if (cpuid < NR_CPUS) {
		platform_send_ipi(cpuid, IA64_CMCP_VECTOR, IA64_IPI_DM_INT, 0);
	} else {
		/* If no log record, switch out of polling mode */
		if (start_count == IA64_LOG_COUNT(SAL_INFO_TYPE_CMC)) {

			printk(KERN_WARNING "Returning to interrupt driven CMC handler\n");
			schedule_work(&cmc_enable_work);
			cmc_polling_enabled = 0;

		} else {

			mod_timer(&cmc_poll_timer, jiffies + CMC_POLL_INTERVAL);
		}

		start_count = -1;
	}

	return IRQ_HANDLED;
}

/*
 *  ia64_mca_cmc_poll
 *
 *	Poll for Corrected Machine Checks (CMCs)
 *
 * Inputs   :   dummy(unused)
 * Outputs  :   None
 *
 */
static void
ia64_mca_cmc_poll (unsigned long dummy)
{
	/* Trigger a CMC interrupt cascade  */
	platform_send_ipi(first_cpu(cpu_online_map), IA64_CMCP_VECTOR, IA64_IPI_DM_INT, 0);
}

/*
 *  ia64_mca_cpe_int_caller
 *
 * 	Triggered by sw interrupt from CPE polling routine.  Calls
 * 	real interrupt handler and either triggers a sw interrupt
 * 	on the next cpu or does cleanup at the end.
 *
 * Inputs
 *	interrupt number
 *	client data arg ptr
 *	saved registers ptr
 * Outputs
 * 	handled
 */
#ifdef CONFIG_ACPI

static irqreturn_t
ia64_mca_cpe_int_caller(int cpe_irq, void *arg, struct pt_regs *ptregs)
{
	static int start_count = -1;
	static int poll_time = MIN_CPE_POLL_INTERVAL;
	unsigned int cpuid;

	cpuid = smp_processor_id();

	/* If first cpu, update count */
	if (start_count == -1)
		start_count = IA64_LOG_COUNT(SAL_INFO_TYPE_CPE);

	ia64_mca_cpe_int_handler(cpe_irq, arg, ptregs);

	for (++cpuid ; cpuid < NR_CPUS && !cpu_online(cpuid) ; cpuid++);

	if (cpuid < NR_CPUS) {
		platform_send_ipi(cpuid, IA64_CPEP_VECTOR, IA64_IPI_DM_INT, 0);
	} else {
		/*
		 * If a log was recorded, increase our polling frequency,
		 * otherwise, backoff or return to interrupt mode.
		 */
		if (start_count != IA64_LOG_COUNT(SAL_INFO_TYPE_CPE)) {
			poll_time = max(MIN_CPE_POLL_INTERVAL, poll_time / 2);
		} else if (cpe_vector < 0) {
			poll_time = min(MAX_CPE_POLL_INTERVAL, poll_time * 2);
		} else {
			poll_time = MIN_CPE_POLL_INTERVAL;

			printk(KERN_WARNING "Returning to interrupt driven CPE handler\n");
			enable_irq(local_vector_to_irq(IA64_CPE_VECTOR));
			cpe_poll_enabled = 0;
		}

		if (cpe_poll_enabled)
			mod_timer(&cpe_poll_timer, jiffies + poll_time);
		start_count = -1;
	}

	return IRQ_HANDLED;
}

/*
 *  ia64_mca_cpe_poll
 *
 *	Poll for Corrected Platform Errors (CPEs), trigger interrupt
 *	on first cpu, from there it will trickle through all the cpus.
 *
 * Inputs   :   dummy(unused)
 * Outputs  :   None
 *
 */
static void
ia64_mca_cpe_poll (unsigned long dummy)
{
	/* Trigger a CPE interrupt cascade  */
	platform_send_ipi(first_cpu(cpu_online_map), IA64_CPEP_VECTOR, IA64_IPI_DM_INT, 0);
}

#endif /* CONFIG_ACPI */

/*
 * C portion of the OS INIT handler
 *
 * Called from ia64_os_init_dispatch
 *
 * Inputs: pointer to pt_regs where processor info was saved.  SAL/OS state for
 * this event.  This code is used for both monarch and slave INIT events, see
 * sos->monarch.
 *
 * All INIT events switch to the INIT stack and change the previous process to
 * blocked status.  If one of the INIT events is the monarch then we are
 * probably processing the nmi button/command.  Use the monarch cpu to dump all
 * the processes.  The slave INIT events all spin until the monarch cpu
 * returns.  We can also get INIT slave events for MCA, in which case the MCA
 * process is the monarch.
 */

void
ia64_init_handler(struct pt_regs *regs, struct switch_stack *sw,
		  struct ia64_sal_os_state *sos)
{
	static atomic_t slaves;
	static atomic_t monarchs;
	task_t *previous_current;
	int cpu = smp_processor_id(), c;
	struct task_struct *g, *t;

	oops_in_progress = 1;	/* FIXME: make printk NMI/MCA/INIT safe */
	console_loglevel = 15;	/* make sure printks make it to console */

	printk(KERN_INFO "Entered OS INIT handler. PSP=%lx cpu=%d monarch=%ld\n",
		sos->proc_state_param, cpu, sos->monarch);
	salinfo_log_wakeup(SAL_INFO_TYPE_INIT, NULL, 0, 0);

	previous_current = ia64_mca_modify_original_stack(regs, sw, sos, "INIT");
	sos->os_status = IA64_INIT_RESUME;

	/* FIXME: Workaround for broken proms that drive all INIT events as
	 * slaves.  The last slave that enters is promoted to be a monarch.
	 * Remove this code in September 2006, that gives platforms a year to
	 * fix their proms and get their customers updated.
	 */
	if (!sos->monarch && atomic_add_return(1, &slaves) == num_online_cpus()) {
		printk(KERN_WARNING "%s: Promoting cpu %d to monarch.\n",
		       __FUNCTION__, cpu);
		atomic_dec(&slaves);
		sos->monarch = 1;
	}

	/* FIXME: Workaround for broken proms that drive all INIT events as