summaryrefslogtreecommitdiff
path: root/arch/powerpc/kernel/irq.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/kernel/irq.c')
-rw-r--r--arch/powerpc/kernel/irq.c691
1 files changed, 691 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
new file mode 100644
index 000000000..45096033d
--- /dev/null
+++ b/arch/powerpc/kernel/irq.c
@@ -0,0 +1,691 @@
+/*
+ * 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/export.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/pci.h>
+#include <linux/debugfs.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+
+#include <asm/uaccess.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>
+#include <asm/smp.h>
+#include <asm/debug.h>
+
+#ifdef CONFIG_PPC64
+#include <asm/paca.h>
+#include <asm/firmware.h>
+#include <asm/lv1call.h>
+#endif
+#define CREATE_TRACE_POINTS
+#include <asm/trace.h>
+
+DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+EXPORT_PER_CPU_SYMBOL(irq_stat);
+
+int __irq_offset_value;
+
+#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
+
+int distribute_irqs = 1;
+
+static inline notrace unsigned long get_irq_happened(void)
+{
+ unsigned long happened;
+
+ __asm__ __volatile__("lbz %0,%1(13)"
+ : "=r" (happened) : "i" (offsetof(struct paca_struct, irq_happened)));
+
+ return happened;
+}
+
+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)));
+}
+
+static inline notrace int decrementer_check_overflow(void)
+{
+ u64 now = get_tb_or_rtc();
+ u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
+
+ return now >= *next_tb;
+}
+
+/* This is called whenever we are re-enabling interrupts
+ * and returns either 0 (nothing to do) or 500/900/280/a00/e80 if
+ * there's an EE, DEC or DBELL to generate.
+ *
+ * This is called in two contexts: From arch_local_irq_restore()
+ * before soft-enabling interrupts, and from the exception exit
+ * path when returning from an interrupt from a soft-disabled to
+ * a soft enabled context. In both case we have interrupts hard
+ * disabled.
+ *
+ * We take care of only clearing the bits we handled in the
+ * PACA irq_happened field since we can only re-emit one at a
+ * time and we don't want to "lose" one.
+ */
+notrace unsigned int __check_irq_replay(void)
+{
+ /*
+ * We use local_paca rather than get_paca() to avoid all
+ * the debug_smp_processor_id() business in this low level
+ * function
+ */
+ unsigned char happened = local_paca->irq_happened;
+
+ /* Clear bit 0 which we wouldn't clear otherwise */
+ local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
+
+ /*
+ * 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, tmp2;
+ lv1_get_version_info(&tmp, &tmp2);
+ }
+
+ /*
+ * We may have missed a decrementer interrupt. We check the
+ * decrementer itself rather than the paca irq_happened field
+ * in case we also had a rollover while hard disabled
+ */
+ local_paca->irq_happened &= ~PACA_IRQ_DEC;
+ if ((happened & PACA_IRQ_DEC) || decrementer_check_overflow())
+ return 0x900;
+
+ /* Finally check if an external interrupt happened */
+ local_paca->irq_happened &= ~PACA_IRQ_EE;
+ if (happened & PACA_IRQ_EE)
+ return 0x500;
+
+#ifdef CONFIG_PPC_BOOK3E
+ /* Finally check if an EPR external interrupt happened
+ * this bit is typically set if we need to handle another
+ * "edge" interrupt from within the MPIC "EPR" handler
+ */
+ local_paca->irq_happened &= ~PACA_IRQ_EE_EDGE;
+ if (happened & PACA_IRQ_EE_EDGE)
+ return 0x500;
+
+ local_paca->irq_happened &= ~PACA_IRQ_DBELL;
+ if (happened & PACA_IRQ_DBELL)
+ return 0x280;
+#else
+ local_paca->irq_happened &= ~PACA_IRQ_DBELL;
+ if (happened & PACA_IRQ_DBELL) {
+ if (cpu_has_feature(CPU_FTR_HVMODE))
+ return 0xe80;
+ return 0xa00;
+ }
+#endif /* CONFIG_PPC_BOOK3E */
+
+ /* Check if an hypervisor Maintenance interrupt happened */
+ local_paca->irq_happened &= ~PACA_IRQ_HMI;
+ if (happened & PACA_IRQ_HMI)
+ return 0xe60;
+
+ /* There should be nothing left ! */
+ BUG_ON(local_paca->irq_happened != 0);
+
+ return 0;
+}
+
+notrace void arch_local_irq_restore(unsigned long en)
+{
+ unsigned char irq_happened;
+ unsigned int replay;
+
+ /* Write the new soft-enabled value */
+ set_soft_enabled(en);
+ if (!en)
+ return;
+ /*
+ * From this point onward, we can take interrupts, preempt,
+ * etc... unless we got hard-disabled. We check if an event
+ * happened. If none happened, we know we can just return.
+ *
+ * We may have preempted before the check below, in which case
+ * we are checking the "new" CPU instead of the old one. This
+ * is only a problem if an event happened on the "old" CPU.
+ *
+ * External interrupt events will have caused interrupts to
+ * be hard-disabled, so there is no problem, we
+ * cannot have preempted.
+ */
+ irq_happened = get_irq_happened();
+ if (!irq_happened)
+ return;
+
+ /*
+ * We need to hard disable to get a trusted value from
+ * __check_irq_replay(). We also need to soft-disable
+ * again to avoid warnings in there due to the use of
+ * per-cpu variables.
+ *
+ * We know that if the value in irq_happened is exactly 0x01
+ * then we are already hard disabled (there are other less
+ * common cases that we'll ignore for now), so we skip the
+ * (expensive) mtmsrd.
+ */
+ if (unlikely(irq_happened != PACA_IRQ_HARD_DIS))
+ __hard_irq_disable();
+#ifdef CONFIG_TRACE_IRQFLAGS
+ else {
+ /*
+ * We should already be hard disabled here. We had bugs
+ * where that wasn't the case so let's dbl check it and
+ * warn if we are wrong. Only do that when IRQ tracing
+ * is enabled as mfmsr() can be costly.
+ */
+ if (WARN_ON(mfmsr() & MSR_EE))
+ __hard_irq_disable();
+ }
+#endif /* CONFIG_TRACE_IRQFLAG */
+
+ set_soft_enabled(0);
+
+ /*
+ * Check if anything needs to be re-emitted. We haven't
+ * soft-enabled yet to avoid warnings in decrementer_check_overflow
+ * accessing per-cpu variables
+ */
+ replay = __check_irq_replay();
+
+ /* We can soft-enable now */
+ set_soft_enabled(1);
+
+ /*
+ * And replay if we have to. This will return with interrupts
+ * hard-enabled.
+ */
+ if (replay) {
+ __replay_interrupt(replay);
+ return;
+ }
+
+ /* Finally, let's ensure we are hard enabled */
+ __hard_irq_enable();
+}
+EXPORT_SYMBOL(arch_local_irq_restore);
+
+/*
+ * This is specifically called by assembly code to re-enable interrupts
+ * if they are currently disabled. This is typically called before
+ * schedule() or do_signal() when returning to userspace. We do it
+ * in C to avoid the burden of dealing with lockdep etc...
+ *
+ * NOTE: This is called with interrupts hard disabled but not marked
+ * as such in paca->irq_happened, so we need to resync this.
+ */
+void notrace restore_interrupts(void)
+{
+ if (irqs_disabled()) {
+ local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
+ local_irq_enable();
+ } else
+ __hard_irq_enable();
+}
+
+/*
+ * This is a helper to use when about to go into idle low-power
+ * when the latter has the side effect of re-enabling interrupts
+ * (such as calling H_CEDE under pHyp).
+ *
+ * You call this function with interrupts soft-disabled (this is
+ * already the case when ppc_md.power_save is called). The function
+ * will return whether to enter power save or just return.
+ *
+ * In the former case, it will have notified lockdep of interrupts
+ * being re-enabled and generally sanitized the lazy irq state,
+ * and in the latter case it will leave with interrupts hard
+ * disabled and marked as such, so the local_irq_enable() call
+ * in arch_cpu_idle() will properly re-enable everything.
+ */
+bool prep_irq_for_idle(void)
+{
+ /*
+ * First we need to hard disable to ensure no interrupt
+ * occurs before we effectively enter the low power state
+ */
+ hard_irq_disable();
+
+ /*
+ * If anything happened while we were soft-disabled,
+ * we return now and do not enter the low power state.
+ */
+ if (lazy_irq_pending())
+ return false;
+
+ /* Tell lockdep we are about to re-enable */
+ trace_hardirqs_on();
+
+ /*
+ * Mark interrupts as soft-enabled and clear the
+ * PACA_IRQ_HARD_DIS from the pending mask since we
+ * are about to hard enable as well as a side effect
+ * of entering the low power state.
+ */
+ local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
+ local_paca->soft_enabled = 1;
+
+ /* Tell the caller to enter the low power state */
+ return true;
+}
+
+#endif /* CONFIG_PPC64 */
+
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+ int j;
+
+#if defined(CONFIG_PPC32) && defined(CONFIG_TAU_INT)
+ if (tau_initialized) {
+ seq_printf(p, "%*s: ", prec, "TAU");
+ for_each_online_cpu(j)
+ seq_printf(p, "%10u ", tau_interrupts(j));
+ seq_puts(p, " PowerPC Thermal Assist (cpu temp)\n");
+ }
+#endif /* CONFIG_PPC32 && CONFIG_TAU_INT */
+
+ seq_printf(p, "%*s: ", prec, "LOC");
+ for_each_online_cpu(j)
+ seq_printf(p, "%10u ", per_cpu(irq_stat, j).timer_irqs_event);
+ seq_printf(p, " Local timer interrupts for timer event device\n");
+
+ seq_printf(p, "%*s: ", prec, "LOC");
+ for_each_online_cpu(j)
+ seq_printf(p, "%10u ", per_cpu(irq_stat, j).timer_irqs_others);
+ seq_printf(p, " Local timer interrupts for others\n");
+
+ seq_printf(p, "%*s: ", prec, "SPU");
+ for_each_online_cpu(j)
+ seq_printf(p, "%10u ", per_cpu(irq_stat, j).spurious_irqs);
+ seq_printf(p, " Spurious interrupts\n");
+
+ seq_printf(p, "%*s: ", prec, "PMI");
+ for_each_online_cpu(j)
+ seq_printf(p, "%10u ", per_cpu(irq_stat, j).pmu_irqs);
+ seq_printf(p, " Performance monitoring interrupts\n");
+
+ seq_printf(p, "%*s: ", prec, "MCE");
+ for_each_online_cpu(j)
+ seq_printf(p, "%10u ", per_cpu(irq_stat, j).mce_exceptions);
+ seq_printf(p, " Machine check exceptions\n");
+
+ if (cpu_has_feature(CPU_FTR_HVMODE)) {
+ seq_printf(p, "%*s: ", prec, "HMI");
+ for_each_online_cpu(j)
+ seq_printf(p, "%10u ",
+ per_cpu(irq_stat, j).hmi_exceptions);
+ seq_printf(p, " Hypervisor Maintenance Interrupts\n");
+ }
+
+#ifdef CONFIG_PPC_DOORBELL
+ if (cpu_has_feature(CPU_FTR_DBELL)) {
+ seq_printf(p, "%*s: ", prec, "DBL");
+ for_each_online_cpu(j)
+ seq_printf(p, "%10u ", per_cpu(irq_stat, j).doorbell_irqs);
+ seq_printf(p, " Doorbell interrupts\n");
+ }
+#endif
+
+ return 0;
+}
+
+/*
+ * /proc/stat helpers
+ */
+u64 arch_irq_stat_cpu(unsigned int cpu)
+{
+ u64 sum = per_cpu(irq_stat, cpu).timer_irqs_event;
+
+ sum += per_cpu(irq_stat, cpu).pmu_irqs;
+ sum += per_cpu(irq_stat, cpu).mce_exceptions;
+ sum += per_cpu(irq_stat, cpu).spurious_irqs;
+ sum += per_cpu(irq_stat, cpu).timer_irqs_others;
+ sum += per_cpu(irq_stat, cpu).hmi_exceptions;
+#ifdef CONFIG_PPC_DOORBELL
+ sum += per_cpu(irq_stat, cpu).doorbell_irqs;
+#endif
+
+ return sum;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+void migrate_irqs(void)
+{
+ struct irq_desc *desc;
+ unsigned int irq;
+ static int warned;
+ cpumask_var_t mask;
+ const struct cpumask *map = cpu_online_mask;
+
+ alloc_cpumask_var(&mask, GFP_KERNEL);
+
+ for_each_irq_desc(irq, desc) {
+ struct irq_data *data;
+ struct irq_chip *chip;
+
+ data = irq_desc_get_irq_data(desc);
+ if (irqd_is_per_cpu(data))
+ continue;
+
+ chip = irq_data_get_irq_chip(data);
+
+ cpumask_and(mask, data->affinity, map);
+ if (cpumask_any(mask) >= nr_cpu_ids) {
+ pr_warn("Breaking affinity for irq %i\n", irq);
+ cpumask_copy(mask, map);
+ }
+ if (chip->irq_set_affinity)
+ chip->irq_set_affinity(data, mask, true);
+ else if (desc->action && !(warned++))
+ pr_err("Cannot set affinity for irq %i\n", irq);
+ }
+
+ free_cpumask_var(mask);
+
+ local_irq_enable();
+ mdelay(1);
+ local_irq_disable();
+}
+#endif
+
+static inline void check_stack_overflow(void)
+{
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+ long sp;
+
+ sp = current_stack_pointer() & (THREAD_SIZE-1);
+
+ /* check for stack overflow: is there less than 2KB free? */
+ if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
+ pr_err("do_IRQ: stack overflow: %ld\n",
+ sp - sizeof(struct thread_info));
+ dump_stack();
+ }
+#endif
+}
+
+void __do_irq(struct pt_regs *regs)
+{
+ unsigned int irq;
+
+ irq_enter();
+
+ trace_irq_entry(regs);
+
+ check_stack_overflow();
+
+ /*
+ * Query the platform PIC for the interrupt & ack it.
+ *
+ * This will typically lower the interrupt line to the CPU
+ */
+ irq = ppc_md.get_irq();
+
+ /* We can hard enable interrupts now to allow perf interrupts */
+ may_hard_irq_enable();
+
+ /* And finally process it */
+ if (unlikely(irq == NO_IRQ))
+ __this_cpu_inc(irq_stat.spurious_irqs);
+ else
+ generic_handle_irq(irq);
+
+ trace_irq_exit(regs);
+
+ irq_exit();
+}
+
+void do_IRQ(struct pt_regs *regs)
+{
+ struct pt_regs *old_regs = set_irq_regs(regs);
+ struct thread_info *curtp, *irqtp, *sirqtp;
+
+ /* Switch to the irq stack to handle this */
+ curtp = current_thread_info();
+ irqtp = hardirq_ctx[raw_smp_processor_id()];
+ sirqtp = softirq_ctx[raw_smp_processor_id()];
+
+ /* Already there ? */
+ if (unlikely(curtp == irqtp || curtp == sirqtp)) {
+ __do_irq(regs);
+ set_irq_regs(old_regs);
+ return;
+ }
+
+ /* Prepare the thread_info in the irq stack */
+ irqtp->task = curtp->task;
+ irqtp->flags = 0;
+
+ /* Copy the preempt_count so that the [soft]irq checks work. */
+ irqtp->preempt_count = curtp->preempt_count;
+
+ /* Switch stack and call */
+ call_do_irq(regs, irqtp);
+
+ /* Restore stack limit */
+ irqtp->task = NULL;
+
+ /* Copy back updates to the thread_info */
+ if (irqtp->flags)
+ set_bits(irqtp->flags, &curtp->flags);
+
+ set_irq_regs(old_regs);
+}
+
+void __init init_IRQ(void)
+{
+ if (ppc_md.init_IRQ)
+ ppc_md.init_IRQ();
+
+ exc_lvl_ctx_init();
+
+ irq_ctx_init();
+}
+
+#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
+struct thread_info *critirq_ctx[NR_CPUS] __read_mostly;
+struct thread_info *dbgirq_ctx[NR_CPUS] __read_mostly;
+struct thread_info *mcheckirq_ctx[NR_CPUS] __read_mostly;
+
+void exc_lvl_ctx_init(void)
+{
+ struct thread_info *tp;
+ int i, cpu_nr;
+
+ for_each_possible_cpu(i) {
+#ifdef CONFIG_PPC64
+ cpu_nr = i;
+#else
+#ifdef CONFIG_SMP
+ cpu_nr = get_hard_smp_processor_id(i);
+#else
+ cpu_nr = 0;
+#endif
+#endif
+
+ memset((void *)critirq_ctx[cpu_nr], 0, THREAD_SIZE);
+ tp = critirq_ctx[cpu_nr];
+ tp->cpu = cpu_nr;
+ tp->preempt_count = 0;
+
+#ifdef CONFIG_BOOKE
+ memset((void *)dbgirq_ctx[cpu_nr], 0, THREAD_SIZE);
+ tp = dbgirq_ctx[cpu_nr];
+ tp->cpu = cpu_nr;
+ tp->preempt_count = 0;
+
+ memset((void *)mcheckirq_ctx[cpu_nr], 0, THREAD_SIZE);
+ tp = mcheckirq_ctx[cpu_nr];
+ tp->cpu = cpu_nr;
+ tp->preempt_count = HARDIRQ_OFFSET;
+#endif
+ }
+}
+#endif
+
+struct thread_info *softirq_ctx[NR_CPUS] __read_mostly;
+struct thread_info *hardirq_ctx[NR_CPUS] __read_mostly;
+
+void irq_ctx_init(void)
+{
+ struct thread_info *tp;
+ int i;
+
+ for_each_possible_cpu(i) {
+ memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
+ tp = softirq_ctx[i];
+ tp->cpu = i;
+
+ memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
+ tp = hardirq_ctx[i];
+ tp->cpu = i;
+ }
+}
+
+void do_softirq_own_stack(void)
+{
+ struct thread_info *curtp, *irqtp;
+
+ curtp = current_thread_info();
+ irqtp = softirq_ctx[smp_processor_id()];
+ irqtp->task = curtp->task;
+ irqtp->flags = 0;
+ call_do_softirq(irqtp);
+ irqtp->task = NULL;
+
+ /* Set any flag that may have been set on the
+ * alternate stack
+ */
+ if (irqtp->flags)
+ set_bits(irqtp->flags, &curtp->flags);
+}
+
+irq_hw_number_t virq_to_hw(unsigned int virq)
+{
+ struct irq_data *irq_data = irq_get_irq_data(virq);
+ return WARN_ON(!irq_data) ? 0 : irq_data->hwirq;
+}
+EXPORT_SYMBOL_GPL(virq_to_hw);
+
+#ifdef CONFIG_SMP
+int irq_choose_cpu(const struct cpumask *mask)
+{
+ int cpuid;
+
+ if (cpumask_equal(mask, cpu_online_mask)) {
+ static int irq_rover;
+ static DEFINE_RAW_SPINLOCK(irq_rover_lock);
+ unsigned long flags;
+
+ /* Round-robin distribution... */
+do_round_robin:
+ raw_spin_lock_irqsave(&irq_rover_lock, flags);
+
+ irq_rover = cpumask_next(irq_rover, cpu_online_mask);
+ if (irq_rover >= nr_cpu_ids)
+ irq_rover = cpumask_first(cpu_online_mask);
+
+ cpuid = irq_rover;
+
+ raw_spin_unlock_irqrestore(&irq_rover_lock, flags);
+ } else {
+ cpuid = cpumask_first_and(mask, cpu_online_mask);
+ if (cpuid >= nr_cpu_ids)
+ goto do_round_robin;
+ }
+
+ return get_hard_smp_processor_id(cpuid);
+}
+#else
+int irq_choose_cpu(const struct cpumask *mask)
+{
+ return hard_smp_processor_id();
+}
+#endif
+
+int arch_early_irq_init(void)
+{
+ return 0;
+}
+
+#ifdef CONFIG_PPC64
+static int __init setup_noirqdistrib(char *str)
+{
+ distribute_irqs = 0;
+ return 1;
+}
+
+__setup("noirqdistrib", setup_noirqdistrib);
+#endif /* CONFIG_PPC64 */