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linux/arch/powerpc/kernel/irq.c

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/*
* 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_PPC_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 <linux/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/livepatch.h>
#include <asm/asm-prototypes.h>
#include <asm/hw_irq.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>
#include <asm/cpu_has_feature.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 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;
/*
* We are responding to the next interrupt, so interrupt-off
* latencies should be reset here.
*/
trace_hardirqs_on();
trace_hardirqs_off();
if (happened & PACA_IRQ_HARD_DIS) {
/* Clear bit 0 which we wouldn't clear otherwise */
local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
/*
* We may have missed a decrementer interrupt if hard disabled.
* Check the decrementer register in case we had a rollover
* while hard disabled.
*/
if (!(happened & PACA_IRQ_DEC)) {
if (decrementer_check_overflow()) {
local_paca->irq_happened |= PACA_IRQ_DEC;
happened |= PACA_IRQ_DEC;
}
}
}
/*
* 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);
}
/*
* Check if an hypervisor Maintenance interrupt happened.
* This is a higher priority interrupt than the others, so
* replay it first.
*/
if (happened & PACA_IRQ_HMI) {
local_paca->irq_happened &= ~PACA_IRQ_HMI;
return 0xe60;
}
if (happened & PACA_IRQ_DEC) {
local_paca->irq_happened &= ~PACA_IRQ_DEC;
return 0x900;
}
if (happened & PACA_IRQ_PMI) {
local_paca->irq_happened &= ~PACA_IRQ_PMI;
return 0xf00;
}
if (happened & PACA_IRQ_EE) {
local_paca->irq_happened &= ~PACA_IRQ_EE;
return 0x500;
}
#ifdef CONFIG_PPC_BOOK3E
/*
* 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.
*/
if (happened & PACA_IRQ_EE_EDGE) {
local_paca->irq_happened &= ~PACA_IRQ_EE_EDGE;
return 0x500;
}
if (happened & PACA_IRQ_DBELL) {
local_paca->irq_happened &= ~PACA_IRQ_DBELL;
return 0x280;
}
#else
if (happened & PACA_IRQ_DBELL) {
local_paca->irq_happened &= ~PACA_IRQ_DBELL;
return 0xa00;
}
#endif /* CONFIG_PPC_BOOK3E */
/* There should be nothing left ! */
BUG_ON(local_paca->irq_happened != 0);
return 0;
}
notrace void arch_local_irq_restore(unsigned long mask)
{
unsigned char irq_happened;
unsigned int replay;
/* Write the new soft-enabled value */
irq_soft_mask_set(mask);
if (mask)
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_PPC_IRQ_SOFT_MASK_DEBUG
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
irq_soft_mask_set(IRQS_ALL_DISABLED);
trace_hardirqs_off();
/*
* 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 */
trace_hardirqs_on();
irq_soft_mask_set(IRQS_ENABLED);
/*
* 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();
local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
/*
* 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;
irq_soft_mask_set(IRQS_ENABLED);
/* Tell the caller to enter the low power state */
return true;
}
#ifdef CONFIG_PPC_BOOK3S
/*
* This is for idle sequences that return with IRQs off, but the
* idle state itself wakes on interrupt. Tell the irq tracer that
* IRQs are enabled for the duration of idle so it does not get long
* off times. Must be paired with fini_irq_for_idle_irqsoff.
*/
bool prep_irq_for_idle_irqsoff(void)
{
WARN_ON(!irqs_disabled());
/*
* First we need to hard disable to ensure no interrupt
* occurs before we effectively enter the low power state
*/
__hard_irq_disable();
local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
/*
* 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();
return true;
}
/*
* Take the SRR1 wakeup reason, index into this table to find the
* appropriate irq_happened bit.
*
* Sytem reset exceptions taken in idle state also come through here,
* but they are NMI interrupts so do not need to wait for IRQs to be
* restored, and should be taken as early as practical. These are marked
* with 0xff in the table. The Power ISA specifies 0100b as the system
* reset interrupt reason.
*/
#define IRQ_SYSTEM_RESET 0xff
static const u8 srr1_to_lazyirq[0x10] = {
0, 0, 0,
PACA_IRQ_DBELL,
IRQ_SYSTEM_RESET,
PACA_IRQ_DBELL,
PACA_IRQ_DEC,
0,
PACA_IRQ_EE,
PACA_IRQ_EE,
PACA_IRQ_HMI,
0, 0, 0, 0, 0 };
void replay_system_reset(void)
{
struct pt_regs regs;
ppc_save_regs(&regs);
regs.trap = 0x100;
get_paca()->in_nmi = 1;
system_reset_exception(&regs);
get_paca()->in_nmi = 0;
}
EXPORT_SYMBOL_GPL(replay_system_reset);
void irq_set_pending_from_srr1(unsigned long srr1)
{
unsigned int idx = (srr1 & SRR1_WAKEMASK_P8) >> 18;
u8 reason = srr1_to_lazyirq[idx];
/*
* Take the system reset now, which is immediately after registers
* are restored from idle. It's an NMI, so interrupts need not be
* re-enabled before it is taken.
*/
if (unlikely(reason == IRQ_SYSTEM_RESET)) {
replay_system_reset();
return;
}
/*
* The 0 index (SRR1[42:45]=b0000) must always evaluate to 0,
* so this can be called unconditionally with the SRR1 wake
* reason as returned by the idle code, which uses 0 to mean no
* interrupt.
*
* If a future CPU was to designate this as an interrupt reason,
* then a new index for no interrupt must be assigned.
*/
local_paca->irq_happened |= reason;
}
#endif /* CONFIG_PPC_BOOK3S */
/*
* Force a replay of the external interrupt handler on this CPU.
*/
void force_external_irq_replay(void)
{
/*
* This must only be called with interrupts soft-disabled,
* the replay will happen when re-enabling.
*/
WARN_ON(!arch_irqs_disabled());
/* Indicate in the PACA that we have an interrupt to replay */
local_paca->irq_happened |= PACA_IRQ_EE;
}
#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");
}
seq_printf(p, "%*s: ", prec, "NMI");
for_each_online_cpu(j)
seq_printf(p, "%10u ", per_cpu(irq_stat, j).sreset_irqs);
seq_printf(p, " System Reset interrupts\n");
#ifdef CONFIG_PPC_WATCHDOG
seq_printf(p, "%*s: ", prec, "WDG");
for_each_online_cpu(j)
seq_printf(p, "%10u ", per_cpu(irq_stat, j).soft_nmi_irqs);
seq_printf(p, " Watchdog soft-NMI interrupts\n");
#endif
#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;
sum += per_cpu(irq_stat, cpu).sreset_irqs;
#ifdef CONFIG_PPC_WATCHDOG
sum += per_cpu(irq_stat, cpu).soft_nmi_irqs;
#endif
#ifdef CONFIG_PPC_DOORBELL
sum += per_cpu(irq_stat, cpu).doorbell_irqs;
#endif
return sum;
}
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))
__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;
klp_init_thread_info(tp);
memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
tp = hardirq_ctx[i];
tp->cpu = i;
klp_init_thread_info(tp);
}
}
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 */
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