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OpenCloudOS-Kernel/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_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/bootmem.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 = &__get_cpu_var(decrementers_next_tb);
if (now >= *next_tb)
set_dec(1);
return now >= *next_tb;
}
/* This is called whenever we are re-enabling interrupts
* and returns either 0 (nothing to do) or 500/900 if there's
* either an EE or a DEC 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 (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;
#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 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 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);
seq_printf(p, " Local timer interrupts\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, "CNT");
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");
return 0;
}
/*
* /proc/stat helpers
*/
u64 arch_irq_stat_cpu(unsigned int cpu)
{
u64 sum = per_cpu(irq_stat, cpu).timer_irqs;
sum += per_cpu(irq_stat, cpu).pmu_irqs;
sum += per_cpu(irq_stat, cpu).mce_exceptions;
sum += per_cpu(irq_stat, cpu).spurious_irqs;
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) {
printk("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++))
printk("Cannot set affinity for irq %i\n", irq);
}
free_cpumask_var(mask);
local_irq_enable();
mdelay(1);
local_irq_disable();
}
#endif
static inline void handle_one_irq(unsigned int irq)
{
struct thread_info *curtp, *irqtp;
unsigned long saved_sp_limit;
struct irq_desc *desc;
desc = irq_to_desc(irq);
if (!desc)
return;
/* Switch to the irq stack to handle this */
curtp = current_thread_info();
irqtp = hardirq_ctx[smp_processor_id()];
if (curtp == irqtp) {
/* We're already on the irq stack, just handle it */
desc->handle_irq(irq, desc);
return;
}
saved_sp_limit = current->thread.ksp_limit;
irqtp->task = curtp->task;
irqtp->flags = 0;
/* Copy the softirq bits in preempt_count so that the
* softirq checks work in the hardirq context. */
irqtp->preempt_count = (irqtp->preempt_count & ~SOFTIRQ_MASK) |
(curtp->preempt_count & SOFTIRQ_MASK);
current->thread.ksp_limit = (unsigned long)irqtp +
_ALIGN_UP(sizeof(struct thread_info), 16);
call_handle_irq(irq, desc, irqtp, desc->handle_irq);
current->thread.ksp_limit = saved_sp_limit;
irqtp->task = NULL;
/* Set any flag that may have been set on the
* alternate stack
*/
if (irqtp->flags)
set_bits(irqtp->flags, &curtp->flags);
}
static inline void check_stack_overflow(void)
{
#ifdef CONFIG_DEBUG_STACKOVERFLOW
long sp;
sp = __get_SP() & (THREAD_SIZE-1);
/* check for stack overflow: is there less than 2KB free? */
if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
printk("do_IRQ: stack overflow: %ld\n",
sp - sizeof(struct thread_info));
dump_stack();
}
#endif
}
void do_IRQ(struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
unsigned int irq;
trace_irq_entry(regs);
irq_enter();
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 */
may_hard_irq_enable();
/* And finally process it */
if (irq != NO_IRQ)
handle_one_irq(irq);
else
__get_cpu_var(irq_stat).spurious_irqs++;
irq_exit();
set_irq_regs(old_regs);
trace_irq_exit(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
cpu_nr = get_hard_smp_processor_id(i);
#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;
tp->preempt_count = 0;
memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
tp = hardirq_ctx[i];
tp->cpu = i;
tp->preempt_count = HARDIRQ_OFFSET;
}
}
static inline void do_softirq_onstack(void)
{
struct thread_info *curtp, *irqtp;
unsigned long saved_sp_limit = current->thread.ksp_limit;
curtp = current_thread_info();
irqtp = softirq_ctx[smp_processor_id()];
irqtp->task = curtp->task;
irqtp->flags = 0;
current->thread.ksp_limit = (unsigned long)irqtp +
_ALIGN_UP(sizeof(struct thread_info), 16);
call_do_softirq(irqtp);
current->thread.ksp_limit = saved_sp_limit;
irqtp->task = NULL;
/* Set any flag that may have been set on the
* alternate stack
*/
if (irqtp->flags)
set_bits(irqtp->flags, &curtp->flags);
}
void do_softirq(void)
{
unsigned long flags;
if (in_interrupt())
return;
local_irq_save(flags);
if (local_softirq_pending())
do_softirq_onstack();
local_irq_restore(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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