OpenCloudOS-Kernel/arch/parisc/kernel/irq.c

601 lines
15 KiB
C
Raw Normal View History

/*
* Code to handle x86 style IRQs plus some generic interrupt stuff.
*
* Copyright (C) 1992 Linus Torvalds
* Copyright (C) 1994, 1995, 1996, 1997, 1998 Ralf Baechle
* Copyright (C) 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org)
* Copyright (C) 1999-2000 Grant Grundler
* Copyright (c) 2005 Matthew Wilcox
*
* 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, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/seq_file.h>
#include <linux/types.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/ldcw.h>
#undef PARISC_IRQ_CR16_COUNTS
extern irqreturn_t timer_interrupt(int, void *);
extern irqreturn_t ipi_interrupt(int, void *);
#define EIEM_MASK(irq) (1UL<<(CPU_IRQ_MAX - irq))
/* Bits in EIEM correlate with cpu_irq_action[].
** Numbered *Big Endian*! (ie bit 0 is MSB)
*/
static volatile unsigned long cpu_eiem = 0;
/*
** local ACK bitmap ... habitually set to 1, but reset to zero
** between ->ack() and ->end() of the interrupt to prevent
** re-interruption of a processing interrupt.
*/
static DEFINE_PER_CPU(unsigned long, local_ack_eiem) = ~0UL;
static void cpu_mask_irq(struct irq_data *d)
{
unsigned long eirr_bit = EIEM_MASK(d->irq);
cpu_eiem &= ~eirr_bit;
/* Do nothing on the other CPUs. If they get this interrupt,
* The & cpu_eiem in the do_cpu_irq_mask() ensures they won't
* handle it, and the set_eiem() at the bottom will ensure it
* then gets disabled */
}
static void __cpu_unmask_irq(unsigned int irq)
{
unsigned long eirr_bit = EIEM_MASK(irq);
cpu_eiem |= eirr_bit;
/* This is just a simple NOP IPI. But what it does is cause
* all the other CPUs to do a set_eiem(cpu_eiem) at the end
* of the interrupt handler */
smp_send_all_nop();
}
static void cpu_unmask_irq(struct irq_data *d)
{
__cpu_unmask_irq(d->irq);
}
void cpu_ack_irq(struct irq_data *d)
{
unsigned long mask = EIEM_MASK(d->irq);
int cpu = smp_processor_id();
/* Clear in EIEM so we can no longer process */
per_cpu(local_ack_eiem, cpu) &= ~mask;
/* disable the interrupt */
set_eiem(cpu_eiem & per_cpu(local_ack_eiem, cpu));
/* and now ack it */
mtctl(mask, 23);
}
void cpu_eoi_irq(struct irq_data *d)
{
unsigned long mask = EIEM_MASK(d->irq);
int cpu = smp_processor_id();
/* set it in the eiems---it's no longer in process */
per_cpu(local_ack_eiem, cpu) |= mask;
/* enable the interrupt */
set_eiem(cpu_eiem & per_cpu(local_ack_eiem, cpu));
}
#ifdef CONFIG_SMP
int cpu_check_affinity(struct irq_data *d, const struct cpumask *dest)
{
int cpu_dest;
/* timer and ipi have to always be received on all CPUs */
if (irqd_is_per_cpu(d))
return -EINVAL;
/* whatever mask they set, we just allow one CPU */
cpu_dest = first_cpu(*dest);
return cpu_dest;
}
static int cpu_set_affinity_irq(struct irq_data *d, const struct cpumask *dest,
bool force)
{
int cpu_dest;
cpu_dest = cpu_check_affinity(d, dest);
if (cpu_dest < 0)
return -1;
cpumask_copy(d->affinity, dest);
return 0;
}
#endif
static struct irq_chip cpu_interrupt_type = {
.name = "CPU",
.irq_mask = cpu_mask_irq,
.irq_unmask = cpu_unmask_irq,
.irq_ack = cpu_ack_irq,
.irq_eoi = cpu_eoi_irq,
#ifdef CONFIG_SMP
.irq_set_affinity = cpu_set_affinity_irq,
#endif
/* XXX: Needs to be written. We managed without it so far, but
* we really ought to write it.
*/
.irq_retrigger = NULL,
};
DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
#define irq_stats(x) (&per_cpu(irq_stat, x))
/*
* /proc/interrupts printing for arch specific interrupts
*/
int arch_show_interrupts(struct seq_file *p, int prec)
{
int j;
#ifdef CONFIG_DEBUG_STACKOVERFLOW
seq_printf(p, "%*s: ", prec, "STK");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->kernel_stack_usage);
seq_puts(p, " Kernel stack usage\n");
# ifdef CONFIG_IRQSTACKS
seq_printf(p, "%*s: ", prec, "IST");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_stack_usage);
seq_puts(p, " Interrupt stack usage\n");
# endif
#endif
#ifdef CONFIG_SMP
seq_printf(p, "%*s: ", prec, "RES");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
seq_puts(p, " Rescheduling interrupts\n");
#endif
seq_printf(p, "%*s: ", prec, "UAH");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_unaligned_count);
seq_puts(p, " Unaligned access handler traps\n");
seq_printf(p, "%*s: ", prec, "FPA");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_fpassist_count);
seq_puts(p, " Floating point assist traps\n");
seq_printf(p, "%*s: ", prec, "TLB");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
seq_puts(p, " TLB shootdowns\n");
return 0;
}
int show_interrupts(struct seq_file *p, void *v)
{
int i = *(loff_t *) v, j;
unsigned long flags;
if (i == 0) {
seq_puts(p, " ");
for_each_online_cpu(j)
seq_printf(p, " CPU%d", j);
#ifdef PARISC_IRQ_CR16_COUNTS
seq_printf(p, " [min/avg/max] (CPU cycle counts)");
#endif
seq_putc(p, '\n');
}
if (i < NR_IRQS) {
struct irq_desc *desc = irq_to_desc(i);
struct irqaction *action;
raw_spin_lock_irqsave(&desc->lock, flags);
action = desc->action;
if (!action)
goto skip;
seq_printf(p, "%3d: ", i);
#ifdef CONFIG_SMP
for_each_online_cpu(j)
seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
#else
seq_printf(p, "%10u ", kstat_irqs(i));
#endif
seq_printf(p, " %14s", irq_desc_get_chip(desc)->name);
#ifndef PARISC_IRQ_CR16_COUNTS
seq_printf(p, " %s", action->name);
while ((action = action->next))
seq_printf(p, ", %s", action->name);
#else
for ( ;action; action = action->next) {
unsigned int k, avg, min, max;
min = max = action->cr16_hist[0];
for (avg = k = 0; k < PARISC_CR16_HIST_SIZE; k++) {
int hist = action->cr16_hist[k];
if (hist) {
avg += hist;
} else
break;
if (hist > max) max = hist;
if (hist < min) min = hist;
}
avg /= k;
seq_printf(p, " %s[%d/%d/%d]", action->name,
min,avg,max);
}
#endif
seq_putc(p, '\n');
skip:
raw_spin_unlock_irqrestore(&desc->lock, flags);
}
if (i == NR_IRQS)
arch_show_interrupts(p, 3);
return 0;
}
/*
** The following form a "set": Virtual IRQ, Transaction Address, Trans Data.
** Respectively, these map to IRQ region+EIRR, Processor HPA, EIRR bit.
**
** To use txn_XXX() interfaces, get a Virtual IRQ first.
** Then use that to get the Transaction address and data.
*/
int cpu_claim_irq(unsigned int irq, struct irq_chip *type, void *data)
{
if (irq_has_action(irq))
return -EBUSY;
if (irq_get_chip(irq) != &cpu_interrupt_type)
return -EBUSY;
/* for iosapic interrupts */
if (type) {
irq_set_chip_and_handler(irq, type, handle_percpu_irq);
irq_set_chip_data(irq, data);
__cpu_unmask_irq(irq);
}
return 0;
}
int txn_claim_irq(int irq)
{
return cpu_claim_irq(irq, NULL, NULL) ? -1 : irq;
}
/*
* The bits_wide parameter accommodates the limitations of the HW/SW which
* use these bits:
* Legacy PA I/O (GSC/NIO): 5 bits (architected EIM register)
* V-class (EPIC): 6 bits
* N/L/A-class (iosapic): 8 bits
* PCI 2.2 MSI: 16 bits
* Some PCI devices: 32 bits (Symbios SCSI/ATM/HyperFabric)
*
* On the service provider side:
* o PA 1.1 (and PA2.0 narrow mode) 5-bits (width of EIR register)
* o PA 2.0 wide mode 6-bits (per processor)
* o IA64 8-bits (0-256 total)
*
* So a Legacy PA I/O device on a PA 2.0 box can't use all the bits supported
* by the processor...and the N/L-class I/O subsystem supports more bits than
* PA2.0 has. The first case is the problem.
*/
int txn_alloc_irq(unsigned int bits_wide)
{
int irq;
/* never return irq 0 cause that's the interval timer */
for (irq = CPU_IRQ_BASE + 1; irq <= CPU_IRQ_MAX; irq++) {
if (cpu_claim_irq(irq, NULL, NULL) < 0)
continue;
if ((irq - CPU_IRQ_BASE) >= (1 << bits_wide))
continue;
return irq;
}
/* unlikely, but be prepared */
return -1;
}
unsigned long txn_affinity_addr(unsigned int irq, int cpu)
{
#ifdef CONFIG_SMP
struct irq_data *d = irq_get_irq_data(irq);
cpumask_copy(d->affinity, cpumask_of(cpu));
#endif
return per_cpu(cpu_data, cpu).txn_addr;
}
unsigned long txn_alloc_addr(unsigned int virt_irq)
{
static int next_cpu = -1;
next_cpu++; /* assign to "next" CPU we want this bugger on */
/* validate entry */
while ((next_cpu < nr_cpu_ids) &&
(!per_cpu(cpu_data, next_cpu).txn_addr ||
!cpu_online(next_cpu)))
next_cpu++;
if (next_cpu >= nr_cpu_ids)
next_cpu = 0; /* nothing else, assign monarch */
return txn_affinity_addr(virt_irq, next_cpu);
}
unsigned int txn_alloc_data(unsigned int virt_irq)
{
return virt_irq - CPU_IRQ_BASE;
}
static inline int eirr_to_irq(unsigned long eirr)
{
int bit = fls_long(eirr);
return (BITS_PER_LONG - bit) + TIMER_IRQ;
}
#ifdef CONFIG_IRQSTACKS
/*
* IRQ STACK - used for irq handler
*/
#define IRQ_STACK_SIZE (4096 << 2) /* 16k irq stack size */
union irq_stack_union {
unsigned long stack[IRQ_STACK_SIZE/sizeof(unsigned long)];
volatile unsigned int slock[4];
volatile unsigned int lock[1];
};
DEFINE_PER_CPU(union irq_stack_union, irq_stack_union) = {
.slock = { 1,1,1,1 },
};
#endif
int sysctl_panic_on_stackoverflow = 1;
static inline void stack_overflow_check(struct pt_regs *regs)
{
#ifdef CONFIG_DEBUG_STACKOVERFLOW
#define STACK_MARGIN (256*6)
/* Our stack starts directly behind the thread_info struct. */
unsigned long stack_start = (unsigned long) current_thread_info();
unsigned long sp = regs->gr[30];
unsigned long stack_usage;
unsigned int *last_usage;
int cpu = smp_processor_id();
/* if sr7 != 0, we interrupted a userspace process which we do not want
* to check for stack overflow. We will only check the kernel stack. */
if (regs->sr[7])
return;
/* calculate kernel stack usage */
stack_usage = sp - stack_start;
#ifdef CONFIG_IRQSTACKS
if (likely(stack_usage <= THREAD_SIZE))
goto check_kernel_stack; /* found kernel stack */
/* check irq stack usage */
stack_start = (unsigned long) &per_cpu(irq_stack_union, cpu).stack;
stack_usage = sp - stack_start;
last_usage = &per_cpu(irq_stat.irq_stack_usage, cpu);
if (unlikely(stack_usage > *last_usage))
*last_usage = stack_usage;
if (likely(stack_usage < (IRQ_STACK_SIZE - STACK_MARGIN)))
return;
pr_emerg("stackcheck: %s will most likely overflow irq stack "
"(sp:%lx, stk bottom-top:%lx-%lx)\n",
current->comm, sp, stack_start, stack_start + IRQ_STACK_SIZE);
goto panic_check;
check_kernel_stack:
#endif
/* check kernel stack usage */
last_usage = &per_cpu(irq_stat.kernel_stack_usage, cpu);
if (unlikely(stack_usage > *last_usage))
*last_usage = stack_usage;
if (likely(stack_usage < (THREAD_SIZE - STACK_MARGIN)))
return;
pr_emerg("stackcheck: %s will most likely overflow kernel stack "
"(sp:%lx, stk bottom-top:%lx-%lx)\n",
current->comm, sp, stack_start, stack_start + THREAD_SIZE);
#ifdef CONFIG_IRQSTACKS
panic_check:
#endif
if (sysctl_panic_on_stackoverflow)
panic("low stack detected by irq handler - check messages\n");
#endif
}
#ifdef CONFIG_IRQSTACKS
/* in entry.S: */
void call_on_stack(unsigned long p1, void *func, unsigned long new_stack);
static void execute_on_irq_stack(void *func, unsigned long param1)
{
union irq_stack_union *union_ptr;
unsigned long irq_stack;
volatile unsigned int *irq_stack_in_use;
union_ptr = &per_cpu(irq_stack_union, smp_processor_id());
irq_stack = (unsigned long) &union_ptr->stack;
irq_stack = ALIGN(irq_stack + sizeof(irq_stack_union.slock),
64); /* align for stack frame usage */
/* We may be called recursive. If we are already using the irq stack,
* just continue to use it. Use spinlocks to serialize
* the irq stack usage.
*/
irq_stack_in_use = (volatile unsigned int *)__ldcw_align(union_ptr);
if (!__ldcw(irq_stack_in_use)) {
void (*direct_call)(unsigned long p1) = func;
/* We are using the IRQ stack already.
* Do direct call on current stack. */
direct_call(param1);
return;
}
/* This is where we switch to the IRQ stack. */
call_on_stack(param1, func, irq_stack);
/* free up irq stack usage. */
*irq_stack_in_use = 1;
}
void do_softirq_own_stack(void)
{
execute_on_irq_stack(__do_softirq, 0);
}
#endif /* CONFIG_IRQSTACKS */
/* ONLY called from entry.S:intr_extint() */
void do_cpu_irq_mask(struct pt_regs *regs)
{
struct pt_regs *old_regs;
unsigned long eirr_val;
int irq, cpu = smp_processor_id();
#ifdef CONFIG_SMP
struct irq_desc *desc;
cpumask_t dest;
#endif
old_regs = set_irq_regs(regs);
local_irq_disable();
irq_enter();
eirr_val = mfctl(23) & cpu_eiem & per_cpu(local_ack_eiem, cpu);
if (!eirr_val)
goto set_out;
irq = eirr_to_irq(eirr_val);
#ifdef CONFIG_SMP
desc = irq_to_desc(irq);
cpumask_copy(&dest, desc->irq_data.affinity);
if (irqd_is_per_cpu(&desc->irq_data) &&
!cpu_isset(smp_processor_id(), dest)) {
int cpu = first_cpu(dest);
printk(KERN_DEBUG "redirecting irq %d from CPU %d to %d\n",
irq, smp_processor_id(), cpu);
gsc_writel(irq + CPU_IRQ_BASE,
per_cpu(cpu_data, cpu).hpa);
goto set_out;
}
#endif
stack_overflow_check(regs);
#ifdef CONFIG_IRQSTACKS
execute_on_irq_stack(&generic_handle_irq, irq);
#else
generic_handle_irq(irq);
#endif /* CONFIG_IRQSTACKS */
[PARISC] Disable nesting of interrupts Disable nesting of interrupts - still has holes The offending sequence starts out like this: 1) take external interrupt 2) set_eiem() to only allow TIMER_IRQ; local interrupts still disabled 3) read the EIRR to get a "list" of pending interrupts 4) clear EIRR of pending interrupts we intend to handle 5) call __do_IRQ() to handle IRQ. 6) handle_IRQ_event() enables local interrupts (I-Bit) 7) take a timer interrupt 8) read EIRR to get a new list of pending interrupts 9) clear EIRR of pending interrupts we just read 10) handle pending interrupts found in (8) 11) set_eiem(cpu_eiem) and return [ TROUBLE! all enabled CPU IRQs are unmasked. } 12) handle remaining interrupts pending from (3) e.g. call __do_IRQ() -> handle_IRQ_event()..etc [ TROUBLE! call to handle_IRQ_event() can now enable *any* IRQ. } 13) set_eiem(cpu_eiem) and return The problem is we now get into ugly race conditions with Timer and IPI interrupts at this point. I'm not exactly sure what happens when things go wrong (perhaps nest calls to IPI or timer interrupt?). But I'm certain it's not good. This sequence will break sooner if (10) would accidentally leave interrupts enabled. I'm pretty sure the right answer is now to make cpu_eiem a per CPU variable since all external interrupts on parisc are per CPU. This means we will NOT need to send an IPI to every CPU in the system when enabling or disabling an IRQ since only one CPU needs to change it's EIEM. Thanks to James Bottomley for (once again) pointing out the problem. Signed-off-by: Grant Grundler <grundler@parisc-linux.org> Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
2005-11-18 05:26:20 +08:00
out:
irq_exit();
set_irq_regs(old_regs);
return;
set_out:
set_eiem(cpu_eiem & per_cpu(local_ack_eiem, cpu));
goto out;
}
static struct irqaction timer_action = {
.handler = timer_interrupt,
.name = "timer",
.flags = IRQF_TIMER | IRQF_PERCPU | IRQF_IRQPOLL,
};
#ifdef CONFIG_SMP
static struct irqaction ipi_action = {
.handler = ipi_interrupt,
.name = "IPI",
.flags = IRQF_PERCPU,
};
#endif
static void claim_cpu_irqs(void)
{
int i;
for (i = CPU_IRQ_BASE; i <= CPU_IRQ_MAX; i++) {
irq_set_chip_and_handler(i, &cpu_interrupt_type,
handle_percpu_irq);
}
irq_set_handler(TIMER_IRQ, handle_percpu_irq);
setup_irq(TIMER_IRQ, &timer_action);
#ifdef CONFIG_SMP
irq_set_handler(IPI_IRQ, handle_percpu_irq);
setup_irq(IPI_IRQ, &ipi_action);
#endif
}
void __init init_IRQ(void)
{
local_irq_disable(); /* PARANOID - should already be disabled */
mtctl(~0UL, 23); /* EIRR : clear all pending external intr */
#ifdef CONFIG_SMP
if (!cpu_eiem) {
claim_cpu_irqs();
cpu_eiem = EIEM_MASK(IPI_IRQ) | EIEM_MASK(TIMER_IRQ);
}
#else
claim_cpu_irqs();
cpu_eiem = EIEM_MASK(TIMER_IRQ);
#endif
set_eiem(cpu_eiem); /* EIEM : enable all external intr */
}