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linux/arch/sparc64/kernel/irq.c

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/* $Id: irq.c,v 1.114 2002/01/11 08:45:38 davem Exp $
* irq.c: UltraSparc IRQ handling/init/registry.
*
* Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 1998 Eddie C. Dost (ecd@skynet.be)
* Copyright (C) 1998 Jakub Jelinek (jj@ultra.linux.cz)
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/atomic.h>
#include <asm/system.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/sbus.h>
#include <asm/iommu.h>
#include <asm/upa.h>
#include <asm/oplib.h>
#include <asm/timer.h>
#include <asm/smp.h>
#include <asm/starfire.h>
#include <asm/uaccess.h>
#include <asm/cache.h>
#include <asm/cpudata.h>
#include <asm/auxio.h>
#include <asm/head.h>
#ifdef CONFIG_SMP
static void distribute_irqs(void);
#endif
/* UPA nodes send interrupt packet to UltraSparc with first data reg
* value low 5 (7 on Starfire) bits holding the IRQ identifier being
* delivered. We must translate this into a non-vector IRQ so we can
* set the softint on this cpu.
*
* To make processing these packets efficient and race free we use
* an array of irq buckets below. The interrupt vector handler in
* entry.S feeds incoming packets into per-cpu pil-indexed lists.
* The IVEC handler does not need to act atomically, the PIL dispatch
* code uses CAS to get an atomic snapshot of the list and clear it
* at the same time.
*/
struct ino_bucket ivector_table[NUM_IVECS] __attribute__ ((aligned (SMP_CACHE_BYTES)));
/* This has to be in the main kernel image, it cannot be
* turned into per-cpu data. The reason is that the main
* kernel image is locked into the TLB and this structure
* is accessed from the vectored interrupt trap handler. If
* access to this structure takes a TLB miss it could cause
* the 5-level sparc v9 trap stack to overflow.
*/
struct irq_work_struct {
unsigned int irq_worklists[16];
};
struct irq_work_struct __irq_work[NR_CPUS];
#define irq_work(__cpu, __pil) &(__irq_work[(__cpu)].irq_worklists[(__pil)])
static struct irqaction *irq_action[NR_IRQS+1];
/* This only synchronizes entities which modify IRQ handler
* state and some selected user-level spots that want to
* read things in the table. IRQ handler processing orders
* its' accesses such that no locking is needed.
*/
static DEFINE_SPINLOCK(irq_action_lock);
static void register_irq_proc (unsigned int irq);
/*
* Upper 2b of irqaction->flags holds the ino.
* irqaction->mask holds the smp affinity information.
*/
#define put_ino_in_irqaction(action, irq) \
action->flags &= 0xffffffffffffUL; \
if (__bucket(irq) == &pil0_dummy_bucket) \
action->flags |= 0xdeadUL << 48; \
else \
action->flags |= __irq_ino(irq) << 48;
#define get_ino_in_irqaction(action) (action->flags >> 48)
#define put_smpaff_in_irqaction(action, smpaff) (action)->mask = (smpaff)
#define get_smpaff_in_irqaction(action) ((action)->mask)
int show_interrupts(struct seq_file *p, void *v)
{
unsigned long flags;
int i = *(loff_t *) v;
struct irqaction *action;
#ifdef CONFIG_SMP
int j;
#endif
spin_lock_irqsave(&irq_action_lock, flags);
if (i <= NR_IRQS) {
if (!(action = *(i + irq_action)))
goto out_unlock;
seq_printf(p, "%3d: ", i);
#ifndef CONFIG_SMP
seq_printf(p, "%10u ", kstat_irqs(i));
#else
for (j = 0; j < NR_CPUS; j++) {
if (!cpu_online(j))
continue;
seq_printf(p, "%10u ",
kstat_cpu(j).irqs[i]);
}
#endif
seq_printf(p, " %s:%lx", action->name,
get_ino_in_irqaction(action));
for (action = action->next; action; action = action->next) {
seq_printf(p, ", %s:%lx", action->name,
get_ino_in_irqaction(action));
}
seq_putc(p, '\n');
}
out_unlock:
spin_unlock_irqrestore(&irq_action_lock, flags);
return 0;
}
/* Now these are always passed a true fully specified sun4u INO. */
void enable_irq(unsigned int irq)
{
struct ino_bucket *bucket = __bucket(irq);
unsigned long imap;
unsigned long tid;
imap = bucket->imap;
if (imap == 0UL)
return;
preempt_disable();
if (tlb_type == cheetah || tlb_type == cheetah_plus) {
unsigned long ver;
__asm__ ("rdpr %%ver, %0" : "=r" (ver));
if ((ver >> 32) == __JALAPENO_ID ||
(ver >> 32) == __SERRANO_ID) {
/* We set it to our JBUS ID. */
__asm__ __volatile__("ldxa [%%g0] %1, %0"
: "=r" (tid)
: "i" (ASI_JBUS_CONFIG));
tid = ((tid & (0x1fUL<<17)) << 9);
tid &= IMAP_TID_JBUS;
} else {
/* We set it to our Safari AID. */
__asm__ __volatile__("ldxa [%%g0] %1, %0"
: "=r" (tid)
: "i" (ASI_SAFARI_CONFIG));
tid = ((tid & (0x3ffUL<<17)) << 9);
tid &= IMAP_AID_SAFARI;
}
} else if (this_is_starfire == 0) {
/* We set it to our UPA MID. */
__asm__ __volatile__("ldxa [%%g0] %1, %0"
: "=r" (tid)
: "i" (ASI_UPA_CONFIG));
tid = ((tid & UPA_CONFIG_MID) << 9);
tid &= IMAP_TID_UPA;
} else {
tid = (starfire_translate(imap, smp_processor_id()) << 26);
tid &= IMAP_TID_UPA;
}
/* NOTE NOTE NOTE, IGN and INO are read-only, IGN is a product
* of this SYSIO's preconfigured IGN in the SYSIO Control
* Register, the hardware just mirrors that value here.
* However for Graphics and UPA Slave devices the full
* IMAP_INR field can be set by the programmer here.
*
* Things like FFB can now be handled via the new IRQ mechanism.
*/
upa_writel(tid | IMAP_VALID, imap);
preempt_enable();
}
/* This now gets passed true ino's as well. */
void disable_irq(unsigned int irq)
{
struct ino_bucket *bucket = __bucket(irq);
unsigned long imap;
imap = bucket->imap;
if (imap != 0UL) {
u32 tmp;
/* NOTE: We do not want to futz with the IRQ clear registers
* and move the state to IDLE, the SCSI code does call
* disable_irq() to assure atomicity in the queue cmd
* SCSI adapter driver code. Thus we'd lose interrupts.
*/
tmp = upa_readl(imap);
tmp &= ~IMAP_VALID;
upa_writel(tmp, imap);
}
}
/* The timer is the one "weird" interrupt which is generated by
* the CPU %tick register and not by some normal vectored interrupt
* source. To handle this special case, we use this dummy INO bucket.
*/
static struct irq_desc pil0_dummy_desc;
static struct ino_bucket pil0_dummy_bucket = {
.irq_info = &pil0_dummy_desc,
};
static void build_irq_error(const char *msg, unsigned int ino, int pil, int inofixup,
unsigned long iclr, unsigned long imap,
struct ino_bucket *bucket)
{
prom_printf("IRQ: INO %04x (%d:%016lx:%016lx) --> "
"(%d:%d:%016lx:%016lx), halting...\n",
ino, bucket->pil, bucket->iclr, bucket->imap,
pil, inofixup, iclr, imap);
prom_halt();
}
unsigned int build_irq(int pil, int inofixup, unsigned long iclr, unsigned long imap)
{
struct ino_bucket *bucket;
int ino;
if (pil == 0) {
if (iclr != 0UL || imap != 0UL) {
prom_printf("Invalid dummy bucket for PIL0 (%lx:%lx)\n",
iclr, imap);
prom_halt();
}
return __irq(&pil0_dummy_bucket);
}
/* RULE: Both must be specified in all other cases. */
if (iclr == 0UL || imap == 0UL) {
prom_printf("Invalid build_irq %d %d %016lx %016lx\n",
pil, inofixup, iclr, imap);
prom_halt();
}
ino = (upa_readl(imap) & (IMAP_IGN | IMAP_INO)) + inofixup;
if (ino > NUM_IVECS) {
prom_printf("Invalid INO %04x (%d:%d:%016lx:%016lx)\n",
ino, pil, inofixup, iclr, imap);
prom_halt();
}
bucket = &ivector_table[ino];
if (bucket->flags & IBF_ACTIVE)
build_irq_error("IRQ: Trying to build active INO bucket.\n",
ino, pil, inofixup, iclr, imap, bucket);
if (bucket->irq_info) {
if (bucket->imap != imap || bucket->iclr != iclr)
build_irq_error("IRQ: Trying to reinit INO bucket.\n",
ino, pil, inofixup, iclr, imap, bucket);
goto out;
}
bucket->irq_info = kmalloc(sizeof(struct irq_desc), GFP_ATOMIC);
if (!bucket->irq_info) {
prom_printf("IRQ: Error, kmalloc(irq_desc) failed.\n");
prom_halt();
}
memset(bucket->irq_info, 0, sizeof(struct irq_desc));
/* Ok, looks good, set it up. Don't touch the irq_chain or
* the pending flag.
*/
bucket->imap = imap;
bucket->iclr = iclr;
bucket->pil = pil;
bucket->flags = 0;
out:
return __irq(bucket);
}
static void atomic_bucket_insert(struct ino_bucket *bucket)
{
unsigned long pstate;
unsigned int *ent;
__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
__asm__ __volatile__("wrpr %0, %1, %%pstate"
: : "r" (pstate), "i" (PSTATE_IE));
ent = irq_work(smp_processor_id(), bucket->pil);
bucket->irq_chain = *ent;
*ent = __irq(bucket);
__asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
}
static int check_irq_sharing(int pil, unsigned long irqflags)
{
struct irqaction *action, *tmp;
action = *(irq_action + pil);
if (action) {
if ((action->flags & SA_SHIRQ) && (irqflags & SA_SHIRQ)) {
for (tmp = action; tmp->next; tmp = tmp->next)
;
} else {
return -EBUSY;
}
}
return 0;
}
static void append_irq_action(int pil, struct irqaction *action)
{
struct irqaction **pp = irq_action + pil;
while (*pp)
pp = &((*pp)->next);
*pp = action;
}
static struct irqaction *get_action_slot(struct ino_bucket *bucket)
{
struct irq_desc *desc = bucket->irq_info;
int max_irq, i;
max_irq = 1;
if (bucket->flags & IBF_PCI)
max_irq = MAX_IRQ_DESC_ACTION;
for (i = 0; i < max_irq; i++) {
struct irqaction *p = &desc->action[i];
u32 mask = (1 << i);
if (desc->action_active_mask & mask)
continue;
desc->action_active_mask |= mask;
return p;
}
return NULL;
}
int request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
unsigned long irqflags, const char *name, void *dev_id)
{
struct irqaction *action;
struct ino_bucket *bucket = __bucket(irq);
unsigned long flags;
int pending = 0;
if (unlikely(!handler))
return -EINVAL;
if (unlikely(!bucket->irq_info))
return -ENODEV;
if ((bucket != &pil0_dummy_bucket) && (irqflags & SA_SAMPLE_RANDOM)) {
/*
* This function might sleep, we want to call it first,
* outside of the atomic block. In SA_STATIC_ALLOC case,
* random driver's kmalloc will fail, but it is safe.
* If already initialized, random driver will not reinit.
* Yes, this might clear the entropy pool if the wrong
* driver is attempted to be loaded, without actually
* installing a new handler, but is this really a problem,
* only the sysadmin is able to do this.
*/
rand_initialize_irq(irq);
}
spin_lock_irqsave(&irq_action_lock, flags);
if (check_irq_sharing(bucket->pil, irqflags)) {
spin_unlock_irqrestore(&irq_action_lock, flags);
return -EBUSY;
}
action = get_action_slot(bucket);
if (!action) {
spin_unlock_irqrestore(&irq_action_lock, flags);
return -ENOMEM;
}
bucket->flags |= IBF_ACTIVE;
pending = 0;
if (bucket != &pil0_dummy_bucket) {
pending = bucket->pending;
if (pending)
bucket->pending = 0;
}
action->handler = handler;
action->flags = irqflags;
action->name = name;
action->next = NULL;
action->dev_id = dev_id;
put_ino_in_irqaction(action, irq);
put_smpaff_in_irqaction(action, CPU_MASK_NONE);
append_irq_action(bucket->pil, action);
enable_irq(irq);
/* We ate the IVEC already, this makes sure it does not get lost. */
if (pending) {
atomic_bucket_insert(bucket);
set_softint(1 << bucket->pil);
}
spin_unlock_irqrestore(&irq_action_lock, flags);
if (bucket != &pil0_dummy_bucket)
register_irq_proc(__irq_ino(irq));
#ifdef CONFIG_SMP
distribute_irqs();
#endif
return 0;
}
EXPORT_SYMBOL(request_irq);
static struct irqaction *unlink_irq_action(unsigned int irq, void *dev_id)
{
struct ino_bucket *bucket = __bucket(irq);
struct irqaction *action, **pp;
pp = irq_action + bucket->pil;
action = *pp;
if (unlikely(!action))
return NULL;
if (unlikely(!action->handler)) {
printk("Freeing free IRQ %d\n", bucket->pil);
return NULL;
}
while (action && action->dev_id != dev_id) {
pp = &action->next;
action = *pp;
}
if (likely(action))
*pp = action->next;
return action;
}
void free_irq(unsigned int irq, void *dev_id)
{
struct irqaction *action;
struct ino_bucket *bucket;
unsigned long flags;
spin_lock_irqsave(&irq_action_lock, flags);
action = unlink_irq_action(irq, dev_id);
spin_unlock_irqrestore(&irq_action_lock, flags);
if (unlikely(!action))
return;
synchronize_irq(irq);
spin_lock_irqsave(&irq_action_lock, flags);
bucket = __bucket(irq);
if (bucket != &pil0_dummy_bucket) {
struct irq_desc *desc = bucket->irq_info;
unsigned long imap = bucket->imap;
int ent, i;
for (i = 0; i < MAX_IRQ_DESC_ACTION; i++) {
struct irqaction *p = &desc->action[i];
if (p == action) {
desc->action_active_mask &= ~(1 << i);
break;
}
}
if (!desc->action_active_mask) {
/* This unique interrupt source is now inactive. */
bucket->flags &= ~IBF_ACTIVE;
/* See if any other buckets share this bucket's IMAP
* and are still active.
*/
for (ent = 0; ent < NUM_IVECS; ent++) {
struct ino_bucket *bp = &ivector_table[ent];
if (bp != bucket &&
bp->imap == imap &&
(bp->flags & IBF_ACTIVE) != 0)
break;
}
/* Only disable when no other sub-irq levels of
* the same IMAP are active.
*/
if (ent == NUM_IVECS)
disable_irq(irq);
}
}
spin_unlock_irqrestore(&irq_action_lock, flags);
}
EXPORT_SYMBOL(free_irq);
#ifdef CONFIG_SMP
void synchronize_irq(unsigned int irq)
{
struct ino_bucket *bucket = __bucket(irq);
#if 0
/* The following is how I wish I could implement this.
* Unfortunately the ICLR registers are read-only, you can
* only write ICLR_foo values to them. To get the current
* IRQ status you would need to get at the IRQ diag registers
* in the PCI/SBUS controller and the layout of those vary
* from one controller to the next, sigh... -DaveM
*/
unsigned long iclr = bucket->iclr;
while (1) {
u32 tmp = upa_readl(iclr);
if (tmp == ICLR_TRANSMIT ||
tmp == ICLR_PENDING) {
cpu_relax();
continue;
}
break;
}
#else
/* So we have to do this with a INPROGRESS bit just like x86. */
while (bucket->flags & IBF_INPROGRESS)
cpu_relax();
#endif
}
#endif /* CONFIG_SMP */
static void process_bucket(int irq, struct ino_bucket *bp, struct pt_regs *regs)
{
struct irq_desc *desc = bp->irq_info;
unsigned char flags = bp->flags;
u32 action_mask, i;
int random;
bp->flags |= IBF_INPROGRESS;
if (unlikely(!(flags & IBF_ACTIVE))) {
bp->pending = 1;
goto out;
}
if (desc->pre_handler)
desc->pre_handler(bp,
desc->pre_handler_arg1,
desc->pre_handler_arg2);
action_mask = desc->action_active_mask;
random = 0;
for (i = 0; i < MAX_IRQ_DESC_ACTION; i++) {
struct irqaction *p = &desc->action[i];
u32 mask = (1 << i);
if (!(action_mask & mask))
continue;
action_mask &= ~mask;
if (p->handler(__irq(bp), p->dev_id, regs) == IRQ_HANDLED)
random |= p->flags;
if (!action_mask)
break;
}
if (bp->pil != 0) {
upa_writel(ICLR_IDLE, bp->iclr);
/* Test and add entropy */
if (random & SA_SAMPLE_RANDOM)
add_interrupt_randomness(irq);
}
out:
bp->flags &= ~IBF_INPROGRESS;
}
void handler_irq(int irq, struct pt_regs *regs)
{
struct ino_bucket *bp;
int cpu = smp_processor_id();
#ifndef CONFIG_SMP
/*
* Check for TICK_INT on level 14 softint.
*/
{
unsigned long clr_mask = 1 << irq;
unsigned long tick_mask = tick_ops->softint_mask;
if ((irq == 14) && (get_softint() & tick_mask)) {
irq = 0;
clr_mask = tick_mask;
}
clear_softint(clr_mask);
}
#else
clear_softint(1 << irq);
#endif
irq_enter();
kstat_this_cpu.irqs[irq]++;
/* Sliiiick... */
#ifndef CONFIG_SMP
bp = ((irq != 0) ?
__bucket(xchg32(irq_work(cpu, irq), 0)) :
&pil0_dummy_bucket);
#else
bp = __bucket(xchg32(irq_work(cpu, irq), 0));
#endif
while (bp) {
struct ino_bucket *nbp = __bucket(bp->irq_chain);
bp->irq_chain = 0;
process_bucket(irq, bp, regs);
bp = nbp;
}
irq_exit();
}
#ifdef CONFIG_BLK_DEV_FD
extern irqreturn_t floppy_interrupt(int, void *, struct pt_regs *);;
/* XXX No easy way to include asm/floppy.h XXX */
extern unsigned char *pdma_vaddr;
extern unsigned long pdma_size;
extern volatile int doing_pdma;
extern unsigned long fdc_status;
irqreturn_t sparc_floppy_irq(int irq, void *dev_cookie, struct pt_regs *regs)
{
if (likely(doing_pdma)) {
void __iomem *stat = (void __iomem *) fdc_status;
unsigned char *vaddr = pdma_vaddr;
unsigned long size = pdma_size;
u8 val;
while (size) {
val = readb(stat);
if (unlikely(!(val & 0x80))) {
pdma_vaddr = vaddr;
pdma_size = size;
return IRQ_HANDLED;
}
if (unlikely(!(val & 0x20))) {
pdma_vaddr = vaddr;
pdma_size = size;
doing_pdma = 0;
goto main_interrupt;
}
if (val & 0x40) {
/* read */
*vaddr++ = readb(stat + 1);
} else {
unsigned char data = *vaddr++;
/* write */
writeb(data, stat + 1);
}
size--;
}
pdma_vaddr = vaddr;
pdma_size = size;
/* Send Terminal Count pulse to floppy controller. */
val = readb(auxio_register);
val |= AUXIO_AUX1_FTCNT;
writeb(val, auxio_register);
val &= ~AUXIO_AUX1_FTCNT;
writeb(val, auxio_register);
doing_pdma = 0;
}
main_interrupt:
return floppy_interrupt(irq, dev_cookie, regs);
}
EXPORT_SYMBOL(sparc_floppy_irq);
#endif
/* We really don't need these at all on the Sparc. We only have
* stubs here because they are exported to modules.
*/
unsigned long probe_irq_on(void)
{
return 0;
}
EXPORT_SYMBOL(probe_irq_on);
int probe_irq_off(unsigned long mask)
{
return 0;
}
EXPORT_SYMBOL(probe_irq_off);
#ifdef CONFIG_SMP
static int retarget_one_irq(struct irqaction *p, int goal_cpu)
{
struct ino_bucket *bucket = get_ino_in_irqaction(p) + ivector_table;
unsigned long imap = bucket->imap;
unsigned int tid;
while (!cpu_online(goal_cpu)) {
if (++goal_cpu >= NR_CPUS)
goal_cpu = 0;
}
if (tlb_type == cheetah || tlb_type == cheetah_plus) {
tid = goal_cpu << 26;
tid &= IMAP_AID_SAFARI;
} else if (this_is_starfire == 0) {
tid = goal_cpu << 26;
tid &= IMAP_TID_UPA;
} else {
tid = (starfire_translate(imap, goal_cpu) << 26);
tid &= IMAP_TID_UPA;
}
upa_writel(tid | IMAP_VALID, imap);
do {
if (++goal_cpu >= NR_CPUS)
goal_cpu = 0;
} while (!cpu_online(goal_cpu));
return goal_cpu;
}
/* Called from request_irq. */
static void distribute_irqs(void)
{
unsigned long flags;
int cpu, level;
spin_lock_irqsave(&irq_action_lock, flags);
cpu = 0;
/*
* Skip the timer at [0], and very rare error/power intrs at [15].
* Also level [12], it causes problems on Ex000 systems.
*/
for (level = 1; level < NR_IRQS; level++) {
struct irqaction *p = irq_action[level];
if (level == 12)
continue;
while(p) {
cpu = retarget_one_irq(p, cpu);
p = p->next;
}
}
spin_unlock_irqrestore(&irq_action_lock, flags);
}
#endif
struct sun5_timer {
u64 count0;
u64 limit0;
u64 count1;
u64 limit1;
};
static struct sun5_timer *prom_timers;
static u64 prom_limit0, prom_limit1;
static void map_prom_timers(void)
{
unsigned int addr[3];
int tnode, err;
/* PROM timer node hangs out in the top level of device siblings... */
tnode = prom_finddevice("/counter-timer");
/* Assume if node is not present, PROM uses different tick mechanism
* which we should not care about.
*/
if (tnode == 0 || tnode == -1) {
prom_timers = (struct sun5_timer *) 0;
return;
}
/* If PROM is really using this, it must be mapped by him. */
err = prom_getproperty(tnode, "address", (char *)addr, sizeof(addr));
if (err == -1) {
prom_printf("PROM does not have timer mapped, trying to continue.\n");
prom_timers = (struct sun5_timer *) 0;
return;
}
prom_timers = (struct sun5_timer *) ((unsigned long)addr[0]);
}
static void kill_prom_timer(void)
{
if (!prom_timers)
return;
/* Save them away for later. */
prom_limit0 = prom_timers->limit0;
prom_limit1 = prom_timers->limit1;
/* Just as in sun4c/sun4m PROM uses timer which ticks at IRQ 14.
* We turn both off here just to be paranoid.
*/
prom_timers->limit0 = 0;
prom_timers->limit1 = 0;
/* Wheee, eat the interrupt packet too... */
__asm__ __volatile__(
" mov 0x40, %%g2\n"
" ldxa [%%g0] %0, %%g1\n"
" ldxa [%%g2] %1, %%g1\n"
" stxa %%g0, [%%g0] %0\n"
" membar #Sync\n"
: /* no outputs */
: "i" (ASI_INTR_RECEIVE), "i" (ASI_INTR_R)
: "g1", "g2");
}
void init_irqwork_curcpu(void)
{
int cpu = hard_smp_processor_id();
[SPARC64]: Elminate all usage of hard-coded trap globals. UltraSPARC has special sets of global registers which are switched to for certain trap types. There is one set for MMU related traps, one set of Interrupt Vector processing, and another set (called the Alternate globals) for all other trap types. For what seems like forever we've hard coded the values in some of these trap registers. Some examples include: 1) Interrupt Vector global %g6 holds current processors interrupt work struct where received interrupts are managed for IRQ handler dispatch. 2) MMU global %g7 holds the base of the page tables of the currently active address space. 3) Alternate global %g6 held the current_thread_info() value. Such hardcoding has resulted in some serious issues in many areas. There are some code sequences where having another register available would help clean up the implementation. Taking traps such as cross-calls from the OBP firmware requires some trick code sequences wherein we have to save away and restore all of the special sets of global registers when we enter/exit OBP. We were also using the IMMU TSB register on SMP to hold the per-cpu area base address, which doesn't work any longer now that we actually use the TSB facility of the cpu. The implementation is pretty straight forward. One tricky bit is getting the current processor ID as that is different on different cpu variants. We use a stub with a fancy calling convention which we patch at boot time. The calling convention is that the stub is branched to and the (PC - 4) to return to is in register %g1. The cpu number is left in %g6. This stub can be invoked by using the __GET_CPUID macro. We use an array of per-cpu trap state to store the current thread and physical address of the current address space's page tables. The TRAP_LOAD_THREAD_REG loads %g6 with the current thread from this table, it uses __GET_CPUID and also clobbers %g1. TRAP_LOAD_IRQ_WORK is used by the interrupt vector processing to load the current processor's IRQ software state into %g6. It also uses __GET_CPUID and clobbers %g1. Finally, TRAP_LOAD_PGD_PHYS loads the physical address base of the current address space's page tables into %g7, it clobbers %g1 and uses __GET_CPUID. Many refinements are possible, as well as some tuning, with this stuff in place. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-27 00:24:22 -07:00
memset(__irq_work + cpu, 0, sizeof(struct irq_work_struct));
}
/* Only invoked on boot processor. */
void __init init_IRQ(void)
{
map_prom_timers();
kill_prom_timer();
memset(&ivector_table[0], 0, sizeof(ivector_table));
/* We need to clear any IRQ's pending in the soft interrupt
* registers, a spurious one could be left around from the
* PROM timer which we just disabled.
*/
clear_softint(get_softint());
/* Now that ivector table is initialized, it is safe
* to receive IRQ vector traps. We will normally take
* one or two right now, in case some device PROM used
* to boot us wants to speak to us. We just ignore them.
*/
__asm__ __volatile__("rdpr %%pstate, %%g1\n\t"
"or %%g1, %0, %%g1\n\t"
"wrpr %%g1, 0x0, %%pstate"
: /* No outputs */
: "i" (PSTATE_IE)
: "g1");
}
static struct proc_dir_entry * root_irq_dir;
static struct proc_dir_entry * irq_dir [NUM_IVECS];
#ifdef CONFIG_SMP
static int irq_affinity_read_proc (char *page, char **start, off_t off,
int count, int *eof, void *data)
{
struct ino_bucket *bp = ivector_table + (long)data;
struct irq_desc *desc = bp->irq_info;
struct irqaction *ap = desc->action;
cpumask_t mask;
int len;
mask = get_smpaff_in_irqaction(ap);
if (cpus_empty(mask))
mask = cpu_online_map;
len = cpumask_scnprintf(page, count, mask);
if (count - len < 2)
return -EINVAL;
len += sprintf(page + len, "\n");
return len;
}
static inline void set_intr_affinity(int irq, cpumask_t hw_aff)
{
struct ino_bucket *bp = ivector_table + irq;
struct irq_desc *desc = bp->irq_info;
struct irqaction *ap = desc->action;
/* Users specify affinity in terms of hw cpu ids.
* As soon as we do this, handler_irq() might see and take action.
*/
put_smpaff_in_irqaction(ap, hw_aff);
/* Migration is simply done by the next cpu to service this
* interrupt.
*/
}
static int irq_affinity_write_proc (struct file *file, const char __user *buffer,
unsigned long count, void *data)
{
int irq = (long) data, full_count = count, err;
cpumask_t new_value;
err = cpumask_parse(buffer, count, new_value);
/*
* Do not allow disabling IRQs completely - it's a too easy
* way to make the system unusable accidentally :-) At least
* one online CPU still has to be targeted.
*/
cpus_and(new_value, new_value, cpu_online_map);
if (cpus_empty(new_value))
return -EINVAL;
set_intr_affinity(irq, new_value);
return full_count;
}
#endif
#define MAX_NAMELEN 10
static void register_irq_proc (unsigned int irq)
{
char name [MAX_NAMELEN];
if (!root_irq_dir || irq_dir[irq])
return;
memset(name, 0, MAX_NAMELEN);
sprintf(name, "%x", irq);
/* create /proc/irq/1234 */
irq_dir[irq] = proc_mkdir(name, root_irq_dir);
#ifdef CONFIG_SMP
/* XXX SMP affinity not supported on starfire yet. */
if (this_is_starfire == 0) {
struct proc_dir_entry *entry;
/* create /proc/irq/1234/smp_affinity */
entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
if (entry) {
entry->nlink = 1;
entry->data = (void *)(long)irq;
entry->read_proc = irq_affinity_read_proc;
entry->write_proc = irq_affinity_write_proc;
}
}
#endif
}
void init_irq_proc (void)
{
/* create /proc/irq */
root_irq_dir = proc_mkdir("irq", NULL);
}