aboutsummaryrefslogtreecommitdiff
path: root/hw/apic.c
diff options
context:
space:
mode:
authorbellard <bellard@c046a42c-6fe2-441c-8c8c-71466251a162>2005-07-23 19:05:37 +0000
committerbellard <bellard@c046a42c-6fe2-441c-8c8c-71466251a162>2005-07-23 19:05:37 +0000
commitd592d3033d7bc41db6159e9387591a216e3c46e0 (patch)
tree8f06d19fb1c8d94005c991d8523e62a2d71f145f /hw/apic.c
parent1ff5c1a68e2784722b66ecc40e30908e87e28a3b (diff)
IOAPIC support (initial patch by Filip Navara)
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@1520 c046a42c-6fe2-441c-8c8c-71466251a162
Diffstat (limited to 'hw/apic.c')
-rw-r--r--hw/apic.c545
1 files changed, 520 insertions, 25 deletions
diff --git a/hw/apic.c b/hw/apic.c
index 486b9bf876..8b33cab370 100644
--- a/hw/apic.c
+++ b/hw/apic.c
@@ -20,6 +20,7 @@
#include "vl.h"
//#define DEBUG_APIC
+//#define DEBUG_IOAPIC
/* APIC Local Vector Table */
#define APIC_LVT_TIMER 0
@@ -39,6 +40,10 @@
#define APIC_DM_SIPI 6
#define APIC_DM_EXTINT 7
+/* APIC destination mode */
+#define APIC_DESTMODE_FLAT 0xf
+#define APIC_DESTMODE_CLUSTER 1
+
#define APIC_TRIGGER_EDGE 0
#define APIC_TRIGGER_LEVEL 1
@@ -49,6 +54,8 @@
#define APIC_INPUT_POLARITY (1<<13)
#define APIC_SEND_PENDING (1<<12)
+#define IOAPIC_NUM_PINS 0x18
+
#define ESR_ILLEGAL_ADDRESS (1 << 7)
#define APIC_SV_ENABLE (1 << 8)
@@ -57,8 +64,11 @@ typedef struct APICState {
CPUState *cpu_env;
uint32_t apicbase;
uint8_t id;
+ uint8_t arb_id;
uint8_t tpr;
uint32_t spurious_vec;
+ uint8_t log_dest;
+ uint8_t dest_mode;
uint32_t isr[8]; /* in service register */
uint32_t tmr[8]; /* trigger mode register */
uint32_t irr[8]; /* interrupt request register */
@@ -71,9 +81,65 @@ typedef struct APICState {
uint32_t initial_count;
int64_t initial_count_load_time, next_time;
QEMUTimer *timer;
+
+ struct APICState *next_apic;
} APICState;
+struct IOAPICState {
+ uint8_t id;
+ uint8_t ioregsel;
+
+ uint32_t irr;
+ uint64_t ioredtbl[IOAPIC_NUM_PINS];
+};
+
static int apic_io_memory;
+static APICState *first_local_apic = NULL;
+static int last_apic_id = 0;
+static IOAPICState *ioapic_state;
+
+static void apic_init_ipi(APICState *s);
+static void apic_set_irq(APICState *s, int vector_num, int trigger_mode);
+static void apic_update_irq(APICState *s);
+
+static void apic_bus_deliver(uint32_t deliver_bitmask, uint8_t delivery_mode,
+ uint8_t vector_num, uint8_t polarity,
+ uint8_t trigger_mode)
+{
+ APICState *apic_iter;
+
+ switch (delivery_mode) {
+ case APIC_DM_LOWPRI:
+ case APIC_DM_FIXED:
+ /* XXX: arbitration */
+ break;
+
+ case APIC_DM_SMI:
+ case APIC_DM_NMI:
+ break;
+
+ case APIC_DM_INIT:
+ /* normal INIT IPI sent to processors */
+ for (apic_iter = first_local_apic; apic_iter != NULL;
+ apic_iter = apic_iter->next_apic) {
+ apic_init_ipi(apic_iter);
+ }
+ return;
+
+ case APIC_DM_EXTINT:
+ /* XXX: implement */
+ break;
+
+ default:
+ return;
+ }
+
+ for (apic_iter = first_local_apic; apic_iter != NULL;
+ apic_iter = apic_iter->next_apic) {
+ if (deliver_bitmask & (1 << apic_iter->id))
+ apic_set_irq(apic_iter, vector_num, trigger_mode);
+ }
+}
void cpu_set_apic_base(CPUState *env, uint64_t val)
{
@@ -104,6 +170,7 @@ void cpu_set_apic_tpr(CPUX86State *env, uint8_t val)
{
APICState *s = env->apic_state;
s->tpr = (val & 0x0f) << 4;
+ apic_update_irq(s);
}
uint8_t cpu_get_apic_tpr(CPUX86State *env)
@@ -112,16 +179,24 @@ uint8_t cpu_get_apic_tpr(CPUX86State *env)
return s->tpr >> 4;
}
-/* return -1 if no bit is set */
-static int get_highest_priority_int(uint32_t *tab)
+int fls_bit(int value)
{
- int i;
- for(i = 0;i < 8; i++) {
- if (tab[i] != 0) {
- return i * 32 + ffs(tab[i]) - 1;
- }
- }
- return -1;
+ unsigned int ret = 0;
+
+#ifdef HOST_I386
+ __asm__ __volatile__ ("bsr %1, %0\n" : "+r" (ret) : "rm" (value));
+ return ret;
+#else
+ if (value > 0xffff)
+ value >>= 16, ret = 16;
+ if (value > 0xff)
+ value >>= 8, ret += 8;
+ if (value > 0xf)
+ value >>= 4, ret += 4;
+ if (value > 0x3)
+ value >>= 2, ret += 2;
+ return ret + (value >> 1);
+#endif
}
static inline void set_bit(uint32_t *tab, int index)
@@ -140,6 +215,18 @@ static inline void reset_bit(uint32_t *tab, int index)
tab[i] &= ~mask;
}
+/* return -1 if no bit is set */
+static int get_highest_priority_int(uint32_t *tab)
+{
+ int i;
+ for(i = 7; i >= 0; i--) {
+ if (tab[i] != 0) {
+ return i * 32 + fls_bit(tab[i]);
+ }
+ }
+ return -1;
+}
+
static int apic_get_ppr(APICState *s)
{
int tpr, isrv, ppr;
@@ -156,16 +243,23 @@ static int apic_get_ppr(APICState *s)
return ppr;
}
+static int apic_get_arb_pri(APICState *s)
+{
+ /* XXX: arbitration */
+ return 0;
+}
+
/* signal the CPU if an irq is pending */
static void apic_update_irq(APICState *s)
{
- int irrv, isrv;
+ int irrv, ppr;
+ if (!(s->spurious_vec & APIC_SV_ENABLE))
+ return;
irrv = get_highest_priority_int(s->irr);
if (irrv < 0)
return;
- isrv = get_highest_priority_int(s->isr);
- /* if the pending irq has less priority, we do not make a new request */
- if (isrv >= 0 && irrv >= isrv)
+ ppr = apic_get_ppr(s);
+ if (ppr && (irrv & 0xf0) <= (ppr & 0xf0))
return;
cpu_interrupt(s->cpu_env, CPU_INTERRUPT_HARD);
}
@@ -187,9 +281,116 @@ static void apic_eoi(APICState *s)
if (isrv < 0)
return;
reset_bit(s->isr, isrv);
+ /* XXX: send the EOI packet to the APIC bus to allow the I/O APIC to
+ set the remote IRR bit for level triggered interrupts. */
apic_update_irq(s);
}
+static uint32_t apic_get_delivery_bitmask(uint8_t dest, uint8_t dest_mode)
+{
+ uint32_t mask = 0;
+ APICState *apic_iter;
+
+ if (dest_mode == 0) {
+ if (dest == 0xff)
+ mask = 0xff;
+ else
+ mask = 1 << dest;
+ } else {
+ /* XXX: cluster mode */
+ for (apic_iter = first_local_apic; apic_iter != NULL;
+ apic_iter = apic_iter->next_apic) {
+ if (dest & apic_iter->log_dest)
+ mask |= (1 << apic_iter->id);
+ }
+ }
+
+ return mask;
+}
+
+
+static void apic_init_ipi(APICState *s)
+{
+ int i;
+
+ for(i = 0; i < APIC_LVT_NB; i++)
+ s->lvt[i] = 1 << 16; /* mask LVT */
+ s->tpr = 0;
+ s->spurious_vec = 0xff;
+ s->log_dest = 0;
+ s->dest_mode = 0;
+ memset(s->isr, 0, sizeof(s->isr));
+ memset(s->tmr, 0, sizeof(s->tmr));
+ memset(s->irr, 0, sizeof(s->irr));
+ memset(s->lvt, 0, sizeof(s->lvt));
+ s->esr = 0;
+ memset(s->icr, 0, sizeof(s->icr));
+ s->divide_conf = 0;
+ s->count_shift = 0;
+ s->initial_count = 0;
+ s->initial_count_load_time = 0;
+ s->next_time = 0;
+}
+
+static void apic_deliver(APICState *s, uint8_t dest, uint8_t dest_mode,
+ uint8_t delivery_mode, uint8_t vector_num,
+ uint8_t polarity, uint8_t trigger_mode)
+{
+ uint32_t deliver_bitmask = 0;
+ int dest_shorthand = (s->icr[0] >> 18) & 3;
+ APICState *apic_iter;
+
+ switch (delivery_mode) {
+ case APIC_DM_LOWPRI:
+ /* XXX: serch for focus processor, arbitration */
+ dest = s->id;
+
+ case APIC_DM_INIT:
+ {
+ int trig_mode = (s->icr[0] >> 15) & 1;
+ int level = (s->icr[0] >> 14) & 1;
+ if (level == 0 && trig_mode == 1) {
+ for (apic_iter = first_local_apic; apic_iter != NULL;
+ apic_iter = apic_iter->next_apic) {
+ if (deliver_bitmask & (1 << apic_iter->id)) {
+ apic_iter->arb_id = apic_iter->id;
+ }
+ }
+ return;
+ }
+ }
+ break;
+
+ case APIC_DM_SIPI:
+ for (apic_iter = first_local_apic; apic_iter != NULL;
+ apic_iter = apic_iter->next_apic) {
+ if (deliver_bitmask & (1 << apic_iter->id)) {
+ /* XXX: SMP support */
+ /* apic_startup(apic_iter); */
+ }
+ }
+ return;
+ }
+
+ switch (dest_shorthand) {
+ case 0:
+ deliver_bitmask = apic_get_delivery_bitmask(dest, dest_mode);
+ break;
+ case 1:
+ deliver_bitmask = (1 << s->id);
+ break;
+ case 2:
+ deliver_bitmask = 0xffffffff;
+ break;
+ case 3:
+ deliver_bitmask = 0xffffffff & ~(1 << s->id);
+ break;
+ }
+
+ apic_bus_deliver(deliver_bitmask, delivery_mode, vector_num, polarity,
+ trigger_mode);
+}
+
int apic_get_interrupt(CPUState *env)
{
APICState *s = env->apic_state;
@@ -207,6 +408,8 @@ int apic_get_interrupt(CPUState *env)
if (intno < 0)
return -1;
reset_bit(s->irr, intno);
+ if (s->tpr && intno <= s->tpr)
+ return s->spurious_vec & 0xff;
set_bit(s->isr, intno);
apic_update_irq(s);
return intno;
@@ -220,7 +423,7 @@ static uint32_t apic_get_current_count(APICState *s)
s->count_shift;
if (s->lvt[APIC_LVT_TIMER] & APIC_LVT_TIMER_PERIODIC) {
/* periodic */
- val = s->initial_count - (d % (s->initial_count + 1));
+ val = s->initial_count - (d % ((uint64_t)s->initial_count + 1));
} else {
if (d >= s->initial_count)
val = 0;
@@ -238,11 +441,11 @@ static void apic_timer_update(APICState *s, int64_t current_time)
d = (current_time - s->initial_count_load_time) >>
s->count_shift;
if (s->lvt[APIC_LVT_TIMER] & APIC_LVT_TIMER_PERIODIC) {
- d = ((d / (s->initial_count + 1)) + 1) * (s->initial_count + 1);
+ d = ((d / ((uint64_t)s->initial_count + 1)) + 1) * ((uint64_t)s->initial_count + 1);
} else {
if (d >= s->initial_count)
goto no_timer;
- d = s->initial_count + 1;
+ d = (uint64_t)s->initial_count + 1;
}
next_time = s->initial_count_load_time + (d << s->count_shift);
qemu_mod_timer(s->timer, next_time);
@@ -304,10 +507,19 @@ static uint32_t apic_mem_readl(void *opaque, target_phys_addr_t addr)
case 0x08:
val = s->tpr;
break;
+ case 0x09:
+ val = apic_get_arb_pri(s);
+ break;
case 0x0a:
/* ppr */
val = apic_get_ppr(s);
break;
+ case 0x0d:
+ val = s->log_dest << 24;
+ break;
+ case 0x0e:
+ val = s->dest_mode << 28;
+ break;
case 0x0f:
val = s->spurious_vec;
break;
@@ -372,16 +584,29 @@ static void apic_mem_writel(void *opaque, target_phys_addr_t addr, uint32_t val)
break;
case 0x08:
s->tpr = val;
+ apic_update_irq(s);
break;
case 0x0b: /* EOI */
apic_eoi(s);
break;
+ case 0x0d:
+ s->log_dest = val >> 24;
+ break;
+ case 0x0e:
+ s->dest_mode = val >> 28;
+ break;
case 0x0f:
s->spurious_vec = val & 0x1ff;
+ apic_update_irq(s);
break;
case 0x30:
+ s->icr[0] = val;
+ apic_deliver(s, (s->icr[1] >> 24) & 0xff, (s->icr[0] >> 11) & 1,
+ (s->icr[0] >> 8) & 7, (s->icr[0] & 0xff),
+ (s->icr[0] >> 14) & 1, (s->icr[0] >> 15) & 1);
+ break;
case 0x31:
- s->icr[index & 1] = val;
+ s->icr[1] = val;
break;
case 0x32 ... 0x37:
{
@@ -410,7 +635,76 @@ static void apic_mem_writel(void *opaque, target_phys_addr_t addr, uint32_t val)
}
}
+static void apic_save(QEMUFile *f, void *opaque)
+{
+ APICState *s = opaque;
+ int i;
+
+ qemu_put_be32s(f, &s->apicbase);
+ qemu_put_8s(f, &s->id);
+ qemu_put_8s(f, &s->arb_id);
+ qemu_put_8s(f, &s->tpr);
+ qemu_put_be32s(f, &s->spurious_vec);
+ qemu_put_8s(f, &s->log_dest);
+ qemu_put_8s(f, &s->dest_mode);
+ for (i = 0; i < 8; i++) {
+ qemu_put_be32s(f, &s->isr[i]);
+ qemu_put_be32s(f, &s->tmr[i]);
+ qemu_put_be32s(f, &s->irr[i]);
+ }
+ for (i = 0; i < APIC_LVT_NB; i++) {
+ qemu_put_be32s(f, &s->lvt[i]);
+ }
+ qemu_put_be32s(f, &s->esr);
+ qemu_put_be32s(f, &s->icr[0]);
+ qemu_put_be32s(f, &s->icr[1]);
+ qemu_put_be32s(f, &s->divide_conf);
+ qemu_put_be32s(f, &s->count_shift);
+ qemu_put_be32s(f, &s->initial_count);
+ qemu_put_be64s(f, &s->initial_count_load_time);
+ qemu_put_be64s(f, &s->next_time);
+}
+
+static int apic_load(QEMUFile *f, void *opaque, int version_id)
+{
+ APICState *s = opaque;
+ int i;
+
+ if (version_id != 1)
+ return -EINVAL;
+
+ /* XXX: what if the base changes? (registered memory regions) */
+ qemu_get_be32s(f, &s->apicbase);
+ qemu_get_8s(f, &s->id);
+ qemu_get_8s(f, &s->arb_id);
+ qemu_get_8s(f, &s->tpr);
+ qemu_get_be32s(f, &s->spurious_vec);
+ qemu_get_8s(f, &s->log_dest);
+ qemu_get_8s(f, &s->dest_mode);
+ for (i = 0; i < 8; i++) {
+ qemu_get_be32s(f, &s->isr[i]);
+ qemu_get_be32s(f, &s->tmr[i]);
+ qemu_get_be32s(f, &s->irr[i]);
+ }
+ for (i = 0; i < APIC_LVT_NB; i++) {
+ qemu_get_be32s(f, &s->lvt[i]);
+ }
+ qemu_get_be32s(f, &s->esr);
+ qemu_get_be32s(f, &s->icr[0]);
+ qemu_get_be32s(f, &s->icr[1]);
+ qemu_get_be32s(f, &s->divide_conf);
+ qemu_get_be32s(f, &s->count_shift);
+ qemu_get_be32s(f, &s->initial_count);
+ qemu_get_be64s(f, &s->initial_count_load_time);
+ qemu_get_be64s(f, &s->next_time);
+ return 0;
+}
+static void apic_reset(void *opaque)
+{
+ APICState *s = opaque;
+ apic_init_ipi(s);
+}
static CPUReadMemoryFunc *apic_mem_read[3] = {
apic_mem_readb,
@@ -427,27 +721,228 @@ static CPUWriteMemoryFunc *apic_mem_write[3] = {
int apic_init(CPUState *env)
{
APICState *s;
- int i;
- s = malloc(sizeof(APICState));
+ s = qemu_mallocz(sizeof(APICState));
if (!s)
return -1;
- memset(s, 0, sizeof(*s));
env->apic_state = s;
+ apic_init_ipi(s);
+ s->id = last_apic_id++;
s->cpu_env = env;
s->apicbase = 0xfee00000 |
- MSR_IA32_APICBASE_BSP | MSR_IA32_APICBASE_ENABLE;
- for(i = 0; i < APIC_LVT_NB; i++)
- s->lvt[i] = 1 << 16; /* mask LVT */
- s->spurious_vec = 0xff;
+ (s->id ? 0 : MSR_IA32_APICBASE_BSP) | MSR_IA32_APICBASE_ENABLE;
+ /* XXX: mapping more APICs at the same memory location */
if (apic_io_memory == 0) {
/* NOTE: the APIC is directly connected to the CPU - it is not
on the global memory bus. */
apic_io_memory = cpu_register_io_memory(0, apic_mem_read,
apic_mem_write, NULL);
- cpu_register_physical_memory(s->apicbase & ~0xfff, 0x1000, apic_io_memory);
+ cpu_register_physical_memory(s->apicbase & ~0xfff, 0x1000,
+ apic_io_memory);
}
s->timer = qemu_new_timer(vm_clock, apic_timer, s);
+
+ register_savevm("apic", 0, 1, apic_save, apic_load, s);
+ qemu_register_reset(apic_reset, s);
+
+ s->next_apic = first_local_apic;
+ first_local_apic = s;
+
+ return 0;
+}
+
+static void ioapic_service(IOAPICState *s)
+{
+ uint8_t vector;
+ uint32_t mask;
+ uint64_t entry;
+ uint8_t dest;
+ uint8_t dest_mode;
+
+ for (vector = 0; vector < IOAPIC_NUM_PINS; vector++) {
+ mask = 1 << vector;
+ if (s->irr & mask) {
+ entry = s->ioredtbl[vector];
+ if (!(entry & APIC_LVT_MASKED)) {
+ if (!((entry >> 15) & 1))
+ s->irr &= ~mask;
+ dest = entry >> 56;
+ dest_mode = (entry >> 11) & 1;
+ apic_bus_deliver(apic_get_delivery_bitmask(dest, dest_mode),
+ (entry >> 8) & 7, entry & 0xff,
+ (entry >> 13) & 1, (entry >> 15) & 1);
+ }
+ }
+ }
+}
+
+void ioapic_set_irq(void *opaque, int vector, int level)
+{
+ IOAPICState *s = opaque;
+
+ if (vector >= 0 && vector < IOAPIC_NUM_PINS) {
+ uint32_t mask = 1 << vector;
+ uint64_t entry = s->ioredtbl[vector];
+
+ if ((entry >> 15) & 1) {
+ /* level triggered */
+ if (level) {
+ s->irr |= mask;
+ ioapic_service(s);
+ } else {
+ s->irr &= ~mask;
+ }
+ } else {
+ /* edge triggered */
+ if (level) {
+ s->irr |= mask;
+ ioapic_service(s);
+ }
+ }
+ }
+}
+
+static uint32_t ioapic_mem_readl(void *opaque, target_phys_addr_t addr)
+{
+ IOAPICState *s = opaque;
+ int index;
+ uint32_t val = 0;
+
+ addr &= 0xff;
+ if (addr == 0x00) {
+ val = s->ioregsel;
+ } else if (addr == 0x10) {
+ switch (s->ioregsel) {
+ case 0x00:
+ val = s->id << 24;
+ break;
+ case 0x01:
+ val = 0x11 | ((IOAPIC_NUM_PINS - 1) << 16); /* version 0x11 */
+ break;
+ case 0x02:
+ val = 0;
+ break;
+ default:
+ index = (s->ioregsel - 0x10) >> 1;
+ if (index >= 0 && index < IOAPIC_NUM_PINS) {
+ if (s->ioregsel & 1)
+ val = s->ioredtbl[index] >> 32;
+ else
+ val = s->ioredtbl[index] & 0xffffffff;
+ }
+ }
+#ifdef DEBUG_IOAPIC
+ printf("I/O APIC read: %08x = %08x\n", s->ioregsel, val);
+#endif
+ }
+ return val;
+}
+
+static void ioapic_mem_writel(void *opaque, target_phys_addr_t addr, uint32_t val)
+{
+ IOAPICState *s = opaque;
+ int index;
+
+ addr &= 0xff;
+ if (addr == 0x00) {
+ s->ioregsel = val;
+ return;
+ } else if (addr == 0x10) {
+#ifdef DEBUG_IOAPIC
+ printf("I/O APIC write: %08x = %08x\n", s->ioregsel, val);
+#endif
+ switch (s->ioregsel) {
+ case 0x00:
+ s->id = (val >> 24) & 0xff;
+ return;
+ case 0x01:
+ case 0x02:
+ return;
+ default:
+ index = (s->ioregsel - 0x10) >> 1;
+ if (index >= 0 && index < IOAPIC_NUM_PINS) {
+ if (s->ioregsel & 1) {
+ s->ioredtbl[index] &= 0xffffffff;
+ s->ioredtbl[index] |= (uint64_t)val << 32;
+ } else {
+ s->ioredtbl[index] &= ~0xffffffffULL;
+ s->ioredtbl[index] |= val;
+ }
+ ioapic_service(s);
+ }
+ }
+ }
+}
+
+static void ioapic_save(QEMUFile *f, void *opaque)
+{
+ IOAPICState *s = opaque;
+ int i;
+
+ qemu_put_8s(f, &s->id);
+ qemu_put_8s(f, &s->ioregsel);
+ for (i = 0; i < IOAPIC_NUM_PINS; i++) {
+ qemu_put_be64s(f, &s->ioredtbl[i]);
+ }
+}
+
+static int ioapic_load(QEMUFile *f, void *opaque, int version_id)
+{
+ IOAPICState *s = opaque;
+ int i;
+
+ if (version_id != 1)
+ return -EINVAL;
+
+ qemu_get_8s(f, &s->id);
+ qemu_get_8s(f, &s->ioregsel);
+ for (i = 0; i < IOAPIC_NUM_PINS; i++) {
+ qemu_get_be64s(f, &s->ioredtbl[i]);
+ }
return 0;
}
+
+static void ioapic_reset(void *opaque)
+{
+ IOAPICState *s = opaque;
+ int i;
+
+ memset(s, 0, sizeof(*s));
+ for(i = 0; i < IOAPIC_NUM_PINS; i++)
+ s->ioredtbl[i] = 1 << 16; /* mask LVT */
+}
+
+static CPUReadMemoryFunc *ioapic_mem_read[3] = {
+ ioapic_mem_readl,
+ ioapic_mem_readl,
+ ioapic_mem_readl,
+};
+
+static CPUWriteMemoryFunc *ioapic_mem_write[3] = {
+ ioapic_mem_writel,
+ ioapic_mem_writel,
+ ioapic_mem_writel,
+};
+
+IOAPICState *ioapic_init(void)
+{
+ IOAPICState *s;
+ int io_memory;
+
+ s = malloc(sizeof(IOAPICState));
+ if (!s)
+ return NULL;
+ ioapic_state = s;
+ ioapic_reset(s);
+ s->id = last_apic_id++;
+
+ io_memory = cpu_register_io_memory(0, ioapic_mem_read,
+ ioapic_mem_write, s);
+ cpu_register_physical_memory(0xfec00000, 0x1000, io_memory);
+
+ register_savevm("ioapic", 0, 1, ioapic_save, ioapic_load, s);
+ qemu_register_reset(ioapic_reset, s);
+
+ return s;
+}