qemu-e2k/hw/core/ptimer.c

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/*
* General purpose implementation of a simple periodic countdown timer.
*
* Copyright (c) 2007 CodeSourcery.
*
* This code is licensed under the GNU LGPL.
*/
#include "qemu/osdep.h"
#include "hw/hw.h"
#include "qemu/timer.h"
#include "hw/ptimer.h"
#include "qemu/host-utils.h"
#include "sysemu/replay.h"
struct ptimer_state
{
uint8_t enabled; /* 0 = disabled, 1 = periodic, 2 = oneshot. */
uint64_t limit;
uint64_t delta;
uint32_t period_frac;
int64_t period;
int64_t last_event;
int64_t next_event;
QEMUBH *bh;
QEMUTimer *timer;
};
/* Use a bottom-half routine to avoid reentrancy issues. */
static void ptimer_trigger(ptimer_state *s)
{
if (s->bh) {
replay_bh_schedule_event(s->bh);
}
}
static void ptimer_reload(ptimer_state *s)
{
hw/ptimer: Fix issues caused by the adjusted timer limit value Multiple issues here related to the timer with a adjusted .limit value: 1) ptimer_get_count() returns incorrect counter value for the disabled timer after loading the counter with a small value, because adjusted limit value is used instead of the original. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 0, 1) 4) ptimer_get_count(t) <-- would return 10000 instead of 0 2) ptimer_get_count() might return incorrect value for the timer running with a adjusted limit value. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 10, 1) 4) ptimer_run(t) 5) ptimer_get_count(t) <-- might return value > 10 3) Neither ptimer_set_period() nor ptimer_set_freq() are adjusting the limit value, so it is still possible to make timer timeout value arbitrary small. For instance: 1) ptimer_set_period(t, 10000) 2) ptimer_set_limit(t, 1, 0) 3) ptimer_set_period(t, 1) <-- bypass limit correction Fix all of the above issues by adjusting timer period instead of the limit. Perform the adjustment for periodic timer only. Use the delta value instead of the limit to make decision whether adjustment is required, as limit could be altered while timer is running, resulting in incorrect value returned by ptimer_get_count. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com> Message-id: cd141f74f5737480ec586b9c7d18cce1d69884e2.1464367869.git.digetx@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-06-06 17:59:30 +02:00
uint32_t period_frac = s->period_frac;
uint64_t period = s->period;
if (s->delta == 0) {
ptimer_trigger(s);
s->delta = s->limit;
}
if (s->delta == 0 || s->period == 0) {
fprintf(stderr, "Timer with period zero, disabling\n");
s->enabled = 0;
return;
}
hw/ptimer: Fix issues caused by the adjusted timer limit value Multiple issues here related to the timer with a adjusted .limit value: 1) ptimer_get_count() returns incorrect counter value for the disabled timer after loading the counter with a small value, because adjusted limit value is used instead of the original. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 0, 1) 4) ptimer_get_count(t) <-- would return 10000 instead of 0 2) ptimer_get_count() might return incorrect value for the timer running with a adjusted limit value. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 10, 1) 4) ptimer_run(t) 5) ptimer_get_count(t) <-- might return value > 10 3) Neither ptimer_set_period() nor ptimer_set_freq() are adjusting the limit value, so it is still possible to make timer timeout value arbitrary small. For instance: 1) ptimer_set_period(t, 10000) 2) ptimer_set_limit(t, 1, 0) 3) ptimer_set_period(t, 1) <-- bypass limit correction Fix all of the above issues by adjusting timer period instead of the limit. Perform the adjustment for periodic timer only. Use the delta value instead of the limit to make decision whether adjustment is required, as limit could be altered while timer is running, resulting in incorrect value returned by ptimer_get_count. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com> Message-id: cd141f74f5737480ec586b9c7d18cce1d69884e2.1464367869.git.digetx@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-06-06 17:59:30 +02:00
/*
* Artificially limit timeout rate to something
* achievable under QEMU. Otherwise, QEMU spends all
* its time generating timer interrupts, and there
* is no forward progress.
* About ten microseconds is the fastest that really works
* on the current generation of host machines.
*/
if (s->enabled == 1 && (s->delta * period < 10000) && !use_icount) {
period = 10000 / s->delta;
period_frac = 0;
}
s->last_event = s->next_event;
hw/ptimer: Fix issues caused by the adjusted timer limit value Multiple issues here related to the timer with a adjusted .limit value: 1) ptimer_get_count() returns incorrect counter value for the disabled timer after loading the counter with a small value, because adjusted limit value is used instead of the original. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 0, 1) 4) ptimer_get_count(t) <-- would return 10000 instead of 0 2) ptimer_get_count() might return incorrect value for the timer running with a adjusted limit value. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 10, 1) 4) ptimer_run(t) 5) ptimer_get_count(t) <-- might return value > 10 3) Neither ptimer_set_period() nor ptimer_set_freq() are adjusting the limit value, so it is still possible to make timer timeout value arbitrary small. For instance: 1) ptimer_set_period(t, 10000) 2) ptimer_set_limit(t, 1, 0) 3) ptimer_set_period(t, 1) <-- bypass limit correction Fix all of the above issues by adjusting timer period instead of the limit. Perform the adjustment for periodic timer only. Use the delta value instead of the limit to make decision whether adjustment is required, as limit could be altered while timer is running, resulting in incorrect value returned by ptimer_get_count. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com> Message-id: cd141f74f5737480ec586b9c7d18cce1d69884e2.1464367869.git.digetx@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-06-06 17:59:30 +02:00
s->next_event = s->last_event + s->delta * period;
if (period_frac) {
s->next_event += ((int64_t)period_frac * s->delta) >> 32;
}
timer_mod(s->timer, s->next_event);
}
static void ptimer_tick(void *opaque)
{
ptimer_state *s = (ptimer_state *)opaque;
ptimer_trigger(s);
s->delta = 0;
if (s->enabled == 2) {
s->enabled = 0;
} else {
ptimer_reload(s);
}
}
uint64_t ptimer_get_count(ptimer_state *s)
{
uint64_t counter;
if (s->enabled) {
int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
int64_t next = s->next_event;
bool expired = (now - next >= 0);
bool oneshot = (s->enabled == 2);
/* Figure out the current counter value. */
if (s->period == 0 || (expired && (oneshot || use_icount))) {
/* Prevent timer underflowing if it should already have
triggered. */
counter = 0;
} else {
uint64_t rem;
uint64_t div;
int clz1, clz2;
int shift;
hw/ptimer: Fix issues caused by the adjusted timer limit value Multiple issues here related to the timer with a adjusted .limit value: 1) ptimer_get_count() returns incorrect counter value for the disabled timer after loading the counter with a small value, because adjusted limit value is used instead of the original. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 0, 1) 4) ptimer_get_count(t) <-- would return 10000 instead of 0 2) ptimer_get_count() might return incorrect value for the timer running with a adjusted limit value. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 10, 1) 4) ptimer_run(t) 5) ptimer_get_count(t) <-- might return value > 10 3) Neither ptimer_set_period() nor ptimer_set_freq() are adjusting the limit value, so it is still possible to make timer timeout value arbitrary small. For instance: 1) ptimer_set_period(t, 10000) 2) ptimer_set_limit(t, 1, 0) 3) ptimer_set_period(t, 1) <-- bypass limit correction Fix all of the above issues by adjusting timer period instead of the limit. Perform the adjustment for periodic timer only. Use the delta value instead of the limit to make decision whether adjustment is required, as limit could be altered while timer is running, resulting in incorrect value returned by ptimer_get_count. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com> Message-id: cd141f74f5737480ec586b9c7d18cce1d69884e2.1464367869.git.digetx@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-06-06 17:59:30 +02:00
uint32_t period_frac = s->period_frac;
uint64_t period = s->period;
if (!oneshot && (s->delta * period < 10000) && !use_icount) {
hw/ptimer: Fix issues caused by the adjusted timer limit value Multiple issues here related to the timer with a adjusted .limit value: 1) ptimer_get_count() returns incorrect counter value for the disabled timer after loading the counter with a small value, because adjusted limit value is used instead of the original. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 0, 1) 4) ptimer_get_count(t) <-- would return 10000 instead of 0 2) ptimer_get_count() might return incorrect value for the timer running with a adjusted limit value. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 10, 1) 4) ptimer_run(t) 5) ptimer_get_count(t) <-- might return value > 10 3) Neither ptimer_set_period() nor ptimer_set_freq() are adjusting the limit value, so it is still possible to make timer timeout value arbitrary small. For instance: 1) ptimer_set_period(t, 10000) 2) ptimer_set_limit(t, 1, 0) 3) ptimer_set_period(t, 1) <-- bypass limit correction Fix all of the above issues by adjusting timer period instead of the limit. Perform the adjustment for periodic timer only. Use the delta value instead of the limit to make decision whether adjustment is required, as limit could be altered while timer is running, resulting in incorrect value returned by ptimer_get_count. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com> Message-id: cd141f74f5737480ec586b9c7d18cce1d69884e2.1464367869.git.digetx@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-06-06 17:59:30 +02:00
period = 10000 / s->delta;
period_frac = 0;
}
/* We need to divide time by period, where time is stored in
rem (64-bit integer) and period is stored in period/period_frac
(64.32 fixed point).
Doing full precision division is hard, so scale values and
do a 64-bit division. The result should be rounded down,
so that the rounding error never causes the timer to go
backwards.
*/
rem = expired ? now - next : next - now;
hw/ptimer: Fix issues caused by the adjusted timer limit value Multiple issues here related to the timer with a adjusted .limit value: 1) ptimer_get_count() returns incorrect counter value for the disabled timer after loading the counter with a small value, because adjusted limit value is used instead of the original. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 0, 1) 4) ptimer_get_count(t) <-- would return 10000 instead of 0 2) ptimer_get_count() might return incorrect value for the timer running with a adjusted limit value. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 10, 1) 4) ptimer_run(t) 5) ptimer_get_count(t) <-- might return value > 10 3) Neither ptimer_set_period() nor ptimer_set_freq() are adjusting the limit value, so it is still possible to make timer timeout value arbitrary small. For instance: 1) ptimer_set_period(t, 10000) 2) ptimer_set_limit(t, 1, 0) 3) ptimer_set_period(t, 1) <-- bypass limit correction Fix all of the above issues by adjusting timer period instead of the limit. Perform the adjustment for periodic timer only. Use the delta value instead of the limit to make decision whether adjustment is required, as limit could be altered while timer is running, resulting in incorrect value returned by ptimer_get_count. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com> Message-id: cd141f74f5737480ec586b9c7d18cce1d69884e2.1464367869.git.digetx@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-06-06 17:59:30 +02:00
div = period;
clz1 = clz64(rem);
clz2 = clz64(div);
shift = clz1 < clz2 ? clz1 : clz2;
rem <<= shift;
div <<= shift;
if (shift >= 32) {
hw/ptimer: Fix issues caused by the adjusted timer limit value Multiple issues here related to the timer with a adjusted .limit value: 1) ptimer_get_count() returns incorrect counter value for the disabled timer after loading the counter with a small value, because adjusted limit value is used instead of the original. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 0, 1) 4) ptimer_get_count(t) <-- would return 10000 instead of 0 2) ptimer_get_count() might return incorrect value for the timer running with a adjusted limit value. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 10, 1) 4) ptimer_run(t) 5) ptimer_get_count(t) <-- might return value > 10 3) Neither ptimer_set_period() nor ptimer_set_freq() are adjusting the limit value, so it is still possible to make timer timeout value arbitrary small. For instance: 1) ptimer_set_period(t, 10000) 2) ptimer_set_limit(t, 1, 0) 3) ptimer_set_period(t, 1) <-- bypass limit correction Fix all of the above issues by adjusting timer period instead of the limit. Perform the adjustment for periodic timer only. Use the delta value instead of the limit to make decision whether adjustment is required, as limit could be altered while timer is running, resulting in incorrect value returned by ptimer_get_count. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com> Message-id: cd141f74f5737480ec586b9c7d18cce1d69884e2.1464367869.git.digetx@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-06-06 17:59:30 +02:00
div |= ((uint64_t)period_frac << (shift - 32));
} else {
if (shift != 0)
hw/ptimer: Fix issues caused by the adjusted timer limit value Multiple issues here related to the timer with a adjusted .limit value: 1) ptimer_get_count() returns incorrect counter value for the disabled timer after loading the counter with a small value, because adjusted limit value is used instead of the original. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 0, 1) 4) ptimer_get_count(t) <-- would return 10000 instead of 0 2) ptimer_get_count() might return incorrect value for the timer running with a adjusted limit value. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 10, 1) 4) ptimer_run(t) 5) ptimer_get_count(t) <-- might return value > 10 3) Neither ptimer_set_period() nor ptimer_set_freq() are adjusting the limit value, so it is still possible to make timer timeout value arbitrary small. For instance: 1) ptimer_set_period(t, 10000) 2) ptimer_set_limit(t, 1, 0) 3) ptimer_set_period(t, 1) <-- bypass limit correction Fix all of the above issues by adjusting timer period instead of the limit. Perform the adjustment for periodic timer only. Use the delta value instead of the limit to make decision whether adjustment is required, as limit could be altered while timer is running, resulting in incorrect value returned by ptimer_get_count. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com> Message-id: cd141f74f5737480ec586b9c7d18cce1d69884e2.1464367869.git.digetx@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-06-06 17:59:30 +02:00
div |= (period_frac >> (32 - shift));
/* Look at remaining bits of period_frac and round div up if
necessary. */
hw/ptimer: Fix issues caused by the adjusted timer limit value Multiple issues here related to the timer with a adjusted .limit value: 1) ptimer_get_count() returns incorrect counter value for the disabled timer after loading the counter with a small value, because adjusted limit value is used instead of the original. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 0, 1) 4) ptimer_get_count(t) <-- would return 10000 instead of 0 2) ptimer_get_count() might return incorrect value for the timer running with a adjusted limit value. For instance: 1) ptimer_stop(t) 2) ptimer_set_period(t, 1) 3) ptimer_set_limit(t, 10, 1) 4) ptimer_run(t) 5) ptimer_get_count(t) <-- might return value > 10 3) Neither ptimer_set_period() nor ptimer_set_freq() are adjusting the limit value, so it is still possible to make timer timeout value arbitrary small. For instance: 1) ptimer_set_period(t, 10000) 2) ptimer_set_limit(t, 1, 0) 3) ptimer_set_period(t, 1) <-- bypass limit correction Fix all of the above issues by adjusting timer period instead of the limit. Perform the adjustment for periodic timer only. Use the delta value instead of the limit to make decision whether adjustment is required, as limit could be altered while timer is running, resulting in incorrect value returned by ptimer_get_count. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com> Message-id: cd141f74f5737480ec586b9c7d18cce1d69884e2.1464367869.git.digetx@gmail.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-06-06 17:59:30 +02:00
if ((uint32_t)(period_frac << shift))
div += 1;
}
counter = rem / div;
if (expired && counter != 0) {
/* Wrap around periodic counter. */
counter = s->limit - (counter - 1) % s->limit;
}
}
} else {
counter = s->delta;
}
return counter;
}
void ptimer_set_count(ptimer_state *s, uint64_t count)
{
s->delta = count;
if (s->enabled) {
s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
ptimer_reload(s);
}
}
void ptimer_run(ptimer_state *s, int oneshot)
{
bool was_disabled = !s->enabled;
if (was_disabled && s->period == 0) {
fprintf(stderr, "Timer with period zero, disabling\n");
return;
}
s->enabled = oneshot ? 2 : 1;
if (was_disabled) {
s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
ptimer_reload(s);
}
}
/* Pause a timer. Note that this may cause it to "lose" time, even if it
is immediately restarted. */
void ptimer_stop(ptimer_state *s)
{
if (!s->enabled)
return;
s->delta = ptimer_get_count(s);
timer_del(s->timer);
s->enabled = 0;
}
/* Set counter increment interval in nanoseconds. */
void ptimer_set_period(ptimer_state *s, int64_t period)
{
s->delta = ptimer_get_count(s);
s->period = period;
s->period_frac = 0;
if (s->enabled) {
s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
ptimer_reload(s);
}
}
/* Set counter frequency in Hz. */
void ptimer_set_freq(ptimer_state *s, uint32_t freq)
{
s->delta = ptimer_get_count(s);
s->period = 1000000000ll / freq;
s->period_frac = (1000000000ll << 32) / freq;
if (s->enabled) {
s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
ptimer_reload(s);
}
}
/* Set the initial countdown value. If reload is nonzero then also set
count = limit. */
void ptimer_set_limit(ptimer_state *s, uint64_t limit, int reload)
{
s->limit = limit;
if (reload)
s->delta = limit;
if (s->enabled && reload) {
s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
ptimer_reload(s);
}
}
uint64_t ptimer_get_limit(ptimer_state *s)
{
return s->limit;
}
const VMStateDescription vmstate_ptimer = {
.name = "ptimer",
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT8(enabled, ptimer_state),
VMSTATE_UINT64(limit, ptimer_state),
VMSTATE_UINT64(delta, ptimer_state),
VMSTATE_UINT32(period_frac, ptimer_state),
VMSTATE_INT64(period, ptimer_state),
VMSTATE_INT64(last_event, ptimer_state),
VMSTATE_INT64(next_event, ptimer_state),
VMSTATE_TIMER_PTR(timer, ptimer_state),
VMSTATE_END_OF_LIST()
}
};
ptimer_state *ptimer_init(QEMUBH *bh)
{
ptimer_state *s;
s = (ptimer_state *)g_malloc0(sizeof(ptimer_state));
s->bh = bh;
s->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, ptimer_tick, s);
return s;
}