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Subject[PATCH 6/11] UML - GENERIC_CLOCKEVENTS support
Enable CONFIG_GENERIC_CLOCKEVENTS.

timer_irq gets its name changed to timer_handler, and becomes the
recipient of timer signals.

The clock_event_device is set up to imitate the current ticking clock,
i.e. CLOCK_EVT_FEAT_ONESHOT is not enabled yet.

disable_timer now doesn't ignore SIGALRM and SIGVTALRM because that
breaks delay calibration.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
---
arch/um/Kconfig | 4 +
arch/um/defconfig | 3 +
arch/um/kernel/time.c | 99 ++++++++++++++++++++++--------------------------
arch/um/os-Linux/time.c | 4 -
4 files changed, 54 insertions(+), 56 deletions(-)
Index: linux-2.6.20/arch/um/Kconfig
===================================================================
--- linux-2.6.20.orig/arch/um/Kconfig 2007-09-19 12:25:06.000000000 -0400
+++ linux-2.6.20/arch/um/Kconfig 2007-09-19 12:25:07.000000000 -0400
@@ -59,6 +59,10 @@ config GENERIC_TIME
bool
default y

+config GENERIC_CLOCKEVENTS
+ bool
+ default y
+
# Used in kernel/irq/manage.c and include/linux/irq.h
config IRQ_RELEASE_METHOD
bool
Index: linux-2.6.20/arch/um/kernel/time.c
===================================================================
--- linux-2.6.20.orig/arch/um/kernel/time.c 2007-09-19 12:25:06.000000000 -0400
+++ linux-2.6.20/arch/um/kernel/time.c 2007-09-19 12:25:07.000000000 -0400
@@ -3,6 +3,7 @@
* Licensed under the GPL
*/

+#include "linux/clockchips.h"
#include "linux/interrupt.h"
#include "linux/jiffies.h"
#include "linux/threads.h"
@@ -24,9 +25,10 @@ static unsigned long long prev_nsecs[NR_
static long long delta[NR_CPUS]; /* Deviation per interval */
#endif

-void timer_irq(struct uml_pt_regs *regs)
+void timer_handler(int sig, struct uml_pt_regs *regs)
{
unsigned long long ticks = 0;
+ unsigned long flags;
#ifdef CONFIG_UML_REAL_TIME_CLOCK
int c = cpu();
if (prev_nsecs[c]) {
@@ -47,89 +49,82 @@ void timer_irq(struct uml_pt_regs *regs)
#else
ticks = 1;
#endif
+
+ local_irq_save(flags);
while (ticks > 0) {
do_IRQ(TIMER_IRQ, regs);
ticks--;
}
+ local_irq_restore(flags);
}

-/* Protects local_offset */
-static DEFINE_SPINLOCK(timer_spinlock);
-static unsigned long long local_offset = 0;
-
-static inline unsigned long long get_time(void)
+static void itimer_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
{
- unsigned long long nsecs;
- unsigned long flags;
-
- spin_lock_irqsave(&timer_spinlock, flags);
- nsecs = os_nsecs();
- nsecs += local_offset;
- spin_unlock_irqrestore(&timer_spinlock, flags);
+ switch(mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ set_interval();
+ break;
+
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_UNUSED:
+ disable_timer();
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ BUG();
+ break;

- return nsecs;
+ case CLOCK_EVT_MODE_RESUME:
+ break;
+ }
}

-irqreturn_t um_timer(int irq, void *dev)
-{
- unsigned long long nsecs;
- unsigned long flags;
-
- write_seqlock_irqsave(&xtime_lock, flags);
+static struct clock_event_device itimer_clockevent = {
+ .name = "itimer",
+ .rating = 250,
+ .cpumask = CPU_MASK_ALL,
+ .features = CLOCK_EVT_FEAT_PERIODIC,
+ .set_mode = itimer_set_mode,
+ .set_next_event = NULL,
+ .shift = 32,
+ .irq = 0,
+};

- do_timer(1);
-
-#ifdef CONFIG_UML_REAL_TIME_CLOCK
- nsecs = get_time();
-#else
- nsecs = (unsigned long long) xtime.tv_sec * BILLION + xtime.tv_nsec +
- BILLION / HZ;
-#endif
- xtime.tv_sec = nsecs / NSEC_PER_SEC;
- xtime.tv_nsec = nsecs - xtime.tv_sec * NSEC_PER_SEC;
-
- write_sequnlock_irqrestore(&xtime_lock, flags);
+static irqreturn_t um_timer(int irq, void *dev)
+{
+ (*itimer_clockevent.event_handler)(&itimer_clockevent);

return IRQ_HANDLED;
}

-static void register_timer(void)
+static void __init setup_itimer(void)
{
int err;

- timer_init();
-
err = request_irq(TIMER_IRQ, um_timer, IRQF_DISABLED, "timer", NULL);
if (err != 0)
printk(KERN_ERR "register_timer : request_irq failed - "
"errno = %d\n", -err);

- err = set_interval();
- if (err != 0)
- printk(KERN_ERR "register_timer : set_interval failed - "
- "errno = %d\n", -err);
+ itimer_clockevent.mult = div_sc(HZ, NSEC_PER_SEC, 32);
+ itimer_clockevent.max_delta_ns =
+ clockevent_delta2ns(60 * HZ, &itimer_clockevent);
+ itimer_clockevent.min_delta_ns =
+ clockevent_delta2ns(1, &itimer_clockevent);
+ clockevents_register_device(&itimer_clockevent);
}

extern void (*late_time_init)(void);

-void time_init(void)
+void __init time_init(void)
{
long long nsecs;

+ timer_init();
+
nsecs = os_nsecs();
set_normalized_timespec(&wall_to_monotonic, -nsecs / BILLION,
-nsecs % BILLION);
set_normalized_timespec(&xtime, nsecs / BILLION, nsecs % BILLION);
- late_time_init = register_timer;
-}
-
-void timer_handler(int sig, struct uml_pt_regs *regs)
-{
- if (current_thread->cpu == 0)
- timer_irq(regs);
- local_irq_disable();
- irq_enter();
- update_process_times(regs->is_user);
- irq_exit();
- local_irq_enable();
+ late_time_init = setup_itimer;
}
Index: linux-2.6.20/arch/um/defconfig
===================================================================
--- linux-2.6.20.orig/arch/um/defconfig 2007-09-19 12:24:52.000000000 -0400
+++ linux-2.6.20/arch/um/defconfig 2007-09-19 12:25:07.000000000 -0400
@@ -73,6 +73,9 @@ CONFIG_FLATMEM=y
CONFIG_FLAT_NODE_MEM_MAP=y
# CONFIG_SPARSEMEM_STATIC is not set
CONFIG_SPLIT_PTLOCK_CPUS=4
+# CONFIG_TICK_ONESHOT is not set
+# CONFIG_NO_HZ is not set
+CONFIG_HIGH_RES_TIMERS=y
CONFIG_LD_SCRIPT_DYN=y
CONFIG_NET=y
CONFIG_BINFMT_ELF=y
Index: linux-2.6.20/arch/um/os-Linux/time.c
===================================================================
--- linux-2.6.20.orig/arch/um/os-Linux/time.c 2007-09-19 12:25:05.000000000 -0400
+++ linux-2.6.20/arch/um/os-Linux/time.c 2007-09-19 12:25:07.000000000 -0400
@@ -34,10 +34,6 @@ void disable_timer(void)
(setitimer(ITIMER_REAL, &disable, NULL) < 0))
printk(UM_KERN_ERR "disable_timer - setitimer failed, "
"errno = %d\n", errno);
-
- /* If there are signals already queued, after unblocking ignore them */
- signal(SIGALRM, SIG_IGN);
- signal(SIGVTALRM, SIG_IGN);
}

int switch_timers(int to_real)
-
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