[PATCH] Don't disable irqs in set_next_event and set_mode callbacks

Eric Miao eric.y.miao at gmail.com
Wed Sep 23 15:01:04 EDT 2009


Don't have time go through all the calling sequences here, and
not sure if there are corner cases that these will be called
without IRQ disabled.

2009/9/21 Kristoffer Ericson <kristoffer.ericson at gmail.com>:
> Dont see the harm (will do a formal test later today), so feel
> free to add acked-by.
>
> /Kristoffer
>
> On Mon, 21 Sep 2009 09:39:22 +0200
> Uwe Kleine-König <u.kleine-koenig at pengutronix.de> wrote:
>
>> These functions are called with irqs already off.
>>
>> at91rm2000 had a WARN_ON_ONCE if irqs were enabled since Nov 2008 with
>> noone reporting having hit it.
>>
>> It should be safe to remove now.
>>
>> Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
>> Cc: Thomas Gleixner <tglx at linutronix.de>
>> Cc: Alessandro Rubini <rubini at unipv.it>
>> Cc: Andrea Gallo <andrea.gallo at stericsson.com>
>> Cc: Andrew Morton <akpm at linux-foundation.org>
>> Cc: Eric Miao <eric.miao at marvell.com>
>> Cc: Hugh Dickins <hugh at veritas.com>
>> Cc: John Stultz <johnstul at us.ibm.com>
>> Cc: Kristoffer Ericson <Kristoffer.Ericson at gmail.com>
>> Cc: Magnus Damm <damm at igel.co.jp>
>> Cc: Nicolas Pitre <nico at marvell.com>
>> Cc: Remy Bohmer <linux at bohmer.net>
>> Cc: Russell King <linux at arm.linux.org.uk>
>> Cc: Rusty Russell <rusty at rustcorp.com.au>
>> ---
>> Hello,
>>
>> should I split the patch?  Would you prefer to add a WARN_ON_ONCE for
>> some time (as at91rm9200 had it)?
>>
>> Best regards
>> Uwe
>>
>>  arch/arm/mach-at91/at91rm9200_time.c  |   14 --------------
>>  arch/arm/mach-at91/at91sam926x_time.c |    6 +-----
>>  arch/arm/mach-nomadik/timer.c         |    9 +--------
>>  arch/arm/mach-pxa/time.c              |   10 +---------
>>  arch/arm/mach-sa1100/time.c           |    8 +-------
>>  5 files changed, 4 insertions(+), 43 deletions(-)
>>
>> diff --git a/arch/arm/mach-at91/at91rm9200_time.c b/arch/arm/mach-at91/at91rm9200_time.c
>> index 309f351..f27ccf6 100644
>> --- a/arch/arm/mach-at91/at91rm9200_time.c
>> +++ b/arch/arm/mach-at91/at91rm9200_time.c
>> @@ -132,24 +132,11 @@ clkevt32k_mode(enum clock_event_mode mode, struct clock_event_device *dev)
>>  static int
>>  clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev)
>>  {
>> -     unsigned long   flags;
>>       u32             alm;
>>       int             status = 0;
>>
>>       BUG_ON(delta < 2);
>>
>> -     /* Use "raw" primitives so we behave correctly on RT kernels. */
>> -     raw_local_irq_save(flags);
>> -
>> -     /*
>> -      * According to Thomas Gleixner irqs are already disabled here.  Simply
>> -      * removing raw_local_irq_save above (and the matching
>> -      * raw_local_irq_restore) was not accepted.  See
>> -      * http://thread.gmane.org/gmane.linux.ports.arm.kernel/41174
>> -      * So for now (2008-11-20) just warn once if irqs were not disabled ...
>> -      */
>> -     WARN_ON_ONCE(!raw_irqs_disabled_flags(flags));
>> -
>>       /* The alarm IRQ uses absolute time (now+delta), not the relative
>>        * time (delta) in our calling convention.  Like all clockevents
>>        * using such "match" hardware, we have a race to defend against.
>> @@ -169,7 +156,6 @@ clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev)
>>       alm += delta;
>>       at91_sys_write(AT91_ST_RTAR, alm);
>>
>> -     raw_local_irq_restore(flags);
>>       return status;
>>  }
>>
>> diff --git a/arch/arm/mach-at91/at91sam926x_time.c b/arch/arm/mach-at91/at91sam926x_time.c
>> index 4bd56ae..c26cd6e 100644
>> --- a/arch/arm/mach-at91/at91sam926x_time.c
>> +++ b/arch/arm/mach-at91/at91sam926x_time.c
>> @@ -62,16 +62,12 @@ static struct clocksource pit_clk = {
>>  static void
>>  pit_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev)
>>  {
>> -     unsigned long   flags;
>> -
>>       switch (mode) {
>>       case CLOCK_EVT_MODE_PERIODIC:
>> -             /* update clocksource counter, then enable the IRQ */
>> -             raw_local_irq_save(flags);
>> +             /* update clocksource counter */
>>               pit_cnt += pit_cycle * PIT_PICNT(at91_sys_read(AT91_PIT_PIVR));
>>               at91_sys_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN
>>                               | AT91_PIT_PITIEN);
>> -             raw_local_irq_restore(flags);
>>               break;
>>       case CLOCK_EVT_MODE_ONESHOT:
>>               BUG();
>> diff --git a/arch/arm/mach-nomadik/timer.c b/arch/arm/mach-nomadik/timer.c
>> index d1738e7..e361be6 100644
>> --- a/arch/arm/mach-nomadik/timer.c
>> +++ b/arch/arm/mach-nomadik/timer.c
>> @@ -54,24 +54,17 @@ static struct clocksource nmdk_clksrc = {
>>  static void nmdk_clkevt_mode(enum clock_event_mode mode,
>>                            struct clock_event_device *dev)
>>  {
>> -     unsigned long flags;
>> -
>>       switch (mode) {
>>       case CLOCK_EVT_MODE_PERIODIC:
>> -             /* enable interrupts -- and count current value? */
>> -             raw_local_irq_save(flags);
>> +             /* count current value? */
>>               writel(readl(mtu_base + MTU_IMSC) | 1, mtu_base + MTU_IMSC);
>> -             raw_local_irq_restore(flags);
>>               break;
>>       case CLOCK_EVT_MODE_ONESHOT:
>>               BUG(); /* Not supported, yet */
>>               /* FALLTHROUGH */
>>       case CLOCK_EVT_MODE_SHUTDOWN:
>>       case CLOCK_EVT_MODE_UNUSED:
>> -             /* disable irq */
>> -             raw_local_irq_save(flags);
>>               writel(readl(mtu_base + MTU_IMSC) & ~1, mtu_base + MTU_IMSC);
>> -             raw_local_irq_restore(flags);
>>               break;
>>       case CLOCK_EVT_MODE_RESUME:
>>               break;
>> diff --git a/arch/arm/mach-pxa/time.c b/arch/arm/mach-pxa/time.c
>> index 750c448..293e40a 100644
>> --- a/arch/arm/mach-pxa/time.c
>> +++ b/arch/arm/mach-pxa/time.c
>> @@ -76,14 +76,12 @@ pxa_ost0_interrupt(int irq, void *dev_id)
>>  static int
>>  pxa_osmr0_set_next_event(unsigned long delta, struct clock_event_device *dev)
>>  {
>> -     unsigned long flags, next, oscr;
>> +     unsigned long next, oscr;
>>
>> -     raw_local_irq_save(flags);
>>       OIER |= OIER_E0;
>>       next = OSCR + delta;
>>       OSMR0 = next;
>>       oscr = OSCR;
>> -     raw_local_irq_restore(flags);
>>
>>       return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
>>  }
>> @@ -91,23 +89,17 @@ pxa_osmr0_set_next_event(unsigned long delta, struct clock_event_device *dev)
>>  static void
>>  pxa_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *dev)
>>  {
>> -     unsigned long irqflags;
>> -
>>       switch (mode) {
>>       case CLOCK_EVT_MODE_ONESHOT:
>> -             raw_local_irq_save(irqflags);
>>               OIER &= ~OIER_E0;
>>               OSSR = OSSR_M0;
>> -             raw_local_irq_restore(irqflags);
>>               break;
>>
>>       case CLOCK_EVT_MODE_UNUSED:
>>       case CLOCK_EVT_MODE_SHUTDOWN:
>>               /* initializing, released, or preparing for suspend */
>> -             raw_local_irq_save(irqflags);
>>               OIER &= ~OIER_E0;
>>               OSSR = OSSR_M0;
>> -             raw_local_irq_restore(irqflags);
>>               break;
>>
>>       case CLOCK_EVT_MODE_RESUME:
>> diff --git a/arch/arm/mach-sa1100/time.c b/arch/arm/mach-sa1100/time.c
>> index 95d92e8..a7a6091 100644
>> --- a/arch/arm/mach-sa1100/time.c
>> +++ b/arch/arm/mach-sa1100/time.c
>> @@ -35,14 +35,12 @@ static irqreturn_t sa1100_ost0_interrupt(int irq, void *dev_id)
>>  static int
>>  sa1100_osmr0_set_next_event(unsigned long delta, struct clock_event_device *c)
>>  {
>> -     unsigned long flags, next, oscr;
>> +     unsigned long next, oscr;
>>
>> -     raw_local_irq_save(flags);
>>       OIER |= OIER_E0;
>>       next = OSCR + delta;
>>       OSMR0 = next;
>>       oscr = OSCR;
>> -     raw_local_irq_restore(flags);
>>
>>       return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
>>  }
>> @@ -50,16 +48,12 @@ sa1100_osmr0_set_next_event(unsigned long delta, struct clock_event_device *c)
>>  static void
>>  sa1100_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *c)
>>  {
>> -     unsigned long flags;
>> -
>>       switch (mode) {
>>       case CLOCK_EVT_MODE_ONESHOT:
>>       case CLOCK_EVT_MODE_UNUSED:
>>       case CLOCK_EVT_MODE_SHUTDOWN:
>> -             raw_local_irq_save(flags);
>>               OIER &= ~OIER_E0;
>>               OSSR = OSSR_M0;
>> -             raw_local_irq_restore(flags);
>>               break;
>>
>>       case CLOCK_EVT_MODE_RESUME:
>> --
>> 1.6.4.3
>>
>
>
> --
> Kristoffer Ericson <kristoffer.ericson at gmail.com>
>
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>



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