Il 10/07/2013 13.37, Gilles Chanteperdrix ha scritto:
On 07/09/2013 01:40 PM, Paolo Minazzi wrote:
Hi,
I would like to make a block of kernel code atomic, so that no one (both
xenomai and Linux) can interrupt it.
I use the following :
#define my_local_irq_save(x) ((x) =
ipipe_test_and_stall_pipeline_head()& 1)
#define my_local_irq_restore(x) ipipe_restore_pipeline_head(x)
my_local_irq_save(flags);
< critical section>
my_local_irq_restore(flags);
It works well enough, but rarely an rtdm irq enter into my critical
section.
The rtdm irq is registered in this way : rtdm_irq_request(&priv->irqHnd,
ETH_PORT_IRQ_NUM(priv->port), irqHandler, RTDM_IRQTYPE_EDGE, "rtdm_eth",
priv);
Is it normal ? Are you sure that it cannot happen ?
Looking at ipipe_test_and_stall_head implementation on the I-pipe
patch for Linux 3.8:
static inline unsigned long ipipe_test_and_stall_head(void)
{
hard_local_irq_disable();
return __test_and_set_bit(IPIPE_STALL_FLAG, &__ipipe_head_status);
}
getting an interrupt in your critical section would mean that
"hard_local_irq_disable" is broken on the architecture where you use it.
That being said, I do not know if I look at the implementation you are
using, since you did not give us any information about version and
architecture you are using.
Hi Gilles, thanks for your answer.
I found this morning that was linux to re-enable interrupts.
The following
#define my_local_irq_save(x) ((x) =
ipipe_test_and_stall_pipeline_head()& 1)
#define my_local_irq_restore(x) ipipe_restore_pipeline_head(x)
works well if no one touch irq flags directly. Unfortunately was not my
case.
Thanks again,
Paolo
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