Hi Philippe,
Philippe Gerum <rpm <at> xenomai.org> writes:
>
> Fixing up ipipe_lock.h to switch the regular locks (i.e. neither
> ipipe/raw) to the sleeping rt_ spinlock variant is pretty much all you
> should have to do these days.
>
> My last experience merging I-pipe+preempt-rt dates back to kernel 2.6.x,
> so a few more conflicts might have popped up since then though. This
> said, I did not see any showstopper in recent kernels that would prevent
> such combo from working.
>
> e.g.:
>
> +#ifdef PREEMPT_RT
> + #define __regular_spin_lock_irqsave(lock, flags) \
> + do { rt_spin_lock(std_spinlock(lock)); flags = 0; } while (0) /* can't
> discard flags */
> +#else
> +#define __regular_spin_lock_irqsave(lock, flags) \
> + __real_raw_spin_lock_irqsave(&std_spinlock(lock)->rlock, flags)
> +#endif
>
> #define PICK_SPINLOCK_IRQSAVE(lock, flags) \
> do { \
> if (ipipe_spinlock_p(lock)) \
> (flags) =
> __ipipe_spin_lock_irqsave(ipipe_spinlock(lock)); \
> else if (std_spinlock_raw_p(lock))
> \
> __real_raw_spin_lock_irqsave(std_spinlock_raw(lock),
> flags); \
> else if (std_spinlock_p(lock)) \
> -
> __real_raw_spin_lock_irqsave(&std_spinlock(lock)->rlock, flags); \
> + __regular_spin_lock_irqsave(lock, flags); \
> else __bad_lock_type(); \
> } while (0)
>
> and so on for all other helpers defining a preempt-rt specific variant.
I'm also trying to use both Xenomai IPipe with RT_PREEMPT patch and stumbled
across this thread. I should say I'm novice in RT world so I just followed
your hint above and did this patch to ipipe_lock.h. I'm using Kernel 3.14.25
with Xenomai 2.6 from Git (snapshot 546d1fd)
[PS: Wanted to attach the patch but Gmane didn't provide a option so pasting
it here]
diff --git a/include/linux/ipipe_lock.h b/include/linux/ipipe_lock.h
index f71d2f1..7959a65 100644
--- a/include/linux/ipipe_lock.h
+++ b/include/linux/ipipe_lock.h
@@ -42,6 +42,20 @@ typedef struct {
#define std_spinlock_raw(lock) ((raw_spinlock_t *)(lock))
#define std_spinlock(lock) ((spinlock_t *)(lock))
+/* Thanks to Philippe Gerrum for this snippet
+ * https://www.mail-archive.com/[email protected]/msg05815.html
+ */
+#ifdef CONFIG_PREEMPT_RT_FULL
+#define __regular_spin_lock_irqsave(lock, flags) \
+ do { rt_spin_lock(std_spinlock(lock)); flags = 0; } while (0) /* Can't
+ * discard
+ * flags
+ * */
+#else
+#define __regular_spin_lock_irqsave(lock, flags) \
+ __real_raw_spin_lock_irqsave(&std_spinlock(lock)->rlock, flags)
+#endif
+
#define PICK_SPINLOCK_IRQSAVE(lock, flags) \
do { \
if (ipipe_spinlock_p(lock)) \
@@ -49,7 +63,7 @@ typedef struct {
else if (std_spinlock_raw_p(lock))
\
__real_raw_spin_lock_irqsave(std_spinlock_raw(lock),
flags); \
else if (std_spinlock_p(lock)) \
-
__real_raw_spin_lock_irqsave(&std_spinlock(lock)->rlock, flags); \
+ __regular_spin_lock_irqsave(lock, flags); \
else __bad_lock_type(); \
} while (0)
@@ -79,6 +93,14 @@ typedef struct {
__ret__; \
})
+#ifdef CONFIG_PREEMPT_RT_FULL
+#define __regular_spin_unlock_irqrestore(lock, flags) \
+ do { rt_spin_unlock(std_spinlock(lock)); flags = 0; } while (0)
+#else
+#define __regular_spin_unlock_irqrestore(lock, flags) \
+ __real_raw_spin_unlock_irqrestore(&std_spinlock(lock)->rlock, flags);
+#endif
+
#define PICK_SPINUNLOCK_IRQRESTORE(lock, flags)
\
do { \
if (ipipe_spinlock_p(lock)) \
@@ -88,10 +110,18 @@ typedef struct {
if (std_spinlock_raw_p(lock)) \
__real_raw_spin_unlock_irqrestore(std_spinlock_raw(lock), flags); \
else if (std_spinlock_p(lock)) \
-
__real_raw_spin_unlock_irqrestore(&std_spinlock(lock)->rlock, flags); \
+ __regular_spin_unlock_irqrestore(lock, flags); \
} \
} while (0)
+#ifdef CONFIG_PREEMPT_RT_FULL
+#define __regular_spin(op, lock) \
+ rt_spin_lock(std_spinlock(lock))
+#else
+#define __regular_spin(op, lock) \
+ __real_raw_spin##op(&std_spinlock(lock)->rlock)
+#endif
+
#define PICK_SPINOP(op, lock) \
({ \
if (ipipe_spinlock_p(lock)) \
@@ -99,7 +129,7 @@ typedef struct {
else if (std_spinlock_raw_p(lock)) \
__real_raw_spin##op(std_spinlock_raw(lock)); \
else if (std_spinlock_p(lock)) \
- __real_raw_spin##op(&std_spinlock(lock)->rlock); \
+ __regular_spin(op, lock); \
else __bad_lock_type(); \
(void)0; \
})
After the patch Kernel did compile, though I've not tested the compiled
kernel yet. Since I've no idea if what I've done is correct or not I would
be happy to get some review on this patch from you or fellow Xenomai folks.
Also after the patching I did see several kernel compile warning similar to
the below
kernel/ipipe/core.c: In function 'ipipe_alloc_virq':
kernel/ipipe/core.c:825:2: warning: passing argument 1 of 'rt_spin_lock'
from incompatible pointer type [enabled by default]
In file included from include/linux/spinlock.h:310:0,
from include/linux/seqlock.h:35,
from include/linux/time.h:5,
from include/linux/stat.h:18,
from include/linux/module.h:10,
from kernel/ipipe/core.c:24:
include/linux/spinlock_rt.h:21:56: note: expected 'struct spinlock_t *' but
argument is of type 'struct __ipipe_spinlock_t *'
kernel/ipipe/core.c:833:2: warning: passing argument 1 of 'rt_spin_unlock'
from incompatible pointer type [enabled by default]
In file included from include/linux/spinlock.h:310:0,
from include/linux/seqlock.h:35,
from include/linux/time.h:5,
from include/linux/stat.h:18,
from include/linux/module.h:10,
from kernel/ipipe/core.c:24:
include/linux/spinlock_rt.h:24:56: note: expected 'struct spinlock_t *' but
argument is of type 'struct __ipipe_spinlock_t *'
kernel/ipipe/core.c: In function 'ipipe_request_irq':
kernel/ipipe/core.c:863:2: warning: passing argument 1 of 'rt_spin_lock'
from incompatible pointer type [enabled by default]
In file included from include/linux/spinlock.h:310:0,
from include/linux/seqlock.h:35,
from include/linux/time.h:5,
from include/linux/stat.h:18,
from include/linux/module.h:10,
from kernel/ipipe/core.c:24:
include/linux/spinlock_rt.h:21:56: note: expected 'struct spinlock_t *' but
argument is of type 'struct __ipipe_spinlock_t *'
kernel/ipipe/core.c:881:2: warning: passing argument 1 of 'rt_spin_unlock'
from incompatible pointer type [enabled by default]
In file included from include/linux/spinlock.h:310:0,
from include/linux/seqlock.h:35,
from include/linux/time.h:5,
from include/linux/stat.h:18,
from include/linux/module.h:10,
from kernel/ipipe/core.c:24:
include/linux/spinlock_rt.h:24:56: note: expected 'struct spinlock_t *' but
argument is of type 'struct __ipipe_spinlock_t *'
kernel/ipipe/core.c: In function 'ipipe_free_irq':
kernel/ipipe/core.c:896:2: warning: passing argument 1 of 'rt_spin_lock'
from incompatible pointer type [enabled by default]
In file included from include/linux/spinlock.h:310:0,
from include/linux/seqlock.h:35,
from include/linux/time.h:5,
from include/linux/stat.h:18,
from include/linux/module.h:10,
from kernel/ipipe/core.c:24:
include/linux/spinlock_rt.h:21:56: note: expected 'struct spinlock_t *' but
argument is of type 'struct __ipipe_spinlock_t *'
kernel/ipipe/core.c:909:2: warning: passing argument 1 of 'rt_spin_unlock'
from incompatible pointer type [enabled by default]
In file included from include/linux/spinlock.h:310:0,
from include/linux/seqlock.h:35,
from include/linux/time.h:5,
from include/linux/stat.h:18,
from include/linux/module.h:10,
from kernel/ipipe/core.c:24:
include/linux/spinlock_rt.h:24:56: note: expected 'struct spinlock_t *' but
argument is of type 'struct __ipipe_spinlock_t *'
Again I couldn't figure out the reasons for warning, and will be happy to
find some hints on fixing this.
Thanks in Advance,
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