__ipipe_root_sync

__ipipe_root_sync

[Steven Seeger]

Why was __ipipe_root_sync moved out of kernel/ipipe/core.c? I see it now in 
arch/arm/kernel/ipipe.c. It is the same exact code I had in the PPC branch in 
kernel/ipipe/core.c. I can move it to the arch-specific code, but was wondering 
why.

Steven

Re: __ipipe_root_sync

[Jan Kiszka]

On 26.04.19 19:07, Steven Seeger via Xenomai wrote:
> Why was __ipipe_root_sync moved out of kernel/ipipe/core.c? I see it now in
> arch/arm/kernel/ipipe.c. It is the same exact code I had in the PPC branch in
> kernel/ipipe/core.c. I can move it to the arch-specific code, but was wondering
> why.

I think you should make sync_root_irqs __ipipe_root_sync (or whatever) again. 
That is already a duplication for ARM.

Jan

-- 
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux

Re: __ipipe_root_sync

[Philippe Gerum]

On 4/26/19 7:07 PM, Steven Seeger via Xenomai wrote:
> Why was __ipipe_root_sync moved out of kernel/ipipe/core.c? I see it now in 
> arch/arm/kernel/ipipe.c. It is the same exact code I had in the PPC branch in 
> kernel/ipipe/core.c. I can move it to the arch-specific code, but was wondering 
> why.
> 

There is a trend in mainline to rewrite the syscall entry code in C,
instead of assembly. Syncing the pipeline is done directly from the
common (C) entry code in that case. x86 and arm64 did that conversion
already.

__ipipe_root_sync was originally meant to be invoked from asm call
sites, so the decision was made to make this code local to the two archs
we support which still do the syscall entry the old fashioned way (arm
and ppc32), anticipating on a future conversion of their entry code.

However, __ipipe_root_sync() is 100% redundant with sync_root_irqs(),
which we need in the generic pipelined syscall handling callable from C.
So the situation is a bit silly ATM. Let's rename sync_root_irqs() to
__ipipe_root_sync() in -noarch, and drop any arch-local equivalent.

-- 
Philippe.

Re: __ipipe_root_sync

[Steven Seeger]

On Friday, April 26, 2019 2:11:30 PM EDT Philippe Gerum wrote:
> 
> However, __ipipe_root_sync() is 100% redundant with sync_root_irqs(),
> which we need in the generic pipelined syscall handling callable from C.
> So the situation is a bit silly ATM. Let's rename sync_root_irqs() to
> __ipipe_root_sync() in -noarch, and drop any arch-local equivalent.

I fully agree with this. I can issue a second patch for 110 once it's done in 
noarch, but there's no real reason to hurry on this.

I can confirm that the 4.14.110 patch I just pushed for powerpc (for all the 
thousands of you working with PPC) that the use of __ipipe_root_sync and 
sync_root_irqs is equivalent with ARM.

Steven