Re: [PATCH 2/9] ARM64: get rid of arch_cpu_idle_prepare()
On Mon, Jan 27, 2014 at 03:51:02PM +, Nicolas Pitre wrote:
> On Mon, 27 Jan 2014, Catalin Marinas wrote:
>
> > On Mon, Jan 27, 2014 at 06:08:17AM +, Nicolas Pitre wrote:
> > > ARM and ARM64 are the only two architectures implementing
> > > arch_cpu_idle_prepare() simply to call local_fiq_enable().
> > >
> > > We have secondary_start_kernel() already calling local_fiq_enable() and
> > > this is done a second time in arch_cpu_idle_prepare() in that case. And
> > > enabling FIQs has nothing to do with idling the CPU to start with.
> > >
> > > So let's introduce init_fiq_boot_cpu() to take care of FIQs on the boot
> > > CPU and remove arch_cpu_idle_prepare(). This is now done a bit earlier
> > > at late_initcall time but this shouldn't make a difference in practice
> > > given that FIQs are not currently used on ARM64.
> > >
> > > Signed-off-by: Nicolas Pitre
> >
> > For arm64, we could simply remove any reference to FIQs. I'm not aware
> > of anyone using them.
>
> OK. What if I sumply remove arch_cpu_idle_prepare() and let you do the
> remove the rest?
>
> IMHO I'd simply remove local_fiq_{enable/disable}() from
> arm64/kernel/smp.c and leave the infrastructure in place in case someone
> needs it eventually. In which case I could include that into my patch
> as well.
Sounds good. We can keep the local_fiq_*() functions but remove about 4
calling sites (process.c and smp.c) until needed.
Thanks.
--
Catalin
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Re: [PATCH 2/9] ARM64: get rid of arch_cpu_idle_prepare()
On Mon, Jan 27, 2014 at 06:08:17AM +, Nicolas Pitre wrote: > ARM and ARM64 are the only two architectures implementing > arch_cpu_idle_prepare() simply to call local_fiq_enable(). > > We have secondary_start_kernel() already calling local_fiq_enable() and > this is done a second time in arch_cpu_idle_prepare() in that case. And > enabling FIQs has nothing to do with idling the CPU to start with. > > So let's introduce init_fiq_boot_cpu() to take care of FIQs on the boot > CPU and remove arch_cpu_idle_prepare(). This is now done a bit earlier > at late_initcall time but this shouldn't make a difference in practice > given that FIQs are not currently used on ARM64. > > Signed-off-by: Nicolas Pitre For arm64, we could simply remove any reference to FIQs. I'm not aware of anyone using them. -- Catalin ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH 2/9] ARM64: get rid of arch_cpu_idle_prepare()
On Mon, 27 Jan 2014, Catalin Marinas wrote:
> On Mon, Jan 27, 2014 at 06:08:17AM +, Nicolas Pitre wrote:
> > ARM and ARM64 are the only two architectures implementing
> > arch_cpu_idle_prepare() simply to call local_fiq_enable().
> >
> > We have secondary_start_kernel() already calling local_fiq_enable() and
> > this is done a second time in arch_cpu_idle_prepare() in that case. And
> > enabling FIQs has nothing to do with idling the CPU to start with.
> >
> > So let's introduce init_fiq_boot_cpu() to take care of FIQs on the boot
> > CPU and remove arch_cpu_idle_prepare(). This is now done a bit earlier
> > at late_initcall time but this shouldn't make a difference in practice
> > given that FIQs are not currently used on ARM64.
> >
> > Signed-off-by: Nicolas Pitre
>
> For arm64, we could simply remove any reference to FIQs. I'm not aware
> of anyone using them.
OK. What if I sumply remove arch_cpu_idle_prepare() and let you do the
remove the rest?
IMHO I'd simply remove local_fiq_{enable/disable}() from
arm64/kernel/smp.c and leave the infrastructure in place in case someone
needs it eventually. In which case I could include that into my patch
as well.
Nicolas
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Re: [PATCH 2/9] ARM64: get rid of arch_cpu_idle_prepare()
On 01/27/2014 07:08 AM, Nicolas Pitre wrote:
ARM and ARM64 are the only two architectures implementing
arch_cpu_idle_prepare() simply to call local_fiq_enable().
We have secondary_start_kernel() already calling local_fiq_enable() and
this is done a second time in arch_cpu_idle_prepare() in that case. And
enabling FIQs has nothing to do with idling the CPU to start with.
So let's introduce init_fiq_boot_cpu() to take care of FIQs on the boot
CPU and remove arch_cpu_idle_prepare(). This is now done a bit earlier
at late_initcall time but this shouldn't make a difference in practice
given that FIQs are not currently used on ARM64.
Signed-off-by: Nicolas Pitre
Reviewed-by: Daniel Lezcano
---
arch/arm64/kernel/process.c | 5 -
arch/arm64/kernel/setup.c | 7 +++
2 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index de17c89985..f6c733da67 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -84,11 +84,6 @@ EXPORT_SYMBOL_GPL(pm_power_off);
void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
EXPORT_SYMBOL_GPL(arm_pm_restart);
-void arch_cpu_idle_prepare(void)
-{
- local_fiq_enable();
-}
-
/*
* This is our default idle handler.
*/
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index bd9bbd0e44..259557983a 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -255,6 +255,13 @@ static int __init arm64_device_init(void)
}
arch_initcall(arm64_device_init);
+static int __init init_fiq_boot_cpu(void)
+{
+ local_fiq_enable();
+ return 0;
+}
+late_initcall(init_fiq_boot_cpu);
+
static DEFINE_PER_CPU(struct cpu, cpu_data);
static int __init topology_init(void)
--
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