| Message ID | 1390802904-28399-3-git-send-email-nicolas.pitre@linaro.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
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 <nico@linaro.org> Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org> > --- > 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) >
On Mon, Jan 27, 2014 at 06:08:17AM +0000, 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 <nico@linaro.org> For arm64, we could simply remove any reference to FIQs. I'm not aware of anyone using them.
On Mon, 27 Jan 2014, Catalin Marinas wrote: > On Mon, Jan 27, 2014 at 06:08:17AM +0000, 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 <nico@linaro.org> > > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Jan 27, 2014 at 03:51:02PM +0000, Nicolas Pitre wrote: > On Mon, 27 Jan 2014, Catalin Marinas wrote: > > > On Mon, Jan 27, 2014 at 06:08:17AM +0000, 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 <nico@linaro.org> > > > > 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.
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)
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 <nico@linaro.org> --- arch/arm64/kernel/process.c | 5 ----- arch/arm64/kernel/setup.c | 7 +++++++ 2 files changed, 7 insertions(+), 5 deletions(-)