Re: [PATCH] arm64/irq: report bug if NR_IPI greater than max SGI during compile time

2020-12-08 Thread Pingfan Liu
On Tue, Dec 8, 2020 at 5:51 PM Marc Zyngier  wrote:
>
> On 2020-12-08 09:43, Pingfan Liu wrote:
> > On Tue, Dec 8, 2020 at 5:31 PM Marc Zyngier  wrote:
> >>
> >> On 2020-12-08 09:21, Pingfan Liu wrote:
> >> > Although there is a runtime WARN_ON() when NR_IPR > max SGI, it had
> >> > better
> >> > do the check during built time, and associate these related code
> >> > together.
> >> >
> >> > Signed-off-by: Pingfan Liu 
> >> > Cc: Catalin Marinas 
> >> > Cc: Will Deacon 
> >> > Cc: Thomas Gleixner 
> >> > Cc: Jason Cooper 
> >> > Cc: Marc Zyngier 
> >> > Cc: Mark Rutland 
> >> > To: linux-arm-ker...@lists.infradead.org
> >> > Cc: linux-kernel@vger.kernel.org
> >> > ---
> >> >  arch/arm64/kernel/smp.c| 2 ++
> >> >  drivers/irqchip/irq-gic-v3.c   | 2 +-
> >> >  drivers/irqchip/irq-gic.c  | 2 +-
> >> >  include/linux/irqchip/arm-gic-common.h | 2 ++
> >> >  4 files changed, 6 insertions(+), 2 deletions(-)
> >> >
> >> > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> >> > index 18e9727..9fc383c 100644
> >> > --- a/arch/arm64/kernel/smp.c
> >> > +++ b/arch/arm64/kernel/smp.c
> >> > @@ -33,6 +33,7 @@
> >> >  #include 
> >> >  #include 
> >> >  #include 
> >> > +#include 
> >> >
> >> >  #include 
> >> >  #include 
> >> > @@ -76,6 +77,7 @@ enum ipi_msg_type {
> >> >   IPI_WAKEUP,
> >> >   NR_IPI
> >> >  };
> >> > +static_assert(NR_IPI <= MAX_SGI_NUM);
> >>
> >> I am trying *very hard* to remove dependencies between the
> >> architecture
> >> code and random drivers, so this kind of check really is
> >> counter-productive.
> >>
> >> Driver code should not have to know the number of IPIs, because there
> >> is
> >> no requirement that all IPIs should map 1:1 to SGIs. Conflating the
> >> two
> >
> > Just curious about this. Is there an IPI which is not implemented by
> > SGI? Or mapping several IPIs to a single SGI, and scatter out due to a
> > global variable value?
>
> We currently have a single NS SGI left, and I'd like to move some of the
> non-critical IPIs over to dispatching mechanism (the two "CPU stop" IPIs
> definitely are candidate for merging). That's not implemented yet, but
> I don't see a need to add checks that would otherwise violate this
> IPI/SGI distinction.

Got it. Thanks for your detailed explanation.

Regards,
Pingfan


Re: [PATCH] arm64/irq: report bug if NR_IPI greater than max SGI during compile time

2020-12-08 Thread Marc Zyngier

On 2020-12-08 09:43, Pingfan Liu wrote:

On Tue, Dec 8, 2020 at 5:31 PM Marc Zyngier  wrote:


On 2020-12-08 09:21, Pingfan Liu wrote:
> Although there is a runtime WARN_ON() when NR_IPR > max SGI, it had
> better
> do the check during built time, and associate these related code
> together.
>
> Signed-off-by: Pingfan Liu 
> Cc: Catalin Marinas 
> Cc: Will Deacon 
> Cc: Thomas Gleixner 
> Cc: Jason Cooper 
> Cc: Marc Zyngier 
> Cc: Mark Rutland 
> To: linux-arm-ker...@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  arch/arm64/kernel/smp.c| 2 ++
>  drivers/irqchip/irq-gic-v3.c   | 2 +-
>  drivers/irqchip/irq-gic.c  | 2 +-
>  include/linux/irqchip/arm-gic-common.h | 2 ++
>  4 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index 18e9727..9fc383c 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -33,6 +33,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>
>  #include 
>  #include 
> @@ -76,6 +77,7 @@ enum ipi_msg_type {
>   IPI_WAKEUP,
>   NR_IPI
>  };
> +static_assert(NR_IPI <= MAX_SGI_NUM);

I am trying *very hard* to remove dependencies between the 
architecture

code and random drivers, so this kind of check really is
counter-productive.

Driver code should not have to know the number of IPIs, because there 
is
no requirement that all IPIs should map 1:1 to SGIs. Conflating the 
two


Just curious about this. Is there an IPI which is not implemented by
SGI? Or mapping several IPIs to a single SGI, and scatter out due to a
global variable value?


We currently have a single NS SGI left, and I'd like to move some of the
non-critical IPIs over to dispatching mechanism (the two "CPU stop" IPIs
definitely are candidate for merging). That's not implemented yet, but
I don't see a need to add checks that would otherwise violate this
IPI/SGI distinction.

Thanks,

 M.
--
Jazz is not dead. It just smells funny...


Re: [PATCH] arm64/irq: report bug if NR_IPI greater than max SGI during compile time

2020-12-08 Thread Pingfan Liu
On Tue, Dec 8, 2020 at 5:31 PM Marc Zyngier  wrote:
>
> On 2020-12-08 09:21, Pingfan Liu wrote:
> > Although there is a runtime WARN_ON() when NR_IPR > max SGI, it had
> > better
> > do the check during built time, and associate these related code
> > together.
> >
> > Signed-off-by: Pingfan Liu 
> > Cc: Catalin Marinas 
> > Cc: Will Deacon 
> > Cc: Thomas Gleixner 
> > Cc: Jason Cooper 
> > Cc: Marc Zyngier 
> > Cc: Mark Rutland 
> > To: linux-arm-ker...@lists.infradead.org
> > Cc: linux-kernel@vger.kernel.org
> > ---
> >  arch/arm64/kernel/smp.c| 2 ++
> >  drivers/irqchip/irq-gic-v3.c   | 2 +-
> >  drivers/irqchip/irq-gic.c  | 2 +-
> >  include/linux/irqchip/arm-gic-common.h | 2 ++
> >  4 files changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> > index 18e9727..9fc383c 100644
> > --- a/arch/arm64/kernel/smp.c
> > +++ b/arch/arm64/kernel/smp.c
> > @@ -33,6 +33,7 @@
> >  #include 
> >  #include 
> >  #include 
> > +#include 
> >
> >  #include 
> >  #include 
> > @@ -76,6 +77,7 @@ enum ipi_msg_type {
> >   IPI_WAKEUP,
> >   NR_IPI
> >  };
> > +static_assert(NR_IPI <= MAX_SGI_NUM);
>
> I am trying *very hard* to remove dependencies between the architecture
> code and random drivers, so this kind of check really is
> counter-productive.
>
> Driver code should not have to know the number of IPIs, because there is
> no requirement that all IPIs should map 1:1 to SGIs. Conflating the two

Just curious about this. Is there an IPI which is not implemented by
SGI? Or mapping several IPIs to a single SGI, and scatter out due to a
global variable value?

Thanks,
Pingfan

> is already wrong, and I really don't want to add more of that.
>
> Thanks,
>
>  M.
> --
> Jazz is not dead. It just smells funny...


Re: [PATCH] arm64/irq: report bug if NR_IPI greater than max SGI during compile time

2020-12-08 Thread Marc Zyngier

On 2020-12-08 09:21, Pingfan Liu wrote:
Although there is a runtime WARN_ON() when NR_IPR > max SGI, it had 
better
do the check during built time, and associate these related code 
together.


Signed-off-by: Pingfan Liu 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Thomas Gleixner 
Cc: Jason Cooper 
Cc: Marc Zyngier 
Cc: Mark Rutland 
To: linux-arm-ker...@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 arch/arm64/kernel/smp.c| 2 ++
 drivers/irqchip/irq-gic-v3.c   | 2 +-
 drivers/irqchip/irq-gic.c  | 2 +-
 include/linux/irqchip/arm-gic-common.h | 2 ++
 4 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 18e9727..9fc383c 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -33,6 +33,7 @@
 #include 
 #include 
 #include 
+#include 

 #include 
 #include 
@@ -76,6 +77,7 @@ enum ipi_msg_type {
IPI_WAKEUP,
NR_IPI
 };
+static_assert(NR_IPI <= MAX_SGI_NUM);


I am trying *very hard* to remove dependencies between the architecture
code and random drivers, so this kind of check really is 
counter-productive.


Driver code should not have to know the number of IPIs, because there is
no requirement that all IPIs should map 1:1 to SGIs. Conflating the two
is already wrong, and I really don't want to add more of that.

Thanks,

M.
--
Jazz is not dead. It just smells funny...


[PATCH] arm64/irq: report bug if NR_IPI greater than max SGI during compile time

2020-12-08 Thread Pingfan Liu
Although there is a runtime WARN_ON() when NR_IPR > max SGI, it had better
do the check during built time, and associate these related code together.

Signed-off-by: Pingfan Liu 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Thomas Gleixner 
Cc: Jason Cooper 
Cc: Marc Zyngier 
Cc: Mark Rutland 
To: linux-arm-ker...@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 arch/arm64/kernel/smp.c| 2 ++
 drivers/irqchip/irq-gic-v3.c   | 2 +-
 drivers/irqchip/irq-gic.c  | 2 +-
 include/linux/irqchip/arm-gic-common.h | 2 ++
 4 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 18e9727..9fc383c 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -33,6 +33,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #include 
 #include 
@@ -76,6 +77,7 @@ enum ipi_msg_type {
IPI_WAKEUP,
NR_IPI
 };
+static_assert(NR_IPI <= MAX_SGI_NUM);
 
 static int ipi_irq_base __read_mostly;
 static int nr_ipi __read_mostly = NR_IPI;
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 16fecc0..ee13f85 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1162,7 +1162,7 @@ static void __init gic_smp_init(void)
  gic_starting_cpu, NULL);
 
/* Register all 8 non-secure SGIs */
-   base_sgi = __irq_domain_alloc_irqs(gic_data.domain, -1, 8,
+   base_sgi = __irq_domain_alloc_irqs(gic_data.domain, -1, MAX_SGI_NUM,
   NUMA_NO_NODE, &sgi_fwspec,
   false, NULL);
if (WARN_ON(base_sgi <= 0))
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 6053245..07d36de 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -845,7 +845,7 @@ static __init void gic_smp_init(void)
  "irqchip/arm/gic:starting",
  gic_starting_cpu, NULL);
 
-   base_sgi = __irq_domain_alloc_irqs(gic_data[0].domain, -1, 8,
+   base_sgi = __irq_domain_alloc_irqs(gic_data[0].domain, -1, MAX_SGI_NUM,
   NUMA_NO_NODE, &sgi_fwspec,
   false, NULL);
if (WARN_ON(base_sgi <= 0))
diff --git a/include/linux/irqchip/arm-gic-common.h 
b/include/linux/irqchip/arm-gic-common.h
index fa8c045..7e45a9f 100644
--- a/include/linux/irqchip/arm-gic-common.h
+++ b/include/linux/irqchip/arm-gic-common.h
@@ -16,6 +16,8 @@
(GICD_INT_DEF_PRI << 8) |\
GICD_INT_DEF_PRI)
 
+#define MAX_SGI_NUM8
+
 enum gic_type {
GIC_V2,
GIC_V3,
-- 
2.7.5