Hi Florian,
Needless to say, I mostly have questions...
On 2019-10-23 01:05, Florian Fainelli wrote:
SGI interrupts are a convenient way for trusted firmware to target a
specific set of CPUs. Update the ARM GIC code to allow the
translation
and mapping of SGI interrupts.
Since the kernel already uses SGIs for various inter-processor
interrupt
activities, we specifically make sure that we do not let users of the
IRQ API to even try to map those.
Internal IPIs remain dispatched through handle_IPI() while public
SGIs
get promoted to a normal interrupt flow management.
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
drivers/irqchip/irq-gic.c | 41
+++++++++++++++++++++++++++------------
1 file changed, 29 insertions(+), 12 deletions(-)
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 30ab623343d3..dcfdbaacdd64 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -385,7 +385,10 @@ static void __exception_irq_entry
gic_handle_irq(struct pt_regs *regs)
* Pairs with the write barrier in gic_raise_softirq
*/
smp_rmb();
- handle_IPI(irqnr, regs);
+ if (irqnr < NR_IPI)
+ handle_IPI(irqnr, regs);
+ else
+ handle_domain_irq(gic->domain, irqnr, regs);
Double EOI, UNPREDICTABLE territory, your state machine is now dead.
#endif
continue;
}
@@ -1005,20 +1008,34 @@ static int gic_irq_domain_translate(struct
irq_domain *d,
if (fwspec->param_count < 3)
return -EINVAL;
- /* Get the interrupt number and add 16 to skip over SGIs */
- *hwirq = fwspec->param[1] + 16;
-
- /*
- * For SPIs, we need to add 16 more to get the GIC irq
- * ID number
- */
- if (!fwspec->param[0])
+ *hwirq = fwspec->param[1];
+ switch (fwspec->param[0]) {
+ case 0:
+ /*
+ * For SPIs, we need to add 16 more to get the GIC irq
+ * ID number
+ */
+ *hwirq += 16;
+ /* fall through */
+ case 1:
+ /* Add 16 to skip over SGIs */
*hwirq += 16;
+ *type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;
- *type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;
+ /* Make it clear that broken DTs are... broken */
+ WARN_ON(*type == IRQ_TYPE_NONE);
+ break;
+ case 2:
+ /* Refuse to map internal IPIs */
+ if (*hwirq < NR_IPI)
So depending on how the kernel uses SGIs, you can or cannot use these
SGIs.
That looks like a good way to corner ourselves into not being to change
much.
Also, do you expect this to work for both Group-0 and Group-1
interrupts
(since you imply that this works as a communication medium with the
secure
side)? Given that the kernel running in NS has no way to enable/disable
Group-0 interrupts, this looks terminally flawed. Or is that Group-1
only?
How do we describe which SGIs are guaranteed to be available to Linux?
+ return -EPERM;
+
+ *type = IRQ_TYPE_NONE;
Or not. SGI are edge triggered, by definition.
+ break;
+ default:
+ break;
+ }
- /* Make it clear that broken DTs are... broken */
- WARN_ON(*type == IRQ_TYPE_NONE);
Really?
M.
--
Jazz is not dead. It just smells funny...
