lkml.org 
[lkml]   [2020]   [Jun]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 04/17] ARM: Allow IPIs to be handled as normal interrupts
On 2020-06-25 19:25, Valentin Schneider wrote:
> On 24/06/20 20:57, Marc Zyngier wrote:
>> @@ -696,9 +696,76 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
>>
>> if ((unsigned)ipinr < NR_IPI)
>> trace_ipi_exit_rcuidle(ipi_types[ipinr]);
>> +}
>> +
>> +/* Legacy version, should go away once all irqchips have been
>> converted */
>> +void handle_IPI(int ipinr, struct pt_regs *regs)
>> +{
>> + struct pt_regs *old_regs = set_irq_regs(regs);
>> +
>> + irq_enter();
>> + do_handle_IPI(ipinr);
>> + irq_exit();
>> +
>> set_irq_regs(old_regs);
>> }
>>
>> +static irqreturn_t ipi_handler(int irq, void *data)
>> +{
>> + do_handle_IPI(irq - ipi_irq_base);
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static void ipi_send(const struct cpumask *target, unsigned int ipi)
>> +{
>> + __ipi_send_mask(ipi_desc[ipi], target);
>> +}
>> +
>> +static void ipi_setup(int cpu)
>> +{
>> + if (ipi_irq_base) {
>> + int i;
>> +
>> + for (i = 0; i < nr_ipi; i++)
>> + enable_percpu_irq(ipi_irq_base + i, 0);
>> + }
>> +}
>> +
>> +static void ipi_teardown(int cpu)
>> +{
>> + if (ipi_irq_base) {
>> + int i;
>> +
>> + for (i = 0; i < nr_ipi; i++)
>> + disable_percpu_irq(ipi_irq_base + i);
>> + }
>> +}
>> +
>> +void __init set_smp_ipi_range(int ipi_base, int n)
>> +{
>> + int i;
>> +
>> + WARN_ON(n < MAX_IPI);
>> + nr_ipi = min(n, MAX_IPI);
>
>
> I got confused by that backtrace thing and NR_IPI vs MAX_IPI.
> I think I got it now : we don't want to call trace_ipi_raise() for
> IPI_CPU_BACKTRACE *but* we still need to alloc the desc and route it
> through the generic IPI layers.

Indeed, and I didn't want to have a bizarre "+ 1" hanging about.

> The only difference I can tell is that now we will get some trace
> events
> for it via the handler entry/exit tracepoints - that shouldn't cause
> any
> issue.

I hope so. I don't see how you can avoid all tracepoints anyway (if that
was the intention).

Thanks,

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

\
 
 \ /
  Last update: 2020-06-29 23:35    [W:0.074 / U:9.232 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site