lkml.org 
[lkml]   [2020]   [May]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v2 2/3] irqchip/sifive-plic: Setup cpuhp once after boot CPU handler is present
From
On Mon, 18 May 2020 02:14:40 PDT (-0700), Anup Patel wrote:
> For multiple PLIC instances, the plic_init() is called once for each
> PLIC instance. Due to this we have two issues:
> 1. cpuhp_setup_state() is called multiple times
> 2. plic_starting_cpu() can crash for boot CPU if cpuhp_setup_state()
> is called before boot CPU PLIC handler is available.
>
> This patch fixes both above issues.
>
> Fixes: f1ad1133b18f ("irqchip/sifive-plic: Add support for multiple PLICs")
> Cc: stable@vger.kernel.org
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> ---
> drivers/irqchip/irq-sifive-plic.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
> index 9f7f8ce88c00..6c54abf5cc5e 100644
> --- a/drivers/irqchip/irq-sifive-plic.c
> +++ b/drivers/irqchip/irq-sifive-plic.c
> @@ -76,6 +76,7 @@ struct plic_handler {
> void __iomem *enable_base;
> struct plic_priv *priv;
> };
> +static bool plic_cpuhp_setup_done;
> static DEFINE_PER_CPU(struct plic_handler, plic_handlers);
>
> static inline void plic_toggle(struct plic_handler *handler,
> @@ -285,6 +286,7 @@ static int __init plic_init(struct device_node *node,
> int error = 0, nr_contexts, nr_handlers = 0, i;
> u32 nr_irqs;
> struct plic_priv *priv;
> + struct plic_handler *handler;
>
> priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> if (!priv)
> @@ -313,7 +315,6 @@ static int __init plic_init(struct device_node *node,
>
> for (i = 0; i < nr_contexts; i++) {
> struct of_phandle_args parent;
> - struct plic_handler *handler;
> irq_hw_number_t hwirq;
> int cpu, hartid;
>
> @@ -367,9 +368,18 @@ static int __init plic_init(struct device_node *node,
> nr_handlers++;
> }
>
> - cpuhp_setup_state(CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
> + /*
> + * We can have multiple PLIC instances so setup cpuhp state only
> + * when context handler for current/boot CPU is present.
> + */
> + handler = this_cpu_ptr(&plic_handlers);
> + if (handler->present && !plic_cpuhp_setup_done) {
> + cpuhp_setup_state(CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
> "irqchip/sifive/plic:starting",
> plic_starting_cpu, plic_dying_cpu);
> + plic_cpuhp_setup_done = true;

So presumably something else is preventing multiple plic_init() calls from
executing at the same time? Assuming that's the case

Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>

> + }
> +
> pr_info("mapped %d interrupts with %d handlers for %d contexts.\n",
> nr_irqs, nr_handlers, nr_contexts);
> set_handle_irq(plic_handle_irq);

\
 
 \ /
  Last update: 2020-05-22 00:08    [W:0.212 / U:0.796 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site