6.9-stable review patch. If anyone has any objections, please let me know.
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From: Samuel Holland samuel.holland@sifive.com
commit e306a894bd511804ba9db7c00ca9cc05b55df1f2 upstream.
Now that the PLIC uses a platform driver, the driver is probed later in the boot process, where interrupts from peripherals might already be pending.
As a result, plic_handle_irq() may be called as early as the call to irq_set_chained_handler() completes. But this call happens before the per-context handler is completely set up, so there is a window where plic_handle_irq() can see incomplete per-context state and crash.
Avoid this by delaying the call to irq_set_chained_handler() until all handlers from all PLICs are initialized.
Fixes: 8ec99b033147 ("irqchip/sifive-plic: Convert PLIC driver into a platform driver") Reported-by: Geert Uytterhoeven geert@linux-m68k.org Signed-off-by: Samuel Holland samuel.holland@sifive.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Tested-by: Geert Uytterhoeven geert+renesas@glider.be Reviewed-by: Anup Patel anup@brainfault.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240529215458.937817-1-samuel.holland@sifive.com Closes: https://lore.kernel.org/r/CAMuHMdVYFFR7K5SbHBLY-JHhb7YpgGMS_hnRWm8H0KD-wBo+4... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/irqchip/irq-sifive-plic.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-)
--- a/drivers/irqchip/irq-sifive-plic.c +++ b/drivers/irqchip/irq-sifive-plic.c @@ -85,7 +85,7 @@ struct plic_handler { struct plic_priv *priv; }; static int plic_parent_irq __ro_after_init; -static bool plic_cpuhp_setup_done __ro_after_init; +static bool plic_global_setup_done __ro_after_init; static DEFINE_PER_CPU(struct plic_handler, plic_handlers);
static int plic_irq_set_type(struct irq_data *d, unsigned int type); @@ -490,10 +490,8 @@ static int plic_probe(struct platform_de unsigned long plic_quirks = 0; struct plic_handler *handler; u32 nr_irqs, parent_hwirq; - struct irq_domain *domain; struct plic_priv *priv; irq_hw_number_t hwirq; - bool cpuhp_setup;
if (is_of_node(dev->fwnode)) { const struct of_device_id *id; @@ -552,14 +550,6 @@ static int plic_probe(struct platform_de continue; }
- /* Find parent domain and register chained handler */ - domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(), DOMAIN_BUS_ANY); - if (!plic_parent_irq && domain) { - plic_parent_irq = irq_create_mapping(domain, RV_IRQ_EXT); - if (plic_parent_irq) - irq_set_chained_handler(plic_parent_irq, plic_handle_irq); - } - /* * When running in M-mode we need to ignore the S-mode handler. * Here we assume it always comes later, but that might be a @@ -600,25 +590,35 @@ done: goto fail_cleanup_contexts;
/* - * We can have multiple PLIC instances so setup cpuhp state + * We can have multiple PLIC instances so setup global state * and register syscore operations only once after context * handlers of all online CPUs are initialized. */ - if (!plic_cpuhp_setup_done) { - cpuhp_setup = true; + if (!plic_global_setup_done) { + struct irq_domain *domain; + bool global_setup = true; + for_each_online_cpu(cpu) { handler = per_cpu_ptr(&plic_handlers, cpu); if (!handler->present) { - cpuhp_setup = false; + global_setup = false; break; } } - if (cpuhp_setup) { + + if (global_setup) { + /* Find parent domain and register chained handler */ + domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(), DOMAIN_BUS_ANY); + if (domain) + plic_parent_irq = irq_create_mapping(domain, RV_IRQ_EXT); + if (plic_parent_irq) + irq_set_chained_handler(plic_parent_irq, plic_handle_irq); + cpuhp_setup_state(CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING, "irqchip/sifive/plic:starting", plic_starting_cpu, plic_dying_cpu); register_syscore_ops(&plic_irq_syscore_ops); - plic_cpuhp_setup_done = true; + plic_global_setup_done = true; } }