We have two enteries (one for M-mode and another for S-mode) in the interrupts-extended DT property of PLIC DT node for each HART. It is expected that firmware/bootloader will set M-mode HWIRQ line of each HART to 0xffffffff (i.e. -1) in interrupts-extended DT property because Linux runs in S-mode only.
If firmware/bootloader is buggy then it will not correctly update interrupts-extended DT property which might result in a plic_handler configured twice. This patch adds a warning in plic_init() if a plic_handler is already marked present. This warning provides us a hint about incorrectly updated interrupts-extended DT property. Signed-off-by: Anup Patel <a...@brainfault.org> Reviewed-by: Christoph Hellwig <h...@lst.de> --- drivers/irqchip/irq-sifive-plic.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c index c23a293a2aae..da09f46fad64 100644 --- a/drivers/irqchip/irq-sifive-plic.c +++ b/drivers/irqchip/irq-sifive-plic.c @@ -229,6 +229,11 @@ static int __init plic_init(struct device_node *node, cpu = riscv_hartid_to_cpuid(hartid); handler = per_cpu_ptr(&plic_handlers, cpu); + if (handler->present) { + pr_warn("handler already present for context %d.\n", i); + continue; + } + handler->present = true; handler->hart_base = plic_regs + CONTEXT_BASE + i * CONTEXT_PER_HART; -- 2.17.1