On Thu, 26 Jul 2018, Christoph Hellwig wrote:
> Add support for a routine that dispatches exceptions with the interrupt
> flags set to either the IPI or irqdomain code (and the clock source in the
> future).
>
> Loosely based on the irq-riscv-int.c irqchip driver from the RISC-V tree.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> arch/riscv/kernel/entry.S | 4 +--
> arch/riscv/kernel/irq.c | 52 ++++++++++++++++++++++++++++++++-------
> 2 files changed, 45 insertions(+), 11 deletions(-)
>
> diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
> index 9aaf6c986771..fa2c08e3c05e 100644
> --- a/arch/riscv/kernel/entry.S
> +++ b/arch/riscv/kernel/entry.S
> @@ -168,8 +168,8 @@ ENTRY(handle_exception)
>
> /* Handle interrupts */
> move a0, sp /* pt_regs */
> - REG_L a1, handle_arch_irq
> - jr a1
> + move a1, s4 /* scause */
> + tail do_IRQ
What's the reason for doing the whole exception dance in ASM ?
> 1:
> /* Exceptions run with interrupts enabled */
> csrs sstatus, SR_SIE
> +asmlinkage void __irq_entry do_IRQ(struct pt_regs *regs, unsigned long cause)
> +{
> + struct pt_regs *old_regs = set_irq_regs(regs);
> +
> + irq_enter();
> + switch (cause & ~INTERRUPT_CAUSE_FLAG) {
> +#ifdef CONFIG_SMP
> + case INTERRUPT_CAUSE_SOFTWARE:
> + /*
> + * We only use software interrupts to pass IPIs, so if a non-SMP
> + * system gets one, then we don't know what to do.
> + */
> + riscv_software_interrupt();
> + break;
> +#endif
> + case INTERRUPT_CAUSE_EXTERNAL:
> + handle_arch_irq(regs);
> + break;
> + default:
> + panic("unexpected interrupt cause");
> + }
> + irq_exit();
Looks about right.
Thanks,
tglx
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