> Date: Mon, 17 Jan 2022 14:43:11 +0000
> From: Visa Hankala <[email protected]>
>
> This fixes two bugs in plic(4). When a particular CPU is not found,
> typically when running GENERIC or RAMDISK on a multiprocessor machine,
> plic_get_cpuid() returns -1. In that case plic_attach() should just
> ignore the entry and move on. The `cpu' variable should also be signed,
> otherwise the condition (cpu < 0) cannot be true.
>
> Strangely enough, RAMDISK has been functional despite the type bug.
> The -Oz optimized code has generated memory addresses that have not
> caused immediate damage but also not triggered any protection errors.
> GENERIC on the other hand crashes because sc_contexts[] is updated
> with index -1, corrupting plic_softc fields sc_ioh and sc_isrcs.
>
> OK?
ok kettenis@
> Index: arch/riscv64/dev/plic.c
> ===================================================================
> RCS file: src/sys/arch/riscv64/dev/plic.c,v
> retrieving revision 1.8
> diff -u -p -r1.8 plic.c
> --- arch/riscv64/dev/plic.c 3 Jan 2022 03:06:50 -0000 1.8
> +++ arch/riscv64/dev/plic.c 17 Jan 2022 14:19:53 -0000
> @@ -162,7 +162,7 @@ plic_attach(struct device *parent, struc
> struct fdt_attach_args *faa;
> uint32_t *cells;
> uint32_t irq;
> - uint32_t cpu;
> + int cpu;
> int node;
> int len;
> int ncell;
> @@ -251,11 +251,8 @@ plic_attach(struct device *parent, struc
>
> /* Get the corresponding cpuid. */
> cpu = plic_get_cpuid(OF_getnodebyphandle(cells[i]));
> - if (cpu < 0) {
> - printf(": invalid hart!\n");
> - free(cells, M_TEMP, len);
> - return;
> - }
> + if (cpu < 0)
> + continue;
>
> /*
> * Set the enable and context register offsets for the CPU.
>
>
