On Fri, Aug 17, 2018 at 07:55:30PM +0200, Mark Kettenis wrote:
> Diff below reduces the number of arm64 CPUs we attach to the maximum
> that we support. Without this diff a kernel running on hardware with
> more than MAXCPUS CPUs will almost certainly crash.
>
> To make this work, the code is changed to bump ncpus whenever we
> attach a secondary CPU instead of bumping it when those cores are
> sucessfully spun up. Should make no difference on correctly
> functioning hardware.
>
> ok?
>
>
> Index: arch/arm64/arm64/cpu.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/arm64/arm64/cpu.c,v
> retrieving revision 1.22
> diff -u -p -r1.22 cpu.c
> --- arch/arm64/arm64/cpu.c 4 Aug 2018 11:55:40 -0000 1.22
> +++ arch/arm64/arm64/cpu.c 17 Aug 2018 17:50:09 -0000
> @@ -211,10 +211,14 @@ int
> cpu_match(struct device *parent, void *cfdata, void *aux)
> {
> struct fdt_attach_args *faa = aux;
> + uint64_t mpidr = READ_SPECIALREG(mpidr_el1);
> char buf[32];
>
> - if (OF_getprop(faa->fa_node, "device_type", buf, sizeof(buf)) > 0 &&
> - strcmp(buf, "cpu") == 0)
> + if (OF_getprop(faa->fa_node, "device_type", buf, sizeof(buf)) <= 0 ||
> + strcmp(buf, "cpu") != 0)
> + return 0;
> +
> + if (ncpus < MAXCPUS || faa->fa_reg[0].addr == (mpidr & MPIDR_AFF))
> return 1;
Should this be && instead of || ?
>
> return 0;
> @@ -243,6 +247,7 @@ cpu_attach(struct device *parent, struct
> ci->ci_next = cpu_info_list->ci_next;
> cpu_info_list->ci_next = ci;
> ci->ci_flags |= CPUF_AP;
> + ncpus++;
> }
> #endif
>
> @@ -429,7 +434,6 @@ cpu_start_secondary(struct cpu_info *ci)
> uint64_t tcr;
> int s;
>
> - ncpus++;
> ci->ci_flags |= CPUF_PRESENT;
> __asm volatile("dsb sy");
>
>
