> Date: Fri, 26 Nov 2010 16:35:28 +1000
> From: David Gwynne <l...@animata.net>
>
> information about each cpu is stored in a statically sized array.
> if we have more physical cpus than entries in that array, we currently
> start storing cpu_info structures in unowned memory after that
> array. this leads to Bad Things(tm).
>
> MAXCPUs should be bumped up on amd64, but we should also avoid
> panicking on ridiculously overspecced boxes. i am sure i will regret
> claiming that a 48core machine is overspecced in the very near
> future though.
>
> Index: amd64/cpu.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/amd64/amd64/cpu.c,v
> retrieving revision 1.38
> diff -u -p -r1.38 cpu.c
> --- amd64/cpu.c 13 Nov 2010 04:16:42 -0000 1.38
> +++ amd64/cpu.c 26 Nov 2010 06:31:53 -0000
> @@ -167,10 +165,24 @@ cpu_match(struct device *parent, void *m
> {
> struct cfdata *cf = match;
> struct cpu_attach_args *caa = aux;
> + int cpunum;
>
> - if (strcmp(caa->caa_name, cf->cf_driver->cd_name) == 0)
> + /*
> + * we cannot attach more cpus than we are set up to store in the
> + * cpu_info array, so fail to match if we have more cpus than slots
> + * in the array.
> + */
> +
> + for (cpunum = 0; cpunum < nitems(cpu_info); cpunum++) {
> + if (cpu_info[cpunum] == NULL)
> + break;
> + }
> +
> + if (cpunum < nitems(cpu_info) &&
> + strcmp(caa->caa_name, cf->cf_driver->cd_name) == 0)
> return 1;
> - return 0;
> +
> + return (0);
> }
>
> static void
>
Sorry, but I think it is better to do this the same way it's done on
hppa. The changes to i386 are a bit arger than strictly necessary to
make the code identical to amd64. Only tested on i386, artificially
limiting MAXCPUS to 1.
Index: amd64/amd64/cpu.c
===================================================================
RCS file: /cvs/src/sys/arch/amd64/amd64/cpu.c,v
retrieving revision 1.38
diff -u -p -r1.38 cpu.c
--- amd64/amd64/cpu.c 13 Nov 2010 04:16:42 -0000 1.38
+++ amd64/amd64/cpu.c 26 Nov 2010 15:00:49 -0000
@@ -168,9 +168,13 @@ cpu_match(struct device *parent, void *m
struct cfdata *cf = match;
struct cpu_attach_args *caa = aux;
- if (strcmp(caa->caa_name, cf->cf_driver->cd_name) == 0)
- return 1;
- return 0;
+ if (strcmp(caa->caa_name, cf->cf_driver->cd_name) != 0)
+ return 0;
+
+ if (cf->cf_unit >= MAXCPUS)
+ return 0;
+
+ return 1;
}
static void
Index: i386/i386/cpu.c
===================================================================
RCS file: /cvs/src/sys/arch/i386/i386/cpu.c,v
retrieving revision 1.41
diff -u -p -r1.41 cpu.c
--- i386/i386/cpu.c 25 Jul 2010 21:43:35 -0000 1.41
+++ i386/i386/cpu.c 26 Nov 2010 15:00:53 -0000
@@ -157,14 +157,18 @@ struct cfdriver cpu_cd = {
};
int
-cpu_match(struct device *parent, void *matchv, void *aux)
+cpu_match(struct device *parent, void *match, void *aux)
{
- struct cfdata *match = (struct cfdata *)matchv;
- struct cpu_attach_args *caa = (struct cpu_attach_args *)aux;
+ struct cfdata *cf = match;
+ struct cpu_attach_args *caa = aux;
- if (strcmp(caa->caa_name, match->cf_driver->cd_name) == 0)
- return (1);
- return (0);
+ if (strcmp(caa->caa_name, cf->cf_driver->cd_name) != 0)
+ return 0;
+
+ if (cf->cf_unit >= MAXCPUS)
+ return 0;
+
+ return 1;
}
void
