diff options
author | avg <avg@FreeBSD.org> | 2010-11-04 08:51:45 +0000 |
---|---|---|
committer | avg <avg@FreeBSD.org> | 2010-11-04 08:51:45 +0000 |
commit | 18175daafce6733afb1b9a5739461f91eebddac0 (patch) | |
tree | 839812957b76fc936643910f6773c7364af7d89b /sys/i386 | |
parent | fd55e0e68b0492c2a6afef17be172d4f7ea44398 (diff) | |
download | FreeBSD-src-18175daafce6733afb1b9a5739461f91eebddac0.zip FreeBSD-src-18175daafce6733afb1b9a5739461f91eebddac0.tar.gz |
x86 topo_probe: do not probe smp topology if only one cpu is visible
This could lead to a division by zero if hardware is multi-core and/or
multi-threaded, but for some (quite unusual) reason FreeBSD sees only
one logical processor. This could happen, for example, if neither MADT
nor MP Table are presented by BIOS.
Also:
- assert in topo_probe_0x4 that BSP is accounted for
- neither cpu_cores nor cpu_logical should be zero after successful
probing, so either being zero is an indication of failed probing
Reported by: vwe, Dan Allen <danallen46@airwired.net>
Tested by: Dan Allen <danallen46@airwired.net>
MFC after: 3 days
Diffstat (limited to 'sys/i386')
-rw-r--r-- | sys/i386/i386/mp_machdep.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/sys/i386/i386/mp_machdep.c b/sys/i386/i386/mp_machdep.c index b99c19c..c4d2672 100644 --- a/sys/i386/i386/mp_machdep.c +++ b/sys/i386/i386/mp_machdep.c @@ -286,6 +286,9 @@ topo_probe_0x4(void) cpu_logical++; } + KASSERT(cpu_cores >= 1 && cpu_logical >= 1, + ("topo_probe_0x4 couldn't find BSP")); + cpu_cores /= cpu_logical; hyperthreading_cpus = cpu_logical; } @@ -357,7 +360,9 @@ topo_probe(void) return; logical_cpus_mask = 0; - if (cpu_vendor_id == CPU_VENDOR_AMD) + if (mp_ncpus <= 1) + cpu_cores = cpu_logical = 1; + else if (cpu_vendor_id == CPU_VENDOR_AMD) topo_probe_amd(); else if (cpu_vendor_id == CPU_VENDOR_INTEL) { /* @@ -379,10 +384,8 @@ topo_probe(void) * Fallback: assume each logical CPU is in separate * physical package. That is, no multi-core, no SMT. */ - if (cpu_cores == 0) - cpu_cores = 1; - if (cpu_logical == 0) - cpu_logical = 1; + if (cpu_cores == 0 || cpu_logical == 0) + cpu_cores = cpu_logical = 1; cpu_topo_probed = 1; } |