Author: avg
Date: Thu Nov 4 08:51:45 2010
New Revision: 214774
URL: http://svn.freebsd.org/changeset/base/214774
Log:
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 <danalle...@airwired.net>
Tested by: Dan Allen <danalle...@airwired.net>
MFC after: 3 days
Modified:
head/sys/amd64/amd64/mp_machdep.c
head/sys/i386/i386/mp_machdep.c
Modified: head/sys/amd64/amd64/mp_machdep.c
==============================================================================
--- head/sys/amd64/amd64/mp_machdep.c Thu Nov 4 07:53:09 2010
(r214773)
+++ head/sys/amd64/amd64/mp_machdep.c Thu Nov 4 08:51:45 2010
(r214774)
@@ -239,6 +239,9 @@ 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;
}
@@ -310,7 +313,9 @@ 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) {
/*
@@ -332,10 +337,8 @@ 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;
}
Modified: head/sys/i386/i386/mp_machdep.c
==============================================================================
--- head/sys/i386/i386/mp_machdep.c Thu Nov 4 07:53:09 2010
(r214773)
+++ head/sys/i386/i386/mp_machdep.c Thu Nov 4 08:51:45 2010
(r214774)
@@ -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;
}
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