Date: Thu, 4 Nov 2010 08:51:45 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r214774 - in head/sys: amd64/amd64 i386/i386 Message-ID: <201011040851.oA48pj96049600@svn.freebsd.org>
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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 <danallen46@airwired.net> Tested by: Dan Allen <danallen46@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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