Messages in this thread Patch in this message |  | | | Date | Wed, 21 Dec 2011 17:45:19 -0800 | | From | Suresh Siddha <> | | Subject | [patch 5/5] x86: skip cpus with apic-ids >= 255 in !x2apic_mode |
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From: Suresh Siddha <suresh.b.siddha@intel.com>
If the x2apic mode is disabled for reasons like interrupt-remapping not available etc, then we need to skip the logical cpu bringup of apic-id's >= 255. Otherwise as the platform is in xapic mode, init/startup IPI's will consider only the low 8-bits and there is a possibility of re-sending init/startup IPI's to the logical cpu that is already online.
This will avoid potential reboots/unpredictable behavior etc.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> --- arch/x86/kernel/smpboot.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) Index: tip/arch/x86/kernel/smpboot.c =================================================================== --- tip.orig/arch/x86/kernel/smpboot.c +++ tip/arch/x86/kernel/smpboot.c @@ -840,7 +840,8 @@ int __cpuinit native_cpu_up(unsigned int pr_debug("++++++++++++++++++++=_---CPU UP %u\n", cpu); if (apicid == BAD_APICID || apicid == boot_cpu_physical_apicid || - !physid_isset(apicid, phys_cpu_present_map)) { + !physid_isset(apicid, phys_cpu_present_map) || + (!x2apic_mode && apicid >= 255)) { printk(KERN_ERR "%s: bad cpu %d\n", __func__, cpu); return -EINVAL; }
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