[tip:x86/urgent] x86: Fix vSMP boot crash

tip-bot for Yinghai Lu
2009-08-26T08:16:44Z

Commit-ID: 295594e9cf6ae2efd73371777aa8feba0f87f42f
Gitweb: http://git.kernel.org/tip/295594e9cf6ae2efd73371777aa8feba0f87f42f
Author: Yinghai Lu <yinghai@kernel.org>
AuthorDate: Tue, 25 Aug 2009 13:44:44 -0700
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 26 Aug 2009 10:13:17 +0200

x86: Fix vSMP boot crash

2.6.31-rc7 does not boot on vSMP systems:

[ 8.501108] CPU31: Thermal monitoring enabled (TM1)
[ 8.501127] CPU 31 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 8.650254] CPU31: Intel(R) Xeon(R) CPU E5540 @ 2.53GHz stepping 04
[ 8.710324] Brought up 32 CPUs
[ 8.713916] Total of 32 processors activated (162314.96 BogoMIPS).
[ 8.721489] ERROR: parent span is not a superset of domain->span
[ 8.727686] ERROR: domain->groups does not contain CPU0
[ 8.733091] ERROR: groups don't span domain->span
[ 8.737975] ERROR: domain->cpu_power not set
[ 8.742416]

Ravikiran Thirumalai bisected it to:

| commit 2759c3287de27266e06f1f4e82cbd2d65f6a044c
| x86: don't call read_apic_id if !cpu_has_apic

The problem is that on vSMP systems the CPUID derived
initial-APICIDs are overlapping - so we need to fall
back on hard_smp_processor_id() which reads the local
APIC.

Both come from the hardware (influenced by firmware
though) so it's a tough call which one to trust.

Doing the quirk expresses the vSMP property properly
and also does not affect other systems, so we go for
this solution instead of a revert.

Reported-and-Tested-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Shai Fultheim <shai@scalex86.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <4A944D3C.5030100@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
arch/x86/kernel/apic/probe_64.c | 10 ++++++++++
1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/apic/probe_64.c b/arch/x86/kernel/apic/probe_64.c
index bc3e880..fcec2f1 100644
--- a/arch/x86/kernel/apic/probe_64.c
+++ b/arch/x86/kernel/apic/probe_64.c
@@ -44,6 +44,11 @@ static struct apic *apic_probe[] __initdata = {
NULL,
};

+static int apicid_phys_pkg_id(int initial_apic_id, int index_msb)
+{
+ return hard_smp_processor_id() >> index_msb;
+}
+
/*
* Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
*/
@@ -69,6 +74,11 @@ void __init default_setup_apic_routing(void)
printk(KERN_INFO "Setting APIC routing to %s\n", apic->name);
}

+ if (is_vsmp_box()) {
+ /* need to update phys_pkg_id */
+ apic->phys_pkg_id = apicid_phys_pkg_id;
+ }
+
/*
* Now that apic routing model is selected, configure the
* fault handling for intr remapping.