path: root/arch
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authorEric W. Biederman <ebiederm@xmission.com>2010-08-04 13:30:27 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-26 16:45:49 -0700
commit7811db7b800fea7a8d85045445d12a6ab639f806 (patch)
tree3c629cd86fd057656f087384ba935f9be738bcfd /arch
parente77930c78bd9dde017a80f87e2a89d670be19202 (diff)
x86, apic: Map the local apic when parsing the MP table.
commit 5989cd6a1cbf86587edcc856791f960978087311 upstream. This fixes a regression in 2.6.35 from 2.6.34, that is present for select models of Intel cpus when people are using an MP table. The commit cf7500c0ea133d66f8449d86392d83f840102632 "x86, ioapic: In mpparse use mp_register_ioapic" started calling mp_register_ioapic from MP_ioapic_info. An extremely simple change that was obviously correct. Unfortunately mp_register_ioapic did just a little more than the previous hand crafted code and so we gained this call path. The problem call path is: MP_ioapic_info() mp_register_ioapic() io_apic_unique_id() io_apic_get_unique_id() get_physical_broadcast() modern_apic() lapic_get_version() apic_read(APIC_LVR) Which turned out to be a problem because the local apic was not mapped, at that point, unlike the similar point in the ACPI parsing code. This problem is fixed by mapping the local apic when parsing the mptable as soon as we reasonably can. Looking at the number of places we setup the fixmap for the local apic, I see some serious simplification opportunities. For the moment except for not duplicating the setting up of the fixmap in init_apic_mappings, I have not acted on them. The regression from 2.6.34 is tracked in bug https://bugzilla.kernel.org/show_bug.cgi?id=16173 Reported-by: David Hill <hilld@binarystorm.net> Reported-by: Tvrtko Ursulin <tvrtko.ursulin@sophos.com> Tested-by: Tvrtko Ursulin <tvrtko.ursulin@sophos.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> LKML-Reference: <m1eiee86jg.fsf_-_@fess.ebiederm.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'arch')
2 files changed, 17 insertions, 1 deletions
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index a96489ee6ca..c07e51391a3 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1606,7 +1606,7 @@ void __init init_apic_mappings(void)
* acpi lapic path already maps that address in
* acpi_register_lapic_address()
- if (!acpi_lapic)
+ if (!acpi_lapic && !smp_found_config)
set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
apic_printk(APIC_VERBOSE, "mapped APIC to %08lx (%08lx)\n",
diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c
index d86dbf7e54b..d7b6f7fb4fe 100644
--- a/arch/x86/kernel/mpparse.c
+++ b/arch/x86/kernel/mpparse.c
@@ -274,6 +274,18 @@ static void __init smp_dump_mptable(struct mpc_table *mpc, unsigned char *mpt)
void __init default_smp_read_mpc_oem(struct mpc_table *mpc) { }
+static void __init smp_register_lapic_address(unsigned long address)
+ mp_lapic_addr = address;
+ set_fixmap_nocache(FIX_APIC_BASE, address);
+ if (boot_cpu_physical_apicid == -1U) {
+ boot_cpu_physical_apicid = read_apic_id();
+ apic_version[boot_cpu_physical_apicid] =
+ }
static int __init smp_read_mpc(struct mpc_table *mpc, unsigned early)
char str[16];
@@ -295,6 +307,10 @@ static int __init smp_read_mpc(struct mpc_table *mpc, unsigned early)
if (early)
return 1;
+ /* Initialize the lapic mapping */
+ if (!acpi_lapic)
+ smp_register_lapic_address(mpc->lapic);
if (mpc->oemptr)