diff options
authorStoney Wang <song-bo.wang@hp.com>2013-02-07 10:53:02 -0800
committerIngo Molnar <mingo@kernel.org>2013-02-11 11:13:00 +0100
commitcb214ede7657db458fd0b2a25ea0b28dbf900ebc (patch)
parent686966d881bd49bd6349b47c59dfc4bfc7b5e3b6 (diff)
x86/apic: Work around boot failure on HP ProLiant DL980 G7 Server systems
When a HP ProLiant DL980 G7 Server boots a regular kernel, there will be intermittent lost interrupts which could result in a hang or (in extreme cases) data loss. The reason is that this system only supports x2apic physical mode, while the kernel boots with a logical-cluster default setting. This bug can be worked around by specifying the "x2apic_phys" or "nox2apic" boot option, but we want to handle this system without requiring manual workarounds. The BIOS sets ACPI_FADT_APIC_PHYSICAL in FADT table. As all apicids are smaller than 255, BIOS need to pass the control to the OS with xapic mode, according to x2apic-spec, chapter 2.9. Current code handle x2apic when BIOS pass with xapic mode enabled: When user specifies x2apic_phys, or FADT indicates PHYSICAL: 1. During madt oem check, apic driver is set with xapic logical or xapic phys driver at first. 2. enable_IR_x2apic() will enable x2apic_mode. 3. if user specifies x2apic_phys on the boot line, x2apic_phys_probe() will install the correct x2apic phys driver and use x2apic phys mode. Otherwise it will skip the driver will let x2apic_cluster_probe to take over to install x2apic cluster driver (wrong one) even though FADT indicates PHYSICAL, because x2apic_phys_probe does not check FADT PHYSICAL. Add checking x2apic_fadt_phys in x2apic_phys_probe() to fix the problem. Signed-off-by: Stoney Wang <song-bo.wang@hp.com> [ updated the changelog and simplified the code ] Signed-off-by: Yinghai Lu <yinghai@kernel.org> Cc: stable@kernel.org Link: http://lkml.kernel.org/r/1360263182-16226-1-git-send-email-yinghai@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 files changed, 11 insertions, 10 deletions
diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
index e03a1e180e8..562a76d433c 100644
--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -20,18 +20,19 @@ static int set_x2apic_phys_mode(char *arg)
early_param("x2apic_phys", set_x2apic_phys_mode);
-static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
+static bool x2apic_fadt_phys(void)
- if (x2apic_phys)
- return x2apic_enabled();
- else if ((acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID) &&
- (acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL) &&
- x2apic_enabled()) {
+ if ((acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID) &&
+ (acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL)) {
printk(KERN_DEBUG "System requires x2apic physical mode\n");
- return 1;
+ return true;
- else
- return 0;
+ return false;
+static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
+ return x2apic_enabled() && (x2apic_phys || x2apic_fadt_phys());
static void
@@ -82,7 +83,7 @@ static void init_x2apic_ldr(void)
static int x2apic_phys_probe(void)
- if (x2apic_mode && x2apic_phys)
+ if (x2apic_mode && (x2apic_phys || x2apic_fadt_phys()))
return 1;
return apic == &apic_x2apic_phys;