Commit-ID: cb214ede7657db458fd0b2a25ea0b28dbf900ebc Gitweb: http://git.kernel.org/tip/cb214ede7657db458fd0b2a25ea0b28dbf900ebc Author: Stoney Wang <song-bo.w...@hp.com> AuthorDate: Thu, 7 Feb 2013 10:53:02 -0800 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Mon, 11 Feb 2013 11:13:00 +0100
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.w...@hp.com> [ updated the changelog and simplified the code ] Signed-off-by: Yinghai Lu <ying...@kernel.org> Cc: sta...@kernel.org Link: http://lkml.kernel.org/r/1360263182-16226-1-git-send-email-ying...@kernel.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/kernel/apic/x2apic_phys.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c index e03a1e1..562a76d 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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
