Hi Greg, This patch is specially for 3.0 by integrating upstream commit cb214ede7657db458fd0b2a25ea0b28dbf900ebc and ea0dcf903e7d76aa5d483d876215fedcfdfe140f . I fixed patch format warning and re-send it as v2. Thanks . ----------------------- ./scripts/checkpatch.pl x2apic_FADT_check_for_3.0.66v2.patch total: 0 errors, 0 warnings, 31 lines checked x2apic_FADT_check_for_3.0.66v2.patch has no obvious style problems and is ready for submission. ---------------------- From: Zhang Lin-Bao <linbao.zhang@xxxxxx> x86/apic: Work around boot failure on HP ProLiant DL980 G7 Server systems commit cb214ede7657db458fd0b2a25ea0b28dbf900ebc and ea0dcf903e7d76aa5d483d876215fedcfdfe140f upstream. 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 "x2apic_phys" or "nox2apic" boot option, but we want to handle this system without requiring manual workarounds. BIOS set ACPI_FADT_APIC_PHYSICAL in FADT table. As all apicids are less 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: When user specify 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 specify x2apic_phys, x2apic_phys_probe() will install right x2apic phys driver and use x2apic phys mode. otherwise will skip and let x2apic_cluster_probe to take over to install x2apic cluster driver (wrong one) even 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@xxxxxx> [ updated the changelog and simplified the code ] Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx> Signed-off-by: Linbao.zhang@xxxxxx [ make a patch specially for 3.0.66] Cc: stable@xxxxxxxxxx Link: http://lkml.kernel.org/r/1360263182-16226-1-git-send-email-yinghai@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/kernel/apic/x2apic_phys.c | 17 ++++++++++++----- 1 files changed, 12 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c index f5373df..0f8cb3a 100644 --- a/arch/x86/kernel/apic/x2apic_phys.c +++ b/arch/x86/kernel/apic/x2apic_phys.c @@ -20,12 +20,19 @@ static int set_x2apic_phys_mode(char *arg) } early_param("x2apic_phys", set_x2apic_phys_mode); +static bool x2apic_fadt_phys(void) +{ + 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 true; + } + return false; +} + static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id) { - if (x2apic_phys) - return x2apic_enabled(); - else - return 0; + return x2apic_enabled() && (x2apic_phys || x2apic_fadt_phys()); } static void @@ -108,7 +115,7 @@ 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; -- 1.7.9 -- Bob(LinBao Zhang) HP linux kernel enginner -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html