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author | Stoney Wang <song-bo.wang@hp.com> | 2013-02-07 10:53:02 -0800 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-02-17 10:49:25 -0800 |
commit | 65f55391cf03b2e4bcfec63b08b8db032b4d6f3a (patch) | |
tree | 2ce99f5095bd900b1c54acfc0f2551f4a4047466 /arch | |
parent | e2ef6aad8a81c730bba92b2a44d758cabd7d9053 (diff) | |
download | lwn-65f55391cf03b2e4bcfec63b08b8db032b4d6f3a.tar.gz lwn-65f55391cf03b2e4bcfec63b08b8db032b4d6f3a.zip |
x86/apic: Work around boot failure on HP ProLiant DL980 G7 Server systems
commit cb214ede7657db458fd0b2a25ea0b28dbf900ebc upstream.
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>
Link: http://lkml.kernel.org/r/1360263182-16226-1-git-send-email-yinghai@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/kernel/apic/x2apic_phys.c | 21 |
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 991e315f4227..db31a2cfc9a9 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 @@ -114,7 +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; |