linux/arch
Stoney Wang cb214ede76 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>
2013-02-11 11:13:00 +01:00
..
alpha ALPHA: drivers: remove __dev* attributes. 2013-01-03 15:57:13 -08:00
arm Merge branch 'fixes' of git://git.linaro.org/people/rmk/linux-arm 2013-01-24 12:44:57 -08:00
arm64 arm64: elf: fix core dumping to match what glibc expects 2013-01-22 17:50:59 +00:00
avr32 ARCH: drivers remove __dev* attributes. 2013-01-03 15:57:13 -08:00
blackfin ARCH: drivers remove __dev* attributes. 2013-01-03 15:57:13 -08:00
c6x These are a few cleanups for asm-generic: 2012-12-21 16:39:08 -08:00
cris ARCH: drivers remove __dev* attributes. 2013-01-03 15:57:13 -08:00
frv ARCH: drivers remove __dev* attributes. 2013-01-03 15:57:13 -08:00
h8300 These are a few cleanups for asm-generic: 2012-12-21 16:39:08 -08:00
hexagon Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2012-12-20 18:05:28 -08:00
ia64 ia64: kill thread_matches(), unexport ptrace_check_attach() 2013-01-20 12:26:05 -08:00
m32r ARCH: drivers remove __dev* attributes. 2013-01-03 15:57:13 -08:00
m68k Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k 2013-01-23 13:31:15 -08:00
microblaze Merge branch 'next' of git://git.monstr.eu/linux-2.6-microblaze 2013-01-07 07:39:32 -08:00
mips MIPS: Function tracer: Fix broken function tracing 2013-01-31 15:28:48 +01:00
mn10300 arch/mn10300/Kconfig: select CONFIG_GENERIC_ATOMIC64 2013-01-11 14:54:55 -08:00
openrisc ARCH: drivers remove __dev* attributes. 2013-01-03 15:57:13 -08:00
parisc parisc: sigaltstack doesn't round ss.ss_sp as required 2013-01-07 23:06:27 +01:00
powerpc powerpc/mm: Fix hash computation function 2013-02-04 15:15:08 +11:00
s390 s390/thp: implement pmdp_set_wrprotect() 2013-01-22 13:32:16 +01:00
score ARCH: drivers remove __dev* attributes. 2013-01-03 15:57:13 -08:00
sh sh: ecovec: add sample amixer settings 2013-01-16 18:30:44 +09:00
sparc sparc: remove __devinit, __devexit annotations 2013-01-12 15:28:45 -08:00
tile ARCH: drivers remove __dev* attributes. 2013-01-03 15:57:13 -08:00
um Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2012-12-20 18:05:28 -08:00
unicore32 ARCH: drivers remove __dev* attributes. 2013-01-03 15:57:13 -08:00
x86 x86/apic: Work around boot failure on HP ProLiant DL980 G7 Server systems 2013-02-11 11:13:00 +01:00
xtensa These are a few cleanups for asm-generic: 2012-12-21 16:39:08 -08:00
.gitignore
Kconfig Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2012-12-20 18:05:28 -08:00