WSL2-Linux-Kernel/arch
Yinghai Lu fd19dce7ac x86: Fix x2apic preenabled system with kexec
Found one x2apic system kexec loop test failed
when CONFIG_NMI_WATCHDOG=y (old) or CONFIG_LOCKUP_DETECTOR=y (current tip)

first kernel can kexec second kernel, but second kernel can not kexec third one.

it can be duplicated on another system with BIOS preenabled x2apic.
First kernel can not kexec second kernel.

It turns out, when kernel boot with pre-enabled x2apic, it will not execute
disable_local_APIC on shutdown path.

when init_apic_mappings() is called in setup_arch, it will skip setting of
apic_phys when x2apic_mode is set. ( x2apic_mode is much early check_x2apic())
Then later, disable_local_APIC() will bail out early because !apic_phys.

So check !x2apic_mode in x2apic_mode in disable_local_APIC with !apic_phys.

another solution could be updating init_apic_mappings() to set apic_phys even
for preenabled x2apic system. Actually even for x2apic system, that lapic
address is mapped already in early stage.

BTW: is there any x2apic preenabled system with apicid of boot cpu > 255?

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4C3EB22B.3000701@kernel.org>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: stable@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-07-16 16:49:41 -07:00
..
alpha
arm Merge master.kernel.org:/home/rmk/linux-2.6-arm 2010-07-14 17:28:13 -07:00
avr32
blackfin
cris
frv
h8300
ia64
m32r
m68k
m68knommu
microblaze lmb: rename to memblock 2010-07-14 17:14:00 +10:00
mips MIPS: Return after handling coprocessor 2 exception 2010-07-05 17:17:33 +01:00
mn10300
parisc
powerpc Merge branch 'lmb-to-memblock' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2010-07-14 17:27:44 -07:00
s390
score
sh lmb: rename to memblock 2010-07-14 17:14:00 +10:00
sparc lmb: rename to memblock 2010-07-14 17:14:00 +10:00
um
x86 x86: Fix x2apic preenabled system with kexec 2010-07-16 16:49:41 -07:00
xtensa
.gitignore
Kconfig