# git rev-parse -q --verify 950b07c14e8c59444e2359f15fd70ed5112e11a0^{commit}
950b07c14e8c59444e2359f15fd70ed5112e11a0
already have revision, skipping fetch
# git checkout -q -f -B kisskb 950b07c14e8c59444e2359f15fd70ed5112e11a0
# git clean -qxdf
# < git log -1
# commit 950b07c14e8c59444e2359f15fd70ed5112e11a0
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Sat Sep 7 14:25:54 2019 -0700
# 
#     Revert "x86/apic: Include the LDR when clearing out APIC registers"
#     
#     This reverts commit 558682b5291937a70748d36fd9ba757fb25b99ae.
#     
#     Chris Wilson reports that it breaks his CPU hotplug test scripts.  In
#     particular, it breaks offlining and then re-onlining the boot CPU, which
#     we treat specially (and the BIOS does too).
#     
#     The symptoms are that we can offline the CPU, but it then does not come
#     back online again:
#     
#         smpboot: CPU 0 is now offline
#         smpboot: Booting Node 0 Processor 0 APIC 0x0
#         smpboot: do_boot_cpu failed(-1) to wakeup CPU#0
#     
#     Thomas says he knows why it's broken (my personal suspicion: our magic
#     handling of the "cpu0_logical_apicid" thing), but for 5.3 the right fix
#     is to just revert it, since we've never touched the LDR bits before, and
#     it's not worth the risk to do anything else at this stage.
#     
#     [ Hotpluging of the boot CPU is special anyway, and should be off by
#       default. See the "BOOTPARAM_HOTPLUG_CPU0" config option and the
#       cpu0_hotplug kernel parameter.
#     
#       In general you should not do it, and it has various known limitations
#       (hibernate and suspend require the boot CPU, for example).
#     
#       But it should work, even if the boot CPU is special and needs careful
#       treatment       - Linus ]
#     
#     Link: https://lore.kernel.org/lkml/156785100521.13300.14461504732265570003@skylake-alporthouse-com/
#     Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
#     Acked-by: Thomas Gleixner <tglx@linutronix.de>
#     Cc: Bandan Das <bsd@redhat.com>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 950b07c14e8c59444e2359f15fd70ed5112e11a0
# < make -s -j 120 ARCH=x86 O=/kisskb/build/linus_x86-allmodconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-  allmodconfig
# Added to kconfig CONFIG_BUILD_DOCSRC=n
# Added to kconfig CONFIG_MODULE_SIG=n
# Added to kconfig CONFIG_SAMPLES=n
# yes \n | make -s -j 120 ARCH=x86 O=/kisskb/build/linus_x86-allmodconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-  oldconfig
yes: standard output: Broken pipe
# make -s -j 120 ARCH=x86 O=/kisskb/build/linus_x86-allmodconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-  
Completed OK
# rm -rf /kisskb/build/linus_x86-allmodconfig_x86_64-gcc8
# Build took: 0:13:19.824428