linux_old1/arch
Linus Torvalds 950b07c14e Revert "x86/apic: Include the LDR when clearing out APIC registers"
This reverts commit 558682b529.

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>
2019-09-07 14:25:54 -07:00
..
alpha Merge branch 'akpm' (patches from Andrew) 2019-07-17 08:58:04 -07:00
arc Wimplicit-fallthrough patches for 5.3-rc7 2019-08-29 09:28:25 -07:00
arm Three fixes for ARM this time around: 2019-08-30 11:58:02 -07:00
arm64 Second Round of Renesas ARM Based SoC Fixes for v5.3 2019-09-05 17:56:30 +02:00
c6x Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu 2019-07-10 21:42:03 -07:00
csky treewide: add "WITH Linux-syscall-note" to SPDX tag of uapi headers 2019-07-25 11:05:10 +02:00
h8300 h8300 update for 5.3 2019-07-17 09:36:38 -07:00
hexagon hexagon: switch to generic version of pte allocation 2019-07-21 09:53:00 -07:00
ia64 Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
m68k arch: mark syscall number 435 reserved for clone3 2019-07-15 00:39:33 +02:00
microblaze clone3-v5.3 2019-07-11 10:09:44 -07:00
mips Wimplicit-fallthrough patches for 5.3-rc6 2019-08-22 11:26:10 -07:00
nds32 nds32: Mark expected switch fall-throughs 2019-08-29 11:06:56 -05:00
nios2 nios2 update for v5.3-rc1 2019-07-12 15:38:05 -07:00
openrisc dma-mapping updates for Linux 5.3 2019-07-12 15:13:55 -07:00
parisc parisc: fix compilation errrors 2019-08-24 19:48:42 -07:00
powerpc powerpc fixes for 5.3 #5 2019-09-06 08:54:45 -07:00
riscv RISC-V: Fix FIXMAP area corruption on RV32 systems 2019-08-28 15:30:12 -07:00
s390 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2019-08-23 17:34:11 -07:00
sh sh: kernel: hw_breakpoint: Fix missing break in switch statement 2019-08-11 16:15:16 -05:00
sparc treewide: add "WITH Linux-syscall-note" to SPDX tag of uapi headers 2019-07-25 11:05:10 +02:00
um um: fix time travel mode 2019-08-23 00:39:53 +02:00
unicore32 Kconfig updates for v5.3 2019-07-12 16:06:27 -07:00
x86 Revert "x86/apic: Include the LDR when clearing out APIC registers" 2019-09-07 14:25:54 -07:00
xtensa xtensa: add missing isync to the cpu_reset TLB code 2019-08-12 15:05:48 -07:00
.gitignore
Kconfig Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-20 10:33:44 -07:00