diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2024-02-13 22:05:54 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-02-15 22:07:43 +0100 |
| commit | 5c5682b9f87a3b7bd4833884f300ec673685f6a6 (patch) | |
| tree | 84273122a8fa878cb1237d0273a83fea3cc8cc1e /Documentation/admin-guide/kernel-parameters.txt | |
| parent | 7c0edad3643f4493c4dafa6f5dfcfb1a86432156 (diff) | |
x86/cpu: Detect real BSP on crash kernels
When a kdump kernel is started from a crashing CPU then there is no
guarantee that this CPU is the real boot CPU (BSP). If the kdump kernel
tries to online the BSP then the INIT sequence will reset the machine.
There is a command line option to prevent this, but in case of nested kdump
kernels this is wrong.
But that command line option is not required at all because the real
BSP is enumerated as the first CPU by firmware. Support for the only
known system which was different (Voyager) got removed long ago.
Detect whether the boot CPU APIC ID is the first APIC ID enumerated by
the firmware. If the first APIC ID enumerated is not matching the boot
CPU APIC ID then skip registering it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240213210252.348542071@linutronix.de
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 9 |
1 files changed, 0 insertions, 9 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 31b3a25680d0..4b9b4d662e31 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1100,15 +1100,6 @@ Disable TLBIE instruction. Currently does not work with KVM, with HASH MMU, or with coherent accelerators. - disable_cpu_apicid= [X86,APIC,SMP] - Format: <int> - The number of initial APIC ID for the - corresponding CPU to be disabled at boot, - mostly used for the kdump 2nd kernel to - disable BSP to wake up multiple CPUs without - causing system reset or hang due to sending - INIT from AP to BSP. - disable_ddw [PPC/PSERIES] Disable Dynamic DMA Window support. Use this to workaround buggy firmware. |