diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2023-06-15 22:34:00 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2023-06-20 14:51:47 +0200 |
| commit | 45e34c8af58f23db4474e2bfe79183efec09a18b (patch) | |
| tree | 9b0394979b5e07d83f76699ce2c79ddd95e5f692 /arch/x86/kernel/smpboot.c | |
| parent | 6087dd5e86ff03a8cd4cffdf463a7f457e65cbff (diff) | |
x86/smp: Put CPUs into INIT on shutdown if possible
Parking CPUs in a HLT loop is not completely safe vs. kexec() as HLT can
resume execution due to NMI, SMI and MCE, which has the same issue as the
MWAIT loop.
Kicking the secondary CPUs into INIT makes this safe against NMI and SMI.
A broadcast MCE will take the machine down, but a broadcast MCE which makes
HLT resume and execute overwritten text, pagetables or data will end up in
a disaster too.
So chose the lesser of two evils and kick the secondary CPUs into INIT
unless the system has installed special wakeup mechanisms which are not
using INIT.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230615193330.608657211@linutronix.de
Diffstat (limited to 'arch/x86/kernel/smpboot.c')
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index b403ead7eebd..4ee43396b910 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1465,6 +1465,25 @@ void arch_thaw_secondary_cpus_end(void) cache_aps_init(); } +bool smp_park_other_cpus_in_init(void) +{ + unsigned int cpu, this_cpu = smp_processor_id(); + unsigned int apicid; + + if (apic->wakeup_secondary_cpu_64 || apic->wakeup_secondary_cpu) + return false; + + for_each_present_cpu(cpu) { + if (cpu == this_cpu) + continue; + apicid = apic->cpu_present_to_apicid(cpu); + if (apicid == BAD_APICID) + continue; + send_init_sequence(apicid); + } + return true; +} + /* * Early setup to make printk work. */ |