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| author | Thomas Gleixner <tglx@linutronix.de> | 2019-07-22 21:47:22 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-07-25 17:12:00 +0300 |
| commit | 6a1cb5f5c6413222b8532722562dd1edb5fdfd38 (patch) | |
| tree | 140ed1ae3359c26ebc75ace8ff334a231a982bf4 /arch/x86/include/asm/apic.h | |
| parent | bdda3b93e66085abf0b2c16bcdf471176e3c816a (diff) | |
| download | linux-6a1cb5f5c6413222b8532722562dd1edb5fdfd38.tar.xz | |
x86/apic: Add static key to Control IPI shorthands
The IPI shorthand functionality delivers IPI/NMI broadcasts to all CPUs in
the system. This can have similar side effects as the MCE broadcasting when
CPUs are waiting in the BIOS or are offlined.
The kernel tracks already the state of offlined CPUs whether they have been
brought up at least once so that the CR4 MCE bit is set to make sure that
MCE broadcasts can't brick the machine.
Utilize that information and compare it to the cpu_present_mask. If all
present CPUs have been brought up at least once then the broadcast side
effect is mitigated by disabling regular interrupt/IPI delivery in the APIC
itself and by the cpu offline check at the begin of the NMI handler.
Use a static key to switch between broadcasting via shorthands or sending
the IPI/NMI one by one.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190722105220.386410643@linutronix.de
Diffstat (limited to 'arch/x86/include/asm/apic.h')
| -rw-r--r-- | arch/x86/include/asm/apic.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index cae7e0d02476..4a0d349ab44d 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -505,8 +505,10 @@ extern int default_check_phys_apicid_present(int phys_apicid); #ifdef CONFIG_SMP bool apic_id_is_primary_thread(unsigned int id); +void apic_smt_update(void); #else static inline bool apic_id_is_primary_thread(unsigned int id) { return false; } +static inline void apic_smt_update(void) { } #endif extern void irq_enter(void); |