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1037e4c53e
The ACPI MADT mailbox wakeup method doesn't allow to offline a CPU after it has been woken up. Currently, offlining is prevented based on the confidential computing attribute which is set for Intel TDX. But TDX is not the only possible user of the wake up method. The MADT wakeup can be implemented outside of a confidential computing environment. Offline support is a property of the wakeup method, not the CoCo implementation. Introduce cpu_hotplug_disable_offlining() that can be called to indicate that CPU offlining should be disabled. This function is going to replace CC_ATTR_HOTPLUG_DISABLED for ACPI MADT wakeup method. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Tao Liu <ltao@redhat.com> Link: https://lore.kernel.org/r/20240614095904.1345461-4-kirill.shutemov@linux.intel.com
50 lines
1.5 KiB
C
50 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* include/linux/cpuhplock.h - CPU hotplug locking
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*
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* Locking functions for CPU hotplug.
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*/
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#ifndef _LINUX_CPUHPLOCK_H_
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#define _LINUX_CPUHPLOCK_H_
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#include <linux/cleanup.h>
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#include <linux/errno.h>
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struct device;
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extern int lockdep_is_cpus_held(void);
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#ifdef CONFIG_HOTPLUG_CPU
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void cpus_write_lock(void);
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void cpus_write_unlock(void);
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void cpus_read_lock(void);
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void cpus_read_unlock(void);
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int cpus_read_trylock(void);
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void lockdep_assert_cpus_held(void);
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void cpu_hotplug_disable_offlining(void);
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void cpu_hotplug_disable(void);
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void cpu_hotplug_enable(void);
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void clear_tasks_mm_cpumask(int cpu);
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int remove_cpu(unsigned int cpu);
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int cpu_device_down(struct device *dev);
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void smp_shutdown_nonboot_cpus(unsigned int primary_cpu);
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#else /* CONFIG_HOTPLUG_CPU */
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static inline void cpus_write_lock(void) { }
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static inline void cpus_write_unlock(void) { }
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static inline void cpus_read_lock(void) { }
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static inline void cpus_read_unlock(void) { }
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static inline int cpus_read_trylock(void) { return true; }
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static inline void lockdep_assert_cpus_held(void) { }
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static inline void cpu_hotplug_disable_offlining(void) { }
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static inline void cpu_hotplug_disable(void) { }
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static inline void cpu_hotplug_enable(void) { }
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static inline int remove_cpu(unsigned int cpu) { return -EPERM; }
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static inline void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) { }
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#endif /* !CONFIG_HOTPLUG_CPU */
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DEFINE_LOCK_GUARD_0(cpus_read_lock, cpus_read_lock(), cpus_read_unlock())
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#endif /* _LINUX_CPUHPLOCK_H_ */
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