arm64/machine_machdep.h Kernel.framework

We cache the following in EL0 registers TPIDRRO_EL0 - the current cthread pointer TPIDR_EL0 - the current CPU number (12 bits) - the current logical cluster id (8 bits) NOTE: Keep this in sync with libsyscall/os/tsd.h, specifically _os_cpu_number(), _os_cpu_cluster_number()

#define MACHDEP_TPIDR_CPUNUM_SHIFT 0

Mask and count of bits that are CPU-dependent instead of being restored from thread state.

#define MACHDEP_TPIDR_CPU_DATA_MASK (MACHDEP_TPIDR_CPUNUM_MASK | MACHDEP_TPIDR_CLUSTERID_MASK)

Count of bits that are restored from thread state.

#define MACHDEP_TPIDR_THREAD_DATA_COUNT (64 - MACHDEP_TPIDR_CPU_DATA_COUNT)

Do not smash x18 on context switch. This bit will only be honored if the thread also has an entitlement allowing x18 to be preserved. This bit is saved and restored during context switch through ARM_MACHINE_THREAD_PRESERVE_X18_SAVE.

#define MACHDEP_TPIDR_FLAG_PRESERVE_X18_SHIFT 48

Mask of bits that are restored from thread state.

#define MACHDEP_TPIDR_THREAD_MASK MACHDEP_TPIDR_FLAG_PRESERVE_X18