Kernel utility functions

upper_32_bits - return bits 32-63 of a number
lower_32_bits - return bits 0-31 of a number
might_sleep - annotation for functions that can sleep
trace_printk - printf formatting in the ftrace buffer
clamp - return a value clamped to a given range with strict typechecking
clamp_t - return a value clamped to a given range using a given type
clamp_val - return a value clamped to a given range using val's type
container_of - cast a member of a structure out to the containing structure
printk - print a kernel message
acquire_console_sem - lock the console system for exclusive use.
release_console_sem - unlock the console system
console_conditional_schedule - yield the CPU if required
printk_timed_ratelimit - caller-controlled printk ratelimiting
panic - halt the system
emergency_restart - reboot the system
kernel_restart - reboot the system
kernel_halt - halt the system
kernel_power_off - power_off the system
orderly_poweroff - Trigger an orderly system poweroff
synchronize_rcu - wait until a grace period has elapsed.
synchronize_sched - wait until an rcu-sched grace period has elapsed.
synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed.