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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>Kernel utility functions</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="Linux Device Drivers" /><link rel="up" href="ch01.html" title="Chapter 1. Driver Basics" /><link rel="prev" href="re128.html" title="kset_create_and_add" /><link rel="next" href="re129.html" title="upper_32_bits" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Kernel utility functions</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re128.html">Prev</a> </td><th width="60%" align="center">Chapter 1. Driver Basics</th><td width="20%" align="right"> <a accesskey="n" href="re129.html">Next</a></td></tr></table><hr /></div><div class="sect1" title="Kernel utility functions"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="id3042397"></a>Kernel utility functions</h2></div></div></div><div class="toc"><dl><dt><span class="refentrytitle"><a href="re129.html"><span>upper_32_bits</span></a></span><span class="refpurpose"> —
return bits 32-63 of a number
</span></dt><dt><span class="refentrytitle"><a href="re130.html"><span>lower_32_bits</span></a></span><span class="refpurpose"> —
return bits 0-31 of a number
</span></dt><dt><span class="refentrytitle"><a href="re131.html"><span>might_sleep</span></a></span><span class="refpurpose"> —
annotation for functions that can sleep
</span></dt><dt><span class="refentrytitle"><a href="re132.html"><span>trace_printk</span></a></span><span class="refpurpose"> —
printf formatting in the ftrace buffer
</span></dt><dt><span class="refentrytitle"><a href="re133.html"><span>clamp</span></a></span><span class="refpurpose"> —
return a value clamped to a given range with strict typechecking
</span></dt><dt><span class="refentrytitle"><a href="re134.html"><span>clamp_t</span></a></span><span class="refpurpose"> —
return a value clamped to a given range using a given type
</span></dt><dt><span class="refentrytitle"><a href="re135.html"><span>clamp_val</span></a></span><span class="refpurpose"> —
return a value clamped to a given range using val's type
</span></dt><dt><span class="refentrytitle"><a href="re136.html"><span>container_of</span></a></span><span class="refpurpose"> —
cast a member of a structure out to the containing structure
</span></dt><dt><span class="refentrytitle"><a href="re137.html"><span>printk</span></a></span><span class="refpurpose"> —
print a kernel message
</span></dt><dt><span class="refentrytitle"><a href="re138.html"><span>acquire_console_sem</span></a></span><span class="refpurpose"> —
lock the console system for exclusive use.
</span></dt><dt><span class="refentrytitle"><a href="re139.html"><span>release_console_sem</span></a></span><span class="refpurpose"> —
unlock the console system
</span></dt><dt><span class="refentrytitle"><a href="re140.html"><span>console_conditional_schedule</span></a></span><span class="refpurpose"> —
yield the CPU if required
</span></dt><dt><span class="refentrytitle"><a href="re141.html"><span>printk_timed_ratelimit</span></a></span><span class="refpurpose"> —
caller-controlled printk ratelimiting
</span></dt><dt><span class="refentrytitle"><a href="re142.html"><span>kmsg_dump_register</span></a></span><span class="refpurpose"> —
register a kernel log dumper.
</span></dt><dt><span class="refentrytitle"><a href="re143.html"><span>kmsg_dump_unregister</span></a></span><span class="refpurpose"> —
unregister a kmsg dumper.
</span></dt><dt><span class="refentrytitle"><a href="re144.html"><span>panic</span></a></span><span class="refpurpose"> —
halt the system
</span></dt><dt><span class="refentrytitle"><a href="re145.html"><span>print_tainted</span></a></span><span class="refpurpose"> —
return a string to represent the kernel taint state.
</span></dt><dt><span class="refentrytitle"><a href="re146.html"><span>emergency_restart</span></a></span><span class="refpurpose"> —
reboot the system
</span></dt><dt><span class="refentrytitle"><a href="re147.html"><span>kernel_restart</span></a></span><span class="refpurpose"> —
reboot the system
</span></dt><dt><span class="refentrytitle"><a href="re148.html"><span>kernel_halt</span></a></span><span class="refpurpose"> —
halt the system
</span></dt><dt><span class="refentrytitle"><a href="re149.html"><span>kernel_power_off</span></a></span><span class="refpurpose"> —
power_off the system
</span></dt><dt><span class="refentrytitle"><a href="re150.html"><span>orderly_poweroff</span></a></span><span class="refpurpose"> —
Trigger an orderly system poweroff
</span></dt><dt><span class="refentrytitle"><a href="re151.html"><span>synchronize_rcu</span></a></span><span class="refpurpose"> —
wait until a grace period has elapsed.
</span></dt><dt><span class="refentrytitle"><a href="re152.html"><span>synchronize_sched</span></a></span><span class="refpurpose"> —
wait until an rcu-sched grace period has elapsed.
</span></dt><dt><span class="refentrytitle"><a href="re153.html"><span>synchronize_rcu_bh</span></a></span><span class="refpurpose"> —
wait until an rcu_bh grace period has elapsed.
</span></dt></dl></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="re128.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch01.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="re129.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>kset_create_and_add</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span>upper_32_bits</span></td></tr></table></div></body></html>
