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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>user_regset_writeback_fn</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="The utrace User Debugging Infrastructure" /><link rel="up" href="ch03.html#regset" title="struct user_regset" /><link rel="prev" href="re24.html" title="user_regset_set_fn" /><link rel="next" href="re26.html" title="struct user_regset" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>user_regset_writeback_fn</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re24.html">Prev</a> </td><th width="60%" align="center"><span class="structname">struct user_regset</span></th><td width="20%" align="right"> <a accesskey="n" href="re26.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="user_regset_writeback_fn"><a id="API-user-regset-writeback-fn"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>user_regset_writeback_fn —
type of <em class="parameter"><code>writeback</code></em> function in <span class="structname">struct user_regset</span>
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">typedef int <b class="fsfunc">user_regset_writeback_fn </b>(</code></td><td>struct task_struct * <var class="pdparam">target</var>, </td></tr><tr><td> </td><td>const struct user_regset * <var class="pdparam">regset</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">immediate</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id3102011"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>target</code></em></span></dt><dd><p>
thread being examined
</p></dd><dt><span class="term"><em class="parameter"><code>regset</code></em></span></dt><dd><p>
regset being examined
</p></dd><dt><span class="term"><em class="parameter"><code>immediate</code></em></span></dt><dd><p>
zero if writeback at completion of next context switch is OK
</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id3102071"></a><h2>Description</h2><p>
This call is optional; usually the pointer is <code class="constant">NULL</code>. When
provided, there is some user memory associated with this regset's
hardware, such as memory backing cached register data on register
window machines; the regset's data controls what user memory is
used (e.g. via the stack pointer value).
</p><p>
Write register data back to user memory. If the <em class="parameter"><code>immediate</code></em> flag
is nonzero, it must be written to the user memory so uaccess or
<code class="function">access_process_vm</code> can see it when this call returns; if zero,
then it must be written back by the time the task completes a
context switch (as synchronized with <code class="function">wait_task_inactive</code>).
Return <code class="constant">0</code> on success or if there was nothing to do, -<code class="constant">EFAULT</code> for
a memory problem (bad stack pointer or whatever), or -<code class="constant">EIO</code> for a
hardware problem.
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="re24.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch03.html#regset">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="re26.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>user_regset_set_fn</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span>struct user_regset</span></td></tr></table></div></body></html>
