xref: /xnu-11215/osfmk/man/vm_machine_attribute.html (revision 186b8fce)

<h2>vm_machine_attribute</h2>
<hr>
<p>
<strong>Function</strong> - Get/set the target memory region's special attributes.
<h3>SYNOPSIS</h3>
<pre>
<strong>kern_return_t   vm_machine_attribute</strong>
                <strong>(vm_task_t</strong>                          <var>target_task</var>,
                 <strong>vm_address_t</strong>                           <var>address</var>,
                 <strong>vm_size_t</strong>                                 <var>size</var>,
                 <strong>vm_machine_attribute_t</strong>               <var>attribute</var>,
                 <strong>vm_machine_attribute_val_t</strong>               <var>value</var><strong>);</strong>
</pre>
<h3>PARAMETERS</h3>
<dl>
<p>
<dt> <var>target_task</var>
<dd>
[in task send right]
The port for the task in whose address space the
memory object is to be manipulated.
<p>
<dt> <var>address</var>
<dd>
[in scalar]
The starting address for the memory region.  The granularity
of rounding of this value to page boundaries is implementation
dependent.
<p>
<dt> <var>size</var>
<dd>
[in scalar]
The number of bytes in the region.  The granularity of
rounding of this value to page boundaries is implementation dependent.
<p>
<dt> <var>attribute</var>
<dd>
[in scalar]
The name of the attribute to be get/set.  Possible values are:
<dl>
<p>
<dt> <strong>MATTR_CACHE</strong>
<dd>
Cachability.  Aside from the generic values listed below, the
following special values are defined:
<dl>
<p>
<dt> <strong>MATTR_VAL_CACHE_FLUSH</strong>
<dd>
Flush from all caches
<p>
<dt> <strong>MATTR_VAL_DCACHE_FLUSH</strong>
<dd>
Flush from data caches
<p>
<dt> <strong>MATTR_VAL_ICACHE_FLUSH</strong>
<dd>
Flush from instruction caches
</dl>
<p>
<dt> <strong>MATTR_MIGRATE</strong>
<dd>
Migratability.
<p>
<dt> <strong>MATTR_REPLICATE</strong>
<dd>
Replicability.
</dl>
<p>
<dt> <var>value</var>
<dd>
[pointer to in/out scalar]
The new value for the attribute.  The old value
is also returned in this variable.  The new value can be a specific value
listed above, or one of the following generic values:
<dl>
<p>
<dt> <strong>MATTR_VAL_OFF</strong>
<dd>
Turn attribute off.
<p>
<dt> <strong>MATTR_VAL_ON</strong>
<dd>
Turn attribute on.
<p>
<dt> <strong>MATTR_VAL_GET</strong>
<dd>
No change, just return current value.
</dl>
</dl>
<h3>DESCRIPTION</h3>
<p>
The <strong>vm_machine_attribute</strong> function gets and sets special
attributes of the
memory region implemented by the underlying <strong>pmap</strong> module.  These attributes
are properties such as cachability, migratability and replicability.
The behavior of this function is machine dependent.
<h3>NOTES</h3>
<p>
This interface is machine word length specific because of the virtual address
parameter.
<h3>RETURN VALUES</h3>
<dl>
<p>
<dt> <strong>KERN_INVALID_ADDRESS</strong>
<dd>
The address is illegal or specifies a non-allocated region.
</dl>
<h3>RELATED INFORMATION</h3>
<p>
Functions:
<a href="vm_wire.html"><strong>vm_wire</strong></a>.