1<h2>vm_machine_attribute</h2>
2<hr>
3<p>
4<strong>Function</strong> - Get/set the target memory region's special attributes.
5<h3>SYNOPSIS</h3>
6<pre>
7<strong>kern_return_t   vm_machine_attribute</strong>
8                <strong>(vm_task_t</strong>                          <var>target_task</var>,
9                 <strong>vm_address_t</strong>                           <var>address</var>,
10                 <strong>vm_size_t</strong>                                 <var>size</var>,
11                 <strong>vm_machine_attribute_t</strong>               <var>attribute</var>,
12                 <strong>vm_machine_attribute_val_t</strong>               <var>value</var><strong>);</strong>
13</pre>
14<h3>PARAMETERS</h3>
15<dl>
16<p>
17<dt> <var>target_task</var> 
18<dd>
19[in task send right]
20The port for the task in whose address space the 
21memory object is to be manipulated.
22<p>
23<dt> <var>address</var> 
24<dd>
25[in scalar]
26The starting address for the memory region.  The granularity 
27of rounding of this value to page boundaries is implementation
28dependent.
29<p>
30<dt> <var>size</var> 
31<dd>
32[in scalar]
33The number of bytes in the region.  The granularity of
34rounding of this value to page boundaries is implementation dependent.
35<p>
36<dt> <var>attribute</var> 
37<dd>
38[in scalar]
39The name of the attribute to be get/set.  Possible values are:
40<dl>
41<p>
42<dt> <strong>MATTR_CACHE</strong>
43<dd>
44Cachability.  Aside from the generic values listed below, the 
45following special values are defined:
46<dl>
47<p>
48<dt> <strong>MATTR_VAL_CACHE_FLUSH</strong>
49<dd>
50Flush from all caches
51<p>
52<dt> <strong>MATTR_VAL_DCACHE_FLUSH</strong>
53<dd>
54Flush from data caches
55<p>
56<dt> <strong>MATTR_VAL_ICACHE_FLUSH</strong>
57<dd>
58Flush from instruction caches
59</dl>
60<p>
61<dt> <strong>MATTR_MIGRATE</strong>
62<dd>
63Migratability.
64<p>
65<dt> <strong>MATTR_REPLICATE</strong>
66<dd>
67Replicability.
68</dl>
69<p>
70<dt> <var>value</var> 
71<dd>
72[pointer to in/out scalar]
73The new value for the attribute.  The old value 
74is also returned in this variable.  The new value can be a specific value 
75listed above, or one of the following generic values:
76<dl>
77<p>
78<dt> <strong>MATTR_VAL_OFF</strong>
79<dd>
80Turn attribute off.
81<p>
82<dt> <strong>MATTR_VAL_ON</strong>
83<dd>
84Turn attribute on.
85<p>
86<dt> <strong>MATTR_VAL_GET</strong>
87<dd>
88No change, just return current value.
89</dl>
90</dl>
91<h3>DESCRIPTION</h3>
92<p>
93The <strong>vm_machine_attribute</strong> function gets and sets special
94attributes of the 
95memory region implemented by the underlying <strong>pmap</strong> module.  These attributes 
96are properties such as cachability, migratability and replicability.
97The behavior of this function is machine dependent.
98<h3>NOTES</h3>
99<p>
100This interface is machine word length specific because of the virtual address
101parameter.
102<h3>RETURN VALUES</h3>
103<dl>
104<p>
105<dt> <strong>KERN_INVALID_ADDRESS</strong>
106<dd>
107The address is illegal or specifies a non-allocated region.
108</dl>
109<h3>RELATED INFORMATION</h3>
110<p>
111Functions:
112<a href="vm_wire.html"><strong>vm_wire</strong></a>.
113