xref: /xnu-10002.41.9/osfmk/man/memory_object_data_error.html (revision 699cd48037512bf4380799317ca44ca453c82f57)
1*699cd480SApple OSS Distributions<h2>memory_object_data_error</h2>
2*699cd480SApple OSS Distributions<hr>
3*699cd480SApple OSS Distributions<p>
4*699cd480SApple OSS Distributions<strong>Function</strong> - An error prevents the supply of previously requested data.
5*699cd480SApple OSS Distributions<h3>SYNOPSIS</h3>
6*699cd480SApple OSS Distributions<pre>
7*699cd480SApple OSS Distributions<strong>kern_return_t   memory_object_data_error</strong>
8*699cd480SApple OSS Distributions                <strong>(memory_object_control_t</strong>         <var>memory_control</var>,
9*699cd480SApple OSS Distributions                 <strong>vm_offset_t</strong>                             <var>offset</var>,
10*699cd480SApple OSS Distributions                 <strong>vm_size_t</strong>                                 <var>size</var>,
11*699cd480SApple OSS Distributions                 <strong>kern_return_t</strong>                           <var>reason</var><strong>);</strong>
12*699cd480SApple OSS Distributions</pre>
13*699cd480SApple OSS Distributions<h3>PARAMETERS</h3>
14*699cd480SApple OSS Distributions<dl>
15*699cd480SApple OSS Distributions<p>
16*699cd480SApple OSS Distributions<dt> <var>memory_control</var>
17*699cd480SApple OSS Distributions<dd>
18*699cd480SApple OSS Distributions[in memory-cache-control send right]
19*699cd480SApple OSS DistributionsThe memory cache control port
20*699cd480SApple OSS Distributionsto be used by the memory manager for cache management requests.
21*699cd480SApple OSS DistributionsThis port is provided by the kernel in a <strong>memory_object_create</strong> call.
22*699cd480SApple OSS Distributions<p>
23*699cd480SApple OSS Distributions<dt> <var>offset</var>
24*699cd480SApple OSS Distributions<dd>
25*699cd480SApple OSS Distributions[in scalar]
26*699cd480SApple OSS DistributionsThe offset within the memory object, in bytes.
27*699cd480SApple OSS Distributions<p>
28*699cd480SApple OSS Distributions<dt> <var>size</var>
29*699cd480SApple OSS Distributions<dd>
30*699cd480SApple OSS Distributions[in scalar]
31*699cd480SApple OSS DistributionsThe number of bytes of data (starting at <var>offset</var>).  The number
32*699cd480SApple OSS Distributionsmust convert to an integral number of memory object pages.
33*699cd480SApple OSS Distributions<p>
34*699cd480SApple OSS Distributions<dt> <var>reason</var>
35*699cd480SApple OSS Distributions<dd>
36*699cd480SApple OSS Distributions[in scalar]
37*699cd480SApple OSS DistributionsReason for the error.
38*699cd480SApple OSS Distributions</dl>
39*699cd480SApple OSS Distributions<h3>DESCRIPTION</h3>
40*699cd480SApple OSS Distributions<p>
41*699cd480SApple OSS DistributionsThe <strong>memory_object_data_error</strong> function indicates that
42*699cd480SApple OSS Distributionsthe memory manager
43*699cd480SApple OSS Distributionscannot provide the kernel with the data requested for the given region,
44*699cd480SApple OSS Distributionsspecifying a reason for the error.
45*699cd480SApple OSS Distributions<p>
46*699cd480SApple OSS DistributionsWhen the kernel issues a <strong>memory_object_data_request</strong> call, the memory
47*699cd480SApple OSS Distributionsmanager can respond with a <strong>memory_object_data_error</strong>
48*699cd480SApple OSS Distributionscall to indicate that the
49*699cd480SApple OSS Distributionspage cannot be retrieved, and that a memory failure exception should be raised
50*699cd480SApple OSS Distributionsin any client threads that are waiting for the page.  Clients
51*699cd480SApple OSS Distributionsare permitted to catch
52*699cd480SApple OSS Distributionsthese exceptions and retry their page faults.  As a result, this
53*699cd480SApple OSS Distributionscall can be used to
54*699cd480SApple OSS Distributionsreport transient errors as well as permanent ones.  A memory manager can use
55*699cd480SApple OSS Distributionsthis call for both hardware errors (for example, disk failures) and software
56*699cd480SApple OSS Distributionserrors (for example, accessing data that does not exist or is protected).
57*699cd480SApple OSS Distributions<h3>NOTES</h3>
58*699cd480SApple OSS Distributions<p>
59*699cd480SApple OSS DistributionsIf reason has a system code of <var>err_kern</var>, the kernel will substitute
60*699cd480SApple OSS Distributionsan error value
61*699cd480SApple OSS Distributionsof <strong>KERN_MEMORY_ERROR</strong>.
62*699cd480SApple OSS Distributions<h3>RETURN VALUES</h3>
63*699cd480SApple OSS Distributions<p>
64*699cd480SApple OSS DistributionsOnly generic errors apply.
65*699cd480SApple OSS Distributions<h3>RELATED INFORMATION</h3>
66*699cd480SApple OSS Distributions<p>
67*699cd480SApple OSS DistributionsFunctions:
68*699cd480SApple OSS Distributions<a href="memory_object_data_request.html"><strong>memory_object_data_request</strong></a>,
69*699cd480SApple OSS Distributions<a href="memory_object_data_supply.html"><strong>memory_object_data_supply</strong></a>,
70*699cd480SApple OSS Distributions<a href="MO_data_unavailable.html"><strong>memory_object_data_unavailable</strong></a>.
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