xref: /freebsd/share/man/man9/pmap_enter.9 (revision f39bffc62c1395bde25d152c7f68fdf7cbaab414)
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27.\" $FreeBSD$
28.\"
29.Dd February 16, 2018
30.Dt PMAP_ENTER 9
31.Os
32.Sh NAME
33.Nm pmap_enter
34.Nd insert a virtual page into a physical map
35.Sh SYNOPSIS
36.In sys/param.h
37.In vm/vm.h
38.In vm/pmap.h
39.Ft int
40.Fo pmap_enter
41.Fa "pmap_t pmap" "vm_offset_t va" "vm_page_t m" "vm_prot_t prot"
42.Fa "u_int flags" "int8_t psind"
43.Fc
44.Sh DESCRIPTION
45The
46.Fn pmap_enter
47function creates a mapping in the physical map
48.Fa pmap
49from the virtual address
50.Fa va
51to the physical page
52.Fa m
53with the protection
54.Fa prot .
55Any previous mapping at the virtual address
56.Fa va
57is destroyed.
58.Pp
59The
60.Fa flags
61argument may have the following values:
62.Bl -tag -width ".Dv PMAP_ENTER_NOSLEEP"
63.It Dv VM_PROT_READ
64A read access to the given virtual address triggered the call.
65.It Dv VM_PROT_WRITE
66A write access to the given virtual address triggered the call.
67.It Dv VM_PROT_EXECUTE
68An execute access to the given virtual address triggered the call.
69.It Dv PMAP_ENTER_WIRED
70The mapping should be marked as wired.
71.It Dv PMAP_ENTER_NOSLEEP
72This function may not sleep during creation of the mapping.
73If the mapping cannot be created without sleeping, an appropriate
74Mach VM error is returned.
75.El
76If the
77.Dv PMAP_ENTER_NOSLEEP
78flag is not specified, this function must create the requested mapping
79before returning.
80It may not fail.
81In order to create the requested mapping, this function may destroy
82any non-wired mapping in any pmap.
83.Pp
84The
85.Fa psind
86parameter specifies the page size that should be used by the mapping.
87The supported page sizes are described by the global array
88.Dv pagesizes[] .
89The desired page size is specified by passing the index of the array
90element that equals the desired page size.
91.Pp
92When the
93.Fn pmap_enter
94function destroys or updates a managed mapping, including an existing
95mapping at virtual address
96.Fa va ,
97it updates the
98.Ft vm_page
99structure corresponding to the previously mapped physical page.
100If the physical page was accessed through the managed mapping,
101then the
102.Ft vm_page
103structure's
104.Dv PGA_REFERENCED
105aflag is set.
106If the physical page was modified through the managed mapping, then the
107.Fn vm_page_dirty
108function is called on the
109.Ft vm_page
110structure.
111.Pp
112The
113.Dv PGA_WRITEABLE
114aflag must be set for the page
115.Fa m
116if the new mapping is managed and writeable.
117It is advised to clear
118.Dv PGA_WRITEABLE
119for destroyed mappings if the implementation can ensure
120that no other writeable managed mappings for the previously
121mapped pages exist.
122.Pp
123If the page
124.Fa m
125is managed, the page must be busied by the caller
126or the owning object must be locked.
127In the later case, the
128.Dv PMAP_ENTER_NOSLEEP
129must be specified by the caller.
130.Pp
131The
132.Fn pmap_enter
133function must handle the multiprocessor TLB consistency for the
134given address.
135.Sh NOTES
136On arm and i386 architectures the existing implementation
137of the
138.Nm
139function is incomplete, only value 0 for
140.Fa psind
141is supported.
142Other supported architectures, except amd64, have
143.Dv pagesizes[]
144array of size 1.
145.Sh RETURN VALUES
146If successful, the
147.Fn pmap_enter
148function returns
149.Er KERN_SUCCESS .
150If the
151.Dv PMAP_ENTER_NOSLEEP
152flag was specified and the resources required for the mapping cannot
153be acquired without sleeping,
154.Dv KERN_RESOURCE_SHORTAGE
155is returned.
156.Sh SEE ALSO
157.Xr pmap 9
158.Sh AUTHORS
159This manual page was first written by
160.An Bruce M Simpson Aq Mt bms@spc.org
161and then rewritten by
162.An Alan Cox Aq Mt alc@FreeBSD.org
163and
164.An Konstantin Belousov Aq Mt kib@FreeBSD.org .
165