xref: /freebsd/share/man/man9/vm_map_protect.9 (revision cd0d51baaa4509a1db83251a601d34404d20c990)
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26.\" $FreeBSD$
27.\"
28.Dd June 20, 2019
29.Dt VM_MAP_PROTECT 9
30.Os
31.Sh NAME
32.Nm vm_map_protect
33.Nd apply protection bits to a virtual memory region
34.Sh SYNOPSIS
35.In sys/param.h
36.In vm/vm.h
37.In vm/vm_map.h
38.Ft int
39.Fo vm_map_protect
40.Fa "vm_map_t map" "vm_offset_t start" "vm_offset_t end" "vm_prot_t new_prot"
41.Fa "boolean_t set_max"
42.Fc
43.Sh DESCRIPTION
44The
45.Fn vm_map_protect
46function sets the protection bits of the address region bounded by
47.Fa start
48and
49.Fa end
50within the map
51.Fa map
52to
53.Fa new_prot .
54The value specified by
55.Fa new_prot
56may not include any protection bits that are not set in
57.Va max_protection
58on every entry within the range.
59.Pp
60If
61.Fa set_max
62is TRUE,
63.Fa new_prot
64is treated as the new
65.Va max_protection
66setting for each underlying entry.
67Protection bits not included
68.Fa new_prot
69will be cleared from existing entries.
70If
71.Fa set_max
72is FALSE only the
73.Va protection
74field is affected.
75.Pp
76The range MUST be contiguous, and MUST NOT contain sub-maps.
77.Sh IMPLEMENTATION NOTES
78The function acquires a lock on the
79.Fa map
80for the duration, by calling
81.Xr vm_map_lock 9 .
82.Sh RETURN VALUES
83The
84.Fn vm_map_protect
85function returns
86.Dv KERN_SUCCESS
87if the protection bits could be set successfully.
88.Pp
89If a sub-map entry was encountered in the range,
90.Dv KERN_INVALID_ARGUMENT
91is returned.
92If the value of
93.Fa new_prot
94would exceed
95.Va max_protection
96for an entry within the range,
97.Dv KERN_PROTECTION_FAILURE
98is returned.
99If a copy-on-write mapping is transitioned from read-only to
100read-write, and too little swap space is available for backing the
101copied pages,
102.Dv KERN_RESOURCE_SHORTAGE
103is returned.
104.Sh SEE ALSO
105.Xr vm_map 9
106.Sh AUTHORS
107This manual page was written by
108.An Bruce M Simpson Aq Mt bms@spc.org .
109