xref: /illumos-gate/usr/src/common/mapfiles/common/map.filter (revision cd3e9333)

#
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#
# A default mapfile for optimizing the creation of a filter shared object.
# Creates a single, read-only, executable text segment to catch all loadable
# sections.
#
# Filters that consist solely of a symbol table can be built directly from
# ld(1) so that no .init/.fini sections are created.  Although the filter can
# be constructed as a single read-only segment, the execute attribute of the
# segment is maintained to allow for simple .init processing (i.e., .init
# processing that requires no relocations), and to accommodate older versions
# of dbx that produce warning messages if they find objects without traditional
# text segments.
#
# If a filter is required to execute .init code that references global data
# then the filter will require relocation (i.e., it will have to be written to
# by ld.so.1).  Filters of this sort should *not* use this mapfile.
#
# This compaction of a filter into a single segment allows ld.so.1 to optimize
# its processing of a filter.  If the filter is small enough this segment may
# be handled in a single page mapping (for example libdl.so.1).
#
# The assignment of all allocatable sections to this segment insures that the
# .dynamic, and any .data or .bss sections, become part of the text.  Note that
# the compiler has a habit of generating empty .data and .bss sections.
#
# Override the default alignment so that this single paged object can be mapped
# more flexibly.

$mapfile_version 2

LOAD_SEGMENT filter {
	FLAGS = READ EXECUTE;
	ALIGN = 0x1000;
	ASSIGN_SECTION {
		FLAGS = ALLOC;
	};
};