PR 9824

        * ld.texinfo (Output Section Constraint): New node.  Documents the
        ONLY_IF_RO and ONLY_IF_RW constraints.
        (Symbolic Constants): New node.  Documents the CONSTANT operator.

1 files changed, 48 insertions, 2 deletions

diff --git a/ld/ld.texinfo b/ld/ld.texinfo
index ca460b3..5a88242 100644
--- a/ld/ld.texinfo
+++ b/ld/ld.texinfo
@@ -3556,7 +3556,10 @@ The full description of an output section looks like this:
 @smallexample
 @group
 @var{section} [@var{address}] [(@var{type})] :
-  [AT(@var{lma})] [ALIGN(@var{section_align})] [SUBALIGN(@var{subsection_align})]
+  [AT(@var{lma})]
+  [ALIGN(@var{section_align})]
+  [SUBALIGN(@var{subsection_align})]
+  [@var{constraint}]
   @{
     @var{output-section-command}
     @var{output-section-command}
@@ -4158,10 +4161,14 @@ section named @samp{/DISCARD/} are not included in the output file.
 @cindex output section attributes
 We showed above that the full description of an output section looked
 like this:
+
 @smallexample
 @group
 @var{section} [@var{address}] [(@var{type})] :
-  [AT(@var{lma})] [ALIGN(@var{section_align})] [SUBALIGN(@var{subsection_align})]
+  [AT(@var{lma})]
+  [ALIGN(@var{section_align})]
+  [SUBALIGN(@var{subsection_align})]
+  [@var{constraint}]
   @{
     @var{output-section-command}
     @var{output-section-command}
@@ -4169,6 +4176,7 @@ like this:
   @} [>@var{region}] [AT>@var{lma_region}] [:@var{phdr} :@var{phdr} @dots{}] [=@var{fillexp}]
 @end group
 @end smallexample
+
 We've already described @var{section}, @var{address}, and
 @var{output-section-command}.  In this section we will describe the
 remaining section attributes.
@@ -4178,6 +4186,7 @@ remaining section attributes.
 * Output Section LMA::		Output section LMA
 * Forced Output Alignment::	Forced Output Alignment
 * Forced Input Alignment::	Forced Input Alignment
+* Output Section Constraint::   Output section constraint
 * Output Section Region::	Output section region
 * Output Section Phdr::		Output section phdr
 * Output Section Fill::		Output section fill
@@ -4311,6 +4320,16 @@ You can force input section alignment within an output section by using
 SUBALIGN.  The value specified overrides any alignment given by input
 sections, whether larger or smaller.
 
+@node Output Section Constraint
+@subsubsection Output Section Constraint
+@kindex ONLY_IF_RO
+@kindex ONLY_IF_RW
+@cindex constraints on output sections
+You can specify that an output section should only be created if all
+of its input sections are read-only or all of its input sections are
+read-write by using the keyword @code{ONLY_IF_RO} and
+@code{ONLY_IF_RW} respectively.
+
 @node Output Section Region
 @subsubsection Output Section Region
 @kindex >@var{region}
@@ -4970,6 +4989,7 @@ expressions.
 
 @menu
 * Constants::			Constants
+* Symbolic Constants::          Symbolic constants
 * Symbols::			Symbol Names
 * Orphan Sections::		Orphan Sections
 * Location Counter::		The Location Counter
@@ -5022,6 +5042,32 @@ _fourk_4 = 10000o;
 Note - the @code{K} and @code{M} suffixes cannot be used in
 conjunction with the base suffixes mentioned above.
 
+@node Symbolic Constants
+@subsection Symbolic Constants
+@cindex symbolic constants
+@kindex CONSTANT
+It is possible to refer to target specific constants via the use of
+the @code{CONSTANT(@var{name})} operator, where @var{name} is one of:
+
+@table @code
+@item MAXPAGESIZE
+@kindex MAXPAGESIZE
+The target's maximum page size.
+
+@item COMMONPAGESIZE
+@kindex COMMONPAGESIZE
+The target's default page size.
+@end table
+
+So for example:
+
+@smallexample
+  .text ALIGN (CONSTANT (MAXPAGESIZE)) : @{ *(.text) @} 
+@end smallexample
+
+will create a text section aligned to the largest page boundary
+supported by the target.
+
 @node Symbols
 @subsection Symbol Names
 @cindex symbol names