[gcc r13-5307] modula-2: Fix stack size request in initPreemptive [PR108405]

[Iain D Sandoe <iains@gcc.gnu.org>]

https://gcc.gnu.org/g:bcc023e2b4dd0dc1fd1fca3ea12664d5bdade4dc

commit r13-5307-gbcc023e2b4dd0dc1fd1fca3ea12664d5bdade4dc
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Sat Jan 14 10:20:47 2023 +0000

    modula-2: Fix stack size request in initPreemptive [PR108405]
    
    As noted in the PR, the problem is that we make a request for additional
    stack that violates the constraints on some systems.
    
    This patch chooses a value that is divisible by common OS page sizes.
    
    TODO: the user value should be checked and then an exception thrown if it
    is not suitable.
    
    Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
    
            PR modula2/108405
    
    gcc/m2/ChangeLog:
    
            * gm2-libs-iso/Preemptive.mod (initPreemptive): Use a value for
            extra space that is divisible by common OS pagesizes.

Diff:
---
 gcc/m2/gm2-libs-iso/Preemptive.mod | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/gcc/m2/gm2-libs-iso/Preemptive.mod b/gcc/m2/gm2-libs-iso/Preemptive.mod
index 53952e1c1cb..44aa62ba48a 100644
--- a/gcc/m2/gm2-libs-iso/Preemptive.mod
+++ b/gcc/m2/gm2-libs-iso/Preemptive.mod
@@ -33,6 +33,9 @@ FROM libc IMPORT printf ;
 
 CONST
    debugging = FALSE ;
+   (* The space we request becomes part of a stack request, which generally
+      has constraints on size and alignment.  *)
+   extraWorkSpace = 10 * 1024 * 1024 ;
 
 (*
    timer - the timer process which runs at maximum scheduling priority with
@@ -107,7 +110,7 @@ BEGIN
    IF NOT init
    THEN
       init := TRUE ;
-      Create (timer, 10000000, MAX (Urgency), NIL, timerId) ;
+      Create (timer, extraWorkSpace, MAX (Urgency), NIL, timerId) ;
       Activate (timerId)
    END
 END initPreemptive ;