# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1709421365 -3600
# Node ID d0929d9fcca9e4341eeb284b3d03e00c0aae13f1
# Parent  e96c7cbee506769de204b23a97b72a70c6940b68
Introduced cache synchronisation for mapped regions. Without this, executable
code may not be read properly on real hardware after a page fault, resulting in
erroneous instruction execution and seemingly nonsensical instruction results.

diff -r e96c7cbee506 -r d0929d9fcca9 libmem/lib/src/ipc.cc
--- a/libmem/lib/src/ipc.cc	Sun Mar 03 00:12:41 2024 +0100
+++ b/libmem/lib/src/ipc.cc	Sun Mar 03 00:16:05 2024 +0100
@@ -1,7 +1,7 @@
 /*
  * Interprocess communication utilities.
  *
- * Copyright (C) 2021, 2022 Paul Boddie <paul@boddie.org.uk>
+ * Copyright (C) 2021, 2022, 2024 Paul Boddie <paul@boddie.org.uk>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
@@ -21,6 +21,7 @@
 
 #include <l4/re/c/dataspace.h>
 #include <l4/re/consts.h>
+#include <l4/sys/cache.h>
 #include <l4/sys/task.h>
 
 #include <mem/send_flexpage.h>
@@ -55,6 +56,12 @@
     if (!send_flexpage.order)
         return -L4_ERANGE;
 
+    /* Make sure that the instruction cache is updated if the content is going
+       to be executed. */
+
+    l4_cache_coherent(send_flexpage.base_addr,
+                      send_flexpage.base_addr + (1UL << send_flexpage.order));
+
     region->fpage = ipc_get_fpage(&send_flexpage);
     region->snd_base = hot_spot;