1 files changed, 30 insertions, 1 deletions

diff --git a/rts/linker/SymbolExtras.c b/rts/linker/SymbolExtras.c
index 04a678898f..b7b558cb41 100644
--- a/rts/linker/SymbolExtras.c
+++ b/rts/linker/SymbolExtras.c
@@ -57,6 +57,8 @@ int ocAllocateExtras(ObjectCode* oc, int count, int first, int bssSize)
 
   if (count > 0 || bssSize > 0) {
     if (!RTS_LINKER_USE_MMAP) {
+      /* N.B. We currently can't mark symbol extras as non-executable in this
+       * case. */
 
       // round up to the nearest 4
       int aligned = (oc->fileSize + 3) & ~3;
@@ -72,6 +74,8 @@ int ocAllocateExtras(ObjectCode* oc, int count, int first, int bssSize)
       oc->symbol_extras = (SymbolExtra *) (oc->image + aligned);
     } else if (USE_CONTIGUOUS_MMAP || RtsFlags.MiscFlags.linkerAlwaysPic) {
       /* Keep image, bssExtras and symbol_extras contiguous */
+      /* N.B. We currently can't mark symbol extras as non-executable in this
+       * case. */
       size_t n = roundUpToPage(oc->fileSize);
       bssSize = roundUpToAlign(bssSize, 8);
       size_t allocated_size = n + bssSize + extras_size;
@@ -93,7 +97,9 @@ int ocAllocateExtras(ObjectCode* oc, int count, int first, int bssSize)
           return 0;
       }
     } else {
-        oc->symbol_extras = m32_alloc(oc->m32, extras_size, 8);
+        /* m32_allocator_flush ensures that these are marked as executable when
+         * we finish building them. */
+        oc->symbol_extras = m32_alloc(oc->rx_m32, extras_size, 8);
         if (oc->symbol_extras == NULL) return 0;
     }
   }
@@ -120,6 +126,29 @@ int ocAllocateExtras(ObjectCode* oc, int count, int first, int bssSize)
   return 1;
 }
 
+/**
+ * Mark the symbol extras as non-writable.
+ */
+void ocProtectExtras(ObjectCode* oc)
+{
+  if (oc->n_symbol_extras == 0) return;
+
+  if (!RTS_LINKER_USE_MMAP) {
+    /*
+     * In this case the symbol extras were allocated via malloc. All we can do
+     * in this case is hope that the platform doesn't mark such allocations as
+     * non-executable.
+     */
+  } else if (USE_CONTIGUOUS_MMAP || RtsFlags.MiscFlags.linkerAlwaysPic) {
+    mmapForLinkerMarkExecutable(oc->symbol_extras, sizeof(SymbolExtra) * oc->n_symbol_extras);
+  } else {
+    /*
+     * The symbol extras were allocated via m32. They will be protected when
+     * the m32 allocator is finalized
+     */
+  }
+}
+
 
 #if !defined(arm_HOST_ARCH)
 SymbolExtra* makeSymbolExtra( ObjectCode const* oc,