#include "PosixSource.h"
#endif
-// Linux needs _GNU_SOURCE to get RTLD_DEFAULT from <dlfcn.h>.
+/* Linux needs _GNU_SOURCE to get RTLD_DEFAULT from <dlfcn.h> and
+ MREMAP_MAYMOVE from <sys/mman.h>.
+ */
#ifdef __linux__
#define _GNU_SOURCE
#endif
static int ocAllocateJumpIslands( ObjectCode* oc, int count, int first )
{
+#ifdef USE_MMAP
+ int pagesize, n, m;
+#endif
int aligned;
if( count > 0 )
{
-#ifdef USE_MMAP
- #error ocAllocateJumpIslands doesnt want USE_MMAP to be defined
-#endif
// round up to the nearest 4
aligned = (oc->fileSize + 3) & ~3;
+#ifdef USE_MMAP
+ #ifndef linux_HOST_OS /* mremap is a linux extension */
+ #error ocAllocateJumpIslands doesnt want USE_MMAP to be defined
+ #endif
+
+ pagesize = getpagesize();
+ n = ROUND_UP( oc->fileSize, pagesize );
+ m = ROUND_UP( aligned + sizeof (ppcJumpIsland) * count, pagesize );
+
+ /* The effect of this mremap() call is only the ensure that we have
+ * a sufficient number of virtually contiguous pages. As returned from
+ * mremap, the pages past the end of the file are not backed. We give
+ * them a backing by using MAP_FIXED to map in anonymous pages.
+ */
+ if( (oc->image = mremap( oc->image, n, m, MREMAP_MAYMOVE )) == MAP_FAILED )
+ {
+ errorBelch( "Unable to mremap for Jump Islands\n" );
+ return 0;
+ }
+
+ if( mmap( oc->image + n, m - n, PROT_READ | PROT_WRITE | PROT_EXEC,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, 0, 0 ) == MAP_FAILED )
+ {
+ errorBelch( "Unable to mmap( MAP_FIXED ) for Jump Islands\n" );
+ return 0;
+ }
+
+#else
oc->image = stgReallocBytes( oc->image,
- aligned + sizeof( ppcJumpIsland ) * count,
+ aligned + sizeof (ppcJumpIsland) * count,
"ocAllocateJumpIslands" );
- oc->jump_islands = (ppcJumpIsland *) (((char *) oc->image) + aligned);
- memset( oc->jump_islands, 0, sizeof( ppcJumpIsland ) * count );
+#endif /* USE_MMAP */
+
+ oc->jump_islands = (ppcJumpIsland *) (oc->image + aligned);
+ memset( oc->jump_islands, 0, sizeof (ppcJumpIsland) * count );
}
else
oc->jump_islands = NULL;