[linker] Fix out of range relocations.

mmap may return address all over the place. mmap_next will ensure we get
the next free page after the requested address.

This is especially important for linking on aarch64, where the memory model with PIC
admits relocations in the +-4GB range, and as such we can't work with
arbitrary object locations in memory.

Of note: we map the rts into process space, so any mapped objects must
not be ouside of the 4GB from the processes address space.

1 files changed, 2 insertions, 1 deletions

diff --git a/rts/LinkerInternals.h b/rts/LinkerInternals.h
index cf0cd35167..1f63f0c485 100644
--- a/rts/LinkerInternals.h
+++ b/rts/LinkerInternals.h
@@ -14,6 +14,7 @@
 
 #if RTS_LINKER_USE_MMAP
 #include <sys/mman.h>
+void* mmap_next(void *addr, size_t length, int prot, int flags, int fd, off_t offset);
 #endif
 
 void printLoadedObjects(void);
@@ -293,7 +294,7 @@ void exitLinker( void );
 void freeObjectCode (ObjectCode *oc);
 SymbolAddr* loadSymbol(SymbolName *lbl, RtsSymbolInfo *pinfo);
 
-void *mmapForLinker (size_t bytes, uint32_t flags, int fd, int offset);
+void *mmapForLinker (size_t bytes, uint32_t prot, uint32_t flags, int fd, int offset);
 void mmapForLinkerMarkExecutable (void *start, size_t len);
 
 void addProddableBlock ( ObjectCode* oc, void* start, int size );