loader: Allow ELF loader to auto-detect the ELF arch

If the caller didn't specify an architecture for the ELF machine
the load_elf() function will auto detect it based on the ELF file.

Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: f2d70b47fcad31445f947f8817a0e146d80a046b.1474331683.git.alistair.francis@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/include/hw/elf_ops.h b/include/hw/elf_ops.h
index f510e7e..5038c7f 100644
--- a/include/hw/elf_ops.h
+++ b/include/hw/elf_ops.h
@@ -280,6 +280,11 @@
         glue(bswap_ehdr, SZ)(&ehdr);
     }
 
+    if (elf_machine <= EM_NONE) {
+        /* The caller didn't specify an ARCH, we can figure it out */
+        elf_machine = ehdr.e_machine;
+    }
+
     switch (elf_machine) {
         case EM_PPC64:
             if (ehdr.e_machine != EM_PPC64) {