Instead of elf_load_bsdsyms() cooking its own variant, let's just make
the generic thing cope with different bitness (paralleling elf_uval()
and alike).

--- a/xen/common/libelf/libelf-loader.c
+++ b/xen/common/libelf/libelf-loader.c
@@ -273,14 +273,6 @@ static void elf_load_bsdsyms(struct elf_
     if ( !elf->bsd_symtab_pstart )
         return;
 
-#define elf_store_field_bitness(_elf, _hdr, _elm, _val)             \
-do {                                                                \
-    if ( elf_64bit(_elf) )                                          \
-        elf_store_field(_elf, _hdr, e64._elm, _val);                \
-    else                                                            \
-        elf_store_field(_elf, _hdr, e32._elm, _val);                \
-} while ( 0 )
-
 #define SYMTAB_INDEX    1
 #define STRTAB_INDEX    2
 
@@ -308,16 +300,16 @@ do {
                     elf_uval(elf, elf->ehdr, e_ehsize));
 
     /* Set the offset to the shdr array. */
-    elf_store_field_bitness(elf, header_handle, e_shoff,
-                            offsetof(typeof(header.elf_header), section));
+    elf_store_field(elf, header_handle, e_shoff,
+                    offsetof(typeof(header.elf_header), section));
 
     /* Set the right number of section headers. */
-    elf_store_field_bitness(elf, header_handle, e_shnum, ELF_BSDSYM_SECTIONS);
+    elf_store_field(elf, header_handle, e_shnum, ELF_BSDSYM_SECTIONS);
 
     /* Clear a couple of fields we don't use. */
-    elf_store_field_bitness(elf, header_handle, e_phoff, 0);
-    elf_store_field_bitness(elf, header_handle, e_phentsize, 0);
-    elf_store_field_bitness(elf, header_handle, e_phnum, 0);
+    elf_store_field(elf, header_handle, e_phoff, 0);
+    elf_store_field(elf, header_handle, e_phentsize, 0);
+    elf_store_field(elf, header_handle, e_phnum, 0);
 
     /* Zero the undefined section. */
     section_handle = ELF_MAKE_HANDLE(elf_shdr,
@@ -354,10 +346,9 @@ do {
     }
 
     /* Adjust the sh_offset and sh_link of the copied section header. */
-    elf_store_field_bitness(elf, section_handle, sh_offset,
-                            symtab_base - elf_header_base);
-    elf_store_field_bitness(elf, section_handle, sh_link,
-                            STRTAB_INDEX);
+    elf_store_field(elf, section_handle, sh_offset,
+                    symtab_base - elf_header_base);
+    elf_store_field(elf, section_handle, sh_link, STRTAB_INDEX);
 
     /* Calculate the guest address where strtab is loaded. */
     strtab_base = elf_round_up(elf, symtab_base +
@@ -387,8 +378,8 @@ do {
         return;
     }
 
-    elf_store_field_bitness(elf, section_handle, sh_offset,
-                            strtab_base - elf_header_base);
+    elf_store_field(elf, section_handle, sh_offset,
+                    strtab_base - elf_header_base);
 
     /* Store the whole size (including headers and loaded sections). */
     header.size = strtab_base + elf_uval(elf, section_handle, sh_size) -
@@ -409,7 +400,6 @@ do {
 
 #undef SYMTAB_INDEX
 #undef STRTAB_INDEX
-#undef elf_store_field_bitness
 }
 
 void elf_parse_binary(struct elf_binary *elf)
--- a/xen/include/xen/libelf.h
+++ b/xen/include/xen/libelf.h
@@ -303,9 +303,13 @@ bool elf_access_ok(struct elf_binary * e
   /* Stores a value at a particular PTRVAL. */
 
 #define elf_store_field(elf, hdr, elm, val)                             \
-    (elf_store_val((elf), ELF__HANDLE_FIELD_TYPE(hdr, elm),                   \
-                   ELF_HANDLE_PTRVAL(hdr) + ELF__HANDLE_FIELD_OFFSET(hdr, elm), \
-                   (val)))
+    ((ELFCLASS64 == (elf)->class)                                       \
+     ? elf_store_val(elf, ELF__HANDLE_FIELD_TYPE(hdr, e64.elm),         \
+                     ELF_HANDLE_PTRVAL(hdr) +                           \
+                     ELF__HANDLE_FIELD_OFFSET(hdr, e64.elm), val)       \
+     : elf_store_val(elf, ELF__HANDLE_FIELD_TYPE(hdr, e32.elm),         \
+                     ELF_HANDLE_PTRVAL(hdr) +                           \
+                     ELF__HANDLE_FIELD_OFFSET(hdr, e32.elm), val))
   /* Stores a 32/64-bit field.  hdr is a HANDLE and elm is the field name. */