modpost: refactor get_secindex()

SPECIAL() is only used in get_secindex(). Squash it.

Make the code more readable with more comments.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index bd874f9..1178f40 100644 (file)
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -156,22 +156,28 @@ static inline int is_shndx_special(unsigned int i)
        return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE;
 }
 
-/*
- * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
- * the way to -256..-1, to avoid conflicting with real section
- * indices.
- */
-#define SPECIAL(i) ((i) - (SHN_HIRESERVE + 1))
-
 /* Accessor for sym->st_shndx, hides ugliness of "64k sections" */
 static inline unsigned int get_secindex(const struct elf_info *info,
                                        const Elf_Sym *sym)
 {
-       if (is_shndx_special(sym->st_shndx))
-               return SPECIAL(sym->st_shndx);
-       if (sym->st_shndx != SHN_XINDEX)
-               return sym->st_shndx;
-       return info->symtab_shndx_start[sym - info->symtab_start];
+       unsigned int index = sym->st_shndx;
+
+       /*
+        * Elf{32,64}_Sym::st_shndx is 2 byte. Big section numbers are available
+        * in the .symtab_shndx section.
+        */
+       if (index == SHN_XINDEX)
+               return info->symtab_shndx_start[sym - info->symtab_start];
+
+       /*
+        * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
+        * the way to UINT_MAX-255..UINT_MAX, to avoid conflicting with real
+        * section indices.
+        */
+       if (index >= SHN_LORESERVE && index <= SHN_HIRESERVE)
+               return index - SHN_HIRESERVE - 1;
+
+       return index;
 }
 
 /* file2alias.c */