linux-user: ARM-FDPIC: Identify ARM FDPIC binaries

Define an ARM-specific version of elf_is_fdpic:
FDPIC ELF objects are identified with e_ident[EI_OSABI] ==
ELFOSABI_ARM_FDPIC.
Co-Authored-By: NMickaël Guêné <mickael.guene@st.com>
Signed-off-by: NChristophe Lyon <christophe.lyon@st.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Message-Id: <20180430080404.7323-3-christophe.lyon@st.com>
Signed-off-by: NLaurent Vivier <laurent@vivier.eu>

include/elf.h

@@ -1483,6 +1483,7 @@ typedef struct elf64_shdr {
 #define ELFOSABI_TRU64          10      /* Compaq TRU64 UNIX.  */
 #define ELFOSABI_MODESTO        11      /* Novell Modesto.  */
 #define ELFOSABI_OPENBSD        12      /* OpenBSD.  */
+#define ELFOSABI_ARM_FDPIC      65      /* ARM FDPIC */
 #define ELFOSABI_ARM            97      /* ARM */
 #define ELFOSABI_STANDALONE     255     /* Standalone (embedded) application */
 

linux-user/elfload.c

@@ -1681,11 +1681,18 @@ static void zero_bss(abi_ulong elf_bss, abi_ulong last_bss, int prot)
     }
 }
 
+#ifdef TARGET_ARM
+static int elf_is_fdpic(struct elfhdr *exec)
+{
+    return exec->e_ident[EI_OSABI] == ELFOSABI_ARM_FDPIC;
+}
+#else
 /* Default implementation, always false.  */
 static int elf_is_fdpic(struct elfhdr *exec)
 {
     return 0;
 }
+#endif
 
 static abi_ulong loader_build_fdpic_loadmap(struct image_info *info, abi_ulong sp)
 {