rtld: Add FDPIC code for arm

	Add FDPIC dynamic relocations support, similar to what other FDPIC
	targets do.

	Lazy binding is implemented in a folllow-up patch.

	Disable the SEND* macros because they involve relocations to
	access constant strings that are unsupported by the existing
	arm version.

	Define DL_START, START, ARCH_NEEDS_BOOTSTRAP_RELOCS,
	DL_CHECK_LIB_TYPE similarly to what other FDPIC targets do.

	Define raise() because _dl_find_hash references __aeabi_uidivmod,
	which uses __aeabi_idiv0 which in turn references raise.

	* include/elf.h (R_ARM_FUNCDESC): Define.
	(R_ARM_FUNCDESC_VALUE): Define.
	* ldso/include/dl-string.h (SEND_STDERR, SEND_ADDRESS_STDERR)
	(SEND_NUMBER_STDERR): Define empty for __FDPIC__.
	* ldso/ldso/arm/dl-inlines.h: New file.
	* ldso/ldso/arm/dl-startup.h (PERFORM_BOOTSTRAP_RELOC): Fix type
	of load_addr. Fix handling of R_ARM_RELATIVE, add support for
	R_ARM_FUNCDESC_VALUE.
	(DL_START, START): Define for __FDPIC__.
	(raise): Define.
	* ldso/ldso/arm/dl-sysdep.h (ARCH_NEEDS_BOOTSTRAP_RELOCS): Define.
	(DL_CHECK_LIB_TYPE): Define.
	(elf_machine_type_class): Take into account FDPIC related
	relocations.
	(elf_machine_load_address): Support __FDPIC__.
	(elf_machine_relative): Likewise.
	* ldso/ldso/arm/elfinterp.c (_dl_linux_resolver): Dummy support
	for __FDPIC__, implemented in a later patch.
	(_dl_do_reloc): Fix reloc_adr computation for __FDPIC__, fix
	handling of local symbols. Fix handling of R_ARM_RELATIVE, add
	support for R_ARM_FUNCDESC_VALUE, R_ARM_FUNCDESC.
	* ldso/ldso/arm/resolve.S: Make _dl_linux_resolve hidden.
	* ldso/ldso/fdpic/dl-inlines.h (htab_delete): Declare.
	* libc/sysdeps/linux/arm/bits/elf-fdpic.h: New file, similar to bfin's.
	* libc/sysdeps/linux/arm/crtreloc.c: Likewise.
	* libc/sysdeps/linux/arm/find_exidx.c (__dl_addr_in_loadaddr) Define.
	(find_exidx_callback): Support __FDPIC__.

Signed-off-by: Mickaël Guêné <mickael.guene@st.com>
Signed-off-by: Christophe Lyon <christophe.lyon@st.com>

1 files changed, 45 insertions, 2 deletions

diff --git a/ldso/ldso/arm/dl-startup.h b/ldso/ldso/arm/dl-startup.h
index 371dc2293..ea1e9f6f9 100644
--- a/ldso/ldso/arm/dl-startup.h
+++ b/ldso/ldso/arm/dl-startup.h
@@ -131,7 +131,7 @@ __asm__(
 /* Handle relocation of the symbols in the dynamic loader. */
 static __always_inline
 void PERFORM_BOOTSTRAP_RELOC(ELF_RELOC *rpnt, unsigned long *reloc_addr,
-	unsigned long symbol_addr, unsigned long load_addr, Elf32_Sym *symtab)
+	unsigned long symbol_addr, DL_LOADADDR_TYPE load_addr, Elf32_Sym *symtab)
 {
 	switch (ELF_R_TYPE(rpnt->r_info)) {
 		case R_ARM_NONE:
@@ -176,12 +176,55 @@ void PERFORM_BOOTSTRAP_RELOC(ELF_RELOC *rpnt, unsigned long *reloc_addr,
 			*reloc_addr = symbol_addr;
 			break;
 		case R_ARM_RELATIVE:
-			*reloc_addr += load_addr;
+			*reloc_addr = DL_RELOC_ADDR(load_addr, *reloc_addr);
 			break;
 		case R_ARM_COPY:
 			break;
+#ifdef __FDPIC__
+		case R_ARM_FUNCDESC_VALUE:
+			{
+				struct funcdesc_value *dst = (struct funcdesc_value *) reloc_addr;
+
+				dst->entry_point += symbol_addr;
+				dst->got_value = load_addr.got_value;
+			}
+			break;
+#endif
 		default:
 			SEND_STDERR("Unsupported relocation type\n");
 			_dl_exit(1);
 	}
 }
+
+#ifdef __FDPIC__
+#undef DL_START
+#define DL_START(X)   \
+static void  __attribute__ ((used)) \
+_dl_start (Elf32_Addr dl_boot_got_pointer, \
+          struct elf32_fdpic_loadmap *dl_boot_progmap, \
+          struct elf32_fdpic_loadmap *dl_boot_ldsomap, \
+          Elf32_Dyn *dl_boot_ldso_dyn_pointer, \
+          struct funcdesc_value *dl_main_funcdesc, \
+          X)
+
+/*
+ * Transfer control to the user's application, once the dynamic loader
+ * is done.  We return the address of the function's entry point to
+ * _dl_boot, see boot1_arch.h.
+ */
+#define START()	do {							\
+  struct elf_resolve *exec_mod = _dl_loaded_modules;			\
+  dl_main_funcdesc->entry_point = _dl_elf_main;				\
+  while (exec_mod->libtype != elf_executable)				\
+    exec_mod = exec_mod->next;						\
+  dl_main_funcdesc->got_value = exec_mod->loadaddr.got_value;		\
+  return;								\
+} while (0)
+
+/* We use __aeabi_idiv0 in _dl_find_hash, so we need to have the raise
+   symbol.  */
+int raise(int sig)
+{
+  _dl_exit(1);
+}
+#endif /* __FDPIC__ */