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, 61 insertions, 6 deletions

diff --git a/ldso/ldso/arm/dl-sysdep.h b/ldso/ldso/arm/dl-sysdep.h
index a47a55213..0f783e1c4 100644
--- a/ldso/ldso/arm/dl-sysdep.h
+++ b/ldso/ldso/arm/dl-sysdep.h
@@ -10,6 +10,19 @@
 /* Define this if the system uses RELOCA.  */
 #undef ELF_USES_RELOCA
 #include <elf.h>
+
+#ifdef __FDPIC__
+/* Need bootstrap relocations */
+#define ARCH_NEEDS_BOOTSTRAP_RELOCS
+
+#define DL_CHECK_LIB_TYPE(epnt, piclib, _dl_progname, libname) \
+do \
+{ \
+  (piclib) = 2; \
+} \
+while (0)
+#endif /* __FDPIC__ */
+
 /* Initialization sequence for the GOT.  */
 #define INIT_GOT(GOT_BASE,MODULE) \
 {				\
@@ -63,11 +76,25 @@ unsigned long _dl_linux_resolver(struct elf_resolve * tpnt, int reloc_entry);
 
    ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
    of the main executable's symbols, as for a COPY reloc.  */
+
+#ifdef __FDPIC__
+/* Avoid R_ARM_ABS32 to go through the PLT so that R_ARM_TARGET1
+   translated to R_ARM_ABS32 doesn't use the PLT: otherwise, this
+   breaks init_array because functions are referenced through the
+   PLT.  */
+#define elf_machine_type_class(type)					\
+  ((((type) == R_ARM_JUMP_SLOT || (type) == R_ARM_TLS_DTPMOD32		\
+     || (type) == R_ARM_FUNCDESC_VALUE || (type) == R_ARM_FUNCDESC || (type) == R_ARM_ABS32 \
+     || (type) == R_ARM_TLS_DTPOFF32 || (type) == R_ARM_TLS_TPOFF32)	\
+    * ELF_RTYPE_CLASS_PLT)						\
+   | (((type) == R_ARM_COPY) * ELF_RTYPE_CLASS_COPY))
+#else
 #define elf_machine_type_class(type)									\
   ((((type) == R_ARM_JUMP_SLOT || (type) == R_ARM_TLS_DTPMOD32			\
      || (type) == R_ARM_TLS_DTPOFF32 || (type) == R_ARM_TLS_TPOFF32)	\
     * ELF_RTYPE_CLASS_PLT)												\
    | (((type) == R_ARM_COPY) * ELF_RTYPE_CLASS_COPY))
+#endif /* __FDPIC__ */
 
 /* Return the link-time address of _DYNAMIC.  Conveniently, this is the
    first element of the GOT.  We used to use the PIC register to do this
@@ -106,10 +133,24 @@ elf_machine_dynamic (void)
 
 extern char __dl_start[] __asm__("_dl_start");
 
+#ifdef __FDPIC__
+/* We must force strings used early in the bootstrap into the data
+   segment.  */
+#undef SEND_EARLY_STDERR
+#define SEND_EARLY_STDERR(S) \
+  do { /* FIXME: implement */; } while (0)
+
+#undef INIT_GOT
+#include "../fdpic/dl-sysdep.h"
+#endif /* __FDPIC__ */
+
 /* Return the run-time load address of the shared object.  */
 static __always_inline Elf32_Addr __attribute__ ((unused))
 elf_machine_load_address (void)
 {
+#if defined(__FDPIC__)
+	return 0;
+#else
 	Elf32_Addr got_addr = (Elf32_Addr) &__dl_start;
 	Elf32_Addr pcrel_addr;
 #if defined __OPTIMIZE__ && !defined __thumb__
@@ -128,19 +169,33 @@ elf_machine_load_address (void)
 		 : "=r" (pcrel_addr), "=r" (tmp));
 #endif
 	return pcrel_addr - got_addr;
+#endif
 }
 
 static __always_inline void
+#ifdef __FDPIC__
+elf_machine_relative (DL_LOADADDR_TYPE load_off, const Elf32_Addr rel_addr,
+#else
 elf_machine_relative (Elf32_Addr load_off, const Elf32_Addr rel_addr,
+#endif
 		      Elf32_Word relative_count)
 {
-	 Elf32_Rel * rpnt = (void *) rel_addr;
-	--rpnt;
-	do {
-		Elf32_Addr *const reloc_addr = (void *) (load_off + (++rpnt)->r_offset);
+#if defined(__FDPIC__)
+    Elf32_Rel *rpnt = (void *) rel_addr;
+
+    do {
+        unsigned long *reloc_addr = (unsigned long *) DL_RELOC_ADDR(load_off, rpnt->r_offset);
 
-		*reloc_addr += load_off;
-	} while (--relative_count);
+        *reloc_addr = DL_RELOC_ADDR(load_off, *reloc_addr);
+        rpnt++;
+#else
+    Elf32_Rel * rpnt = (void *) rel_addr;
+    --rpnt;
+    do {
+      Elf32_Addr *const reloc_addr = (void *) (load_off + (++rpnt)->r_offset);
+      *reloc_addr += load_off;
+#endif
+    } while(--relative_count);
 }
 #endif /* !_ARCH_DL_SYSDEP */