xtensa: add FDPIC support

This change implements Xtensa FDPIC ABI as specified in the first
version of the following document:

 https://github.com/jcmvbkbc/xtensa-abi/blob/master/fdpic-xtensa.txt

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

1 files changed, 89 insertions, 25 deletions

diff --git a/ldso/ldso/xtensa/elfinterp.c b/ldso/ldso/xtensa/elfinterp.c
index e38a02666..d97f23435 100644
--- a/ldso/ldso/xtensa/elfinterp.c
+++ b/ldso/ldso/xtensa/elfinterp.c
@@ -36,6 +36,13 @@
 #include "tlsdeschtab.h"
 #endif
 
+#ifdef __FDPIC__
+unsigned long
+_dl_linux_resolver (struct elf_resolve *tpnt, int reloc_entry)
+{
+	return 0;
+}
+#else
 unsigned long
 _dl_linux_resolver (struct elf_resolve *tpnt, int reloc_entry)
 {
@@ -83,7 +90,7 @@ _dl_linux_resolver (struct elf_resolve *tpnt, int reloc_entry)
 
 	return (unsigned long) new_addr;
 }
-
+#endif
 
 static int
 _dl_parse (struct elf_resolve *tpnt, struct r_scope_elem *scope,
@@ -145,8 +152,8 @@ _dl_do_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
 	int reloc_type;
 	int symtab_index;
 	char *symname;
-#if defined USE_TLS && USE_TLS
-	struct elf_resolve *tls_tpnt = NULL;
+#if defined USE_TLS && USE_TLS || defined (__FDPIC__)
+	struct elf_resolve *def_mod = NULL;
 #endif
 	struct symbol_ref sym_ref;
 	ElfW(Addr) *reloc_addr;
@@ -155,7 +162,7 @@ _dl_do_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
 	ElfW(Addr) old_val;
 #endif
 
-	reloc_addr = (ElfW(Addr) *) (tpnt->loadaddr + rpnt->r_offset);
+	reloc_addr = (ElfW(Addr) *) DL_RELOC_ADDR(tpnt->loadaddr, rpnt->r_offset);
 	reloc_type = ELF_R_TYPE (rpnt->r_info);
 	symtab_index = ELF_R_SYM (rpnt->r_info);
 	sym_ref.sym = &symtab[symtab_index];
@@ -164,9 +171,17 @@ _dl_do_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
 	symname = strtab + sym_ref.sym->st_name;
 
 	if (symtab_index) {
-		symbol_addr = (ElfW(Addr))
-			_dl_find_hash (symname, scope, tpnt,
-						   elf_machine_type_class (reloc_type), &sym_ref);
+		if (ELF_ST_BIND (sym_ref.sym->st_info) == STB_LOCAL) {
+			symbol_addr = (ElfW(Addr))
+				DL_RELOC_ADDR(tpnt->loadaddr,
+					      symtab[symtab_index].st_value);
+			sym_ref.tpnt = tpnt;
+		} else {
+			symbol_addr = (ElfW(Addr))
+				_dl_find_hash (symname, scope, tpnt,
+					       elf_machine_type_class (reloc_type),
+					       &sym_ref);
+		}
 
 		/*
 		 * We want to allow undefined references to weak symbols - this might
@@ -182,13 +197,13 @@ _dl_do_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
 			_dl_debug_lookup (symname, tpnt, &symtab[symtab_index],
 						&sym_ref, elf_machine_type_class(reloc_type));
 		}
-#if defined USE_TLS && USE_TLS
-		tls_tpnt = sym_ref.tpnt;
+#if defined USE_TLS && USE_TLS || defined (__FDPIC__)
+		def_mod = sym_ref.tpnt;
 #endif
 	} else {
 		symbol_addr =symtab[symtab_index].st_value;
-#if defined USE_TLS && USE_TLS
-		tls_tpnt = tpnt;
+#if defined USE_TLS && USE_TLS || defined (__FDPIC__)
+		def_mod = tpnt;
 #endif
 	}
 
@@ -202,6 +217,7 @@ _dl_do_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
 
 	case R_XTENSA_GLOB_DAT:
 	case R_XTENSA_JMP_SLOT:
+	case R_XTENSA_SYM32:
 		*reloc_addr = symbol_addr + rpnt->r_addend;
 		break;
 
@@ -219,19 +235,63 @@ _dl_do_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
 		break;
 
 	case R_XTENSA_RELATIVE:
-		*reloc_addr += tpnt->loadaddr + rpnt->r_addend;
+		*reloc_addr += DL_RELOC_ADDR(tpnt->loadaddr, rpnt->r_addend);
 		break;
 
+#ifdef __FDPIC__
+	case R_XTENSA_FUNCDESC_VALUE:
+		{
+			struct funcdesc_value *dst = (struct funcdesc_value *) reloc_addr;
+
+			dst->entry_point = (void *) (symbol_addr + rpnt->r_addend);
+			dst->got_value = def_mod->loadaddr.got_value;
+		}
+		break;
+	case R_XTENSA_FUNCDESC:
+		if (symbol_addr)
+			*reloc_addr = (unsigned long)
+				_dl_funcdesc_for((void *) (symbol_addr + rpnt->r_addend),
+						 sym_ref.tpnt->loadaddr.got_value);
+		else
+			/* Relocation against an undefined weak symbol:
+			   set funcdesc to zero.  */
+			*reloc_addr = 0;
+		break;
+	case R_XTENSA_TLS_TPOFF:
+		CHECK_STATIC_TLS((struct link_map *) def_mod);
+		*reloc_addr = symbol_addr + rpnt->r_addend + def_mod->l_tls_offset;
+		break;
+	case R_XTENSA_TLSDESC:
+		{
+			struct tlsdesc *td = (struct tlsdesc *) reloc_addr;
+#ifndef SHARED
+			CHECK_STATIC_TLS((struct link_map *) def_mod);
+#else
+			if (!TRY_STATIC_TLS ((struct link_map *) def_mod))
+			{
+				td->entry = _dl_tlsdesc_dynamic;
+				td->argument = _dl_make_tlsdesc_dynamic((struct link_map *) def_mod,
+									symbol_addr + rpnt->r_addend);
+			}
+			else
+#endif
+			{
+				td->entry = _dl_tlsdesc_return;
+				td->argument = (void *) (symbol_addr + rpnt->r_addend + def_mod->l_tls_offset);
+			}
+		}
+		break;
+#else
 #if defined USE_TLS && USE_TLS
 	case R_XTENSA_TLS_TPOFF:
-		CHECK_STATIC_TLS((struct link_map *) tls_tpnt);
-		*reloc_addr = symbol_addr + tls_tpnt->l_tls_offset + rpnt->r_addend;
+		CHECK_STATIC_TLS((struct link_map *) def_mod);
+		*reloc_addr = symbol_addr + rpnt->r_addend + def_mod->l_tls_offset;
 		break;
 	case R_XTENSA_TLSDESC_FN:
 #ifndef SHARED
-		CHECK_STATIC_TLS((struct link_map *) tls_tpnt);
+		CHECK_STATIC_TLS((struct link_map *) def_mod);
 #else
-		if (!TRY_STATIC_TLS ((struct link_map *) tls_tpnt))
+		if (!TRY_STATIC_TLS ((struct link_map *) def_mod))
 			*reloc_addr = (ElfW(Addr)) _dl_tlsdesc_dynamic;
 		else
 #endif
@@ -239,25 +299,25 @@ _dl_do_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
 		break;
 	case R_XTENSA_TLSDESC_ARG:
 #ifndef SHARED
-		CHECK_STATIC_TLS((struct link_map *) tls_tpnt);
+		CHECK_STATIC_TLS((struct link_map *) def_mod);
 #else
-		if (!TRY_STATIC_TLS ((struct link_map *) tls_tpnt))
+		if (!TRY_STATIC_TLS ((struct link_map *) def_mod))
 			*reloc_addr = (ElfW(Addr))
-				_dl_make_tlsdesc_dynamic((struct link_map *) tls_tpnt,
+				_dl_make_tlsdesc_dynamic((struct link_map *) def_mod,
 							 symbol_addr + rpnt->r_addend);
 		else
 #endif
 			*reloc_addr = symbol_addr + rpnt->r_addend +
-				tls_tpnt->l_tls_offset;
+				def_mod->l_tls_offset;
 		break;
 #endif
-
+#endif
 	default:
 		return -1; /* Calls _dl_exit(1).  */
 	}
 #if defined (__SUPPORT_LD_DEBUG__)
 	if (_dl_debug_reloc && _dl_debug_detail)
-		_dl_dprintf (_dl_debug_file, "\tpatched: %x ==> %x @ %x\n",
+		_dl_dprintf (_dl_debug_file, "\tpatched: %x ==> %x @ %p\n",
 					 old_val, *reloc_addr, reloc_addr);
 #endif
 
@@ -275,7 +335,7 @@ _dl_do_lazy_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
 	ElfW(Addr) old_val;
 #endif
 
-	reloc_addr = (ElfW(Addr) *) (tpnt->loadaddr + rpnt->r_offset);
+	reloc_addr = (ElfW(Addr) *) DL_RELOC_ADDR(tpnt->loadaddr, rpnt->r_offset);
 	reloc_type = ELF_R_TYPE (rpnt->r_info);
 
 #if defined (__SUPPORT_LD_DEBUG__)
@@ -286,7 +346,7 @@ _dl_do_lazy_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
 	case R_XTENSA_JMP_SLOT:
 		/* Perform a RELATIVE reloc on the GOT entry that transfers
 		   to the stub function.  */
-		*reloc_addr += tpnt->loadaddr;
+		*reloc_addr = DL_RELOC_ADDR(tpnt->loadaddr, *reloc_addr);
 		break;
 	case R_XTENSA_NONE:
 		break;
@@ -296,7 +356,7 @@ _dl_do_lazy_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
 
 #if defined (__SUPPORT_LD_DEBUG__)
 	if (_dl_debug_reloc && _dl_debug_detail)
-		_dl_dprintf (_dl_debug_file, "\tpatched: %x ==> %x @ %x\n",
+		_dl_dprintf (_dl_debug_file, "\tpatched: %x ==> %x @ %p\n",
 					 old_val, *reloc_addr, reloc_addr);
 #endif
 	return 0;
@@ -320,3 +380,7 @@ _dl_parse_relocation_information (struct dyn_elf *rpnt,
 	return _dl_parse (rpnt->dyn, scope, rel_addr, rel_size,
 					  _dl_do_reloc);
 }
+
+#ifndef IS_IN_libdl
+# include "../../libc/sysdeps/linux/xtensa/crtreloc.c"
+#endif