m68k: add NPTL/TLS support

Port over NPTL/TLS support from GNU C Library.
In the first step only the slower syscall is used for TLS
access. The uClibc-ng testsuite shows 79 errors, so their
is room for bugfixes and improvements.

3 files changed, 90 insertions, 15 deletions

diff --git a/ldso/ldso/m68k/dl-sysdep.h b/ldso/ldso/m68k/dl-sysdep.h
index 8ac892655..21937b259 100644
--- a/ldso/ldso/m68k/dl-sysdep.h
+++ b/ldso/ldso/m68k/dl-sysdep.h
@@ -27,12 +27,16 @@ do { \
 struct elf_resolve;
 extern unsigned long _dl_linux_resolver (struct elf_resolve *, int);
 
-/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so
-   PLT entries should not be allowed to define the value.
-   ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
+/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
+   TLS variable, so undefined references should not be allowed to
+   define the value.
+   ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve to one
    of the main executable's symbols, as for a COPY reloc.  */
 #define elf_machine_type_class(type) \
-  ((((type) == R_68K_JMP_SLOT) * ELF_RTYPE_CLASS_PLT)	\
+  ((((type) == R_68K_JMP_SLOT	     \
+     || (type) == R_68K_TLS_DTPMOD32 \
+     || (type) == R_68K_TLS_DTPREL32 \
+     || (type) == R_68K_TLS_TPREL32) * ELF_RTYPE_CLASS_PLT)	\
    | (((type) == R_68K_COPY) * ELF_RTYPE_CLASS_COPY))
 
 /* Return the link-time address of _DYNAMIC.  Conveniently, this is the
diff --git a/ldso/ldso/m68k/elfinterp.c b/ldso/ldso/m68k/elfinterp.c
index 15a2c43b1..25ea23067 100644
--- a/ldso/ldso/m68k/elfinterp.c
+++ b/ldso/ldso/m68k/elfinterp.c
@@ -150,6 +150,9 @@ _dl_do_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
 #if defined (__SUPPORT_LD_DEBUG__)
 	ElfW(Addr) old_val;
 #endif
+#if defined USE_TLS && USE_TLS
+	struct elf_resolve *tls_tpnt = NULL;
+#endif
 
 	reloc_addr = (ElfW(Addr)*)(tpnt->loadaddr + (unsigned long)rpnt->r_offset);
 	reloc_type = ELF_R_TYPE(rpnt->r_info);
@@ -167,16 +170,28 @@ _dl_do_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
 		 * might have been intentional.  We should not be linking local
 		 * symbols here, so all bases should be covered.
 		 */
-		if (unlikely(!symbol_addr && ELF_ST_BIND(sym_ref.sym->st_info) != STB_WEAK)) {
-			_dl_dprintf(2, "%s: can't resolve symbol '%s'\n", _dl_progname, symname);
-			_dl_exit(1);
+		if (unlikely (!symbol_addr &&
+					  ELF_ST_TYPE (sym_ref.sym->st_info) != STT_TLS &&
+					  ELF_ST_BIND (sym_ref.sym->st_info) != STB_WEAK)) {
+			return 1;
 		}
 		if (_dl_trace_prelink) {
 			_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;
+#endif
 	}
 
+#if defined USE_TLS && USE_TLS
+	/* In case of a TLS reloc, tls_tpnt NULL means we have an 'anonymous'
+	   symbol.  This is the case for a static tls variable, so the lookup
+	   module is just that one is referencing the tls variable. */
+	if (!tls_tpnt)
+		tls_tpnt = tpnt;
+#endif
+
 #if defined (__SUPPORT_LD_DEBUG__)
 	old_val = *reloc_addr;
 #endif
@@ -209,13 +224,6 @@ _dl_do_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
 		case R_68K_JMP_SLOT:
 			*reloc_addr = symbol_addr + rpnt->r_addend;
 			break;
-		/* handled by elf_machine_relative()
-		case R_68K_RELATIVE:
-			*reloc_addr = ((unsigned int) tpnt->loadaddr
-			              / * Compatibility kludge.  * /
-			              + (rpnt->r_addend ? : *reloc_addr));
-		*/
-			break;
 		case R_68K_COPY:
 			if (symbol_addr) {
 #if defined (__SUPPORT_LD_DEBUG__)
@@ -234,7 +242,22 @@ _dl_do_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
 				_dl_dprintf(_dl_debug_file, "no symbol_addr to copy !?\n");
 #endif
 			break;
-
+#if defined USE_TLS && USE_TLS
+		case R_68K_TLS_DTPMOD32:
+			*reloc_addr = tls_tpnt->l_tls_modid;
+			break;
+		case R_68K_TLS_DTPREL32:
+			if (sym_ref.sym != NULL)
+			  *reloc_addr = TLS_DTPREL_VALUE (sym_ref.sym, rpnt);
+			break;
+		case R_68K_TLS_TPREL32:
+			if (sym_ref.sym != NULL)
+			{
+			  CHECK_STATIC_TLS ((struct link_map *) tls_tpnt);
+			  *reloc_addr = TLS_TPREL_VALUE ((struct link_map *) tls_tpnt, sym_ref.sym, rpnt);
+			}
+			break;
+#endif
 		default:
 			return -1;	/* Calls _dl_exit(1). */
 	}
diff --git a/ldso/ldso/m68k/m68k_read_tp.S b/ldso/ldso/m68k/m68k_read_tp.S
new file mode 100644
index 000000000..cb5280e67
--- /dev/null
+++ b/ldso/ldso/m68k/m68k_read_tp.S
@@ -0,0 +1,48 @@
+/* Copyright (C) 2010-2017 Free Software Foundation, Inc.
+   Contributed by Maxim Kuvyrkov <maxim@codesourcery.com>, 2010.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file with other
+   programs, and to distribute those programs without any restriction
+   coming from the use of this file. (The GNU Lesser General Public
+   License restrictions do apply in other respects; for example, they
+   cover modification of the file, and distribution when not linked
+   into another program.)
+
+   Note that people who make modified versions of this file are not
+   obligated to grant this special exception for their modified
+   versions; it is their choice whether to do so. The GNU Lesser
+   General Public License gives permission to release a modified
+   version without this exception; this exception also makes it
+   possible to release a modified version which carries forward this
+   exception.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+	.text
+# ifdef IS_IN_rtld
+/* rtld gets a hidden copy of __m68k_read_tp.  */
+	.hidden __m68k_read_tp
+# endif
+
+ENTRY (__m68k_read_tp)
+	move.l	#__NR_get_thread_area, %d0
+	trap	#0
+	move.l	%d0, %a0
+	rts
+END (__m68k_read_tp)