ldso: Add ARC support

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

1 files changed, 279 insertions, 0 deletions

diff --git a/ldso/ldso/arc/elfinterp.c b/ldso/ldso/arc/elfinterp.c
new file mode 100644
index 000000000..a3d741b65
--- /dev/null
+++ b/ldso/ldso/arc/elfinterp.c
@@ -0,0 +1,279 @@
+/*
+ * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Lots of code copied from ../i386/elfinterp.c, so:
+ * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
+ *               David Engel, Hongjiu Lu and Mitch D'Souza
+ * Copyright (C) 2001-2002, Erik Andersen
+ * All rights reserved.
+ *
+ * Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
+ */
+#include "ldso.h"
+
+#define ARC_PLT_SIZE	12
+
+unsigned long
+_dl_linux_resolver(struct elf_resolve *tpnt, unsigned int plt_pc)
+{
+	ELF_RELOC *this_reloc, *rel_base;
+	char *strtab, *symname, *new_addr;
+	ElfW(Sym) *symtab;
+	int symtab_index;
+	unsigned int *got_addr;
+	unsigned long plt_base;
+	int plt_idx;
+
+	/* start of .rela.plt */
+	rel_base = (ELF_RELOC *)(tpnt->dynamic_info[DT_JMPREL]);
+
+	/* starts of .plt (addr of PLT0) */
+	plt_base = tpnt->dynamic_info[DT_PLTGOT];
+
+	/*
+	 * compute the idx of the yet-unresolved PLT entry in .plt
+	 * Same idx will be used to find the relo entry in .rela.plt
+	 */
+	plt_idx = (plt_pc - plt_base)/ARC_PLT_SIZE  - 2; /* ignoring 2 dummy PLTs */
+
+	this_reloc = rel_base + plt_idx;
+
+	symtab_index = ELF_R_SYM(this_reloc->r_info);
+	symtab = (ElfW(Sym) *)(intptr_t) (tpnt->dynamic_info[DT_SYMTAB]);
+	strtab = (char *) (tpnt->dynamic_info[DT_STRTAB]);
+	symname= strtab + symtab[symtab_index].st_name;
+
+	/* relo-offset to fixup, shd be a .got entry */
+	got_addr = (unsigned int *)(this_reloc->r_offset + tpnt->loadaddr);
+
+	/* Get the address of the GOT entry */
+	new_addr = _dl_find_hash(symname, &_dl_loaded_modules->symbol_scope, tpnt,
+				 ELF_RTYPE_CLASS_PLT, NULL);
+
+	if (unlikely(!new_addr)) {
+		_dl_dprintf(2, "%s: can't resolve symbol '%s'\n", _dl_progname, symname);
+		_dl_exit(1);
+	}
+
+
+#if defined __SUPPORT_LD_DEBUG__
+	if (_dl_debug_bindings) {
+		_dl_dprintf(_dl_debug_file, "\nresolve function: %s", symname);
+		if(_dl_debug_detail)
+			_dl_dprintf(_dl_debug_file, "\n\tpatched %x ==> %pc @ %pl\n",
+					*got_addr, new_addr, got_addr);
+	}
+
+	if (!_dl_debug_nofixups)
+		*got_addr = (unsigned int)new_addr;
+#else
+	/* Update the .got entry with the runtime address of symbol */
+	*got_addr = (unsigned int)new_addr;
+#endif
+
+	/*
+	 * Return the new addres, where the asm trampoline will jump to
+	 *  after re-setting up the orig args
+	 */
+	return (unsigned long) new_addr;
+}
+
+
+static int
+_dl_do_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
+	     ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab)
+{
+	int reloc_type;
+	int symtab_index;
+	char *symname;
+	unsigned long *reloc_addr;
+	unsigned long symbol_addr;
+#if defined __SUPPORT_LD_DEBUG__
+	unsigned long old_val = 0;
+#endif
+	struct symbol_ref sym_ref;
+
+	reloc_addr   = (unsigned long *)(tpnt->loadaddr + rpnt->r_offset);
+	reloc_type   = ELF_R_TYPE(rpnt->r_info);
+	symtab_index = ELF_R_SYM(rpnt->r_info);
+	symbol_addr  = 0;
+
+	sym_ref.sym = &symtab[symtab_index];
+	sym_ref.tpnt = NULL;
+
+#if defined __SUPPORT_LD_DEBUG__
+	if (reloc_addr)
+		old_val = *reloc_addr;
+#endif
+
+	if (symtab_index) {
+		symname = strtab + symtab[symtab_index].st_name;
+		symbol_addr = (unsigned long) _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 have been intentional. We should not be linking
+		 * local symbols here, so all bases should be covered.
+		 */
+
+		if (unlikely(!symbol_addr
+		    && ELF_ST_BIND(symtab[symtab_index].st_info) != STB_WEAK)) {
+			/* Non-fatal if called from dlopen, hence different ret code */
+			return 1;
+		}
+	} else if (reloc_type == R_ARC_RELATIVE ) {
+		*reloc_addr += tpnt->loadaddr;
+		goto log_entry;
+	}
+
+	switch (reloc_type) {
+	case R_ARC_32:
+		*reloc_addr += symbol_addr + rpnt->r_addend;
+		break;
+	case R_ARC_PC32:
+		*reloc_addr += symbol_addr + rpnt->r_addend - (unsigned long) reloc_addr;
+		break;
+	case R_ARC_GLOB_DAT:
+	case R_ARC_JMP_SLOT:
+		*reloc_addr = symbol_addr;
+		break;
+	case R_ARC_COPY:
+		_dl_memcpy((void *) reloc_addr,(void *) symbol_addr,
+				symtab[symtab_index].st_size);
+		break;
+	default:
+		return -1;
+	}
+
+log_entry:
+#if defined __SUPPORT_LD_DEBUG__
+	if(_dl_debug_detail)
+		_dl_dprintf(_dl_debug_file,"\tpatched: %lx ==> %lx @ %pl: addend %x ",
+				old_val, *reloc_addr, reloc_addr, rpnt->r_addend);
+#endif
+
+	return 0;
+}
+
+static int
+_dl_do_lazy_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
+		  ELF_RELOC *rpnt)
+{
+	int reloc_type;
+	unsigned long *reloc_addr;
+#if defined __SUPPORT_LD_DEBUG__
+	unsigned long old_val;
+#endif
+
+	reloc_addr = (unsigned long *)(tpnt->loadaddr + rpnt->r_offset);
+	reloc_type = ELF_R_TYPE(rpnt->r_info);
+
+#if defined __SUPPORT_LD_DEBUG__
+	old_val = *reloc_addr;
+#endif
+
+	switch (reloc_type) {
+	case R_ARC_JMP_SLOT:
+		*reloc_addr += tpnt->loadaddr;
+		break;
+	default:
+		return -1;
+	}
+
+#if defined __SUPPORT_LD_DEBUG__
+	if(_dl_debug_reloc && _dl_debug_detail)
+		_dl_dprintf(_dl_debug_file, "\tpatched: %lx ==> %lx @ %pl\n",
+				old_val, *reloc_addr, reloc_addr);
+#endif
+
+	return 0;
+}
+
+#define ___DO_LAZY  1
+#define ___DO_NOW   2
+
+static int _dl_parse(struct elf_resolve *tpnt, struct r_scope_elem *scope,
+		     unsigned long rel_addr, unsigned long rel_size, int type)
+{
+	unsigned int i;
+	char *strtab;
+	ElfW(Sym) *symtab;
+	ELF_RELOC *rpnt;
+	int symtab_index;
+	int res = 0;
+
+	/* Now parse the relocation information */
+	rpnt = (ELF_RELOC *)(intptr_t) (rel_addr);
+	rel_size = rel_size / sizeof(ELF_RELOC);
+
+	symtab = (ElfW(Sym) *)(intptr_t) (tpnt->dynamic_info[DT_SYMTAB]);
+	strtab = (char *) (tpnt->dynamic_info[DT_STRTAB]);
+
+	for (i = 0; i < rel_size; i++, rpnt++) {
+
+		symtab_index = ELF_R_SYM(rpnt->r_info);
+
+		debug_sym(symtab,strtab,symtab_index);
+		debug_reloc(symtab,strtab,rpnt);
+
+		/* constant propagation subsumes the 'if' */
+		if (type == ___DO_LAZY)
+			res = _dl_do_lazy_reloc(tpnt, scope, rpnt);
+		else
+			res = _dl_do_reloc(tpnt, scope, rpnt, symtab, strtab);
+
+		if (res != 0)
+			break;
+	}
+
+	if (unlikely(res != 0)) {
+		if (res < 0) {
+			int reloc_type = ELF_R_TYPE(rpnt->r_info);
+#if defined __SUPPORT_LD_DEBUG__
+			_dl_dprintf(2, "can't handle reloc type %s\n ",
+				    _dl_reltypes(reloc_type));
+#else
+			_dl_dprintf(2, "can't handle reloc type %x\n",
+				    reloc_type);
+#endif
+			_dl_exit(-res);
+		} else {
+			_dl_dprintf(2, "can't resolve symbol\n");
+			/* Fall thru to return res */
+		}
+	}
+
+	return res;
+}
+
+void
+_dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
+				      unsigned long rel_addr,
+				      unsigned long rel_size)
+{
+	/* This func is called for processing .rela.plt of loaded module(s)
+	 * The relo entries handled are JMP_SLOT type for fixing up .got slots
+	 * for external function calls.
+	 * This function doesn't resolve the slots: that is done lazily at
+	 * runtime. The build linker (at least thats what happens for ARC) had
+	 * pre-init the .got slots to point to PLT0. All that is done here is
+	 * to fix them up to point to load value of PLT0 (as opposed to the
+	 * build value).
+	 * On ARC, the loadaddr of dyn exec is zero, thus elfaddr == loadaddr
+	 * Thus there is no point in adding "0" to values and un-necessarily
+	 * stir up the caches and TLB.
+	 * For lsdo processing busybox binary, this skips over 380 relo entries
+	 */
+	if (rpnt->dyn->loadaddr != 0)
+		_dl_parse(rpnt->dyn, NULL, rel_addr, rel_size, ___DO_LAZY);
+}
+
+int
+_dl_parse_relocation_information(struct dyn_elf  *rpnt,
+				 struct r_scope_elem *scope,
+				 unsigned long rel_addr,
+				 unsigned long rel_size)
+{
+	return _dl_parse(rpnt->dyn, scope, rel_addr, rel_size, ___DO_NOW);
+}