Commit ab6ce22b authored by Tiezhu Yang's avatar Tiezhu Yang Committed by Josh Poimboeuf
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objtool: Handle various symbol types of rodata 



In the relocation section ".rela.rodata" of each .o file compiled with
LoongArch toolchain, there are various symbol types such as STT_NOTYPE,
STT_OBJECT, STT_FUNC in addition to the usual STT_SECTION, it needs to
use reloc symbol offset instead of reloc addend to find the destination
instruction in find_jump_table() and add_jump_table().

For the most part, an absolute relocation type is used for rodata. In the
case of STT_SECTION, reloc->sym->offset is always zero, and for the other
symbol types, reloc_addend(reloc) is always zero, thus it can use a simple
statement "reloc->sym->offset + reloc_addend(reloc)" to obtain the symbol
offset for various symbol types.

Signed-off-by: default avatarTiezhu Yang <yangtiezhu@loongson.cn>
Link: https://lore.kernel.org/r/20250211115016.26913-2-yangtiezhu@loongson.cn


Acked-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
parent bf71940f

tools/objtool/check.c

+11 −5
Original line number Diff line number Diff line
@@ -1954,6 +1954,7 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, 
	unsigned int prev_offset = 0;

	struct reloc *reloc = table;

	struct alternative *alt;

	unsigned long sym_offset;



	/*

	 * Each @reloc is a switch table relocation which points to the target
@@ -1971,9 +1972,10 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, 
		if (prev_offset && reloc_offset(reloc) != prev_offset + 8)

			break;



		sym_offset = reloc->sym->offset + reloc_addend(reloc);



		/* Detect function pointers from contiguous objects: */

		if (reloc->sym->sec == pfunc->sec &&

		    reloc_addend(reloc) == pfunc->offset)

		if (reloc->sym->sec == pfunc->sec && sym_offset == pfunc->offset)

			break;



		/*
@@ -1981,10 +1983,10 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, 
		 * which point to the end of the function.  Ignore them.

		 */

		if (reloc->sym->sec == pfunc->sec &&

		    reloc_addend(reloc) == pfunc->offset + pfunc->len)

		    sym_offset == pfunc->offset + pfunc->len)

			goto next;



		dest_insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));

		dest_insn = find_insn(file, reloc->sym->sec, sym_offset);

		if (!dest_insn)

			break;
@@ -2023,6 +2025,7 @@ static void find_jump_table(struct objtool_file *file, struct symbol *func, 
	struct reloc *table_reloc;

	struct instruction *dest_insn, *orig_insn = insn;

	unsigned long table_size;

	unsigned long sym_offset;



	/*

	 * Backward search using the @first_jump_src links, these help avoid
@@ -2046,7 +2049,10 @@ static void find_jump_table(struct objtool_file *file, struct symbol *func, 
		table_reloc = arch_find_switch_table(file, insn, &table_size);

		if (!table_reloc)

			continue;

		dest_insn = find_insn(file, table_reloc->sym->sec, reloc_addend(table_reloc));



		sym_offset = table_reloc->sym->offset + reloc_addend(table_reloc);



		dest_insn = find_insn(file, table_reloc->sym->sec, sym_offset);

		if (!dest_insn || !insn_func(dest_insn) || insn_func(dest_insn)->pfunc != func)

			continue;