Commit 71378888 authored by Sami Tolvanen's avatar Sami Tolvanen Committed by Masahiro Yamada
Browse files

gendwarfksyms: Add symbol versioning 



Calculate symbol versions from the fully expanded type strings in
type_map, and output the versions in a genksyms-compatible format.

Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
Reviewed-by: default avatarPetr Pavlu <petr.pavlu@suse.com>
Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
parent ab443998

scripts/gendwarfksyms/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -8,4 +8,4 @@ gendwarfksyms-objs += dwarf.o 
gendwarfksyms-objs += symbols.o

gendwarfksyms-objs += types.o



HOSTLDLIBS_gendwarfksyms := -ldw -lelf
 
HOSTLDLIBS_gendwarfksyms := -ldw -lelf -lz

scripts/gendwarfksyms/dwarf.c

+23 −2
Original line number Diff line number Diff line
@@ -740,12 +740,33 @@ static int process_type(struct state *state, struct die *parent, Dwarf_Die *die) 
/*

 * Exported symbol processing

 */

static struct die *get_symbol_cache(struct state *state, Dwarf_Die *die)

{

	struct die *cache;



	cache = die_map_get(die, DIE_SYMBOL);



	if (cache->state != DIE_INCOMPLETE)

		return NULL; /* We already processed a symbol for this DIE */



	cache->tag = dwarf_tag(die);

	return cache;

}



static void process_symbol(struct state *state, Dwarf_Die *die,

			   die_callback_t process_func)

{

	struct die *cache;



	symbol_set_die(state->sym, die);



	cache = get_symbol_cache(state, die);

	if (!cache)

		return;



	debug("%s", state->sym->name);

	check(process_func(state, NULL, die));

	state->sym->state = SYMBOL_MAPPED;

	check(process_func(state, cache, die));

	cache->state = DIE_SYMBOL;

	if (dump_dies)

		fputs("\n", stderr);

}

scripts/gendwarfksyms/gendwarfksyms.c

+8 −2
Original line number Diff line number Diff line
@@ -23,6 +23,8 @@ int dump_dies; 
int dump_die_map;

/* Print out type strings (i.e. type_map) */

int dump_types;

/* Print out expanded type strings used for symbol versions */

int dump_versions;

/* Write a symtypes file */

int symtypes;

static const char *symtypes_file;
@@ -35,6 +37,7 @@ static void usage(void) 
	      "      --dump-dies      Dump DWARF DIE contents\n"

	      "      --dump-die-map   Print debugging information about die_map changes\n"

	      "      --dump-types     Dump type strings\n"

	      "      --dump-versions  Dump expanded type strings used for symbol versions\n"

	      "  -T, --symtypes file  Write a symtypes file\n"

	      "  -h, --help           Print this message\n"

	      "\n",
@@ -69,9 +72,10 @@ static int process_module(Dwfl_Module *mod, void **userdata, const char *name, 
	} while (cu);



	/*

	 * Use die_map to expand type strings and write them to `symfile`.

	 * Use die_map to expand type strings, write them to `symfile`, and

	 * calculate symbol versions.

	 */

	generate_symtypes(symfile);

	generate_symtypes_and_versions(symfile);

	die_map_free();



	return DWARF_CB_OK;
@@ -93,6 +97,7 @@ int main(int argc, char **argv) 
		{ "dump-dies", 0, &dump_dies, 1 },

		{ "dump-die-map", 0, &dump_die_map, 1 },

		{ "dump-types", 0, &dump_types, 1 },

		{ "dump-versions", 0, &dump_versions, 1 },

		{ "symtypes", 1, NULL, 'T' },

		{ "help", 0, NULL, 'h' },

		{ 0, 0, NULL, 0 }
@@ -166,6 +171,7 @@ int main(int argc, char **argv) 
	if (symfile)

		check(fclose(symfile));



	symbol_print_versions();

	symbol_free();



	return 0;

scripts/gendwarfksyms/gendwarfksyms.h

+11 −2
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ extern int debug; 
extern int dump_dies;

extern int dump_die_map;

extern int dump_types;

extern int dump_versions;

extern int symtypes;



/*
@@ -95,6 +96,7 @@ static inline unsigned int addr_hash(uintptr_t addr) 
enum symbol_state {

	SYMBOL_UNPROCESSED,

	SYMBOL_MAPPED,

	SYMBOL_PROCESSED

};



struct symbol_addr {
@@ -109,6 +111,7 @@ struct symbol { 
	struct hlist_node name_hash;

	enum symbol_state state;

	uintptr_t die_addr;

	unsigned long crc;

};



typedef void (*symbol_callback_t)(struct symbol *, void *arg);
@@ -116,6 +119,10 @@ typedef void (*symbol_callback_t)(struct symbol *, void *arg); 
void symbol_read_exports(FILE *file);

void symbol_read_symtab(int fd);

struct symbol *symbol_get(const char *name);

void symbol_set_die(struct symbol *sym, Dwarf_Die *die);

void symbol_set_crc(struct symbol *sym, unsigned long crc);

void symbol_for_each(symbol_callback_t func, void *arg);

void symbol_print_versions(void);

void symbol_free(void);



/*
@@ -126,7 +133,8 @@ enum die_state { 
	DIE_INCOMPLETE,

	DIE_UNEXPANDED,

	DIE_COMPLETE,

	DIE_LAST = DIE_COMPLETE

	DIE_SYMBOL,

	DIE_LAST = DIE_SYMBOL

};



enum die_fragment_type {
@@ -156,6 +164,7 @@ static inline const char *die_state_name(enum die_state state) 
	CASE_CONST_TO_STR(DIE_INCOMPLETE)

	CASE_CONST_TO_STR(DIE_UNEXPANDED)

	CASE_CONST_TO_STR(DIE_COMPLETE)

	CASE_CONST_TO_STR(DIE_SYMBOL)

	}



	error("unexpected die_state: %d", state);
@@ -252,6 +261,6 @@ void process_cu(Dwarf_Die *cudie); 
 * types.c

 */



void generate_symtypes(FILE *file);

void generate_symtypes_and_versions(FILE *file);



#endif /* __GENDWARFKSYMS_H */

scripts/gendwarfksyms/symbols.c

+53 −0
Original line number Diff line number Diff line
@@ -66,6 +66,36 @@ static unsigned int for_each(const char *name, symbol_callback_t func, 
	return 0;

}



static void set_crc(struct symbol *sym, void *data)

{

	unsigned long *crc = data;



	if (sym->state == SYMBOL_PROCESSED && sym->crc != *crc)

		warn("overriding version for symbol %s (crc %lx vs. %lx)",

		     sym->name, sym->crc, *crc);



	sym->state = SYMBOL_PROCESSED;

	sym->crc = *crc;

}



void symbol_set_crc(struct symbol *sym, unsigned long crc)

{

	if (for_each(sym->name, set_crc, &crc) == 0)

		error("no matching symbols: '%s'", sym->name);

}



static void set_die(struct symbol *sym, void *data)

{

	sym->die_addr = (uintptr_t)((Dwarf_Die *)data)->addr;

	sym->state = SYMBOL_MAPPED;

}



void symbol_set_die(struct symbol *sym, Dwarf_Die *die)

{

	if (for_each(sym->name, set_die, die) == 0)

		error("no matching symbols: '%s'", sym->name);

}



static bool is_exported(const char *name)

{

	return for_each(name, NULL, NULL) > 0;
@@ -120,6 +150,16 @@ struct symbol *symbol_get(const char *name) 
	return sym;

}



void symbol_for_each(symbol_callback_t func, void *arg)

{

	struct hlist_node *tmp;

	struct symbol *sym;



	hash_for_each_safe(symbol_names, sym, tmp, name_hash) {

		func(sym, arg);

	}

}



typedef void (*elf_symbol_callback_t)(const char *name, GElf_Sym *sym,

				      Elf32_Word xndx, void *arg);
@@ -246,6 +286,19 @@ void symbol_read_symtab(int fd) 
	elf_for_each_global(fd, elf_set_symbol_addr, NULL);

}



void symbol_print_versions(void)

{

	struct hlist_node *tmp;

	struct symbol *sym;



	hash_for_each_safe(symbol_names, sym, tmp, name_hash) {

		if (sym->state != SYMBOL_PROCESSED)

			warn("no information for symbol %s", sym->name);



		printf("#SYMVER %s 0x%08lx\n", sym->name, sym->crc);

	}

}



void symbol_free(void)

{

	struct hlist_node *tmp;