Add a basic DWARF parser, which uses libdw to traverse the debugging
information in an object file and looks for functions and variables.
In follow-up patches, this will be expanded to produce symbol versions
for CONFIG_MODVERSIONS from DWARF.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
---
kernel/module/Kconfig | 8 ++
scripts/Makefile | 1 +
scripts/gendwarfksyms/.gitignore | 2 +
scripts/gendwarfksyms/Makefile | 8 ++
scripts/gendwarfksyms/dwarf.c | 166 ++++++++++++++++++++++++++
scripts/gendwarfksyms/gendwarfksyms.c | 126 +++++++++++++++++++
scripts/gendwarfksyms/gendwarfksyms.h | 100 ++++++++++++++++
scripts/gendwarfksyms/symbols.c | 96 +++++++++++++++
8 files changed, 507 insertions(+)
create mode 100644 scripts/gendwarfksyms/.gitignore
create mode 100644 scripts/gendwarfksyms/Makefile
create mode 100644 scripts/gendwarfksyms/dwarf.c
create mode 100644 scripts/gendwarfksyms/gendwarfksyms.c
create mode 100644 scripts/gendwarfksyms/gendwarfksyms.h
create mode 100644 scripts/gendwarfksyms/symbols.c
diff --git a/kernel/module/Kconfig b/kernel/module/Kconfig
index 7c6588148d42..f9e5f82fa88b 100644
--- a/kernel/module/Kconfig
+++ b/kernel/module/Kconfig
@@ -169,6 +169,14 @@ config MODVERSIONS
make them incompatible with the kernel you are running. If
unsure, say N.
+config GENDWARFKSYMS
+ bool
+ depends on DEBUG_INFO
+ # Requires full debugging information, split DWARF not supported.
+ depends on !DEBUG_INFO_REDUCED && !DEBUG_INFO_SPLIT
+ # Requires ELF object files.
+ depends on !LTO
+
config ASM_MODVERSIONS
bool
default HAVE_ASM_MODVERSIONS && MODVERSIONS
diff --git a/scripts/Makefile b/scripts/Makefile
index 6bcda4b9d054..d7fec46d38c0 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -54,6 +54,7 @@ targets += module.lds
subdir-$(CONFIG_GCC_PLUGINS) += gcc-plugins
subdir-$(CONFIG_MODVERSIONS) += genksyms
+subdir-$(CONFIG_GENDWARFKSYMS) += gendwarfksyms
subdir-$(CONFIG_SECURITY_SELINUX) += selinux
subdir-$(CONFIG_SECURITY_IPE) += ipe
diff --git a/scripts/gendwarfksyms/.gitignore b/scripts/gendwarfksyms/.gitignore
new file mode 100644
index 000000000000..0927f8d3cd96
--- /dev/null
+++ b/scripts/gendwarfksyms/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+/gendwarfksyms
diff --git a/scripts/gendwarfksyms/Makefile b/scripts/gendwarfksyms/Makefile
new file mode 100644
index 000000000000..9f8fec4fd39b
--- /dev/null
+++ b/scripts/gendwarfksyms/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+hostprogs-always-y += gendwarfksyms
+
+gendwarfksyms-objs += gendwarfksyms.o
+gendwarfksyms-objs += dwarf.o
+gendwarfksyms-objs += symbols.o
+
+HOSTLDLIBS_gendwarfksyms := -ldw -lelf
diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c
new file mode 100644
index 000000000000..81df3e2ad3ae
--- /dev/null
+++ b/scripts/gendwarfksyms/dwarf.c
@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Google LLC
+ */
+
+#include "gendwarfksyms.h"
+
+static bool get_ref_die_attr(Dwarf_Die *die, unsigned int id, Dwarf_Die *value)
+{
+ Dwarf_Attribute da;
+
+ /* dwarf_formref_die returns a pointer instead of an error value. */
+ return dwarf_attr(die, id, &da) && dwarf_formref_die(&da, value);
+}
+
+#define DEFINE_GET_STRING_ATTR(attr) \
+ static const char *get_##attr##_attr(Dwarf_Die *die) \
+ { \
+ Dwarf_Attribute da; \
+ if (dwarf_attr(die, DW_AT_##attr, &da)) \
+ return dwarf_formstring(&da); \
+ return NULL; \
+ }
+
+DEFINE_GET_STRING_ATTR(name)
+DEFINE_GET_STRING_ATTR(linkage_name)
+
+static const char *get_symbol_name(Dwarf_Die *die)
+{
+ const char *name;
+
+ /* rustc uses DW_AT_linkage_name for exported symbols */
+ name = get_linkage_name_attr(die);
+ if (!name)
+ name = get_name_attr(die);
+
+ return name;
+}
+
+static bool match_export_symbol(struct state *state, Dwarf_Die *die)
+{
+ Dwarf_Die *source = die;
+ Dwarf_Die origin;
+
+ /* If the DIE has an abstract origin, use it for type information. */
+ if (get_ref_die_attr(die, DW_AT_abstract_origin, &origin))
+ source = &origin;
+
+ state->sym = symbol_get(get_symbol_name(die));
+
+ /* Look up using the origin name if there are no matches. */
+ if (!state->sym && source != die)
+ state->sym = symbol_get(get_symbol_name(source));
+
+ state->die = *source;
+ return !!state->sym;
+}
+
+/*
+ * Type string processing
+ */
+static void process(const char *s)
+{
+ s = s ?: "<null>";
+
+ if (dump_dies)
+ fputs(s, stderr);
+}
+
+bool match_all(Dwarf_Die *die)
+{
+ return true;
+}
+
+int process_die_container(struct state *state, Dwarf_Die *die,
+ die_callback_t func, die_match_callback_t match)
+{
+ Dwarf_Die current;
+ int res;
+
+ res = checkp(dwarf_child(die, ¤t));
+ while (!res) {
+ if (match(¤t)) {
+ /* <0 = error, 0 = continue, >0 = stop */
+ res = checkp(func(state, ¤t));
+ if (res)
+ return res;
+ }
+
+ res = checkp(dwarf_siblingof(¤t, ¤t));
+ }
+
+ return 0;
+}
+
+/*
+ * Exported symbol processing
+ */
+static void process_symbol(struct state *state, Dwarf_Die *die,
+ die_callback_t process_func)
+{
+ debug("%s", state->sym->name);
+ check(process_func(state, die));
+ if (dump_dies)
+ fputs("\n", stderr);
+}
+
+static int __process_subprogram(struct state *state, Dwarf_Die *die)
+{
+ process("subprogram");
+ return 0;
+}
+
+static void process_subprogram(struct state *state, Dwarf_Die *die)
+{
+ process_symbol(state, die, __process_subprogram);
+}
+
+static int __process_variable(struct state *state, Dwarf_Die *die)
+{
+ process("variable ");
+ return 0;
+}
+
+static void process_variable(struct state *state, Dwarf_Die *die)
+{
+ process_symbol(state, die, __process_variable);
+}
+
+static int process_exported_symbols(struct state *unused, Dwarf_Die *die)
+{
+ int tag = dwarf_tag(die);
+
+ switch (tag) {
+ /* Possible containers of exported symbols */
+ case DW_TAG_namespace:
+ case DW_TAG_class_type:
+ case DW_TAG_structure_type:
+ return check(process_die_container(
+ NULL, die, process_exported_symbols, match_all));
+
+ /* Possible exported symbols */
+ case DW_TAG_subprogram:
+ case DW_TAG_variable: {
+ struct state state;
+
+ if (!match_export_symbol(&state, die))
+ return 0;
+
+ if (tag == DW_TAG_subprogram)
+ process_subprogram(&state, &state.die);
+ else
+ process_variable(&state, &state.die);
+
+ return 0;
+ }
+ default:
+ return 0;
+ }
+}
+
+void process_cu(Dwarf_Die *cudie)
+{
+ check(process_die_container(NULL, cudie, process_exported_symbols,
+ match_all));
+}
diff --git a/scripts/gendwarfksyms/gendwarfksyms.c b/scripts/gendwarfksyms/gendwarfksyms.c
new file mode 100644
index 000000000000..f84fa98fcbdb
--- /dev/null
+++ b/scripts/gendwarfksyms/gendwarfksyms.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Google LLC
+ */
+
+#include <fcntl.h>
+#include <getopt.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+#include "gendwarfksyms.h"
+
+/*
+ * Options
+ */
+
+/* Print debugging information to stderr */
+int debug;
+/* Dump DIE contents */
+int dump_dies;
+
+static void usage(void)
+{
+ fputs("Usage: gendwarfksyms [options] elf-object-file ... < symbol-list\n\n"
+ "Options:\n"
+ " -d, --debug Print debugging information\n"
+ " --dump-dies Dump DWARF DIE contents\n"
+ " -h, --help Print this message\n"
+ "\n",
+ stderr);
+}
+
+static int process_module(Dwfl_Module *mod, void **userdata, const char *name,
+ Dwarf_Addr base, void *arg)
+{
+ Dwarf_Addr dwbias;
+ Dwarf_Die cudie;
+ Dwarf_CU *cu = NULL;
+ Dwarf *dbg;
+ int res;
+
+ debug("%s", name);
+ dbg = dwfl_module_getdwarf(mod, &dwbias);
+
+ do {
+ res = dwarf_get_units(dbg, cu, &cu, NULL, NULL, &cudie, NULL);
+ if (res < 0)
+ error("dwarf_get_units failed: no debugging information?");
+ if (res == 1)
+ break; /* No more units */
+
+ process_cu(&cudie);
+ } while (cu);
+
+ return DWARF_CB_OK;
+}
+
+static const Dwfl_Callbacks callbacks = {
+ .section_address = dwfl_offline_section_address,
+ .find_debuginfo = dwfl_standard_find_debuginfo,
+};
+
+int main(int argc, char **argv)
+{
+ unsigned int n;
+ int opt;
+
+ struct option opts[] = { { "debug", 0, NULL, 'd' },
+ { "dump-dies", 0, &dump_dies, 1 },
+ { "help", 0, NULL, 'h' },
+ { 0, 0, NULL, 0 } };
+
+ while ((opt = getopt_long(argc, argv, "dh", opts, NULL)) != EOF) {
+ switch (opt) {
+ case 0:
+ break;
+ case 'd':
+ debug = 1;
+ break;
+ case 'h':
+ usage();
+ return 0;
+ default:
+ usage();
+ return 1;
+ }
+ }
+
+ if (optind >= argc) {
+ usage();
+ error("no input files?");
+ }
+
+ symbol_read_exports(stdin);
+
+ for (n = optind; n < argc; n++) {
+ Dwfl *dwfl;
+ int fd;
+
+ fd = open(argv[n], O_RDONLY);
+ if (fd == -1)
+ error("open failed for '%s': %s", argv[n],
+ strerror(errno));
+
+ dwfl = dwfl_begin(&callbacks);
+ if (!dwfl)
+ error("dwfl_begin failed for '%s': %s", argv[n],
+ dwarf_errmsg(-1));
+
+ if (!dwfl_report_offline(dwfl, argv[n], argv[n], fd))
+ error("dwfl_report_offline failed for '%s': %s",
+ argv[n], dwarf_errmsg(-1));
+
+ dwfl_report_end(dwfl, NULL, NULL);
+
+ if (dwfl_getmodules(dwfl, &process_module, NULL, 0))
+ error("dwfl_getmodules failed for '%s'", argv[n]);
+
+ dwfl_end(dwfl);
+ }
+
+ symbol_free();
+
+ return 0;
+}
diff --git a/scripts/gendwarfksyms/gendwarfksyms.h b/scripts/gendwarfksyms/gendwarfksyms.h
new file mode 100644
index 000000000000..23e484af5d22
--- /dev/null
+++ b/scripts/gendwarfksyms/gendwarfksyms.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2024 Google LLC
+ */
+
+#define _GNU_SOURCE
+
+#include <dwarf.h>
+#include <elfutils/libdw.h>
+#include <elfutils/libdwfl.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <hash.h>
+#include <hashtable.h>
+#include <list.h>
+#include <xalloc.h>
+
+#ifndef __GENDWARFKSYMS_H
+#define __GENDWARFKSYMS_H
+
+/*
+ * Options -- in gendwarfksyms.c
+ */
+extern int debug;
+extern int dump_dies;
+
+/*
+ * Output helpers
+ */
+#define __PREFIX "gendwarfksyms: "
+#define __println(prefix, format, ...) \
+ fprintf(stderr, prefix __PREFIX "%s: " format "\n", __func__, \
+ ##__VA_ARGS__)
+
+#define debug(format, ...) \
+ do { \
+ if (debug) \
+ __println("", format, ##__VA_ARGS__); \
+ } while (0)
+
+#define warn(format, ...) __println("warning: ", format, ##__VA_ARGS__)
+#define error(format, ...) \
+ do { \
+ __println("error: ", format, ##__VA_ARGS__); \
+ exit(1); \
+ } while (0)
+
+/*
+ * Error handling helpers
+ */
+#define __check(expr, test) \
+ ({ \
+ int __res = expr; \
+ if (test) \
+ error("`%s` failed: %d", #expr, __res); \
+ __res; \
+ })
+
+/* Error == non-zero values */
+#define check(expr) __check(expr, __res)
+/* Error == negative values */
+#define checkp(expr) __check(expr, __res < 0)
+
+/*
+ * symbols.c
+ */
+
+struct symbol {
+ const char *name;
+ struct hlist_node name_hash;
+};
+
+typedef void (*symbol_callback_t)(struct symbol *, void *arg);
+
+void symbol_read_exports(FILE *file);
+struct symbol *symbol_get(const char *name);
+void symbol_free(void);
+
+/*
+ * dwarf.c
+ */
+
+struct state {
+ struct symbol *sym;
+ Dwarf_Die die;
+};
+
+typedef int (*die_callback_t)(struct state *state, Dwarf_Die *die);
+typedef bool (*die_match_callback_t)(Dwarf_Die *die);
+bool match_all(Dwarf_Die *die);
+
+int process_die_container(struct state *state, Dwarf_Die *die,
+ die_callback_t func, die_match_callback_t match);
+
+void process_cu(Dwarf_Die *cudie);
+
+#endif /* __GENDWARFKSYMS_H */
diff --git a/scripts/gendwarfksyms/symbols.c b/scripts/gendwarfksyms/symbols.c
new file mode 100644
index 000000000000..2c901670224b
--- /dev/null
+++ b/scripts/gendwarfksyms/symbols.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Google LLC
+ */
+
+#include "gendwarfksyms.h"
+
+#define SYMBOL_HASH_BITS 15
+static HASHTABLE_DEFINE(symbol_names, 1 << SYMBOL_HASH_BITS);
+
+static unsigned int for_each(const char *name, symbol_callback_t func,
+ void *data)
+{
+ struct hlist_node *tmp;
+ struct symbol *match;
+
+ if (!name || !*name)
+ return 0;
+
+ hash_for_each_possible_safe(symbol_names, match, tmp, name_hash,
+ hash_str(name)) {
+ if (strcmp(match->name, name))
+ continue;
+
+ if (func)
+ func(match, data);
+
+ return 1;
+ }
+
+ return 0;
+}
+
+static bool is_exported(const char *name)
+{
+ return for_each(name, NULL, NULL) > 0;
+}
+
+void symbol_read_exports(FILE *file)
+{
+ struct symbol *sym;
+ char *line = NULL;
+ char *name = NULL;
+ size_t size = 0;
+ int nsym = 0;
+
+ while (getline(&line, &size, file) > 0) {
+ if (sscanf(line, "%ms\n", &name) != 1)
+ error("malformed input line: %s", line);
+
+ if (is_exported(name)) {
+ /* Ignore duplicates */
+ free(name);
+ continue;
+ }
+
+ sym = xcalloc(1, sizeof(struct symbol));
+ sym->name = name;
+
+ hash_add(symbol_names, &sym->name_hash, hash_str(sym->name));
+ ++nsym;
+
+ debug("%s", sym->name);
+ }
+
+ free(line);
+ debug("%d exported symbols", nsym);
+}
+
+static void get_symbol(struct symbol *sym, void *arg)
+{
+ struct symbol **res = arg;
+
+ *res = sym;
+}
+
+struct symbol *symbol_get(const char *name)
+{
+ struct symbol *sym = NULL;
+
+ for_each(name, get_symbol, &sym);
+ return sym;
+}
+
+void symbol_free(void)
+{
+ struct hlist_node *tmp;
+ struct symbol *sym;
+
+ hash_for_each_safe(symbol_names, sym, tmp, name_hash) {
+ free((void *)sym->name);
+ free(sym);
+ }
+
+ hash_init(symbol_names);
+}
--
2.47.0.371.ga323438b13-googOn 11/21/2024 9:42 PM, Sami Tolvanen wrote:
> Add a basic DWARF parser, which uses libdw to traverse the debugging
> information in an object file and looks for functions and variables.
> In follow-up patches, this will be expanded to produce symbol versions
> for CONFIG_MODVERSIONS from DWARF.
>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
> Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
> ---
> kernel/module/Kconfig | 8 ++
> scripts/Makefile | 1 +
> scripts/gendwarfksyms/.gitignore | 2 +
> scripts/gendwarfksyms/Makefile | 8 ++
> scripts/gendwarfksyms/dwarf.c | 166 ++++++++++++++++++++++++++
> scripts/gendwarfksyms/gendwarfksyms.c | 126 +++++++++++++++++++
> scripts/gendwarfksyms/gendwarfksyms.h | 100 ++++++++++++++++
> scripts/gendwarfksyms/symbols.c | 96 +++++++++++++++
> 8 files changed, 507 insertions(+)
> create mode 100644 scripts/gendwarfksyms/.gitignore
> create mode 100644 scripts/gendwarfksyms/Makefile
> create mode 100644 scripts/gendwarfksyms/dwarf.c
> create mode 100644 scripts/gendwarfksyms/gendwarfksyms.c
> create mode 100644 scripts/gendwarfksyms/gendwarfksyms.h
> create mode 100644 scripts/gendwarfksyms/symbols.c
>
> diff --git a/kernel/module/Kconfig b/kernel/module/Kconfig
> index 7c6588148d42..f9e5f82fa88b 100644
> --- a/kernel/module/Kconfig
> +++ b/kernel/module/Kconfig
> @@ -169,6 +169,14 @@ config MODVERSIONS
> make them incompatible with the kernel you are running. If
> unsure, say N.
>
> +config GENDWARFKSYMS
> + bool
> + depends on DEBUG_INFO
> + # Requires full debugging information, split DWARF not supported.
> + depends on !DEBUG_INFO_REDUCED && !DEBUG_INFO_SPLIT
> + # Requires ELF object files.
> + depends on !LTO
> +
> config ASM_MODVERSIONS
> bool
> default HAVE_ASM_MODVERSIONS && MODVERSIONS
> diff --git a/scripts/Makefile b/scripts/Makefile
> index 6bcda4b9d054..d7fec46d38c0 100644
> --- a/scripts/Makefile
> +++ b/scripts/Makefile
> @@ -54,6 +54,7 @@ targets += module.lds
>
> subdir-$(CONFIG_GCC_PLUGINS) += gcc-plugins
> subdir-$(CONFIG_MODVERSIONS) += genksyms
> +subdir-$(CONFIG_GENDWARFKSYMS) += gendwarfksyms
> subdir-$(CONFIG_SECURITY_SELINUX) += selinux
> subdir-$(CONFIG_SECURITY_IPE) += ipe
>
> diff --git a/scripts/gendwarfksyms/.gitignore b/scripts/gendwarfksyms/.gitignore
> new file mode 100644
> index 000000000000..0927f8d3cd96
> --- /dev/null
> +++ b/scripts/gendwarfksyms/.gitignore
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0
> +/gendwarfksyms
> diff --git a/scripts/gendwarfksyms/Makefile b/scripts/gendwarfksyms/Makefile
> new file mode 100644
> index 000000000000..9f8fec4fd39b
> --- /dev/null
> +++ b/scripts/gendwarfksyms/Makefile
> @@ -0,0 +1,8 @@
> +# SPDX-License-Identifier: GPL-2.0
> +hostprogs-always-y += gendwarfksyms
> +
> +gendwarfksyms-objs += gendwarfksyms.o
> +gendwarfksyms-objs += dwarf.o
> +gendwarfksyms-objs += symbols.o
> +
> +HOSTLDLIBS_gendwarfksyms := -ldw -lelf
> diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c
> new file mode 100644
> index 000000000000..81df3e2ad3ae
> --- /dev/null
> +++ b/scripts/gendwarfksyms/dwarf.c
> @@ -0,0 +1,166 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2024 Google LLC
> + */
> +
> +#include "gendwarfksyms.h"
> +
> +static bool get_ref_die_attr(Dwarf_Die *die, unsigned int id, Dwarf_Die *value)
> +{
> + Dwarf_Attribute da;
> +
> + /* dwarf_formref_die returns a pointer instead of an error value. */
> + return dwarf_attr(die, id, &da) && dwarf_formref_die(&da, value);
> +}
> +
> +#define DEFINE_GET_STRING_ATTR(attr) \
> + static const char *get_##attr##_attr(Dwarf_Die *die) \
> + { \
> + Dwarf_Attribute da; \
> + if (dwarf_attr(die, DW_AT_##attr, &da)) \
> + return dwarf_formstring(&da); \
> + return NULL; \
> + }
> +
> +DEFINE_GET_STRING_ATTR(name)
> +DEFINE_GET_STRING_ATTR(linkage_name)
> +
> +static const char *get_symbol_name(Dwarf_Die *die)
> +{
> + const char *name;
> +
> + /* rustc uses DW_AT_linkage_name for exported symbols */
> + name = get_linkage_name_attr(die);
> + if (!name)
> + name = get_name_attr(die);
> +
> + return name;
> +}
> +
> +static bool match_export_symbol(struct state *state, Dwarf_Die *die)
> +{
> + Dwarf_Die *source = die;
> + Dwarf_Die origin;
> +
> + /* If the DIE has an abstract origin, use it for type information. */
> + if (get_ref_die_attr(die, DW_AT_abstract_origin, &origin))
> + source = &origin;
> +
> + state->sym = symbol_get(get_symbol_name(die));
> +
> + /* Look up using the origin name if there are no matches. */
> + if (!state->sym && source != die)
> + state->sym = symbol_get(get_symbol_name(source));
> +
> + state->die = *source;
> + return !!state->sym;
> +}
> +
> +/*
> + * Type string processing
> + */
> +static void process(const char *s)
> +{
> + s = s ?: "<null>";
> +
> + if (dump_dies)
> + fputs(s, stderr);
> +}
> +
> +bool match_all(Dwarf_Die *die)
> +{
> + return true;
> +}
> +
> +int process_die_container(struct state *state, Dwarf_Die *die,
> + die_callback_t func, die_match_callback_t match)
> +{
> + Dwarf_Die current;
> + int res;
> +
> + res = checkp(dwarf_child(die, ¤t));
> + while (!res) {
> + if (match(¤t)) {
> + /* <0 = error, 0 = continue, >0 = stop */
> + res = checkp(func(state, ¤t));
> + if (res)
> + return res;
> + }
> +
> + res = checkp(dwarf_siblingof(¤t, ¤t));
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * Exported symbol processing
> + */
> +static void process_symbol(struct state *state, Dwarf_Die *die,
> + die_callback_t process_func)
> +{
> + debug("%s", state->sym->name);
> + check(process_func(state, die));
> + if (dump_dies)
> + fputs("\n", stderr);
> +}
> +
> +static int __process_subprogram(struct state *state, Dwarf_Die *die)
> +{
> + process("subprogram");
> + return 0;
> +}
> +
> +static void process_subprogram(struct state *state, Dwarf_Die *die)
> +{
> + process_symbol(state, die, __process_subprogram);
> +}
> +
> +static int __process_variable(struct state *state, Dwarf_Die *die)
> +{
> + process("variable ");
> + return 0;
> +}
> +
> +static void process_variable(struct state *state, Dwarf_Die *die)
> +{
> + process_symbol(state, die, __process_variable);
> +}
> +
> +static int process_exported_symbols(struct state *unused, Dwarf_Die *die)
> +{
> + int tag = dwarf_tag(die);
> +
> + switch (tag) {
> + /* Possible containers of exported symbols */
> + case DW_TAG_namespace:
> + case DW_TAG_class_type:
> + case DW_TAG_structure_type:
> + return check(process_die_container(
> + NULL, die, process_exported_symbols, match_all));
> +
> + /* Possible exported symbols */
> + case DW_TAG_subprogram:
> + case DW_TAG_variable: {
> + struct state state;
> +
> + if (!match_export_symbol(&state, die))
> + return 0;
> +
> + if (tag == DW_TAG_subprogram)
> + process_subprogram(&state, &state.die);
> + else
> + process_variable(&state, &state.die);
> +
> + return 0;
> + }
> + default:
> + return 0;
> + }
> +}
> +
> +void process_cu(Dwarf_Die *cudie)
> +{
> + check(process_die_container(NULL, cudie, process_exported_symbols,
> + match_all));
> +}
> diff --git a/scripts/gendwarfksyms/gendwarfksyms.c b/scripts/gendwarfksyms/gendwarfksyms.c
> new file mode 100644
> index 000000000000..f84fa98fcbdb
> --- /dev/null
> +++ b/scripts/gendwarfksyms/gendwarfksyms.c
> @@ -0,0 +1,126 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2024 Google LLC
> + */
> +
> +#include <fcntl.h>
> +#include <getopt.h>
> +#include <errno.h>
> +#include <stdarg.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include "gendwarfksyms.h"
> +
> +/*
> + * Options
> + */
> +
> +/* Print debugging information to stderr */
> +int debug;
> +/* Dump DIE contents */
> +int dump_dies;
> +
> +static void usage(void)
> +{
> + fputs("Usage: gendwarfksyms [options] elf-object-file ... < symbol-list\n\n"
> + "Options:\n"
> + " -d, --debug Print debugging information\n"
> + " --dump-dies Dump DWARF DIE contents\n"
> + " -h, --help Print this message\n"
> + "\n",
> + stderr);
> +}
> +
> +static int process_module(Dwfl_Module *mod, void **userdata, const char *name,
> + Dwarf_Addr base, void *arg)
> +{
> + Dwarf_Addr dwbias;
> + Dwarf_Die cudie;
> + Dwarf_CU *cu = NULL;
> + Dwarf *dbg;
> + int res;
> +
> + debug("%s", name);
> + dbg = dwfl_module_getdwarf(mod, &dwbias);
> +
> + do {
> + res = dwarf_get_units(dbg, cu, &cu, NULL, NULL, &cudie, NULL);
> + if (res < 0)
> + error("dwarf_get_units failed: no debugging information?");
> + if (res == 1)
> + break; /* No more units */
> +
> + process_cu(&cudie);
> + } while (cu);
> +
> + return DWARF_CB_OK;
> +}
> +
> +static const Dwfl_Callbacks callbacks = {
> + .section_address = dwfl_offline_section_address,
> + .find_debuginfo = dwfl_standard_find_debuginfo,
> +};
> +
> +int main(int argc, char **argv)
> +{
> + unsigned int n;
> + int opt;
> +
> + struct option opts[] = { { "debug", 0, NULL, 'd' },
> + { "dump-dies", 0, &dump_dies, 1 },
> + { "help", 0, NULL, 'h' },
> + { 0, 0, NULL, 0 } };
> +
> + while ((opt = getopt_long(argc, argv, "dh", opts, NULL)) != EOF) {
> + switch (opt) {
> + case 0:
> + break;
> + case 'd':
> + debug = 1;
> + break;
> + case 'h':
> + usage();
> + return 0;
> + default:
> + usage();
> + return 1;
> + }
> + }
> +
> + if (optind >= argc) {
> + usage();
> + error("no input files?");
> + }
> +
> + symbol_read_exports(stdin);
> +
> + for (n = optind; n < argc; n++) {
> + Dwfl *dwfl;
> + int fd;
> +
> + fd = open(argv[n], O_RDONLY);
> + if (fd == -1)
> + error("open failed for '%s': %s", argv[n],
> + strerror(errno));
> +
> + dwfl = dwfl_begin(&callbacks);
> + if (!dwfl)
> + error("dwfl_begin failed for '%s': %s", argv[n],
> + dwarf_errmsg(-1));
> +
> + if (!dwfl_report_offline(dwfl, argv[n], argv[n], fd))
> + error("dwfl_report_offline failed for '%s': %s",
> + argv[n], dwarf_errmsg(-1));
> +
> + dwfl_report_end(dwfl, NULL, NULL);
> +
> + if (dwfl_getmodules(dwfl, &process_module, NULL, 0))
> + error("dwfl_getmodules failed for '%s'", argv[n]);
> +
> + dwfl_end(dwfl);
> + }
> +
> + symbol_free();
> +
> + return 0;
> +}
> diff --git a/scripts/gendwarfksyms/gendwarfksyms.h b/scripts/gendwarfksyms/gendwarfksyms.h
> new file mode 100644
> index 000000000000..23e484af5d22
> --- /dev/null
> +++ b/scripts/gendwarfksyms/gendwarfksyms.h
> @@ -0,0 +1,100 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2024 Google LLC
> + */
> +
> +#define _GNU_SOURCE
I'm getting these warnings:
scripts/gendwarfksyms/kabi.c:245:6: warning: implicit declaration of
function 'asprintf' is invalid in C99 [-Wimplicit-function-declaration]
if (asprintf(&target, "%s %s", fqn, field) < 0)
^
1 warning generated.
HOSTCC scripts/gendwarfksyms/symbols.o
HOSTCC scripts/gendwarfksyms/types.o
scripts/gendwarfksyms/types.c:260:6: warning: implicit declaration of
function 'asprintf' is invalid in C99 [-Wimplicit-function-declaration]
if (asprintf(&name, "%c#%s%s%s", prefix, quote, cache->fqn,
quote) < 0)
^
1 warning generated.
I think it may be cleaner to define _GNU_SOURCE in the CFLAGS instead.
> +
> +#include <dwarf.h>
> +#include <elfutils/libdw.h>
> +#include <elfutils/libdwfl.h>
> +#include <inttypes.h>
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <string.h>
> +
> +#include <hash.h>
> +#include <hashtable.h>
> +#include <list.h>
> +#include <xalloc.h>
> +
> +#ifndef __GENDWARFKSYMS_H
> +#define __GENDWARFKSYMS_H
> +
> +/*
> + * Options -- in gendwarfksyms.c
> + */
> +extern int debug;
> +extern int dump_dies;
> +
> +/*
> + * Output helpers
> + */
> +#define __PREFIX "gendwarfksyms: "
> +#define __println(prefix, format, ...) \
> + fprintf(stderr, prefix __PREFIX "%s: " format "\n", __func__, \
> + ##__VA_ARGS__)
> +
> +#define debug(format, ...) \
> + do { \
> + if (debug) \
> + __println("", format, ##__VA_ARGS__); \
> + } while (0)
> +
> +#define warn(format, ...) __println("warning: ", format, ##__VA_ARGS__)
> +#define error(format, ...) \
> + do { \
> + __println("error: ", format, ##__VA_ARGS__); \
> + exit(1); \
> + } while (0)
> +
> +/*
> + * Error handling helpers
> + */
> +#define __check(expr, test) \
> + ({ \
> + int __res = expr; \
> + if (test) \
> + error("`%s` failed: %d", #expr, __res); \
> + __res; \
> + })
> +
> +/* Error == non-zero values */
> +#define check(expr) __check(expr, __res)
> +/* Error == negative values */
> +#define checkp(expr) __check(expr, __res < 0)
> +
> +/*
> + * symbols.c
> + */
> +
> +struct symbol {
> + const char *name;
> + struct hlist_node name_hash;
> +};
> +
> +typedef void (*symbol_callback_t)(struct symbol *, void *arg);
> +
> +void symbol_read_exports(FILE *file);
> +struct symbol *symbol_get(const char *name);
> +void symbol_free(void);
> +
> +/*
> + * dwarf.c
> + */
> +
> +struct state {
> + struct symbol *sym;
> + Dwarf_Die die;
> +};
> +
> +typedef int (*die_callback_t)(struct state *state, Dwarf_Die *die);
> +typedef bool (*die_match_callback_t)(Dwarf_Die *die);
> +bool match_all(Dwarf_Die *die);
> +
> +int process_die_container(struct state *state, Dwarf_Die *die,
> + die_callback_t func, die_match_callback_t match);
> +
> +void process_cu(Dwarf_Die *cudie);
> +
> +#endif /* __GENDWARFKSYMS_H */
> diff --git a/scripts/gendwarfksyms/symbols.c b/scripts/gendwarfksyms/symbols.c
> new file mode 100644
> index 000000000000..2c901670224b
> --- /dev/null
> +++ b/scripts/gendwarfksyms/symbols.c
> @@ -0,0 +1,96 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2024 Google LLC
> + */
> +
> +#include "gendwarfksyms.h"
> +
> +#define SYMBOL_HASH_BITS 15
> +static HASHTABLE_DEFINE(symbol_names, 1 << SYMBOL_HASH_BITS);
> +
> +static unsigned int for_each(const char *name, symbol_callback_t func,
> + void *data)
> +{
> + struct hlist_node *tmp;
> + struct symbol *match;
> +
> + if (!name || !*name)
> + return 0;
> +
> + hash_for_each_possible_safe(symbol_names, match, tmp, name_hash,
> + hash_str(name)) {
> + if (strcmp(match->name, name))
> + continue;
> +
> + if (func)
> + func(match, data);
> +
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +static bool is_exported(const char *name)
> +{
> + return for_each(name, NULL, NULL) > 0;
> +}
> +
> +void symbol_read_exports(FILE *file)
> +{
> + struct symbol *sym;
> + char *line = NULL;
> + char *name = NULL;
> + size_t size = 0;
> + int nsym = 0;
> +
> + while (getline(&line, &size, file) > 0) {
> + if (sscanf(line, "%ms\n", &name) != 1)
> + error("malformed input line: %s", line);
> +
> + if (is_exported(name)) {
> + /* Ignore duplicates */
> + free(name);
> + continue;
> + }
> +
> + sym = xcalloc(1, sizeof(struct symbol));
> + sym->name = name;
> +
> + hash_add(symbol_names, &sym->name_hash, hash_str(sym->name));
> + ++nsym;
> +
> + debug("%s", sym->name);
> + }
> +
> + free(line);
> + debug("%d exported symbols", nsym);
> +}
> +
> +static void get_symbol(struct symbol *sym, void *arg)
> +{
> + struct symbol **res = arg;
> +
> + *res = sym;
> +}
> +
> +struct symbol *symbol_get(const char *name)
> +{
> + struct symbol *sym = NULL;
> +
> + for_each(name, get_symbol, &sym);
> + return sym;
> +}
> +
> +void symbol_free(void)
> +{
> + struct hlist_node *tmp;
> + struct symbol *sym;
> +
> + hash_for_each_safe(symbol_names, sym, tmp, name_hash) {
> + free((void *)sym->name);
> + free(sym);
> + }
> +
> + hash_init(symbol_names);
> +}
On Wed, Dec 4, 2024 at 11:14 PM Daniel Gomez <da.gomez@samsung.com> wrote:
>
> On 11/21/2024 9:42 PM, Sami Tolvanen wrote:
> > Add a basic DWARF parser, which uses libdw to traverse the debugging
> > information in an object file and looks for functions and variables.
> > In follow-up patches, this will be expanded to produce symbol versions
> > for CONFIG_MODVERSIONS from DWARF.
> >
> > Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
> > Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
> > ---
> > kernel/module/Kconfig | 8 ++
> > scripts/Makefile | 1 +
> > scripts/gendwarfksyms/.gitignore | 2 +
> > scripts/gendwarfksyms/Makefile | 8 ++
> > scripts/gendwarfksyms/dwarf.c | 166 ++++++++++++++++++++++++++
> > scripts/gendwarfksyms/gendwarfksyms.c | 126 +++++++++++++++++++
> > scripts/gendwarfksyms/gendwarfksyms.h | 100 ++++++++++++++++
> > scripts/gendwarfksyms/symbols.c | 96 +++++++++++++++
> > 8 files changed, 507 insertions(+)
> > create mode 100644 scripts/gendwarfksyms/.gitignore
> > create mode 100644 scripts/gendwarfksyms/Makefile
> > create mode 100644 scripts/gendwarfksyms/dwarf.c
> > create mode 100644 scripts/gendwarfksyms/gendwarfksyms.c
> > create mode 100644 scripts/gendwarfksyms/gendwarfksyms.h
> > create mode 100644 scripts/gendwarfksyms/symbols.c
> >
> > diff --git a/kernel/module/Kconfig b/kernel/module/Kconfig
> > index 7c6588148d42..f9e5f82fa88b 100644
> > --- a/kernel/module/Kconfig
> > +++ b/kernel/module/Kconfig
> > @@ -169,6 +169,14 @@ config MODVERSIONS
> > make them incompatible with the kernel you are running. If
> > unsure, say N.
> >
> > +config GENDWARFKSYMS
> > + bool
> > + depends on DEBUG_INFO
> > + # Requires full debugging information, split DWARF not supported.
> > + depends on !DEBUG_INFO_REDUCED && !DEBUG_INFO_SPLIT
> > + # Requires ELF object files.
> > + depends on !LTO
> > +
> > config ASM_MODVERSIONS
> > bool
> > default HAVE_ASM_MODVERSIONS && MODVERSIONS
> > diff --git a/scripts/Makefile b/scripts/Makefile
> > index 6bcda4b9d054..d7fec46d38c0 100644
> > --- a/scripts/Makefile
> > +++ b/scripts/Makefile
> > @@ -54,6 +54,7 @@ targets += module.lds
> >
> > subdir-$(CONFIG_GCC_PLUGINS) += gcc-plugins
> > subdir-$(CONFIG_MODVERSIONS) += genksyms
> > +subdir-$(CONFIG_GENDWARFKSYMS) += gendwarfksyms
> > subdir-$(CONFIG_SECURITY_SELINUX) += selinux
> > subdir-$(CONFIG_SECURITY_IPE) += ipe
> >
> > diff --git a/scripts/gendwarfksyms/.gitignore b/scripts/gendwarfksyms/.gitignore
> > new file mode 100644
> > index 000000000000..0927f8d3cd96
> > --- /dev/null
> > +++ b/scripts/gendwarfksyms/.gitignore
> > @@ -0,0 +1,2 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +/gendwarfksyms
> > diff --git a/scripts/gendwarfksyms/Makefile b/scripts/gendwarfksyms/Makefile
> > new file mode 100644
> > index 000000000000..9f8fec4fd39b
> > --- /dev/null
> > +++ b/scripts/gendwarfksyms/Makefile
> > @@ -0,0 +1,8 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +hostprogs-always-y += gendwarfksyms
> > +
> > +gendwarfksyms-objs += gendwarfksyms.o
> > +gendwarfksyms-objs += dwarf.o
> > +gendwarfksyms-objs += symbols.o
> > +
> > +HOSTLDLIBS_gendwarfksyms := -ldw -lelf
> > diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c
> > new file mode 100644
> > index 000000000000..81df3e2ad3ae
> > --- /dev/null
> > +++ b/scripts/gendwarfksyms/dwarf.c
> > @@ -0,0 +1,166 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2024 Google LLC
> > + */
> > +
> > +#include "gendwarfksyms.h"
> > +
> > +static bool get_ref_die_attr(Dwarf_Die *die, unsigned int id, Dwarf_Die *value)
> > +{
> > + Dwarf_Attribute da;
> > +
> > + /* dwarf_formref_die returns a pointer instead of an error value. */
> > + return dwarf_attr(die, id, &da) && dwarf_formref_die(&da, value);
> > +}
> > +
> > +#define DEFINE_GET_STRING_ATTR(attr) \
> > + static const char *get_##attr##_attr(Dwarf_Die *die) \
> > + { \
> > + Dwarf_Attribute da; \
> > + if (dwarf_attr(die, DW_AT_##attr, &da)) \
> > + return dwarf_formstring(&da); \
> > + return NULL; \
> > + }
> > +
> > +DEFINE_GET_STRING_ATTR(name)
> > +DEFINE_GET_STRING_ATTR(linkage_name)
> > +
> > +static const char *get_symbol_name(Dwarf_Die *die)
> > +{
> > + const char *name;
> > +
> > + /* rustc uses DW_AT_linkage_name for exported symbols */
> > + name = get_linkage_name_attr(die);
> > + if (!name)
> > + name = get_name_attr(die);
> > +
> > + return name;
> > +}
> > +
> > +static bool match_export_symbol(struct state *state, Dwarf_Die *die)
> > +{
> > + Dwarf_Die *source = die;
> > + Dwarf_Die origin;
> > +
> > + /* If the DIE has an abstract origin, use it for type information. */
> > + if (get_ref_die_attr(die, DW_AT_abstract_origin, &origin))
> > + source = &origin;
> > +
> > + state->sym = symbol_get(get_symbol_name(die));
> > +
> > + /* Look up using the origin name if there are no matches. */
> > + if (!state->sym && source != die)
> > + state->sym = symbol_get(get_symbol_name(source));
> > +
> > + state->die = *source;
> > + return !!state->sym;
> > +}
> > +
> > +/*
> > + * Type string processing
> > + */
> > +static void process(const char *s)
> > +{
> > + s = s ?: "<null>";
> > +
> > + if (dump_dies)
> > + fputs(s, stderr);
> > +}
> > +
> > +bool match_all(Dwarf_Die *die)
> > +{
> > + return true;
> > +}
> > +
> > +int process_die_container(struct state *state, Dwarf_Die *die,
> > + die_callback_t func, die_match_callback_t match)
> > +{
> > + Dwarf_Die current;
> > + int res;
> > +
> > + res = checkp(dwarf_child(die, ¤t));
> > + while (!res) {
> > + if (match(¤t)) {
> > + /* <0 = error, 0 = continue, >0 = stop */
> > + res = checkp(func(state, ¤t));
> > + if (res)
> > + return res;
> > + }
> > +
> > + res = checkp(dwarf_siblingof(¤t, ¤t));
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +/*
> > + * Exported symbol processing
> > + */
> > +static void process_symbol(struct state *state, Dwarf_Die *die,
> > + die_callback_t process_func)
> > +{
> > + debug("%s", state->sym->name);
> > + check(process_func(state, die));
> > + if (dump_dies)
> > + fputs("\n", stderr);
> > +}
> > +
> > +static int __process_subprogram(struct state *state, Dwarf_Die *die)
> > +{
> > + process("subprogram");
> > + return 0;
> > +}
> > +
> > +static void process_subprogram(struct state *state, Dwarf_Die *die)
> > +{
> > + process_symbol(state, die, __process_subprogram);
> > +}
> > +
> > +static int __process_variable(struct state *state, Dwarf_Die *die)
> > +{
> > + process("variable ");
> > + return 0;
> > +}
> > +
> > +static void process_variable(struct state *state, Dwarf_Die *die)
> > +{
> > + process_symbol(state, die, __process_variable);
> > +}
> > +
> > +static int process_exported_symbols(struct state *unused, Dwarf_Die *die)
> > +{
> > + int tag = dwarf_tag(die);
> > +
> > + switch (tag) {
> > + /* Possible containers of exported symbols */
> > + case DW_TAG_namespace:
> > + case DW_TAG_class_type:
> > + case DW_TAG_structure_type:
> > + return check(process_die_container(
> > + NULL, die, process_exported_symbols, match_all));
> > +
> > + /* Possible exported symbols */
> > + case DW_TAG_subprogram:
> > + case DW_TAG_variable: {
> > + struct state state;
> > +
> > + if (!match_export_symbol(&state, die))
> > + return 0;
> > +
> > + if (tag == DW_TAG_subprogram)
> > + process_subprogram(&state, &state.die);
> > + else
> > + process_variable(&state, &state.die);
> > +
> > + return 0;
> > + }
> > + default:
> > + return 0;
> > + }
> > +}
> > +
> > +void process_cu(Dwarf_Die *cudie)
> > +{
> > + check(process_die_container(NULL, cudie, process_exported_symbols,
> > + match_all));
> > +}
> > diff --git a/scripts/gendwarfksyms/gendwarfksyms.c b/scripts/gendwarfksyms/gendwarfksyms.c
> > new file mode 100644
> > index 000000000000..f84fa98fcbdb
> > --- /dev/null
> > +++ b/scripts/gendwarfksyms/gendwarfksyms.c
> > @@ -0,0 +1,126 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2024 Google LLC
> > + */
> > +
> > +#include <fcntl.h>
> > +#include <getopt.h>
> > +#include <errno.h>
> > +#include <stdarg.h>
> > +#include <string.h>
> > +#include <unistd.h>
> > +#include "gendwarfksyms.h"
> > +
> > +/*
> > + * Options
> > + */
> > +
> > +/* Print debugging information to stderr */
> > +int debug;
> > +/* Dump DIE contents */
> > +int dump_dies;
> > +
> > +static void usage(void)
> > +{
> > + fputs("Usage: gendwarfksyms [options] elf-object-file ... < symbol-list\n\n"
> > + "Options:\n"
> > + " -d, --debug Print debugging information\n"
> > + " --dump-dies Dump DWARF DIE contents\n"
> > + " -h, --help Print this message\n"
> > + "\n",
> > + stderr);
> > +}
> > +
> > +static int process_module(Dwfl_Module *mod, void **userdata, const char *name,
> > + Dwarf_Addr base, void *arg)
> > +{
> > + Dwarf_Addr dwbias;
> > + Dwarf_Die cudie;
> > + Dwarf_CU *cu = NULL;
> > + Dwarf *dbg;
> > + int res;
> > +
> > + debug("%s", name);
> > + dbg = dwfl_module_getdwarf(mod, &dwbias);
> > +
> > + do {
> > + res = dwarf_get_units(dbg, cu, &cu, NULL, NULL, &cudie, NULL);
> > + if (res < 0)
> > + error("dwarf_get_units failed: no debugging information?");
> > + if (res == 1)
> > + break; /* No more units */
> > +
> > + process_cu(&cudie);
> > + } while (cu);
> > +
> > + return DWARF_CB_OK;
> > +}
> > +
> > +static const Dwfl_Callbacks callbacks = {
> > + .section_address = dwfl_offline_section_address,
> > + .find_debuginfo = dwfl_standard_find_debuginfo,
> > +};
> > +
> > +int main(int argc, char **argv)
> > +{
> > + unsigned int n;
> > + int opt;
> > +
> > + struct option opts[] = { { "debug", 0, NULL, 'd' },
> > + { "dump-dies", 0, &dump_dies, 1 },
> > + { "help", 0, NULL, 'h' },
> > + { 0, 0, NULL, 0 } };
> > +
> > + while ((opt = getopt_long(argc, argv, "dh", opts, NULL)) != EOF) {
> > + switch (opt) {
> > + case 0:
> > + break;
> > + case 'd':
> > + debug = 1;
> > + break;
> > + case 'h':
> > + usage();
> > + return 0;
> > + default:
> > + usage();
> > + return 1;
> > + }
> > + }
> > +
> > + if (optind >= argc) {
> > + usage();
> > + error("no input files?");
> > + }
> > +
> > + symbol_read_exports(stdin);
> > +
> > + for (n = optind; n < argc; n++) {
> > + Dwfl *dwfl;
> > + int fd;
> > +
> > + fd = open(argv[n], O_RDONLY);
> > + if (fd == -1)
> > + error("open failed for '%s': %s", argv[n],
> > + strerror(errno));
> > +
> > + dwfl = dwfl_begin(&callbacks);
> > + if (!dwfl)
> > + error("dwfl_begin failed for '%s': %s", argv[n],
> > + dwarf_errmsg(-1));
> > +
> > + if (!dwfl_report_offline(dwfl, argv[n], argv[n], fd))
> > + error("dwfl_report_offline failed for '%s': %s",
> > + argv[n], dwarf_errmsg(-1));
> > +
> > + dwfl_report_end(dwfl, NULL, NULL);
> > +
> > + if (dwfl_getmodules(dwfl, &process_module, NULL, 0))
> > + error("dwfl_getmodules failed for '%s'", argv[n]);
> > +
> > + dwfl_end(dwfl);
> > + }
> > +
> > + symbol_free();
> > +
> > + return 0;
> > +}
> > diff --git a/scripts/gendwarfksyms/gendwarfksyms.h b/scripts/gendwarfksyms/gendwarfksyms.h
> > new file mode 100644
> > index 000000000000..23e484af5d22
> > --- /dev/null
> > +++ b/scripts/gendwarfksyms/gendwarfksyms.h
> > @@ -0,0 +1,100 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2024 Google LLC
> > + */
> > +
> > +#define _GNU_SOURCE
>
>
> I'm getting these warnings:
>
> scripts/gendwarfksyms/kabi.c:245:6: warning: implicit declaration of
> function 'asprintf' is invalid in C99 [-Wimplicit-function-declaration]
> if (asprintf(&target, "%s %s", fqn, field) < 0)
> ^
> 1 warning generated.
> HOSTCC scripts/gendwarfksyms/symbols.o
> HOSTCC scripts/gendwarfksyms/types.o
> scripts/gendwarfksyms/types.c:260:6: warning: implicit declaration of
> function 'asprintf' is invalid in C99 [-Wimplicit-function-declaration]
> if (asprintf(&name, "%c#%s%s%s", prefix, quote, cache->fqn,
> quote) < 0)
> ^
> 1 warning generated.
>
>
> I think it may be cleaner to define _GNU_SOURCE in the CFLAGS instead.
I do not think so.
I believe the standard approach would be to define the necessary
macros and include headers where they are used.
diff --git a/scripts/gendwarfksyms/gendwarfksyms.h
b/scripts/gendwarfksyms/gendwarfksyms.h
index 86b3a3f2f558..127dceaf838d 100644
--- a/scripts/gendwarfksyms/gendwarfksyms.h
+++ b/scripts/gendwarfksyms/gendwarfksyms.h
@@ -3,8 +3,6 @@
* Copyright (C) 2024 Google LLC
*/
-#define _GNU_SOURCE
-
#include <dwarf.h>
#include <elfutils/libdw.h>
#include <elfutils/libdwfl.h>
diff --git a/scripts/gendwarfksyms/kabi.c b/scripts/gendwarfksyms/kabi.c
index 2c6670ff1ac9..a3b5bb9e5487 100644
--- a/scripts/gendwarfksyms/kabi.c
+++ b/scripts/gendwarfksyms/kabi.c
@@ -3,7 +3,10 @@
* Copyright (C) 2024 Google LLC
*/
+#define _GNU_SOURCE
#include <errno.h>
+#include <stdio.h>
+
#include "gendwarfksyms.h"
#define KABI_RULE_SECTION ".discard.gendwarfksyms.kabi_rules"
diff --git a/scripts/gendwarfksyms/types.c b/scripts/gendwarfksyms/types.c
index f4dbd21b83e6..c37afdb90fe9 100644
--- a/scripts/gendwarfksyms/types.c
+++ b/scripts/gendwarfksyms/types.c
@@ -3,7 +3,10 @@
* Copyright (C) 2024 Google LLC
*/
+#define _GNU_SOURCE
+#include <stdio.h>
#include <zlib.h>
+
#include "gendwarfksyms.h"
static struct cache expansion_cache;
The current code adopts:
- Collect all library header includes to gendwarfksyms.h
- All C files include "gendwarfksyms.h" but nothing else.
This smells like "please include <windows.h> from every file
when you program in Visual C++".
Personally I do not do that, but others may think differently.
--
Best Regards
Masahiro Yamada
On Fri, Nov 22, 2024 at 5:42 AM Sami Tolvanen <samitolvanen@google.com> wrote: > > Add a basic DWARF parser, which uses libdw to traverse the debugging > information in an object file and looks for functions and variables. > In follow-up patches, this will be expanded to produce symbol versions > for CONFIG_MODVERSIONS from DWARF. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> > --- > kernel/module/Kconfig | 8 ++ > scripts/Makefile | 1 + > scripts/gendwarfksyms/.gitignore | 2 + > scripts/gendwarfksyms/Makefile | 8 ++ > scripts/gendwarfksyms/dwarf.c | 166 ++++++++++++++++++++++++++ > scripts/gendwarfksyms/gendwarfksyms.c | 126 +++++++++++++++++++ > scripts/gendwarfksyms/gendwarfksyms.h | 100 ++++++++++++++++ > scripts/gendwarfksyms/symbols.c | 96 +++++++++++++++ > 8 files changed, 507 insertions(+) > create mode 100644 scripts/gendwarfksyms/.gitignore > create mode 100644 scripts/gendwarfksyms/Makefile > create mode 100644 scripts/gendwarfksyms/dwarf.c > create mode 100644 scripts/gendwarfksyms/gendwarfksyms.c > create mode 100644 scripts/gendwarfksyms/gendwarfksyms.h > create mode 100644 scripts/gendwarfksyms/symbols.c > > diff --git a/kernel/module/Kconfig b/kernel/module/Kconfig > index 7c6588148d42..f9e5f82fa88b 100644 > --- a/kernel/module/Kconfig > +++ b/kernel/module/Kconfig > @@ -169,6 +169,14 @@ config MODVERSIONS > make them incompatible with the kernel you are running. If > unsure, say N. > > +config GENDWARFKSYMS > + bool You can move the prompt addition from 17/18 to this patch. - bool + bool "gendwarfksyms (from debugging information)" You split the patch set into a large number of patches, but I cannot compile-test each of them until 17/18 is applied. -- Best Regards Masahiro Yamada
On Thu, Nov 21, 2024 at 08:42:22PM +0000, Sami Tolvanen wrote: > Add a basic DWARF parser, which uses libdw to traverse the debugging > information in an object file and looks for functions and variables. > In follow-up patches, this will be expanded to produce symbol versions > for CONFIG_MODVERSIONS from DWARF. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> > --- > kernel/module/Kconfig | 8 ++ > scripts/Makefile | 1 + > scripts/gendwarfksyms/.gitignore | 2 + This doesn't add scripts/gendwarfksyms to MAINTAINERS but then again scripts/genksyms/ is not there either but it does got to Masahiro. Masahiro, should we just add both to KERNEL BUILD and add Sami as a Reviewer to help with gendwarfksyms? Luis
On Tue, Nov 26, 2024 at 8:30 AM Luis Chamberlain <mcgrof@kernel.org> wrote: > > On Thu, Nov 21, 2024 at 08:42:22PM +0000, Sami Tolvanen wrote: > > Add a basic DWARF parser, which uses libdw to traverse the debugging > > information in an object file and looks for functions and variables. > > In follow-up patches, this will be expanded to produce symbol versions > > for CONFIG_MODVERSIONS from DWARF. > > > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > > Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> > > --- > > kernel/module/Kconfig | 8 ++ > > scripts/Makefile | 1 + > > scripts/gendwarfksyms/.gitignore | 2 + > > This doesn't add scripts/gendwarfksyms to MAINTAINERS > but then again scripts/genksyms/ is not there either > but it does got to Masahiro. scripts/genksyms/ is a very old tool with no maintainer. It defaults to the maintainer of the scripts/ directory (i.e. me) > > Masahiro, should we just add both to KERNEL BUILD and add > Sami as a Reviewer to help with gendwarfksyms? I think it is better to have a separate entry for F: scripts/gendwarfksyms/ with Sami as the maintainer. > > Luis -- Best Regards Masahiro Yamada
On Tue, Nov 26, 2024 at 12:50:48PM +0900, Masahiro Yamada wrote: > On Tue, Nov 26, 2024 at 8:30 AM Luis Chamberlain <mcgrof@kernel.org> wrote: > > > > On Thu, Nov 21, 2024 at 08:42:22PM +0000, Sami Tolvanen wrote: > > > Add a basic DWARF parser, which uses libdw to traverse the debugging > > > information in an object file and looks for functions and variables. > > > In follow-up patches, this will be expanded to produce symbol versions > > > for CONFIG_MODVERSIONS from DWARF. > > > > > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > > > Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> > > > --- > > > kernel/module/Kconfig | 8 ++ > > > scripts/Makefile | 1 + > > > scripts/gendwarfksyms/.gitignore | 2 + > > > > This doesn't add scripts/gendwarfksyms to MAINTAINERS > > but then again scripts/genksyms/ is not there either > > but it does got to Masahiro. > > scripts/genksyms/ is a very old tool with no maintainer. > > It defaults to the maintainer of the scripts/ directory (i.e. me) > > > Masahiro, should we just add both to KERNEL BUILD and add > > Sami as a Reviewer to help with gendwarfksyms? > > I think it is better to have a separate entry for > > F: scripts/gendwarfksyms/ > > with Sami as the maintainer. OK do you want this and the extended modversions to go through your tree or modules tree? Luis
On Wed, Nov 27, 2024 at 3:26 AM Luis Chamberlain <mcgrof@kernel.org> wrote: > > On Tue, Nov 26, 2024 at 12:50:48PM +0900, Masahiro Yamada wrote: > > On Tue, Nov 26, 2024 at 8:30 AM Luis Chamberlain <mcgrof@kernel.org> wrote: > > > > > > On Thu, Nov 21, 2024 at 08:42:22PM +0000, Sami Tolvanen wrote: > > > > Add a basic DWARF parser, which uses libdw to traverse the debugging > > > > information in an object file and looks for functions and variables. > > > > In follow-up patches, this will be expanded to produce symbol versions > > > > for CONFIG_MODVERSIONS from DWARF. > > > > > > > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > > > > Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> > > > > --- > > > > kernel/module/Kconfig | 8 ++ > > > > scripts/Makefile | 1 + > > > > scripts/gendwarfksyms/.gitignore | 2 + > > > > > > This doesn't add scripts/gendwarfksyms to MAINTAINERS > > > but then again scripts/genksyms/ is not there either > > > but it does got to Masahiro. > > > > scripts/genksyms/ is a very old tool with no maintainer. > > > > It defaults to the maintainer of the scripts/ directory (i.e. me) > > > > > Masahiro, should we just add both to KERNEL BUILD and add > > > Sami as a Reviewer to help with gendwarfksyms? > > > > I think it is better to have a separate entry for > > > > F: scripts/gendwarfksyms/ > > > > with Sami as the maintainer. > > OK do you want this and the extended modversions to go through your tree > or modules tree? > > Luis I guess I can pick up them. I was just thinking about a possibility to make this (and the other one) less worse. -- Best Regards Masahiro Yamada
Hi, On Thu, Dec 5, 2024 at 5:46 AM Masahiro Yamada <masahiroy@kernel.org> wrote: > > On Wed, Nov 27, 2024 at 3:26 AM Luis Chamberlain <mcgrof@kernel.org> wrote: > > > > On Tue, Nov 26, 2024 at 12:50:48PM +0900, Masahiro Yamada wrote: > > > On Tue, Nov 26, 2024 at 8:30 AM Luis Chamberlain <mcgrof@kernel.org> wrote: > > > > > > > > On Thu, Nov 21, 2024 at 08:42:22PM +0000, Sami Tolvanen wrote: > > > > > Add a basic DWARF parser, which uses libdw to traverse the debugging > > > > > information in an object file and looks for functions and variables. > > > > > In follow-up patches, this will be expanded to produce symbol versions > > > > > for CONFIG_MODVERSIONS from DWARF. > > > > > > > > > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > > > > > Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> > > > > > --- > > > > > kernel/module/Kconfig | 8 ++ > > > > > scripts/Makefile | 1 + > > > > > scripts/gendwarfksyms/.gitignore | 2 + > > > > > > > > This doesn't add scripts/gendwarfksyms to MAINTAINERS > > > > but then again scripts/genksyms/ is not there either > > > > but it does got to Masahiro. > > > > > > scripts/genksyms/ is a very old tool with no maintainer. > > > > > > It defaults to the maintainer of the scripts/ directory (i.e. me) > > > > > > > Masahiro, should we just add both to KERNEL BUILD and add > > > > Sami as a Reviewer to help with gendwarfksyms? > > > > > > I think it is better to have a separate entry for > > > > > > F: scripts/gendwarfksyms/ > > > > > > with Sami as the maintainer. > > > > OK do you want this and the extended modversions to go through your tree > > or modules tree? > > > > Luis > > > I guess I can pick up them. > > I was just thinking about a possibility to > make this (and the other one) less worse. Note that I'm planning to send out v7 with the recent feedback addressed ~mid-December when I'm back in the office, and I'm sure Matt is also happy to make any improvements to his patches that you have in mind. Sami
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