| Message ID | 20241121204220.2378181-21-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Implement DWARF modversions | expand |
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 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.
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 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.
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.
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
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); +}