gendwarfksyms-objs += cache.o
gendwarfksyms-objs += die.o
gendwarfksyms-objs += dwarf.o
+gendwarfksyms-objs += kabi.o
gendwarfksyms-objs += symbols.o
gendwarfksyms-objs += types.o
return !!res;
}
-static bool is_kabi_definition(Dwarf_Die *die)
+static bool is_kabi_definition(struct die *cache, Dwarf_Die *die)
{
bool value;
if (get_flag_attr(die, DW_AT_declaration, &value) && value)
return false;
+ if (kabi_is_declonly(cache->fqn))
+ return false;
+
return !is_definition_private(die);
}
process(cache, " {");
process_linebreak(cache, 1);
- expand = state->expand.expand && is_kabi_definition(die);
+ expand = state->expand.expand && is_kabi_definition(cache, die);
if (expand) {
+ state->expand.current_fqn = cache->fqn;
check(process_die_container(state, cache, die, process_func,
match_func));
}
static void process_enumerator_type(struct state *state, struct die *cache,
Dwarf_Die *die)
{
+ bool overridden = false;
Dwarf_Word value;
+ if (stable) {
+ /* Get the fqn before we process anything */
+ update_fqn(cache, die);
+
+ if (kabi_is_enumerator_ignored(state->expand.current_fqn,
+ cache->fqn))
+ return;
+
+ overridden = kabi_get_enumerator_value(
+ state->expand.current_fqn, cache->fqn, &value);
+ }
+
process_list_comma(state, cache);
process(cache, "enumerator");
process_fqn(cache, die);
- if (get_udata_attr(die, DW_AT_const_value, &value)) {
+ if (overridden || get_udata_attr(die, DW_AT_const_value, &value)) {
process(cache, " = ");
process_fmt(cache, "%" PRIu64, value);
}
static void state_init(struct state *state)
{
state->expand.expand = true;
+ state->expand.current_fqn = NULL;
cache_init(&state->expansion_cache);
}
struct expansion_state *saved)
{
state->expand = saved->expand;
+ state->current_fqn = saved->current_fqn;
}
static void expansion_state_save(struct expansion_state *state,
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2024 Google LLC
+ *
+ * Example macros for maintaining kABI stability.
+ *
+ * This file is based on android_kabi.h, which has the following notice:
+ *
+ * Heavily influenced by rh_kabi.h which came from the RHEL/CENTOS kernel
+ * and was:
+ * Copyright (c) 2014 Don Zickus
+ * Copyright (c) 2015-2018 Jiri Benc
+ * Copyright (c) 2015 Sabrina Dubroca, Hannes Frederic Sowa
+ * Copyright (c) 2016-2018 Prarit Bhargava
+ * Copyright (c) 2017 Paolo Abeni, Larry Woodman
+ */
+
+#ifndef __KABI_H__
+#define __KABI_H__
+
+/* Kernel macros for userspace testing. */
+#ifndef __aligned
+#define __aligned(x) __attribute__((__aligned__(x)))
+#endif
+#ifndef __used
+#define __used __attribute__((__used__))
+#endif
+#ifndef __section
+#define __section(section) __attribute__((__section__(section)))
+#endif
+#ifndef __PASTE
+#define ___PASTE(a, b) a##b
+#define __PASTE(a, b) ___PASTE(a, b)
+#endif
+#ifndef __stringify
+#define __stringify_1(x...) #x
+#define __stringify(x...) __stringify_1(x)
+#endif
+
+#define __KABI_RULE(hint, target, value) \
+ static const char __PASTE(__gendwarfksyms_rule_, \
+ __COUNTER__)[] __used __aligned(1) \
+ __section(".discard.gendwarfksyms.kabi_rules") = \
+ "1\0" #hint "\0" #target "\0" #value
+
+/*
+ * KABI_DECLONLY(fqn)
+ * Treat the struct/union/enum fqn as a declaration, i.e. even if
+ * a definition is available, don't expand the contents.
+ */
+#define KABI_DECLONLY(fqn) __KABI_RULE(declonly, fqn, )
+
+/*
+ * KABI_ENUMERATOR_IGNORE(fqn, field)
+ * When expanding enum fqn, skip the provided field. This makes it
+ * possible to hide added enum fields from versioning.
+ */
+#define KABI_ENUMERATOR_IGNORE(fqn, field) \
+ __KABI_RULE(enumerator_ignore, fqn field, )
+
+/*
+ * KABI_ENUMERATOR_VALUE(fqn, field, value)
+ * When expanding enum fqn, use the provided value for the
+ * specified field. This makes it possible to override enumerator
+ * values when calculating versions.
+ */
+#define KABI_ENUMERATOR_VALUE(fqn, field, value) \
+ __KABI_RULE(enumerator_value, fqn field, value)
+
+#endif /* __KABI_H__ */
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kabi_ex.c
+ *
+ * Copyright (C) 2024 Google LLC
+ *
+ * Examples for kABI stability features with --stable. See kabi_ex.h
+ * for details.
+ */
+
+#include "kabi_ex.h"
+
+struct s e0;
+enum e e1;
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * kabi_ex.h
+ *
+ * Copyright (C) 2024 Google LLC
+ *
+ * Examples for kABI stability features with --stable.
+ */
+
+/*
+ * The comments below each example contain the expected gendwarfksyms
+ * output, which can be verified using LLVM's FileCheck tool:
+ *
+ * https://llvm.org/docs/CommandGuide/FileCheck.html
+ *
+ * Usage:
+ *
+ * $ gcc -g -c examples/kabi_ex.c -o examples/kabi_ex.o
+ *
+ * $ nm examples/kabi_ex.o | awk '{ print $NF }' | \
+ * ./gendwarfksyms --stable --dump-dies \
+ * examples/kabi_ex.o 2>&1 >/dev/null | \
+ * FileCheck examples/kabi_ex.h --check-prefix=STABLE
+ */
+
+#ifndef __KABI_EX_H__
+#define __KABI_EX_H__
+
+#include "kabi.h"
+
+/*
+ * Example: kABI rules
+ */
+
+struct s {
+ int a;
+};
+
+KABI_DECLONLY(s);
+
+/*
+ * STABLE: variable structure_type s {
+ * STABLE-NEXT: }
+ */
+
+enum e {
+ A,
+ B,
+ C,
+ D,
+};
+
+KABI_ENUMERATOR_IGNORE(e, B);
+KABI_ENUMERATOR_IGNORE(e, C);
+KABI_ENUMERATOR_VALUE(e, D, 123456789);
+
+/*
+ * STABLE: variable enumeration_type e {
+ * STABLE-NEXT: enumerator A = 0 ,
+ * STABLE-NEXT: enumerator D = 123456789
+ * STABLE-NEXT: } byte_size(4)
+ */
+
+#endif /* __KABI_EX_H__ */
int dump_types;
/* Print out expanded type strings used for symbol versions */
int dump_versions;
+/* Support kABI stability features */
+int stable;
/* Write a symtypes file */
int symtypes;
static const char *symtypes_file;
" --dump-die-map Print debugging information about die_map changes\n"
" --dump-types Dump type strings\n"
" --dump-versions Dump expanded type strings used for symbol versions\n"
+ " -s, --stable Support kABI stability features\n"
" -T, --symtypes file Write a symtypes file\n"
" -h, --help Print this message\n"
"\n",
{ "dump-die-map", 0, &dump_die_map, 1 },
{ "dump-types", 0, &dump_types, 1 },
{ "dump-versions", 0, &dump_versions, 1 },
+ { "stable", 0, NULL, 's' },
{ "symtypes", 1, NULL, 'T' },
{ "help", 0, NULL, 'h' },
{ 0, 0, NULL, 0 }
};
- while ((opt = getopt_long(argc, argv, "dT:h", opts, NULL)) != EOF) {
+ while ((opt = getopt_long(argc, argv, "dsT:h", opts, NULL)) != EOF) {
switch (opt) {
case 0:
break;
case 'd':
debug = 1;
break;
+ case 's':
+ stable = 1;
+ break;
case 'T':
symtypes = 1;
symtypes_file = optarg;
strerror(errno));
symbol_read_symtab(fd);
+ kabi_read_rules(fd);
dwfl = dwfl_begin(&callbacks);
if (!dwfl)
error("dwfl_getmodules failed for '%s'", argv[n]);
dwfl_end(dwfl);
+ kabi_free();
}
if (symfile)
extern int dump_die_map;
extern int dump_types;
extern int dump_versions;
+extern int stable;
extern int symtypes;
/*
struct expansion_state {
bool expand;
+ const char *current_fqn;
};
struct state {
void generate_symtypes_and_versions(FILE *file);
+/*
+ * kabi.c
+ */
+
+bool kabi_is_enumerator_ignored(const char *fqn, const char *field);
+bool kabi_get_enumerator_value(const char *fqn, const char *field,
+ unsigned long *value);
+bool kabi_is_declonly(const char *fqn);
+
+void kabi_read_rules(int fd);
+void kabi_free(void);
+
#endif /* __GENDWARFKSYMS_H */
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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"
+#define KABI_RULE_VERSION "1"
+
+/*
+ * The rule section consists of four null-terminated strings per
+ * entry:
+ *
+ * 1. version
+ * Entry format version. Must match KABI_RULE_VERSION.
+ *
+ * 2. type
+ * Type of the kABI rule. Must be one of the tags defined below.
+ *
+ * 3. target
+ * Rule-dependent target, typically the fully qualified name of
+ * the target DIE.
+ *
+ * 4. value
+ * Rule-dependent value.
+ */
+#define KABI_RULE_MIN_ENTRY_SIZE \
+ (/* version\0 */ 2 + /* type\0 */ 2 + /* target\0" */ 1 + \
+ /* value\0 */ 1)
+#define KABI_RULE_EMPTY_VALUE ""
+
+/*
+ * Rule: declonly
+ * - For the struct/enum/union in the target field, treat it as a
+ * declaration only even if a definition is available.
+ */
+#define KABI_RULE_TAG_DECLONLY "declonly"
+
+/*
+ * Rule: enumerator_ignore
+ * - For the enum_field in the target field, ignore the enumerator.
+ */
+#define KABI_RULE_TAG_ENUMERATOR_IGNORE "enumerator_ignore"
+
+/*
+ * Rule: enumerator_value
+ * - For the fqn_field in the target field, set the value to the
+ * unsigned integer in the value field.
+ */
+#define KABI_RULE_TAG_ENUMERATOR_VALUE "enumerator_value"
+
+enum kabi_rule_type {
+ KABI_RULE_TYPE_UNKNOWN,
+ KABI_RULE_TYPE_DECLONLY,
+ KABI_RULE_TYPE_ENUMERATOR_IGNORE,
+ KABI_RULE_TYPE_ENUMERATOR_VALUE,
+};
+
+#define RULE_HASH_BITS 7
+
+struct rule {
+ enum kabi_rule_type type;
+ const char *target;
+ const char *value;
+ struct hlist_node hash;
+};
+
+/* { type, target } -> struct rule */
+static HASHTABLE_DEFINE(rules, 1 << RULE_HASH_BITS);
+
+static inline unsigned int rule_values_hash(enum kabi_rule_type type,
+ const char *target)
+{
+ return hash_32(type) ^ hash_str(target);
+}
+
+static inline unsigned int rule_hash(const struct rule *rule)
+{
+ return rule_values_hash(rule->type, rule->target);
+}
+
+static inline const char *get_rule_field(const char **pos, ssize_t *left)
+{
+ const char *start = *pos;
+ size_t len;
+
+ if (*left <= 0)
+ error("unexpected end of kABI rules");
+
+ len = strnlen(start, *left) + 1;
+ *pos += len;
+ *left -= len;
+
+ return start;
+}
+
+void kabi_read_rules(int fd)
+{
+ GElf_Shdr shdr_mem;
+ GElf_Shdr *shdr;
+ Elf_Data *rule_data = NULL;
+ Elf_Scn *scn;
+ Elf *elf;
+ size_t shstrndx;
+ const char *rule_str;
+ ssize_t left;
+ int i;
+
+ const struct {
+ enum kabi_rule_type type;
+ const char *tag;
+ } rule_types[] = {
+ {
+ .type = KABI_RULE_TYPE_DECLONLY,
+ .tag = KABI_RULE_TAG_DECLONLY,
+ },
+ {
+ .type = KABI_RULE_TYPE_ENUMERATOR_IGNORE,
+ .tag = KABI_RULE_TAG_ENUMERATOR_IGNORE,
+ },
+ {
+ .type = KABI_RULE_TYPE_ENUMERATOR_VALUE,
+ .tag = KABI_RULE_TAG_ENUMERATOR_VALUE,
+ },
+ };
+
+ if (!stable)
+ return;
+
+ if (elf_version(EV_CURRENT) != EV_CURRENT)
+ error("elf_version failed: %s", elf_errmsg(-1));
+
+ elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+ if (!elf)
+ error("elf_begin failed: %s", elf_errmsg(-1));
+
+ if (elf_getshdrstrndx(elf, &shstrndx) < 0)
+ error("elf_getshdrstrndx failed: %s", elf_errmsg(-1));
+
+ scn = elf_nextscn(elf, NULL);
+
+ while (scn) {
+ const char *sname;
+
+ shdr = gelf_getshdr(scn, &shdr_mem);
+ if (!shdr)
+ error("gelf_getshdr failed: %s", elf_errmsg(-1));
+
+ sname = elf_strptr(elf, shstrndx, shdr->sh_name);
+ if (!sname)
+ error("elf_strptr failed: %s", elf_errmsg(-1));
+
+ if (!strcmp(sname, KABI_RULE_SECTION)) {
+ rule_data = elf_getdata(scn, NULL);
+ if (!rule_data)
+ error("elf_getdata failed: %s", elf_errmsg(-1));
+ break;
+ }
+
+ scn = elf_nextscn(elf, scn);
+ }
+
+ if (!rule_data) {
+ debug("kABI rules not found");
+ check(elf_end(elf));
+ return;
+ }
+
+ rule_str = rule_data->d_buf;
+ left = shdr->sh_size;
+
+ if (left < KABI_RULE_MIN_ENTRY_SIZE)
+ error("kABI rule section too small: %zd bytes", left);
+
+ if (rule_str[left - 1] != '\0')
+ error("kABI rules are not null-terminated");
+
+ while (left > KABI_RULE_MIN_ENTRY_SIZE) {
+ enum kabi_rule_type type = KABI_RULE_TYPE_UNKNOWN;
+ const char *field;
+ struct rule *rule;
+
+ /* version */
+ field = get_rule_field(&rule_str, &left);
+
+ if (strcmp(field, KABI_RULE_VERSION))
+ error("unsupported kABI rule version: '%s'", field);
+
+ /* type */
+ field = get_rule_field(&rule_str, &left);
+
+ for (i = 0; i < ARRAY_SIZE(rule_types); i++) {
+ if (!strcmp(field, rule_types[i].tag)) {
+ type = rule_types[i].type;
+ break;
+ }
+ }
+
+ if (type == KABI_RULE_TYPE_UNKNOWN)
+ error("unsupported kABI rule type: '%s'", field);
+
+ rule = xmalloc(sizeof(struct rule));
+
+ rule->type = type;
+ rule->target = xstrdup(get_rule_field(&rule_str, &left));
+ rule->value = xstrdup(get_rule_field(&rule_str, &left));
+
+ hash_add(rules, &rule->hash, rule_hash(rule));
+
+ debug("kABI rule: type: '%s', target: '%s', value: '%s'", field,
+ rule->target, rule->value);
+ }
+
+ if (left > 0)
+ warn("unexpected data at the end of the kABI rules section");
+
+ check(elf_end(elf));
+}
+
+bool kabi_is_declonly(const char *fqn)
+{
+ struct rule *rule;
+
+ if (!stable)
+ return false;
+ if (!fqn || !*fqn)
+ return false;
+
+ hash_for_each_possible(rules, rule, hash,
+ rule_values_hash(KABI_RULE_TYPE_DECLONLY, fqn)) {
+ if (rule->type == KABI_RULE_TYPE_DECLONLY &&
+ !strcmp(fqn, rule->target))
+ return true;
+ }
+
+ return false;
+}
+
+static char *get_enumerator_target(const char *fqn, const char *field)
+{
+ char *target = NULL;
+
+ if (asprintf(&target, "%s %s", fqn, field) < 0)
+ error("asprintf failed for '%s %s'", fqn, field);
+
+ return target;
+}
+
+static unsigned long get_ulong_value(const char *value)
+{
+ unsigned long result = 0;
+ char *endptr = NULL;
+
+ errno = 0;
+ result = strtoul(value, &endptr, 10);
+
+ if (errno || *endptr)
+ error("invalid unsigned value '%s'", value);
+
+ return result;
+}
+
+bool kabi_is_enumerator_ignored(const char *fqn, const char *field)
+{
+ bool match = false;
+ struct rule *rule;
+ char *target;
+
+ if (!stable)
+ return false;
+ if (!fqn || !*fqn || !field || !*field)
+ return false;
+
+ target = get_enumerator_target(fqn, field);
+
+ hash_for_each_possible(
+ rules, rule, hash,
+ rule_values_hash(KABI_RULE_TYPE_ENUMERATOR_IGNORE, target)) {
+ if (rule->type == KABI_RULE_TYPE_ENUMERATOR_IGNORE &&
+ !strcmp(target, rule->target)) {
+ match = true;
+ break;
+ }
+ }
+
+ free(target);
+ return match;
+}
+
+bool kabi_get_enumerator_value(const char *fqn, const char *field,
+ unsigned long *value)
+{
+ bool match = false;
+ struct rule *rule;
+ char *target;
+
+ if (!stable)
+ return false;
+ if (!fqn || !*fqn || !field || !*field)
+ return false;
+
+ target = get_enumerator_target(fqn, field);
+
+ hash_for_each_possible(rules, rule, hash,
+ rule_values_hash(KABI_RULE_TYPE_ENUMERATOR_VALUE,
+ target)) {
+ if (rule->type == KABI_RULE_TYPE_ENUMERATOR_VALUE &&
+ !strcmp(target, rule->target)) {
+ *value = get_ulong_value(rule->value);
+ match = true;
+ break;
+ }
+ }
+
+ free(target);
+ return match;
+}
+
+void kabi_free(void)
+{
+ struct hlist_node *tmp;
+ struct rule *rule;
+
+ hash_for_each_safe(rules, rule, tmp, hash) {
+ free((void *)rule->target);
+ free((void *)rule->value);
+ free(rule);
+ }
+
+ hash_init(rules);
+}
projects / users / jedix / linux-maple.git / commitdiff