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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-09-22 19:34:46 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-09-22 19:34:46 +0200 |
commit | e0703556644a531e50b5dc61b9f6ea83af5f6604 (patch) | |
tree | a0aa73809630d716f25b124cd2aa99a1f4743a55 /scripts/mod | |
parent | Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm (diff) | |
parent | module: Remove leftover '#undef' from export header (diff) | |
download | linux-e0703556644a531e50b5dc61b9f6ea83af5f6604.tar.xz linux-e0703556644a531e50b5dc61b9f6ea83af5f6604.zip |
Merge tag 'modules-for-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu:
"The main bulk of this pull request introduces a new exported symbol
namespaces feature. The number of exported symbols is increasingly
growing with each release (we're at about 31k exports as of 5.3-rc7)
and we currently have no way of visualizing how these symbols are
"clustered" or making sense of this huge export surface.
Namespacing exported symbols allows kernel developers to more
explicitly partition and categorize exported symbols, as well as more
easily limiting the availability of namespaced symbols to other parts
of the kernel. For starters, we have introduced the USB_STORAGE
namespace to demonstrate the API's usage. I have briefly summarized
the feature and its main motivations in the tag below.
Summary:
- Introduce exported symbol namespaces.
This new feature allows subsystem maintainers to partition and
categorize their exported symbols into explicit namespaces. Module
authors are now required to import the namespaces they need.
Some of the main motivations of this feature include: allowing
kernel developers to better manage the export surface, allow
subsystem maintainers to explicitly state that usage of some
exported symbols should only be limited to certain users (think:
inter-module or inter-driver symbols, debugging symbols, etc), as
well as more easily limiting the availability of namespaced symbols
to other parts of the kernel.
With the module import requirement, it is also easier to spot the
misuse of exported symbols during patch review.
Two new macros are introduced: EXPORT_SYMBOL_NS() and
EXPORT_SYMBOL_NS_GPL(). The API is thoroughly documented in
Documentation/kbuild/namespaces.rst.
- Some small code and kbuild cleanups here and there"
* tag 'modules-for-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: Remove leftover '#undef' from export header
module: remove unneeded casts in cmp_name()
module: move CONFIG_UNUSED_SYMBOLS to the sub-menu of MODULES
module: remove redundant 'depends on MODULES'
module: Fix link failure due to invalid relocation on namespace offset
usb-storage: export symbols in USB_STORAGE namespace
usb-storage: remove single-use define for debugging
docs: Add documentation for Symbol Namespaces
scripts: Coccinelle script for namespace dependencies.
modpost: add support for generating namespace dependencies
export: allow definition default namespaces in Makefiles or sources
module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
modpost: add support for symbol namespaces
module: add support for symbol namespaces.
export: explicitly align struct kernel_symbol
module: support reading multiple values per modinfo tag
Diffstat (limited to 'scripts/mod')
-rw-r--r-- | scripts/mod/modpost.c | 150 | ||||
-rw-r--r-- | scripts/mod/modpost.h | 9 |
2 files changed, 142 insertions, 17 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 820eed87fb43..3961941e8e7a 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -38,6 +38,8 @@ static int sec_mismatch_count = 0; static int sec_mismatch_fatal = 0; /* ignore missing files */ static int ignore_missing_files; +/* write namespace dependencies */ +static int write_namespace_deps; enum export { export_plain, export_unused, export_gpl, @@ -164,6 +166,7 @@ struct symbol { struct module *module; unsigned int crc; int crc_valid; + const char *namespace; unsigned int weak:1; unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */ unsigned int kernel:1; /* 1 if symbol is from kernel @@ -235,6 +238,37 @@ static struct symbol *find_symbol(const char *name) return NULL; } +static bool contains_namespace(struct namespace_list *list, + const char *namespace) +{ + struct namespace_list *ns_entry; + + for (ns_entry = list; ns_entry != NULL; ns_entry = ns_entry->next) + if (strcmp(ns_entry->namespace, namespace) == 0) + return true; + + return false; +} + +static void add_namespace(struct namespace_list **list, const char *namespace) +{ + struct namespace_list *ns_entry; + + if (!contains_namespace(*list, namespace)) { + ns_entry = NOFAIL(malloc(sizeof(struct namespace_list) + + strlen(namespace) + 1)); + strcpy(ns_entry->namespace, namespace); + ns_entry->next = *list; + *list = ns_entry; + } +} + +static bool module_imports_namespace(struct module *module, + const char *namespace) +{ + return contains_namespace(module->imported_namespaces, namespace); +} + static const struct { const char *str; enum export export; @@ -314,23 +348,39 @@ static enum export export_from_sec(struct elf_info *elf, unsigned int sec) return export_unknown; } +static const char *sym_extract_namespace(const char **symname) +{ + size_t n; + char *dupsymname; + + n = strcspn(*symname, "."); + if (n < strlen(*symname) - 1) { + dupsymname = NOFAIL(strdup(*symname)); + dupsymname[n] = '\0'; + *symname = dupsymname; + return dupsymname + n + 1; + } + + return NULL; +} + /** * Add an exported symbol - it may have already been added without a * CRC, in this case just update the CRC **/ -static struct symbol *sym_add_exported(const char *name, struct module *mod, - enum export export) +static struct symbol *sym_add_exported(const char *name, const char *namespace, + struct module *mod, enum export export) { struct symbol *s = find_symbol(name); if (!s) { s = new_symbol(name, mod, export); + s->namespace = namespace; } else { if (!s->preloaded) { - warn("%s: '%s' exported twice. Previous export " - "was in %s%s\n", mod->name, name, - s->module->name, - is_vmlinux(s->module->name) ?"":".ko"); + warn("%s: '%s' exported twice. Previous export was in %s%s\n", + mod->name, name, s->module->name, + is_vmlinux(s->module->name) ? "" : ".ko"); } else { /* In case Module.symvers was out of date */ s->module = mod; @@ -622,6 +672,7 @@ static void handle_modversions(struct module *mod, struct elf_info *info, unsigned int crc; enum export export; bool is_crc = false; + const char *name, *namespace; if ((!is_vmlinux(mod->name) || mod->is_dot_o) && strstarts(symname, "__ksymtab")) @@ -693,8 +744,9 @@ static void handle_modversions(struct module *mod, struct elf_info *info, default: /* All exported symbols */ if (strstarts(symname, "__ksymtab_")) { - sym_add_exported(symname + strlen("__ksymtab_"), mod, - export); + name = symname + strlen("__ksymtab_"); + namespace = sym_extract_namespace(&name); + sym_add_exported(name, namespace, mod, export); } if (strcmp(symname, "init_module") == 0) mod->has_init = 1; @@ -1945,6 +1997,7 @@ static void read_symbols(const char *modname) const char *symname; char *version; char *license; + char *namespace; struct module *mod; struct elf_info info = { }; Elf_Sym *sym; @@ -1976,6 +2029,12 @@ static void read_symbols(const char *modname) license = get_next_modinfo(&info, "license", license); } + namespace = get_modinfo(&info, "import_ns"); + while (namespace) { + add_namespace(&mod->imported_namespaces, namespace); + namespace = get_next_modinfo(&info, "import_ns", namespace); + } + for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { symname = remove_dot(info.strtab + sym->st_name); @@ -2135,6 +2194,18 @@ static int check_exports(struct module *mod) basename++; else basename = mod->name; + + if (exp->namespace) { + add_namespace(&mod->required_namespaces, + exp->namespace); + + if (!write_namespace_deps && + !module_imports_namespace(mod, exp->namespace)) { + warn("module %s uses symbol %s from namespace %s, but does not import it.\n", + basename, exp->name, exp->namespace); + } + } + if (!mod->gpl_compatible) check_for_gpl_usage(exp->export, basename, exp->name); check_for_unused(exp->export, basename, exp->name); @@ -2354,7 +2425,7 @@ static void read_dump(const char *fname, unsigned int kernel) return; while ((line = get_next_line(&pos, file, size))) { - char *symname, *modname, *d, *export, *end; + char *symname, *namespace, *modname, *d, *export, *end; unsigned int crc; struct module *mod; struct symbol *s; @@ -2362,7 +2433,10 @@ static void read_dump(const char *fname, unsigned int kernel) if (!(symname = strchr(line, '\t'))) goto fail; *symname++ = '\0'; - if (!(modname = strchr(symname, '\t'))) + if (!(namespace = strchr(symname, '\t'))) + goto fail; + *namespace++ = '\0'; + if (!(modname = strchr(namespace, '\t'))) goto fail; *modname++ = '\0'; if ((export = strchr(modname, '\t')) != NULL) @@ -2379,7 +2453,8 @@ static void read_dump(const char *fname, unsigned int kernel) mod = new_module(modname); mod->skip = 1; } - s = sym_add_exported(symname, mod, export_no(export)); + s = sym_add_exported(symname, namespace, mod, + export_no(export)); s->kernel = kernel; s->preloaded = 1; s->is_static = 0; @@ -2409,16 +2484,20 @@ static void write_dump(const char *fname) { struct buffer buf = { }; struct symbol *symbol; + const char *namespace; int n; for (n = 0; n < SYMBOL_HASH_SIZE ; n++) { symbol = symbolhash[n]; while (symbol) { - if (dump_sym(symbol)) - buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n", - symbol->crc, symbol->name, - symbol->module->name, - export_str(symbol->export)); + if (dump_sym(symbol)) { + namespace = symbol->namespace; + buf_printf(&buf, "0x%08x\t%s\t%s\t%s\t%s\n", + symbol->crc, symbol->name, + namespace ? namespace : "", + symbol->module->name, + export_str(symbol->export)); + } symbol = symbol->next; } } @@ -2426,6 +2505,31 @@ static void write_dump(const char *fname) free(buf.p); } +static void write_namespace_deps_files(void) +{ + struct module *mod; + struct namespace_list *ns; + struct buffer ns_deps_buf = {}; + + for (mod = modules; mod; mod = mod->next) { + char fname[PATH_MAX]; + + if (mod->skip) + continue; + + ns_deps_buf.pos = 0; + + for (ns = mod->required_namespaces; ns; ns = ns->next) + buf_printf(&ns_deps_buf, "%s\n", ns->namespace); + + if (ns_deps_buf.pos == 0) + continue; + + sprintf(fname, "%s.ns_deps", mod->name); + write_if_changed(&ns_deps_buf, fname); + } +} + struct ext_sym_list { struct ext_sym_list *next; const char *file; @@ -2443,7 +2547,7 @@ int main(int argc, char **argv) struct ext_sym_list *extsym_iter; struct ext_sym_list *extsym_start = NULL; - while ((opt = getopt(argc, argv, "i:I:e:mnsT:o:awE")) != -1) { + while ((opt = getopt(argc, argv, "i:I:e:mnsT:o:awEd")) != -1) { switch (opt) { case 'i': kernel_read = optarg; @@ -2484,6 +2588,9 @@ int main(int argc, char **argv) case 'E': sec_mismatch_fatal = 1; break; + case 'd': + write_namespace_deps = 1; + break; default: exit(1); } @@ -2518,6 +2625,9 @@ int main(int argc, char **argv) err |= check_modname_len(mod); err |= check_exports(mod); + if (write_namespace_deps) + continue; + add_header(&buf, mod); add_intree_flag(&buf, !external_module); add_retpoline(&buf); @@ -2530,6 +2640,12 @@ int main(int argc, char **argv) sprintf(fname, "%s.mod.c", mod->name); write_if_changed(&buf, fname); } + + if (write_namespace_deps) { + write_namespace_deps_files(); + return 0; + } + if (dump_write) write_dump(dump_write); if (sec_mismatch_count && sec_mismatch_fatal) diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 8453d6ac2f77..92a926d375d2 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -109,6 +109,11 @@ buf_printf(struct buffer *buf, const char *fmt, ...); void buf_write(struct buffer *buf, const char *s, int len); +struct namespace_list { + struct namespace_list *next; + char namespace[0]; +}; + struct module { struct module *next; const char *name; @@ -121,6 +126,10 @@ struct module { struct buffer dev_table_buf; char srcversion[25]; int is_dot_o; + // Required namespace dependencies + struct namespace_list *required_namespaces; + // Actual imported namespaces + struct namespace_list *imported_namespaces; }; struct elf_info { |