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module: remove EXPORT_UNUSED_SYMBOL* 

EXPORT_UNUSED_SYMBOL* is not actually used anywhere.  Remove the
unused functionality as we generally just remove unused code anyway.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
This commit is contained in:
Christoph Hellwig 2021-02-02 13:13:34 +01:00 committed by Jessica Yu
parent f1c3d73e97
commit 367948220f
24 changed files with 13 additions and 193 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/arm/configs/bcm2835_defconfig
View File

@ -177,7 +177,6 @@ CONFIG_BOOT_PRINTK_DELAY=y
CONFIG_DYNAMIC_DEBUG=y
CONFIG_DEBUG_INFO=y
# CONFIG_ENABLE_MUST_CHECK is not set
CONFIG_UNUSED_SYMBOLS=y
CONFIG_DEBUG_MEMORY_INIT=y
CONFIG_LOCKUP_DETECTOR=y
CONFIG_SCHED_TRACER=y

1
arch/arm/configs/mxs_defconfig
View File

@ -164,7 +164,6 @@ CONFIG_FONTS=y
CONFIG_PRINTK_TIME=y
CONFIG_DEBUG_INFO=y
CONFIG_FRAME_WARN=2048
CONFIG_UNUSED_SYMBOLS=y
CONFIG_MAGIC_SYSRQ=y
CONFIG_DEBUG_KERNEL=y
CONFIG_SOFTLOCKUP_DETECTOR=y

1
arch/mips/configs/nlm_xlp_defconfig
View File

@ -549,7 +549,6 @@ CONFIG_PRINTK_TIME=y
CONFIG_DEBUG_INFO=y
# CONFIG_ENABLE_MUST_CHECK is not set
CONFIG_FRAME_WARN=1024
CONFIG_UNUSED_SYMBOLS=y
CONFIG_DEBUG_MEMORY_INIT=y
CONFIG_DETECT_HUNG_TASK=y
CONFIG_SCHEDSTATS=y

1
arch/mips/configs/nlm_xlr_defconfig
View File

@ -500,7 +500,6 @@ CONFIG_CRC7=m
CONFIG_PRINTK_TIME=y
CONFIG_DEBUG_INFO=y
# CONFIG_ENABLE_MUST_CHECK is not set
CONFIG_UNUSED_SYMBOLS=y
CONFIG_DEBUG_MEMORY_INIT=y
CONFIG_DETECT_HUNG_TASK=y
CONFIG_SCHEDSTATS=y

1
arch/parisc/configs/generic-32bit_defconfig
View File

@ -22,7 +22,6 @@ CONFIG_PCI_LBA=y
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODULE_FORCE_UNLOAD=y
CONFIG_UNUSED_SYMBOLS=y
# CONFIG_BLK_DEV_BSG is not set
# CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
CONFIG_BINFMT_MISC=m

1
arch/parisc/configs/generic-64bit_defconfig
View File

@ -31,7 +31,6 @@ CONFIG_MODULE_FORCE_LOAD=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODULE_FORCE_UNLOAD=y
CONFIG_MODVERSIONS=y
CONFIG_UNUSED_SYMBOLS=y
CONFIG_BLK_DEV_INTEGRITY=y
CONFIG_BINFMT_MISC=m
# CONFIG_COMPACTION is not set

1
arch/powerpc/configs/ppc6xx_defconfig
View File

@ -1072,7 +1072,6 @@ CONFIG_NLS_ISO8859_15=m
CONFIG_NLS_KOI8_R=m
CONFIG_NLS_KOI8_U=m
CONFIG_DEBUG_INFO=y
CONFIG_UNUSED_SYMBOLS=y
CONFIG_HEADERS_INSTALL=y
CONFIG_MAGIC_SYSRQ=y
CONFIG_DEBUG_KERNEL=y

1
arch/s390/configs/debug_defconfig
View File

@ -71,7 +71,6 @@ CONFIG_MODULE_FORCE_UNLOAD=y
CONFIG_MODVERSIONS=y
CONFIG_MODULE_SRCVERSION_ALL=y
CONFIG_MODULE_SIG_SHA256=y
CONFIG_UNUSED_SYMBOLS=y
CONFIG_BLK_DEV_INTEGRITY=y
CONFIG_BLK_DEV_THROTTLING=y
CONFIG_BLK_WBT=y

1
arch/s390/configs/defconfig
View File

@ -66,7 +66,6 @@ CONFIG_MODULE_FORCE_UNLOAD=y
CONFIG_MODVERSIONS=y
CONFIG_MODULE_SRCVERSION_ALL=y
CONFIG_MODULE_SIG_SHA256=y
CONFIG_UNUSED_SYMBOLS=y
CONFIG_BLK_DEV_THROTTLING=y
CONFIG_BLK_WBT=y
CONFIG_BLK_CGROUP_IOLATENCY=y

1
arch/sh/configs/edosk7760_defconfig
View File

@ -102,7 +102,6 @@ CONFIG_NLS_UTF8=y
CONFIG_PRINTK_TIME=y
# CONFIG_ENABLE_MUST_CHECK is not set
CONFIG_MAGIC_SYSRQ=y
CONFIG_UNUSED_SYMBOLS=y
CONFIG_DEBUG_KERNEL=y
CONFIG_DEBUG_SHIRQ=y
CONFIG_DETECT_HUNG_TASK=y

1
arch/sh/configs/sdk7780_defconfig
View File

@ -130,7 +130,6 @@ CONFIG_NLS_ISO8859_15=y
CONFIG_NLS_UTF8=y
# CONFIG_ENABLE_MUST_CHECK is not set
CONFIG_MAGIC_SYSRQ=y
CONFIG_UNUSED_SYMBOLS=y
CONFIG_DEBUG_KERNEL=y
CONFIG_DETECT_HUNG_TASK=y
# CONFIG_SCHED_DEBUG is not set

1
arch/x86/configs/i386_defconfig
View File

@ -50,7 +50,6 @@ CONFIG_JUMP_LABEL=y
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODULE_FORCE_UNLOAD=y
# CONFIG_UNUSED_SYMBOLS is not set
CONFIG_BINFMT_MISC=y
CONFIG_NET=y
CONFIG_PACKET=y

1
arch/x86/configs/x86_64_defconfig
View File

@ -48,7 +48,6 @@ CONFIG_JUMP_LABEL=y
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODULE_FORCE_UNLOAD=y
# CONFIG_UNUSED_SYMBOLS is not set
CONFIG_BINFMT_MISC=y
CONFIG_NET=y
CONFIG_PACKET=y

4
arch/x86/tools/relocs.c
View File

@ -61,8 +61,8 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
"(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
"__(start|end)_pci_.*|"
"__(start|end)_builtin_fw|"
"__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl)|"
"__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl)|"
"__(start|stop)___ksymtab(|_gpl)|"
"__(start|stop)___kcrctab(|_gpl)|"
"__(start|stop)___param|"
"__(start|stop)___modver|"
"__(start|stop)___bug_table|"

28
include/asm-generic/vmlinux.lds.h
View File

@ -481,20 +481,6 @@
__stop___ksymtab_gpl = .; \
} \
\
/* Kernel symbol table: Normal unused symbols */ \
__ksymtab_unused : AT(ADDR(__ksymtab_unused) - LOAD_OFFSET) { \
__start___ksymtab_unused = .; \
KEEP(*(SORT(___ksymtab_unused+*))) \
__stop___ksymtab_unused = .; \
} \
\
/* Kernel symbol table: GPL-only unused symbols */ \
__ksymtab_unused_gpl : AT(ADDR(__ksymtab_unused_gpl) - LOAD_OFFSET) { \
__start___ksymtab_unused_gpl = .; \
KEEP(*(SORT(___ksymtab_unused_gpl+*))) \
__stop___ksymtab_unused_gpl = .; \
} \
\
/* Kernel symbol table: Normal symbols */ \
__kcrctab : AT(ADDR(__kcrctab) - LOAD_OFFSET) { \
__start___kcrctab = .; \
@ -509,20 +495,6 @@
__stop___kcrctab_gpl = .; \
} \
\
/* Kernel symbol table: Normal unused symbols */ \
__kcrctab_unused : AT(ADDR(__kcrctab_unused) - LOAD_OFFSET) { \
__start___kcrctab_unused = .; \
KEEP(*(SORT(___kcrctab_unused+*))) \
__stop___kcrctab_unused = .; \
} \
\
/* Kernel symbol table: GPL-only unused symbols */ \
__kcrctab_unused_gpl : AT(ADDR(__kcrctab_unused_gpl) - LOAD_OFFSET) { \
__start___kcrctab_unused_gpl = .; \
KEEP(*(SORT(___kcrctab_unused_gpl+*))) \
__stop___kcrctab_unused_gpl = .; \
} \
\
/* Kernel symbol table: strings */ \
__ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
*(__ksymtab_strings) \

8
include/linux/export.h
View File

@ -160,14 +160,6 @@ struct kernel_symbol {
#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", #ns)
#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", #ns)
#ifdef CONFIG_UNUSED_SYMBOLS
#define EXPORT_UNUSED_SYMBOL(sym) _EXPORT_SYMBOL(sym, "_unused")
#define EXPORT_UNUSED_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_unused_gpl")
#else
#define EXPORT_UNUSED_SYMBOL(sym)
#define EXPORT_UNUSED_SYMBOL_GPL(sym)
#endif
#endif /* !__ASSEMBLY__ */
#endif /* _LINUX_EXPORT_H */

12
include/linux/module.h
View File

@ -392,18 +392,6 @@ struct module {
const s32 *gpl_crcs;
bool using_gplonly_symbols;
#ifdef CONFIG_UNUSED_SYMBOLS
/* unused exported symbols. */
const struct kernel_symbol *unused_syms;
const s32 *unused_crcs;
unsigned int num_unused_syms;
/* GPL-only, unused exported symbols. */
unsigned int num_unused_gpl_syms;
const struct kernel_symbol *unused_gpl_syms;
const s32 *unused_gpl_crcs;
#endif
#ifdef CONFIG_MODULE_SIG
/* Signature was verified. */
bool sig_ok;

17
init/Kconfig
View File

@ -2262,25 +2262,8 @@ config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
If unsure, say N.
config UNUSED_SYMBOLS
bool "Enable unused/obsolete exported symbols"
default y if X86
help
Unused but exported symbols make the kernel needlessly bigger. For
that reason most of these unused exports will soon be removed. This
option is provided temporarily to provide a transition period in case
some external kernel module needs one of these symbols anyway. If you
encounter such a case in your module, consider if you are actually
using the right API. (rationale: since nobody in the kernel is using
this in a module, there is a pretty good chance it's actually the
wrong interface to use). If you really need the symbol, please send a
mail to the linux kernel mailing list mentioning the symbol and why
you really need it, and what the merge plan to the mainline kernel for
your module is.
config TRIM_UNUSED_KSYMS
bool "Trim unused exported kernel symbols"
depends on !UNUSED_SYMBOLS
help
The kernel and some modules make many symbols available for
other modules to use via EXPORT_SYMBOL() and variants. Depending

71
kernel/module.c
View File

@ -410,14 +410,6 @@ extern const struct kernel_symbol __start___ksymtab_gpl[];
extern const struct kernel_symbol __stop___ksymtab_gpl[];
extern const s32 __start___kcrctab[];
extern const s32 __start___kcrctab_gpl[];
#ifdef CONFIG_UNUSED_SYMBOLS
extern const struct kernel_symbol __start___ksymtab_unused[];
extern const struct kernel_symbol __stop___ksymtab_unused[];
extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
extern const s32 __start___kcrctab_unused[];
extern const s32 __start___kcrctab_unused_gpl[];
#endif
#ifndef CONFIG_MODVERSIONS
#define symversion(base, idx) NULL
@ -432,7 +424,6 @@ struct symsearch {
NOT_GPL_ONLY,
GPL_ONLY,
} license;
bool unused;
};
struct find_symbol_arg {
@ -456,19 +447,6 @@ static bool check_exported_symbol(const struct symsearch *syms,
if (!fsa->gplok && syms->license == GPL_ONLY)
return false;
#ifdef CONFIG_UNUSED_SYMBOLS
if (syms->unused && fsa->warn) {
pr_warn("Symbol %s is marked as UNUSED, however this module is "
"using it.\n", fsa->name);
pr_warn("This symbol will go away in the future.\n");
pr_warn("Please evaluate if this is the right api to use and "
"if it really is, submit a report to the linux kernel "
"mailing list together with submitting your code for "
"inclusion.\n");
}
#endif
fsa->owner = owner;
fsa->crc = symversion(syms->crcs, symnum);
fsa->sym = &syms->start[symnum];
@ -535,18 +513,10 @@ static bool find_symbol(struct find_symbol_arg *fsa)
{
static const struct symsearch arr[] = {
{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
NOT_GPL_ONLY, false },
NOT_GPL_ONLY },
{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
__start___kcrctab_gpl,
GPL_ONLY, false },
#ifdef CONFIG_UNUSED_SYMBOLS
{ __start___ksymtab_unused, __stop___ksymtab_unused,
__start___kcrctab_unused,
NOT_GPL_ONLY, true },
{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
__start___kcrctab_unused_gpl,
GPL_ONLY, true },
#endif
GPL_ONLY },
};
struct module *mod;
unsigned int i;
@ -561,20 +531,10 @@ static bool find_symbol(struct find_symbol_arg *fsa)
lockdep_is_held(&module_mutex)) {
struct symsearch arr[] = {
{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
NOT_GPL_ONLY, false },
NOT_GPL_ONLY },
{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
mod->gpl_crcs,
GPL_ONLY, false },
#ifdef CONFIG_UNUSED_SYMBOLS
{ mod->unused_syms,
mod->unused_syms + mod->num_unused_syms,
mod->unused_crcs,
NOT_GPL_ONLY, true },
{ mod->unused_gpl_syms,
mod->unused_gpl_syms + mod->num_unused_gpl_syms,
mod->unused_gpl_crcs,
GPL_ONLY, true },
#endif
GPL_ONLY },
};
if (mod->state == MODULE_STATE_UNFORMED)
@ -2274,10 +2234,6 @@ static int verify_exported_symbols(struct module *mod)
} arr[] = {
{ mod->syms, mod->num_syms },
{ mod->gpl_syms, mod->num_gpl_syms },
#ifdef CONFIG_UNUSED_SYMBOLS
{ mod->unused_syms, mod->num_unused_syms },
{ mod->unused_gpl_syms, mod->num_unused_gpl_syms },
#endif
};
for (i = 0; i < ARRAY_SIZE(arr); i++) {
@ -3290,16 +3246,6 @@ static int find_module_sections(struct module *mod, struct load_info *info)
&mod->num_gpl_syms);
mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
#ifdef CONFIG_UNUSED_SYMBOLS
mod->unused_syms = section_objs(info, "__ksymtab_unused",
sizeof(*mod->unused_syms),
&mod->num_unused_syms);
mod->unused_crcs = section_addr(info, "__kcrctab_unused");
mod->unused_gpl_syms = section_objs(info, "__ksymtab_unused_gpl",
sizeof(*mod->unused_gpl_syms),
&mod->num_unused_gpl_syms);
mod->unused_gpl_crcs = section_addr(info, "__kcrctab_unused_gpl");
#endif
#ifdef CONFIG_CONSTRUCTORS
mod->ctors = section_objs(info, ".ctors",
sizeof(*mod->ctors), &mod->num_ctors);
@ -3480,13 +3426,8 @@ static int check_module_license_and_versions(struct module *mod)
pr_warn("%s: module license taints kernel.\n", mod->name);
#ifdef CONFIG_MODVERSIONS
if ((mod->num_syms && !mod->crcs)
|| (mod->num_gpl_syms && !mod->gpl_crcs)
#ifdef CONFIG_UNUSED_SYMBOLS
|| (mod->num_unused_syms && !mod->unused_crcs)
|| (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
#endif
) {
if ((mod->num_syms && !mod->crcs) ||
(mod->num_gpl_syms && !mod->gpl_crcs)) {
return try_to_force_load(mod,
"no versions for exported symbols");
}

6
scripts/checkpatch.pl
View File

@ -4290,8 +4290,7 @@ sub process {
if (defined $realline_next &&
exists $lines[$realline_next - 1] &&
!defined $suppress_export{$realline_next} &&
($lines[$realline_next - 1] =~ /EXPORT_SYMBOL.*\((.*)\)/ ||
$lines[$realline_next - 1] =~ /EXPORT_UNUSED_SYMBOL.*\((.*)\)/)) {
($lines[$realline_next - 1] =~ /EXPORT_SYMBOL.*\((.*)\)/)) {
# Handle definitions which produce identifiers with
# a prefix:
# XXX(foo);
@ -4318,8 +4317,7 @@ sub process {
}
if (!defined $suppress_export{$linenr} &&
$prevline =~ /^.\s*$/ &&
($line =~ /EXPORT_SYMBOL.*\((.*)\)/ ||
$line =~ /EXPORT_UNUSED_SYMBOL.*\((.*)\)/)) {
($line =~ /EXPORT_SYMBOL.*\((.*)\)/)) {
#print "FOO B <$lines[$linenr - 1]>\n";
$suppress_export{$linenr} = 2;
}

39
scripts/mod/modpost.c
View File

@ -43,8 +43,9 @@ static int allow_missing_ns_imports;
static bool error_occurred;
enum export {
export_plain, export_unused, export_gpl,
export_unused_gpl, export_unknown
export_plain,
export_gpl,
export_unknown
};
/* In kernel, this size is defined in linux/module.h;
@ -301,9 +302,7 @@ static const struct {
enum export export;
} export_list[] = {
{ .str = "EXPORT_SYMBOL", .export = export_plain },
{ .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
{ .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
{ .str = "(unknown)", .export = export_unknown },
};
@ -362,12 +361,8 @@ static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
if (strstarts(secname, "___ksymtab+"))
return export_plain;
else if (strstarts(secname, "___ksymtab_unused+"))
return export_unused;
else if (strstarts(secname, "___ksymtab_gpl+"))
return export_gpl;
else if (strstarts(secname, "___ksymtab_unused_gpl+"))
return export_unused_gpl;
else
return export_unknown;
}
@ -376,12 +371,8 @@ static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
{
if (sec == elf->export_sec)
return export_plain;
else if (sec == elf->export_unused_sec)
return export_unused;
else if (sec == elf->export_gpl_sec)
return export_gpl;
else if (sec == elf->export_unused_gpl_sec)
return export_unused_gpl;
else
return export_unknown;
}
@ -585,12 +576,8 @@ static int parse_elf(struct elf_info *info, const char *filename)
info->modinfo_len = sechdrs[i].sh_size;
} else if (strcmp(secname, "__ksymtab") == 0)
info->export_sec = i;
else if (strcmp(secname, "__ksymtab_unused") == 0)
info->export_unused_sec = i;
else if (strcmp(secname, "__ksymtab_gpl") == 0)
info->export_gpl_sec = i;
else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
info->export_unused_gpl_sec = i;
if (sechdrs[i].sh_type == SHT_SYMTAB) {
unsigned int sh_link_idx;
@ -2141,32 +2128,13 @@ static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
m, s);
break;
case export_unused_gpl:
error("GPL-incompatible module %s.ko uses GPL-only symbol marked UNUSED '%s'\n",
m, s);
break;
case export_plain:
case export_unused:
case export_unknown:
/* ignore */
break;
}
}
static void check_for_unused(enum export exp, const char *m, const char *s)
{
switch (exp) {
case export_unused:
case export_unused_gpl:
warn("module %s.ko uses symbol '%s' marked UNUSED\n",
m, s);
break;
default:
/* ignore */
break;
}
}
static void check_exports(struct module *mod)
{
struct symbol *s, *exp;
@ -2197,7 +2165,6 @@ static void check_exports(struct module *mod)
if (!mod->gpl_compatible)
check_for_gpl_usage(exp->export, basename, exp->name);
check_for_unused(exp->export, basename, exp->name);
}
}

2
scripts/mod/modpost.h
View File

@ -139,9 +139,7 @@ struct elf_info {
Elf_Sym *symtab_start;
Elf_Sym *symtab_stop;
Elf_Section export_sec;
Elf_Section export_unused_sec;
Elf_Section export_gpl_sec;
Elf_Section export_unused_gpl_sec;
char *strtab;
char *modinfo;
unsigned int modinfo_len;

4
scripts/module.lds.S
View File

@ -11,12 +11,8 @@ SECTIONS {
__ksymtab 0 : { *(SORT(___ksymtab+*)) }
__ksymtab_gpl 0 : { *(SORT(___ksymtab_gpl+*)) }
__ksymtab_unused 0 : { *(SORT(___ksymtab_unused+*)) }
__ksymtab_unused_gpl 0 : { *(SORT(___ksymtab_unused_gpl+*)) }
__kcrctab 0 : { *(SORT(___kcrctab+*)) }
__kcrctab_gpl 0 : { *(SORT(___kcrctab_gpl+*)) }
__kcrctab_unused 0 : { *(SORT(___kcrctab_unused+*)) }
__kcrctab_unused_gpl 0 : { *(SORT(___kcrctab_unused_gpl+*)) }
.init_array 0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) }

2
tools/include/linux/export.h
View File

@ -3,7 +3,5 @@
#define EXPORT_SYMBOL(sym)
#define EXPORT_SYMBOL_GPL(sym)
#define EXPORT_UNUSED_SYMBOL(sym)
#define EXPORT_UNUSED_SYMBOL_GPL(sym)
#endif