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Revert "kbuild: strip generated symbols from *.ko"
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This reverts commit ad7a953.

And commit: ("allow stripping of generated symbols under CONFIG_KALLSYMS_ALL")
            9bb4824

These stripping patches has caused a set of issues:

1) People have reported compatibility issues with binutils due to
   lack of support for `--strip-unneeded-symbols' with objcopy 2.15.92.0.2
   Reported by: Wenji
2) ccache and distcc no longer works as expeced
   Reported by: Ted, Roland, + others
3) The installed modules increased a lot in size
   Reported by: Ted, Davej + others

Reported-by: Wenji Huang <[email protected]>
Reported-by: "Theodore Ts'o" <[email protected]>
Reported-by: Dave Jones <[email protected]>
Reported-by: Roland McGrath <[email protected]>
Signed-off-by: Sam Ravnborg <[email protected]>
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@sravnborg
sravnborg committed Jan 14, 2009
1 parent a652504 commit 2ea0389
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Showing 12 changed files with 166 additions and 237 deletions.
59 changes: 18 additions & 41 deletions Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -606,25 +606,20 @@ export INSTALL_PATH ?= /boot
MODLIB = $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
export MODLIB

strip-symbols := $(srctree)/scripts/strip-symbols \
$(wildcard $(srctree)/arch/$(ARCH)/scripts/strip-symbols)

#
# INSTALL_MOD_STRIP, if defined, will cause modules to be stripped while
# they get installed. If INSTALL_MOD_STRIP is '1', then the default
# options (see below) will be used. Otherwise, INSTALL_MOD_STRIP will
# be used as the option(s) to the objcopy command.
# INSTALL_MOD_STRIP, if defined, will cause modules to be
# stripped after they are installed. If INSTALL_MOD_STRIP is '1', then
# the default option --strip-debug will be used. Otherwise,
# INSTALL_MOD_STRIP will used as the options to the strip command.

ifdef INSTALL_MOD_STRIP
ifeq ($(INSTALL_MOD_STRIP),1)
mod_strip_cmd = $(OBJCOPY) --strip-debug
ifeq ($(CONFIG_KALLSYMS_ALL),$(CONFIG_KALLSYMS_STRIP_GENERATED))
mod_strip_cmd += --wildcard $(addprefix --strip-symbols ,$(strip-symbols))
endif
mod_strip_cmd = $(STRIP) --strip-debug
else
mod_strip_cmd = $(OBJCOPY) $(INSTALL_MOD_STRIP)
mod_strip_cmd = $(STRIP) $(INSTALL_MOD_STRIP)
endif # INSTALL_MOD_STRIP=1
else
mod_strip_cmd = false
mod_strip_cmd = true
endif # INSTALL_MOD_STRIP
export mod_strip_cmd

Expand Down Expand Up @@ -754,7 +749,6 @@ last_kallsyms := 2
endif

kallsyms.o := .tmp_kallsyms$(last_kallsyms).o
kallsyms.h := $(wildcard include/config/kallsyms/*.h) $(wildcard include/config/kallsyms/*/*.h)

define verify_kallsyms
$(Q)$(if $($(quiet)cmd_sysmap), \
Expand All @@ -779,41 +773,24 @@ endef

# Generate .S file with all kernel symbols
quiet_cmd_kallsyms = KSYM $@
cmd_kallsyms = { test $* -eq 0 || $(NM) -n $<; } \
| $(KALLSYMS) $(if $(CONFIG_KALLSYMS_ALL),--all-symbols) >$@

quiet_cmd_kstrip = STRIP $@
cmd_kstrip = $(OBJCOPY) --wildcard $(addprefix --strip$(if $(CONFIG_RELOCATABLE),-unneeded)-symbols ,$(filter %/scripts/strip-symbols,$^)) $< $@
cmd_kallsyms = $(NM) -n $< | $(KALLSYMS) \
$(if $(CONFIG_KALLSYMS_ALL),--all-symbols) > $@

$(foreach n,0 1 2 3,.tmp_kallsyms$(n).o): KBUILD_AFLAGS += -Wa,--strip-local-absolute
$(foreach n,0 1 2 3,.tmp_kallsyms$(n).o): %.o: %.S scripts FORCE
.tmp_kallsyms1.o .tmp_kallsyms2.o .tmp_kallsyms3.o: %.o: %.S scripts FORCE
$(call if_changed_dep,as_o_S)

ifeq ($(CONFIG_KALLSYMS_STRIP_GENERATED),y)
strip-ext := .stripped
endif

.tmp_kallsyms%.S: .tmp_vmlinux%$(strip-ext) $(KALLSYMS) $(kallsyms.h)
.tmp_kallsyms%.S: .tmp_vmlinux% $(KALLSYMS)
$(call cmd,kallsyms)

# make -jN seems to have problems with intermediate files, see bug #3330.
.SECONDARY: $(foreach n,1 2 3,.tmp_vmlinux$(n).stripped)
.tmp_vmlinux%.stripped: .tmp_vmlinux% $(strip-symbols) $(kallsyms.h)
$(call cmd,kstrip)

ifneq ($(CONFIG_DEBUG_INFO),y)
.tmp_vmlinux%: LDFLAGS_vmlinux += -S
endif
# .tmp_vmlinux1 must be complete except kallsyms, so update vmlinux version
.tmp_vmlinux%: $(vmlinux-lds) $(vmlinux-all) FORCE
$(if $(filter 1,$*),$(call if_changed_rule,ksym_ld),$(call if_changed,vmlinux__))
.tmp_vmlinux1: $(vmlinux-lds) $(vmlinux-all) FORCE
$(call if_changed_rule,ksym_ld)

.tmp_vmlinux0$(strip-ext):
$(Q)echo "placeholder" >$@
.tmp_vmlinux2: $(vmlinux-lds) $(vmlinux-all) .tmp_kallsyms1.o FORCE
$(call if_changed,vmlinux__)

.tmp_vmlinux1: .tmp_kallsyms0.o
.tmp_vmlinux2: .tmp_kallsyms1.o
.tmp_vmlinux3: .tmp_kallsyms2.o
.tmp_vmlinux3: $(vmlinux-lds) $(vmlinux-all) .tmp_kallsyms2.o FORCE
$(call if_changed,vmlinux__)

# Needs to visit scripts/ before $(KALLSYMS) can be used.
$(KALLSYMS): scripts ;
Expand Down
1 change: 0 additions & 1 deletion arch/x86/scripts/strip-symbols
View file

This file was deleted.

7 changes: 0 additions & 7 deletions init/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -626,13 +626,6 @@ config KALLSYMS_ALL

Say N.

config KALLSYMS_STRIP_GENERATED
bool "Strip machine generated symbols from kallsyms"
depends on KALLSYMS_ALL
default y
help
Say N if you want kallsyms to retain even machine generated symbols.

config KALLSYMS_EXTRA_PASS
bool "Do an extra kallsyms pass"
depends on KALLSYMS
Expand Down
16 changes: 10 additions & 6 deletions kernel/kallsyms.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,19 +30,20 @@
#define all_var 0
#endif

extern const unsigned long kallsyms_addresses[];
extern const u8 kallsyms_names[];
/* These will be re-linked against their real values during the second link stage */
extern const unsigned long kallsyms_addresses[] __attribute__((weak));
extern const u8 kallsyms_names[] __attribute__((weak));

/* tell the compiler that the count isn't in the small data section if the arch
* has one (eg: FRV)
*/
extern const unsigned long kallsyms_num_syms
__attribute__((__section__(".rodata")));
__attribute__((weak, section(".rodata")));

extern const u8 kallsyms_token_table[];
extern const u16 kallsyms_token_index[];
extern const u8 kallsyms_token_table[] __attribute__((weak));
extern const u16 kallsyms_token_index[] __attribute__((weak));

extern const unsigned long kallsyms_markers[];
extern const unsigned long kallsyms_markers[] __attribute__((weak));

static inline int is_kernel_inittext(unsigned long addr)
{
Expand Down Expand Up @@ -167,6 +168,9 @@ static unsigned long get_symbol_pos(unsigned long addr,
unsigned long symbol_start = 0, symbol_end = 0;
unsigned long i, low, high, mid;

/* This kernel should never had been booted. */
BUG_ON(!kallsyms_addresses);

/* do a binary search on the sorted kallsyms_addresses array */
low = 0;
high = kallsyms_num_syms;
Expand Down
55 changes: 20 additions & 35 deletions scripts/Makefile.build
View file
Original file line number Diff line number Diff line change
Expand Up @@ -151,16 +151,16 @@ cmd_cc_i_c = $(CPP) $(c_flags) -o $@ $<
$(obj)/%.i: $(src)/%.c FORCE
$(call if_changed_dep,cc_i_c)

cmd_genksyms = \
cmd_gensymtypes = \
$(CPP) -D__GENKSYMS__ $(c_flags) $< | \
$(GENKSYMS) -T $@ -A -a $(ARCH) \
$(GENKSYMS) -T $@ -a $(ARCH) \
$(if $(KBUILD_PRESERVE),-p) \
$(if $(1),-r $(firstword $(wildcard $(@:.symtypes=.symref) /dev/null)))

quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
cmd_cc_symtypes_c = \
set -e; \
$(call cmd_genksyms, true) >/dev/null; \
$(call cmd_gensymtypes, true) >/dev/null; \
test -s $@ || rm -f $@

$(obj)/%.symtypes : $(src)/%.c FORCE
Expand All @@ -177,38 +177,28 @@ cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<

else
# When module versioning is enabled the following steps are executed:
# o compile a .tmp_<file>.s from <file>.c
# o if .tmp_<file>.s doesn't contain a __ksymtab version, i.e. does
# not export symbols, we just assemble .tmp_<file>.s to <file>.o and
# o compile a .tmp_<file>.o from <file>.c
# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
# not export symbols, we just rename .tmp_<file>.o to <file>.o and
# are done.
# o otherwise, we calculate symbol versions using the good old
# genksyms on the preprocessed source and postprocess them in a way
# that they are usable as assembly source
# o assemble <file>.o from .tmp_<file>.s forcing inclusion of directives
# defining the actual values of __crc_*, followed by objcopy-ing them
# to force these symbols to be local to permit stripping them later.
s_file = $(@D)/.tmp_$(@F:.o=.s)
v_file = $(@D)/.tmp_$(@F:.o=.v)
tmp_o_file = $(@D)/.tmp_$(@F)
no_g_c_flags = $(filter-out -g%,$(c_flags))

cmd_cc_o_c = $(CC) $(c_flags) -S -o $(s_file) $<
# that they are usable as a linker script
# o generate <file>.o from .tmp_<file>.o using the linker to
# replace the unresolved symbols __crc_exported_symbol with
# the actual value of the checksum generated by genksyms

cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
cmd_modversions = \
if grep -q __ksymtab $(s_file); then \
if $(call cmd_genksyms, $(KBUILD_SYMTYPES)) > $(v_file) \
&& $(CC) $(no_g_c_flags) -c -Wa,$(v_file) \
-o $(tmp_o_file) $(s_file) \
&& $(OBJCOPY) -L '__crc_*' -L '___crc_*' -w \
$(tmp_o_file) $@; \
then \
: ; \
else \
rm -f $@; exit 1; \
fi; \
if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
$(call cmd_gensymtypes, $(KBUILD_SYMTYPES)) \
> $(@D)/.tmp_$(@F:.o=.ver); \
\
$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
-T $(@D)/.tmp_$(@F:.o=.ver); \
rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
else \
rm -f $(v_file); \
$(CC) $(no_g_c_flags) -c -o $@ $(s_file); \
mv -f $(@D)/.tmp_$(@F) $@; \
fi;
endif

Expand All @@ -225,12 +215,7 @@ define rule_cc_o_c
$(cmd_record_mcount) \
scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > \
$(dot-target).tmp; \
if [ -r $(@D)/.tmp_$(@F:.o=.v) ]; then \
echo >> $(dot-target).tmp; \
echo '$@: $(GENKSYMS)' >> $(dot-target).tmp; \
echo '$(GENKSYMS):: ;' >> $(dot-target).tmp; \
fi; \
rm -f $(depfile) $(@D)/.tmp_$(@F:.o=.?); \
rm -f $(depfile); \
mv -f $(dot-target).tmp $(dot-target).cmd
endef

Expand Down
3 changes: 1 addition & 2 deletions scripts/Makefile.modinst
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Original file line number Diff line number Diff line change
Expand Up @@ -17,8 +17,7 @@ __modinst: $(modules)
@:

quiet_cmd_modules_install = INSTALL $@
cmd_modules_install = mkdir -p $(2); \
$(mod_strip_cmd) $@ $(2)/$(notdir $@) || cp $@ $(2)
cmd_modules_install = mkdir -p $(2); cp $@ $(2) ; $(mod_strip_cmd) $(2)/$(notdir $@)

# Modules built outside the kernel source tree go into extra by default
INSTALL_MOD_DIR ?= extra
Expand Down
21 changes: 6 additions & 15 deletions scripts/genksyms/genksyms.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -43,7 +43,7 @@ int cur_line = 1;
char *cur_filename;

static int flag_debug, flag_dump_defs, flag_reference, flag_dump_types,
flag_preserve, flag_warnings, flag_asm;
flag_preserve, flag_warnings;
static const char *arch = "";
static const char *mod_prefix = "";

Expand Down Expand Up @@ -610,11 +610,8 @@ void export_symbol(const char *name)
if (flag_dump_defs)
fputs(">\n", debugfile);

/* Used as assembly source or a linker script. */
printf(flag_asm
? ".equiv %s__crc_%s, %#08lx\n"
: "%s__crc_%s = %#08lx ;\n",
mod_prefix, name, crc);
/* Used as a linker script. */
printf("%s__crc_%s = 0x%08lx ;\n", mod_prefix, name, crc);
}
}

Expand Down Expand Up @@ -651,10 +648,9 @@ void error_with_pos(const char *fmt, ...)

static void genksyms_usage(void)
{
fputs("Usage:\n" "genksyms [-aAdDTwqhV] > /path/to/.tmp_obj.ver\n" "\n"
fputs("Usage:\n" "genksyms [-adDTwqhV] > /path/to/.tmp_obj.ver\n" "\n"
#ifdef __GNU_LIBRARY__
" -a, --arch Select architecture\n"
" -A, --asm Generate assembly rather than linker script\n"
" -d, --debug Increment the debug level (repeatable)\n"
" -D, --dump Dump expanded symbol defs (for debugging only)\n"
" -r, --reference file Read reference symbols from a file\n"
Expand All @@ -666,7 +662,6 @@ static void genksyms_usage(void)
" -V, --version Print the release version\n"
#else /* __GNU_LIBRARY__ */
" -a Select architecture\n"
" -A Generate assembly rather than linker script\n"
" -d Increment the debug level (repeatable)\n"
" -D Dump expanded symbol defs (for debugging only)\n"
" -r file Read reference symbols from a file\n"
Expand All @@ -688,7 +683,6 @@ int main(int argc, char **argv)
#ifdef __GNU_LIBRARY__
struct option long_opts[] = {
{"arch", 1, 0, 'a'},
{"asm", 0, 0, 'A'},
{"debug", 0, 0, 'd'},
{"warnings", 0, 0, 'w'},
{"quiet", 0, 0, 'q'},
Expand All @@ -701,10 +695,10 @@ int main(int argc, char **argv)
{0, 0, 0, 0}
};

while ((o = getopt_long(argc, argv, "a:dwqVADr:T:ph",
while ((o = getopt_long(argc, argv, "a:dwqVDr:T:ph",
&long_opts[0], NULL)) != EOF)
#else /* __GNU_LIBRARY__ */
while ((o = getopt(argc, argv, "a:dwqVADr:T:ph")) != EOF)
while ((o = getopt(argc, argv, "a:dwqVDr:T:ph")) != EOF)
#endif /* __GNU_LIBRARY__ */
switch (o) {
case 'a':
Expand All @@ -722,9 +716,6 @@ int main(int argc, char **argv)
case 'V':
fputs("genksyms version 2.5.60\n", stderr);
break;
case 'A':
flag_asm = 1;
break;
case 'D':
flag_dump_defs = 1;
break;
Expand Down
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