]> bbs.cooldavid.org Git - net-next-2.6.git/commitdiff
kbuild: strip generated symbols from *.ko
authorJan Beulich <jbeulich@novell.com>
Tue, 16 Dec 2008 11:28:14 +0000 (11:28 +0000)
committerSam Ravnborg <sam@ravnborg.org>
Fri, 19 Dec 2008 21:41:15 +0000 (22:41 +0100)
This patch changes the way __crc_ symbols are being resolved from
using ld to do so to using the assembler, thus allowing these symbols
to be marked local (the linker creates then as global ones) and hence
allow stripping (for modules) or ignoring (for vmlinux) them. While at
this, also strip other generated symbols during module installation.

One potentially debatable point is the handling of the flags passeed
to gcc when translating the intermediate assembly file into an object:
passing $(c_flags) unchanged doesn't work as gcc passes --gdwarf2 to
gas whenever is sees any -g* option, even for -g0, and despite the
fact that the compiler would have already produced all necessary debug
info in the C->assembly translation phase. I took the approach of just
filtering out all -g* options, but an alternative to such negative
filtering might be to have a positive filter which might, in the ideal
case allow just all the -Wa,* options to pass through.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Makefile
scripts/Makefile.build
scripts/Makefile.modinst
scripts/genksyms/genksyms.c
scripts/mksysmap
scripts/strip-symbols [new file with mode: 0644]

index e1c5ae8a8162845b1e76c7d80542d8cf5b1a0652..5dd0ed3b12c60a437e74c681b6f6d144c0cfeaa1 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -605,19 +605,19 @@ MODLIB    = $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
 export MODLIB
 
 #
-#  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.
-
+# 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.
 ifdef INSTALL_MOD_STRIP
 ifeq ($(INSTALL_MOD_STRIP),1)
-mod_strip_cmd = $(STRIP) --strip-debug
+mod_strip_cmd = $(OBJCOPY) --strip-debug --strip-symbols \
+               $(srctree)/scripts/strip-symbols --wildcard
 else
-mod_strip_cmd = $(STRIP) $(INSTALL_MOD_STRIP)
+mod_strip_cmd = $(OBJCOPY) $(INSTALL_MOD_STRIP)
 endif # INSTALL_MOD_STRIP=1
 else
-mod_strip_cmd = true
+mod_strip_cmd = false
 endif # INSTALL_MOD_STRIP
 export mod_strip_cmd
 
index c1da14b9f59de00d20da8dfae8b36a392ddf6f80..6a2153891592738b309d421b3ef9915e6ed57030 100644 (file)
@@ -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_gensymtypes =                                                           \
+cmd_genksyms =                                                              \
     $(CPP) -D__GENKSYMS__ $(c_flags) $< |                                   \
-    $(GENKSYMS) -T $@ -a $(ARCH)                                            \
+    $(GENKSYMS) -T $@ -A -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_gensymtypes, true) >/dev/null;                               \
+    $(call cmd_genksyms, true) >/dev/null;                                  \
     test -s $@ || rm -f $@
 
 $(obj)/%.symtypes : $(src)/%.c FORCE
@@ -177,28 +177,38 @@ 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>.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
+# 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
 #   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 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
+#   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) $<
 
-cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
 cmd_modversions =                                                      \
-       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);        \
+       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;                                                     \
        else                                                            \
-               mv -f $(@D)/.tmp_$(@F) $@;                              \
+               rm -f $(v_file);                                        \
+               $(CC) $(no_g_c_flags) -c -o $@ $(s_file);               \
        fi;
 endif
 
@@ -221,7 +231,12 @@ define rule_cc_o_c
        $(cmd_record_mcount)                                              \
        scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' >    \
                                                      $(dot-target).tmp;  \
-       rm -f $(depfile);                                                 \
+       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=.?);                          \
        mv -f $(dot-target).tmp $(dot-target).cmd
 endef
 
index efa5d940e6324caa0aa120343043b89475502e74..a5122dce126421803f5b19c1729261fb819aa182 100644 (file)
@@ -17,7 +17,8 @@ __modinst: $(modules)
        @:
 
 quiet_cmd_modules_install = INSTALL $@
-      cmd_modules_install = mkdir -p $(2); cp $@ $(2) ; $(mod_strip_cmd) $(2)/$(notdir $@)
+      cmd_modules_install = mkdir -p $(2); \
+                           $(mod_strip_cmd) $@ $(2)/$(notdir $@) || cp $@ $(2)
 
 # Modules built outside the kernel source tree go into extra by default
 INSTALL_MOD_DIR ?= extra
index 3a8297b5184cb1e1443c659905fdc41d9346902b..f8bb4cabd62d30b7b3d762cd8b8f2cde0b7b72be 100644 (file)
@@ -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_preserve, flag_warnings, flag_asm;
 static const char *arch = "";
 static const char *mod_prefix = "";
 
@@ -610,8 +610,11 @@ void export_symbol(const char *name)
                if (flag_dump_defs)
                        fputs(">\n", debugfile);
 
-               /* Used as a linker script. */
-               printf("%s__crc_%s = 0x%08lx ;\n", mod_prefix, name, crc);
+               /* 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);
        }
 }
 
@@ -648,9 +651,10 @@ void error_with_pos(const char *fmt, ...)
 
 static void genksyms_usage(void)
 {
-       fputs("Usage:\n" "genksyms [-adDTwqhV] > /path/to/.tmp_obj.ver\n" "\n"
+       fputs("Usage:\n" "genksyms [-aAdDTwqhV] > /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"
@@ -662,6 +666,7 @@ 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"
@@ -683,6 +688,7 @@ 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'},
@@ -695,10 +701,10 @@ int main(int argc, char **argv)
                {0, 0, 0, 0}
        };
 
-       while ((o = getopt_long(argc, argv, "a:dwqVDr:T:ph",
+       while ((o = getopt_long(argc, argv, "a:dwqVADr:T:ph",
                                &long_opts[0], NULL)) != EOF)
 #else                          /* __GNU_LIBRARY__ */
-       while ((o = getopt(argc, argv, "a:dwqVDr:T:ph")) != EOF)
+       while ((o = getopt(argc, argv, "a:dwqVADr:T:ph")) != EOF)
 #endif                         /* __GNU_LIBRARY__ */
                switch (o) {
                case 'a':
@@ -716,6 +722,9 @@ 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;
index 6e133a0bae7a8db162a5233fbf4af319f5ede35f..1db316a3712b640f38541d65c8e1d2ff5ebb4c7e 100644 (file)
@@ -37,9 +37,6 @@
 
 # readprofile starts reading symbols when _stext is found, and
 # continue until it finds a symbol which is not either of 'T', 't',
-# 'W' or 'w'. __crc_ are 'A' and placed in the middle
-# so we just ignore them to let readprofile continue to work.
-# (At least sparc64 has __crc_ in the middle).
-
-$NM -n $1 | grep -v '\( [aNUw] \)\|\(__crc_\)\|\( \$[adt]\)' > $2
+# 'W' or 'w'.
 
+$NM -n $1 | grep -v '\( [aNUw] \)\|\( \$[adt]\)' > $2
diff --git a/scripts/strip-symbols b/scripts/strip-symbols
new file mode 100644 (file)
index 0000000..29ee8c1
--- /dev/null
@@ -0,0 +1,22 @@
+<*>
+*.h
+__compound_literal[$.][0-9]*
+__crc_[a-zA-Z_]*
+__exitcall_[a-zA-Z_]*
+__func__[$.][0-9]*
+__FUNCTION__[$.][0-9]*
+gcc[0-9]_compiled[$.]
+__initcall_[a-zA-Z_]*
+__kcrctab_[a-zA-Z_]*
+__kstrtab_[a-zA-Z_]*
+__ksymtab_[a-zA-Z_]*
+__mod_[a-zA-Z_]*[0-9]
+__module_depends
+__param_[a-zA-Z_]*
+__pci_fixup_*PCI_ANY_IDPCI_ANY_ID*
+__pci_fixup_*PCI_ANY_IDPCI_DEVICE_ID_*
+__pci_fixup_*PCI_VENDOR_ID_*PCI_ANY_ID*
+__pci_fixup_*PCI_VENDOR_ID_*PCI_DEVICE_ID_*
+__PRETTY_FUNCTION__[$.][0-9]*
+__setup_[a-zA-Z_]*
+____versions