libbb: make bb_common_bufsiz1 1 kbyte, add capability to use bss tail for it

The config item is FEATURE_USE_BSS_TAIL. When it is off (default):

function                                             old     new   delta
read_config                                          210     228     +18
doCommands                                          2279    2294     +15
ipneigh_list_or_flush                                763     772      +9
ipaddr_list_or_flush                                1256    1261      +5
display_process_list                                1301    1306      +5
conspy_main                                         1378    1383      +5
do_lzo_compress                                      352     355      +3
do_lzo_decompress                                    565     567      +2
push                                                  46      44      -2
inetd_main                                          2136    2134      -2
uevent_main                                          421     418      -3
addLines                                              97      92      -5
bb_common_bufsiz1                                   8193    1024   -7169
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 8/5 up/down: 62/-7181)        Total: -7119 bytes
   text	   data	    bss	    dec	    hex	filename
 829850	   4086	   9080	 843016	  cdd08	busybox_old
 829901	   4086	   1904	 835891	  cc133	busybox_unstripped

FEATURE_USE_BSS_TAIL=y:

read_config                                          210     228     +18
doCommands                                          2279    2294     +15
ipneigh_list_or_flush                                763     772      +9
ipaddr_list_or_flush                                1256    1261      +5
display_process_list                                1301    1306      +5
conspy_main                                         1378    1383      +5
do_lzo_compress                                      352     355      +3
do_lzo_decompress                                    565     567      +2
inetd_main                                          2136    2134      -2
bb_common_bufsiz1                                   8193       -   -8193
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 8/1 up/down: 62/-8195)        Total: -8133 bytes
   text	   data	    bss	    dec	    hex	filename
 829850	   4086	   9080	 843016	  cdd08	busybox_old
 829911	   4086	    880	 834877	  cbd3d	busybox_unstripped

FIXME: setup_common_bufsiz() calls are missing.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index dab807805..75a33c1fb 100644
--- a/Makefile
+++ b/Makefile
@@ -610,7 +610,8 @@ quiet_cmd_busybox__ ?= LINK    $@
       "$(LDFLAGS) $(EXTRA_LDFLAGS)" \
       "$(core-y)" \
       "$(libs-y)" \
-      "$(LDLIBS)"
+      "$(LDLIBS)" \
+      && $(srctree)/scripts/generate_BUFSIZ.sh include/common_bufsiz.h
 
 # Generate System.map
 quiet_cmd_sysmap = SYSMAP
@@ -844,12 +845,15 @@ export CPPFLAGS_busybox.lds += -P -C -U$(ARCH)
 #       Split autoconf.h into include/linux/config/*
 quiet_cmd_gen_bbconfigopts = GEN     include/bbconfigopts.h
       cmd_gen_bbconfigopts = $(srctree)/scripts/mkconfigs include/bbconfigopts.h include/bbconfigopts_bz2.h
+quiet_cmd_gen_common_bufsiz = GEN     include/common_bufsiz.h
+      cmd_gen_common_bufsiz = $(srctree)/scripts/generate_BUFSIZ.sh include/common_bufsiz.h
 quiet_cmd_split_autoconf   = SPLIT   include/autoconf.h -> include/config/*
       cmd_split_autoconf   = scripts/basic/split-include include/autoconf.h include/config
 #bbox# piggybacked generation of few .h files
 include/config/MARKER: scripts/basic/split-include include/autoconf.h
         $(call cmd,split_autoconf)
         $(call cmd,gen_bbconfigopts)
+        $(call cmd,gen_common_bufsiz)
         @touch $@
 
 # Generate some files
@@ -965,6 +969,7 @@ CLEAN_FILES +=	busybox busybox_unstripped* busybox.links \
 MRPROPER_DIRS  += include/config include2
 MRPROPER_FILES += .config .config.old include/asm .version .old_version \
                   include/NUM_APPLETS.h \
+                  include/common_bufsiz.h \
                   include/autoconf.h \
                   include/bbconfigopts.h \
                   include/bbconfigopts_bz2.h \