build system: make CONFIG_FEATURE_USE_BSS_TAIL less funky
CONFIG_FEATURE_USE_BSS_TAIL code was aliasing bb_common_bufsiz1 to _end. This is unreliable: _end may be not sufficiently aligned. Change code to simply enlarge COMMON_BUFSIZE when we detect that _end has significant amount of space to the end of page. Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
8f4faa1e3d
commit
5b8c89d1f2
@ -36,11 +36,10 @@ generate_std_and_exit() {
|
||||
}
|
||||
|
||||
generate_big_and_exit() {
|
||||
$debug && echo "Configuring: bb_common_bufsiz1[] in _end[], COMMON_BUFSIZE = $1"
|
||||
$debug && echo "Configuring: bb_common_bufsiz1[] in bss, COMMON_BUFSIZE = $1"
|
||||
{
|
||||
echo "enum { COMMON_BUFSIZE = $1 };"
|
||||
echo "extern char _end[]; /* linker-provided label */"
|
||||
echo "#define bb_common_bufsiz1 _end"
|
||||
echo "extern char bb_common_bufsiz1[];"
|
||||
echo "#define setup_common_bufsiz() ((void)0)"
|
||||
} | regenerate "$common_bufsiz_h"
|
||||
echo "$2" >"$common_bufsiz_h.method"
|
||||
@ -51,20 +50,10 @@ generate_1k_and_exit() {
|
||||
generate_big_and_exit 1024 "1k"
|
||||
}
|
||||
|
||||
|
||||
generate_malloc_and_exit() {
|
||||
$debug && echo "Configuring: bb_common_bufsiz1[] is malloced"
|
||||
{
|
||||
echo "enum { COMMON_BUFSIZE = 1024 };"
|
||||
echo "extern char *const bb_common_bufsiz1;"
|
||||
echo "void setup_common_bufsiz(void);"
|
||||
} | regenerate "$common_bufsiz_h"
|
||||
echo "malloc" >"$common_bufsiz_h.method"
|
||||
$exitcmd
|
||||
}
|
||||
|
||||
round_down_COMMON_BUFSIZE() {
|
||||
COMMON_BUFSIZE=$(( ($1-32) & 0xfffffe0 ))
|
||||
COMMON_BUFSIZE=1024
|
||||
test "$1" -le 32 && return
|
||||
COMMON_BUFSIZE=$(( ($1-32) & 0x0ffffff0 ))
|
||||
COMMON_BUFSIZE=$(( COMMON_BUFSIZE < 1024 ? 1024 : COMMON_BUFSIZE ))
|
||||
}
|
||||
|
||||
@ -104,77 +93,44 @@ if $postcompile; then
|
||||
test x"$PAGE_SIZE" = x"" && exit 1
|
||||
$debug && echo "PAGE_SIZE:0x$PAGE_SIZE $((0x$PAGE_SIZE))"
|
||||
PAGE_SIZE=$((0x$PAGE_SIZE))
|
||||
test $PAGE_SIZE -lt 512 && exit 1
|
||||
test $PAGE_SIZE -lt 1024 && exit 1
|
||||
|
||||
# How much space between _end[] and next page?
|
||||
PAGE_MASK=$((PAGE_SIZE-1))
|
||||
TAIL_SIZE=$(( (-END) & PAGE_MASK ))
|
||||
$debug && echo "TAIL_SIZE:$TAIL_SIZE bytes"
|
||||
|
||||
if test x"$method" = x"1k" || test x"$method" = x"big"; then
|
||||
if test $TAIL_SIZE -lt 1024; then
|
||||
# _end[] has no enough space for bb_common_bufsiz1[]
|
||||
echo "Warning! Space in _end[] is too small ($TAIL_SIZE bytes)!"
|
||||
echo "Rerun make to build a binary which doesn't use it!"
|
||||
rm -- "$common_bufsiz_h.1k.OK" 2>/dev/null
|
||||
{ md5sum <.config | cut -d' ' -f1; stat -c "%Y" .config; } >"$common_bufsiz_h.1k.FAIL"
|
||||
rm busybox_unstripped busybox 2>/dev/null
|
||||
# Note: here we can do either a "malloc" or "std" build.
|
||||
# "malloc" gives a bit bigger code:
|
||||
# text bss filename
|
||||
# 804355 5385 busybox.std
|
||||
# 804618 4361 busybox.malloc
|
||||
# but may have a smaller .bss (not guaranteed!). Use "pmap -x" to verify.
|
||||
exitcmd="exit 1"
|
||||
generate_malloc_and_exit
|
||||
else
|
||||
PREV_SIZE=1024
|
||||
test x"$method" = x"big" && PREV_SIZE=`cat -- "$common_bufsiz_h.1k.OK"`
|
||||
round_down_COMMON_BUFSIZE $PREV_SIZE
|
||||
PREV_BUFSIZE=$COMMON_BUFSIZE
|
||||
|
||||
rm -- "$common_bufsiz_h.1k.FAIL" 2>/dev/null
|
||||
echo $TAIL_SIZE >"$common_bufsiz_h.1k.OK"
|
||||
round_down_COMMON_BUFSIZE $TAIL_SIZE
|
||||
if test x"$method" = x"1k"; then
|
||||
{
|
||||
echo $TAIL_SIZE
|
||||
md5sum <.config | cut -d' ' -f1
|
||||
stat -c "%Y" .config
|
||||
} >"$common_bufsiz_h.1k.OK"
|
||||
round_down_COMMON_BUFSIZE $((1024 + TAIL_SIZE))
|
||||
# emit message only if COMMON_BUFSIZE is indeed larger
|
||||
test $COMMON_BUFSIZE -gt $PREV_BUFSIZE \
|
||||
test $COMMON_BUFSIZE -gt 1024 \
|
||||
&& echo "Rerun make to use larger COMMON_BUFSIZE ($COMMON_BUFSIZE)"
|
||||
#TODO: test $PREV_BUFSIZE -lt $TAIL_SIZE && PANIC!!!
|
||||
#Code size with COMMON_BUFSIZE > 1024 may be bigger than code with COMMON_BUFSIZE = 1024!
|
||||
#(currently we just hope "-32 and round down to 32" saves us)
|
||||
|
||||
test $COMMON_BUFSIZE = 1024 && generate_1k_and_exit
|
||||
generate_big_and_exit $COMMON_BUFSIZE "big"
|
||||
fi
|
||||
fi
|
||||
fi
|
||||
|
||||
# Based on past success/fail of 1k build, decide next build type
|
||||
|
||||
if test -f "$common_bufsiz_h.1k.OK"; then
|
||||
# Previous build succeeded fitting 1k into _end[].
|
||||
# Try bigger COMMON_BUFSIZE if possible.
|
||||
TAIL_SIZE=`cat -- "$common_bufsiz_h.1k.OK"`
|
||||
round_down_COMMON_BUFSIZE $TAIL_SIZE
|
||||
# previous 1k build succeeded
|
||||
oldcfg=`tail -n2 -- "$common_bufsiz_h.1k.OK"`
|
||||
curcfg=`md5sum <.config | cut -d' ' -f1; stat -c "%Y" .config`
|
||||
# config did not change
|
||||
if test x"$oldcfg" = x"$curcfg"; then
|
||||
# Try bigger COMMON_BUFSIZE if possible
|
||||
TAIL_SIZE=`head -n1 -- "$common_bufsiz_h.1k.OK"`
|
||||
round_down_COMMON_BUFSIZE $((1024 + TAIL_SIZE))
|
||||
test $COMMON_BUFSIZE = 1024 && generate_1k_and_exit
|
||||
generate_big_and_exit $COMMON_BUFSIZE "big"
|
||||
fi
|
||||
|
||||
if test -f "$common_bufsiz_h.1k.FAIL"; then
|
||||
# Previous build FAILED to fit 1k into _end[].
|
||||
# Was it with same .config?
|
||||
oldcfg=`cat -- "$common_bufsiz_h.1k.FAIL"`
|
||||
curcfg=`md5sum <.config | cut -d' ' -f1; stat -c "%Y" .config`
|
||||
# If yes, then build a "malloced" version
|
||||
if test x"$oldcfg" = x"$curcfg"; then
|
||||
echo "Will not try 1k build, it failed before. Touch .config to override"
|
||||
# Note: here we can do either a "malloc" or "std" build.
|
||||
generate_malloc_and_exit
|
||||
fi
|
||||
# else: try 1k version
|
||||
echo "New .config, will try 1k build"
|
||||
rm -- "$common_bufsiz_h.1k.FAIL"
|
||||
generate_1k_and_exit
|
||||
# config did change
|
||||
rm -rf -- "$common_bufsiz_h.1k.OK"
|
||||
fi
|
||||
|
||||
# There was no 1k build yet. Try it.
|
||||
|
||||
Loading…
Reference in New Issue
Block a user