5b8c89d1f2
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>
138 lines
3.9 KiB
Bash
Executable File
138 lines
3.9 KiB
Bash
Executable File
#!/bin/sh
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# Called from top-level directory a-la
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#
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# scripts/generate_BUFSIZ.sh include/common_bufsiz.h
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. ./.config || exit 1
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debug=false
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#debug=true
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postcompile=false
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test x"$1" = x"--post" && { postcompile=true; shift; }
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common_bufsiz_h=$1
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test x"$NM" = x"" && NM="${CONFIG_CROSS_COMPILER_PREFIX}nm"
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test x"$CC" = x"" && CC="${CONFIG_CROSS_COMPILER_PREFIX}gcc"
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exitcmd="exit 0"
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regenerate() {
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cat >"$1.$$"
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test -f "$1" && diff "$1.$$" "$1" >/dev/null && rm "$1.$$" && return
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mv "$1.$$" "$1"
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}
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generate_std_and_exit() {
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$debug && echo "Configuring: bb_common_bufsiz1[] in bss"
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{
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echo "enum { COMMON_BUFSIZE = 1024 };"
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echo "extern char bb_common_bufsiz1[];"
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echo "#define setup_common_bufsiz() ((void)0)"
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} | regenerate "$common_bufsiz_h"
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echo "std" >"$common_bufsiz_h.method"
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$exitcmd
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}
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generate_big_and_exit() {
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$debug && echo "Configuring: bb_common_bufsiz1[] in bss, COMMON_BUFSIZE = $1"
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{
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echo "enum { COMMON_BUFSIZE = $1 };"
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echo "extern char bb_common_bufsiz1[];"
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echo "#define setup_common_bufsiz() ((void)0)"
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} | regenerate "$common_bufsiz_h"
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echo "$2" >"$common_bufsiz_h.method"
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$exitcmd
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}
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generate_1k_and_exit() {
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generate_big_and_exit 1024 "1k"
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}
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round_down_COMMON_BUFSIZE() {
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COMMON_BUFSIZE=1024
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test "$1" -le 32 && return
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COMMON_BUFSIZE=$(( ($1-32) & 0x0ffffff0 ))
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COMMON_BUFSIZE=$(( COMMON_BUFSIZE < 1024 ? 1024 : COMMON_BUFSIZE ))
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}
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# User does not want any funky stuff?
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test x"$CONFIG_FEATURE_USE_BSS_TAIL" = x"y" || generate_std_and_exit
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# The script is run two times: before compilation, when it needs to
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# (re)generate $common_bufsiz_h, and directly after successful build,
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# when it needs to assess whether the build is ok to use at all (not buggy),
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# and (re)generate $common_bufsiz_h for a future build.
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if $postcompile; then
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# Postcompile needs to create/delete OK/FAIL files
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test -f busybox_unstripped || exit 1
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test -f "$common_bufsiz_h.method" || exit 1
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# How the build was done?
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method=`cat -- "$common_bufsiz_h.method"`
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# Get _end address
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END=`$NM busybox_unstripped | grep ' . _end$'| cut -d' ' -f1`
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test x"$END" = x"" && generate_std_and_exit
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$debug && echo "END:0x$END $((0x$END))"
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END=$((0x$END))
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# Get PAGE_SIZE
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{
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echo "#include <sys/user.h>"
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echo "#if defined(PAGE_SIZE) && PAGE_SIZE > 0"
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echo "char page_size[PAGE_SIZE];"
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echo "#endif"
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} >page_size_$$.c
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$CC -c "page_size_$$.c" || exit 1
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PAGE_SIZE=`$NM --size-sort "page_size_$$.o" | cut -d' ' -f1`
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rm "page_size_$$.c" "page_size_$$.o"
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test x"$PAGE_SIZE" = x"" && exit 1
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$debug && echo "PAGE_SIZE:0x$PAGE_SIZE $((0x$PAGE_SIZE))"
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PAGE_SIZE=$((0x$PAGE_SIZE))
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test $PAGE_SIZE -lt 1024 && exit 1
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# How much space between _end[] and next page?
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PAGE_MASK=$((PAGE_SIZE-1))
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TAIL_SIZE=$(( (-END) & PAGE_MASK ))
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$debug && echo "TAIL_SIZE:$TAIL_SIZE bytes"
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if test x"$method" = x"1k"; then
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{
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echo $TAIL_SIZE
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md5sum <.config | cut -d' ' -f1
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stat -c "%Y" .config
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} >"$common_bufsiz_h.1k.OK"
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round_down_COMMON_BUFSIZE $((1024 + TAIL_SIZE))
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# emit message only if COMMON_BUFSIZE is indeed larger
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test $COMMON_BUFSIZE -gt 1024 \
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&& echo "Rerun make to use larger COMMON_BUFSIZE ($COMMON_BUFSIZE)"
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test $COMMON_BUFSIZE = 1024 && generate_1k_and_exit
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generate_big_and_exit $COMMON_BUFSIZE "big"
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fi
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fi
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# Based on past success/fail of 1k build, decide next build type
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if test -f "$common_bufsiz_h.1k.OK"; then
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# previous 1k build succeeded
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oldcfg=`tail -n2 -- "$common_bufsiz_h.1k.OK"`
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curcfg=`md5sum <.config | cut -d' ' -f1; stat -c "%Y" .config`
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# config did not change
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if test x"$oldcfg" = x"$curcfg"; then
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# Try bigger COMMON_BUFSIZE if possible
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TAIL_SIZE=`head -n1 -- "$common_bufsiz_h.1k.OK"`
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round_down_COMMON_BUFSIZE $((1024 + TAIL_SIZE))
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test $COMMON_BUFSIZE = 1024 && generate_1k_and_exit
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generate_big_and_exit $COMMON_BUFSIZE "big"
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fi
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# config did change
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rm -rf -- "$common_bufsiz_h.1k.OK"
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fi
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# There was no 1k build yet. Try it.
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generate_1k_and_exit
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