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scripts: fix gfp-translate after ___GFP_*_BITS conversion to an enum

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Richard reports that since 772dd03427 ("mm: enumerate all gfp flags"),
gfp-translate is broken, as the bit numbers are implicit, leaving the
shell script unable to extract them.  Even more, some bits are now at a
variable location, making it double extra hard to parse using a simple
shell script.

Use a brute-force approach to the problem by generating a small C stub
that will use the enum to dump the interesting bits.

As an added bonus, we are now able to identify invalid bits for a given
configuration.  As an added drawback, we cannot parse include files that
predate this change anymore.  Tough luck.

Link: https://lkml.kernel.org/r/20240823163850.3791201-1-maz@kernel.org
Fixes: 772dd03427 ("mm: enumerate all gfp flags")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reported-by: Richard Weinberger <richard@nod.at>
Cc: Petr Tesařík <petr@tesarici.cz>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Marc Zyngier 2024-08-23 17:38:50 +01:00 committed by Andrew Morton
parent bfe0857c20
commit a3f6a89c83
1 changed files with 49 additions and 17 deletions
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66
scripts/gfp-translate
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@ -62,25 +62,57 @@ if [ "$GFPMASK" = "none" ]; then
fi
# Extract GFP flags from the kernel source
TMPFILE=`mktemp -t gfptranslate-XXXXXX` || exit 1
grep -q ___GFP $SOURCE/include/linux/gfp_types.h
if [ $? -eq 0 ]; then
grep "^#define ___GFP" $SOURCE/include/linux/gfp_types.h | sed -e 's/u$//' | grep -v GFP_BITS > $TMPFILE
else
grep "^#define __GFP" $SOURCE/include/linux/gfp_types.h | sed -e 's/(__force gfp_t)//' | sed -e 's/u)/)/' | grep -v GFP_BITS | sed -e 's/)\//) \//' > $TMPFILE
fi
TMPFILE=`mktemp -t gfptranslate-XXXXXX.c` || exit 1
# Parse the flags
IFS="
"
echo Source: $SOURCE
echo Parsing: $GFPMASK
for LINE in `cat $TMPFILE`; do
MASK=`echo $LINE | awk '{print $3}'`
if [ $(($GFPMASK&$MASK)) -ne 0 ]; then
echo $LINE
fi
done
rm -f $TMPFILE
(
cat <<EOF
#include <stdint.h>
#include <stdio.h>
// Try to fool compiler.h into not including extra stuff
#define __ASSEMBLY__ 1
#include <generated/autoconf.h>
#include <linux/gfp_types.h>
static const char *masks[] = {
EOF
sed -nEe 's/^[[:space:]]+(___GFP_.*)_BIT,.*$/\1/p' $SOURCE/include/linux/gfp_types.h |
while read b; do
cat <<EOF
#if defined($b) && ($b > 0)
[${b}_BIT] = "$b",
#endif
EOF
done
cat <<EOF
};
int main(int argc, char *argv[])
{
unsigned long long mask = $GFPMASK;
for (int i = 0; i < sizeof(mask) * 8; i++) {
unsigned long long bit = 1ULL << i;
if (mask & bit)
printf("\t%-25s0x%llx\n",
(i < ___GFP_LAST_BIT && masks[i]) ?
masks[i] : "*** INVALID ***",
bit);
}
return 0;
}
EOF
) > $TMPFILE
${CC:-gcc} -Wall -o ${TMPFILE}.bin -I $SOURCE/include $TMPFILE && ${TMPFILE}.bin
rm -f $TMPFILE ${TMPFILE}.bin
exit 0