/usr/src/linux-source-4.4.0/debian/scripts/retpoline-extract is in linux-source-4.4.0 4.4.0-116.140.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 | #!/bin/bash
cd "$1" || exit 1
{
echo "./vmlinux"
find . -name \*.ko
} | xargs objdump --disassemble | \
awk -F' ' '
/^.\// { file=$1; sub(":.*", "", file); sub("^.*/", "", file); }
/^[0-9a-f][0-9a-f]* <.*>:/ { tag=$1; sub(".*<", "", tag); sub(">.*", "", tag); tag=file " " tag; }
$3 ~ /(callq|jmpq) *\*%/ { print(tag " " $3); }
'
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