#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
# description: Kprobe event argument syntax

[ -f kprobe_events ] || exit_unsupported # this is configurable

grep "x8/16/32/64" README > /dev/null || exit_unsupported # version issue

echo 0 > events/enable
echo > kprobe_events

PROBEFUNC="vfs_read"
GOODREG=
BADREG=
GOODSYM="_sdata"
if ! grep -qw ${GOODSYM} /proc/kallsyms ; then
  GOODSYM=$PROBEFUNC
fi
BADSYM="deaqswdefr"
SYMADDR=0x`grep -w ${GOODSYM} /proc/kallsyms | cut -f 1 -d " "`
GOODTYPE="x16"
BADTYPE="y16"

case `uname -m` in
x86_64|i[3456]86)
  GOODREG=%ax
  BADREG=%ex
;;
aarch64)
  GOODREG=%x0
  BADREG=%ax
;;
arm*)
  GOODREG=%r0
  BADREG=%ax
;;
ppc*)
  GOODREG=%r3
  BADREG=%msr
;;
*)
  echo "Please implement other architecture here"
  exit_untested
esac

test_goodarg() # Good-args
{
  while [ "$1" ]; do
    echo "p ${PROBEFUNC} $1" > kprobe_events
    shift 1
  done;
}

test_badarg() # Bad-args
{
  while [ "$1" ]; do
    ! echo "p ${PROBEFUNC} $1" > kprobe_events
    shift 1
  done;
}

echo > kprobe_events

: "Register access"
test_goodarg ${GOODREG}
test_badarg ${BADREG}

: "Symbol access"
test_goodarg "@${GOODSYM}" "@${SYMADDR}" "@${GOODSYM}+10" "@${GOODSYM}-10"
test_badarg "@" "@${BADSYM}" "@${GOODSYM}*10" "@${GOODSYM}/10" \
	    "@${GOODSYM}%10" "@${GOODSYM}&10" "@${GOODSYM}|10"

: "Stack access"
test_goodarg "\$stack" "\$stack0" "\$stack1"
test_badarg "\$stackp" "\$stack0+10" "\$stack1-10"

: "Retval access"
echo "r ${PROBEFUNC} \$retval" > kprobe_events
! echo "p ${PROBEFUNC} \$retval" > kprobe_events

# $comm was introduced in 4.8, older kernels reject it.
if grep -A1 "fetcharg:" README | grep -q '\$comm' ; then
: "Comm access"
test_goodarg "\$comm"
fi

: "Indirect memory access"
test_goodarg "+0(${GOODREG})" "-0(${GOODREG})" "+10(\$stack)" \
	"+0(\$stack1)" "+10(@${GOODSYM}-10)" "+0(+10(+20(\$stack)))"
test_badarg "+(${GOODREG})" "(${GOODREG}+10)" "-(${GOODREG})" "(${GOODREG})" \
	"+10(\$comm)" "+0(${GOODREG})+10"

: "Name assignment"
test_goodarg "varname=${GOODREG}"
test_badarg "varname=varname2=${GOODREG}"

: "Type syntax"
test_goodarg "${GOODREG}:${GOODTYPE}"
test_badarg "${GOODREG}::${GOODTYPE}" "${GOODREG}:${BADTYPE}" \
	"${GOODTYPE}:${GOODREG}"

: "Combination check"

test_goodarg "\$comm:string" "+0(\$stack):string"
test_badarg "\$comm:x64" "\$stack:string" "${GOODREG}:string"

echo > kprobe_events