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mcctrl: lookup unexported symbols at runtime

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Instead of parsing System.map, use kallsyms_lookup_name() to
get unexported symbols addresses at module loading time.

This lets mckernel work with kaslr enabled (it gets enabled by
default from el7.5 onwards)

Change-Id: Ie4349fc1145ebce44f37f1f40c16f9d75584074d
This commit is contained in:
Dominique Martinet
2018-08-03 13:12:08 +09:00
committed by Masamichi Takagi
parent 794684985f
commit e8f8660b73
10 changed files with 151 additions and 672 deletions
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72
configure.ac
View File

@ -339,78 +339,6 @@ KDIR="$WITH_KERNELSRC"
UNAME_R="$WITH_UNAME_R"
TARGET="$WITH_TARGET"
MCCTRL_LINUX_SYMTAB=""
case "X$WITH_SYSTEM_MAP" in
Xyes | Xno | X)
MCCTRL_LINUX_SYMTAB=""
;;
*)
MCCTRL_LINUX_SYMTAB="$WITH_SYSTEM_MAP"
;;
esac
AC_MSG_CHECKING([[for System.map]])
if test -r "$MCCTRL_LINUX_SYMTAB"; then
MCCTRL_LINUX_SYMTAB="$MCCTRL_LINUX_SYMTAB"
elif test -r "/boot/System.map-`uname -r`"; then
MCCTRL_LINUX_SYMTAB="/boot/System.map-`uname -r`"
elif test -r "$KDIR/System.map"; then
MCCTRL_LINUX_SYMTAB="$KDIR/System.map"
fi
if test "$MCCTRL_LINUX_SYMTAB" == ""; then
AC_MSG_ERROR([could not find])
fi
if test -z "`eval cat $MCCTRL_LINUX_SYMTAB`"; then
AC_MSG_ERROR([could not read System.map file, no read permission?])
fi
AC_MSG_RESULT([$MCCTRL_LINUX_SYMTAB])
MCCTRL_LINUX_SYMTAB_CMD="cat $MCCTRL_LINUX_SYMTAB"
# MCCTRL_FIND_KSYM(SYMBOL)
# ------------------------------------------------------
# Search System.map for address of the given symbol and
# do one of three things in config.h:
# If not found, leave MCCTRL_KSYM_foo undefined
# If found to be exported, "#define MCCTRL_KSYM_foo 0"
# If found not to be exported, "#define MCCTRL_KSYM_foo 0x<value>"
AC_DEFUN([MCCTRL_FIND_KSYM],[
AC_MSG_CHECKING([[System.map for symbol $1]])
mcctrl_addr=`eval $MCCTRL_LINUX_SYMTAB_CMD | grep " $1\$" | cut -d\ -f1`
if test -z $mcctrl_addr; then
AC_MSG_RESULT([not found])
else
mcctrl_result=$mcctrl_addr
mcctrl_addr="0x$mcctrl_addr"
m4_ifval([$2],[],[
if `eval $MCCTRL_LINUX_SYMTAB_CMD | grep " __ksymtab_$1\$" >/dev/null`; then
mcctrl_result="exported"
mcctrl_addr="0"
fi
])
AC_MSG_RESULT([$mcctrl_result])
AC_DEFINE_UNQUOTED(MCCTRL_KSYM_[]$1,$mcctrl_addr,[Define to address of kernel symbol $1, or 0 if exported])
fi
])
MCCTRL_FIND_KSYM([sys_mount])
MCCTRL_FIND_KSYM([sys_umount])
MCCTRL_FIND_KSYM([sys_unshare])
MCCTRL_FIND_KSYM([zap_page_range])
MCCTRL_FIND_KSYM([vdso_image_64])
MCCTRL_FIND_KSYM([vdso_start])
MCCTRL_FIND_KSYM([vdso_end])
MCCTRL_FIND_KSYM([vdso_pages])
MCCTRL_FIND_KSYM([__vvar_page])
MCCTRL_FIND_KSYM([hpet_address])
# POSTK_DEBUG_ARCH_DEP_50, add:find kernel symbol.
MCCTRL_FIND_KSYM([vdso_spec])
MCCTRL_FIND_KSYM([hv_clock])
MCCTRL_FIND_KSYM([sys_readlink])
MCCTRL_FIND_KSYM([walk_page_range])
case $ENABLE_MEMDUMP in
yes|no|auto)
;;