mirror_zfs/config/kernel-objtool.m4
Attila Fülöp 6cf17f6538
Linux build: handle CONFIG_OBJTOOL_WERROR=y
Linux 5.16 by default fails the build on objtool warnings. We have
known and understood objtool warnings we can't fix without
involving Linux maintainers.

To work around this we introduce an objtool wrapper script which
removes the `--Werror` flag.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Attila Fülöp <attila@fueloep.org>
Closes #17456
2025-06-16 08:12:09 -07:00

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dnl #
dnl # Detect objtool functionality.
dnl #
dnl #
dnl # Kernel 5.10: linux/frame.h was renamed linux/objtool.h
dnl #
AC_DEFUN([ZFS_AC_KERNEL_OBJTOOL_HEADER], [
AC_MSG_CHECKING([whether objtool header is available])
ZFS_LINUX_TRY_COMPILE([
#include <linux/objtool.h>
],[
],[
objtool_header=$LINUX/include/linux/objtool.h
AC_DEFINE(HAVE_KERNEL_OBJTOOL_HEADER, 1,
[kernel has linux/objtool.h])
AC_MSG_RESULT(linux/objtool.h)
],[
objtool_header=$LINUX/include/linux/frame.h
AC_MSG_RESULT(linux/frame.h)
])
])
dnl #
dnl # Check for objtool support.
dnl #
AC_DEFUN([ZFS_AC_KERNEL_SRC_OBJTOOL], [
dnl # 4.6 API for compile-time stack validation
ZFS_LINUX_TEST_SRC([objtool], [
#undef __ASSEMBLY__
#include <asm/ptrace.h>
#include <asm/frame.h>
],[
#if !defined(FRAME_BEGIN)
#error "FRAME_BEGIN is not defined"
#endif
])
dnl # 4.6 API added STACK_FRAME_NON_STANDARD macro
ZFS_LINUX_TEST_SRC([stack_frame_non_standard], [
#ifdef HAVE_KERNEL_OBJTOOL_HEADER
#include <linux/objtool.h>
#else
#include <linux/frame.h>
#endif
],[
#if !defined(STACK_FRAME_NON_STANDARD)
#error "STACK_FRAME_NON_STANDARD is not defined."
#endif
])
dnl # 6.15 made CONFIG_OBJTOOL_WERROR=y the default. We need to handle
dnl # this or our build will fail.
ZFS_LINUX_TEST_SRC([config_objtool_werror], [
#if !defined(CONFIG_OBJTOOL_WERROR)
#error "CONFIG_OBJTOOL_WERROR is not defined."
#endif
])
])
AC_DEFUN([ZFS_AC_KERNEL_OBJTOOL], [
AC_MSG_CHECKING(
[whether compile-time stack validation (objtool) is available])
ZFS_LINUX_TEST_RESULT([objtool], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_KERNEL_OBJTOOL, 1,
[kernel does stack verification])
AC_MSG_CHECKING([whether STACK_FRAME_NON_STANDARD is defined])
ZFS_LINUX_TEST_RESULT([stack_frame_non_standard], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_STACK_FRAME_NON_STANDARD, 1,
[STACK_FRAME_NON_STANDARD is defined])
dnl # Needed for kernels missing the asm macro. We grep
dnl # for it in the header file since there is currently
dnl # no test to check the result of assembling a file.
AC_MSG_CHECKING(
[whether STACK_FRAME_NON_STANDARD asm macro is defined])
dnl # Escape square brackets.
sp='@<:@@<:@:space:@:>@@:>@'
dotmacro='@<:@.@:>@macro'
regexp="^$sp*$dotmacro$sp+STACK_FRAME_NON_STANDARD$sp"
AS_IF([$EGREP -s -q "$regexp" $objtool_header],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_STACK_FRAME_NON_STANDARD_ASM, 1,
[STACK_FRAME_NON_STANDARD asm macro is defined])
],[
AC_MSG_RESULT(no)
])
],[
AC_MSG_RESULT(no)
])
AC_MSG_CHECKING([whether CONFIG_OBJTOOL_WERROR is defined])
ZFS_LINUX_TEST_RESULT([config_objtool_werror],[
AC_MSG_RESULT(yes)
CONFIG_OBJTOOL_WERROR_DEFINED=yes
],[
AC_MSG_RESULT(no)
])
],[
AC_MSG_RESULT(no)
])
])