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authorMasahiro Yamada <masahiroy@kernel.org>2020-04-29 06:45:13 +0300
committerMasahiro Yamada <masahiroy@kernel.org>2020-05-17 12:52:01 +0300
commit9371f86ecb60f6f1f120e3d93fe892bbb70d04c0 (patch)
tree3bf829d594785687c136b1d8295197f58b2038ef /init
parent59721d4eb7f66f27440ad74f875b97e64133ee3b (diff)
downloadlinux-9371f86ecb60f6f1f120e3d93fe892bbb70d04c0.tar.xz
bpfilter: match bit size of bpfilter_umh to that of the kernel
bpfilter_umh is built for the default machine bit of the compiler, which may not match to the bit size of the kernel. This happens in the scenario below: You can use biarch GCC that defaults to 64-bit for building the 32-bit kernel. In this case, Kbuild passes -m32 to teach the compiler to produce 32-bit kernel space objects. However, it is missing when building bpfilter_umh. It is built as a 64-bit ELF, and then embedded into the 32-bit kernel. The 32-bit kernel and 64-bit umh is a bad combination. In theory, we can have 32-bit umh running on 64-bit kernel, but we do not have a good reason to support such a usecase. The best is to match the bit size between them. Pass -m32 or -m64 to the umh build command if it is found in $(KBUILD_CFLAGS). Evaluate CC_CAN_LINK against the kernel bit-size. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'init')
-rw-r--r--init/Kconfig4
1 files changed, 3 insertions, 1 deletions
diff --git a/init/Kconfig b/init/Kconfig
index ed1d82c9f1df..b2ce83c2e84c 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -45,7 +45,9 @@ config CLANG_VERSION
default $(shell,$(srctree)/scripts/clang-version.sh $(CC))
config CC_CAN_LINK
- def_bool $(success,$(srctree)/scripts/cc-can-link.sh $(CC))
+ bool
+ default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(m64-flag)) if 64BIT
+ default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(m32-flag))
config CC_HAS_ASM_GOTO
def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))