kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:

    vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
    can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd

The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.

This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.

Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.

Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 114 insertions, 0 deletions

diff --git a/security/apparmor/Makefile b/security/apparmor/Makefile
new file mode 100644
index 000000000..12fb41971
--- /dev/null
+++ b/security/apparmor/Makefile
@@ -0,0 +1,114 @@
+# SPDX-License-Identifier: GPL-2.0
+# Makefile for AppArmor Linux Security Module
+#
+obj-$(CONFIG_SECURITY_APPARMOR) += apparmor.o
+
+apparmor-y := apparmorfs.o audit.o capability.o task.o ipc.o lib.o match.o \
+              path.o domain.o policy.o policy_unpack.o procattr.o lsm.o \
+              resource.o secid.o file.o policy_ns.o label.o mount.o net.o \
+              policy_compat.o af_unix.o
+apparmor-$(CONFIG_SECURITY_APPARMOR_HASH) += crypto.o
+
+obj-$(CONFIG_SECURITY_APPARMOR_KUNIT_TEST) += apparmor_policy_unpack_test.o
+apparmor_policy_unpack_test-objs += policy_unpack_test.o
+
+clean-files := capability_names.h rlim_names.h net_names.h
+
+# Build a lower case string table of address family names
+# Transform lines from
+#    #define AF_LOCAL		1	/* POSIX name for AF_UNIX	*/
+#    #define AF_INET		2	/* Internet IP Protocol 	*/
+# to
+#    [1] = "local",
+#    [2] = "inet",
+#
+# and build the securityfs entries for the mapping.
+# Transforms lines from
+#    #define AF_INET		2	/* Internet IP Protocol 	*/
+# to
+#    #define AA_SFS_AF_MASK "local inet"
+quiet_cmd_make-af = GEN     $@
+cmd_make-af = echo "static const char *const address_family_names[] = {" > $@ ;\
+	sed $< >>$@ -r -n -e "/AF_MAX/d" -e "/AF_LOCAL/d" -e "/AF_ROUTE/d" -e \
+	 's/^\#define[ \t]+AF_([A-Z0-9_]+)[ \t]+([0-9]+)(.*)/[\2] = "\L\1",/p';\
+	echo "};" >> $@ ;\
+	printf '%s' '\#define AA_SFS_AF_MASK "' >> $@ ;\
+	sed -r -n -e "/AF_MAX/d" -e "/AF_LOCAL/d" -e "/AF_ROUTE/d" -e \
+	 's/^\#define[ \t]+AF_([A-Z0-9_]+)[ \t]+([0-9]+)(.*)/\L\1/p'\
+	 $< | tr '\n' ' ' | sed -e 's/ $$/"\n/' >> $@
+
+# Build a lower case string table of sock type names
+# Transform lines from
+#    SOCK_STREAM	= 1,
+# to
+#    [1] = "stream",
+quiet_cmd_make-sock = GEN     $@
+cmd_make-sock = echo "static const char *const sock_type_names[] = {" >> $@ ;\
+	sed $^ >>$@ -r -n \
+	-e 's/^\tSOCK_([A-Z0-9_]+)[\t]+=[ \t]+([0-9]+)(.*)/[\2] = "\L\1",/p';\
+	echo "};" >> $@
+
+# Build a lower case string table of capability names
+# Transforms lines from
+#    #define CAP_DAC_OVERRIDE     1
+# to
+#    [1] = "dac_override",
+quiet_cmd_make-caps = GEN     $@
+cmd_make-caps = echo "static const char *const capability_names[] = {" > $@ ;\
+	sed $< >>$@ -r -n -e '/CAP_FS_MASK/d' \
+	-e 's/^\#define[ \t]+CAP_([A-Z0-9_]+)[ \t]+([0-9]+)/[\2] = "\L\1",/p';\
+	echo "};" >> $@ ;\
+	printf '%s' '\#define AA_SFS_CAPS_MASK "' >> $@ ;\
+	sed $< -r -n -e '/CAP_FS_MASK/d' \
+	    -e 's/^\#define[ \t]+CAP_([A-Z0-9_]+)[ \t]+([0-9]+)/\L\1/p' | \
+	     tr '\n' ' ' | sed -e 's/ $$/"\n/' >> $@
+
+
+# Build a lower case string table of rlimit names.
+# Transforms lines from
+#    #define RLIMIT_STACK		3	/* max stack size */
+# to
+#    [RLIMIT_STACK] = "stack",
+#
+# and build a second integer table (with the second sed cmd), that maps
+# RLIMIT defines to the order defined in asm-generic/resource.h  This is
+# required by policy load to map policy ordering of RLIMITs to internal
+# ordering for architectures that redefine an RLIMIT.
+# Transforms lines from
+#    #define RLIMIT_STACK		3	/* max stack size */
+# to
+# RLIMIT_STACK, 
+#
+# and build the securityfs entries for the mapping.
+# Transforms lines from
+#    #define RLIMIT_FSIZE        1   /* Maximum filesize */
+#    #define RLIMIT_STACK		3	/* max stack size */
+# to
+# #define AA_SFS_RLIMIT_MASK "fsize stack"
+quiet_cmd_make-rlim = GEN     $@
+cmd_make-rlim = echo "static const char *const rlim_names[RLIM_NLIMITS] = {" \
+	> $@ ;\
+	sed $< >> $@ -r -n \
+	    -e 's/^\# ?define[ \t]+(RLIMIT_([A-Z0-9_]+)).*/[\1] = "\L\2",/p';\
+	echo "};" >> $@ ;\
+	echo "static const int rlim_map[RLIM_NLIMITS] = {" >> $@ ;\
+	sed -r -n "s/^\# ?define[ \t]+(RLIMIT_[A-Z0-9_]+).*/\1,/p" $< >> $@ ;\
+	echo "};" >> $@ ; \
+	printf '%s' '\#define AA_SFS_RLIMIT_MASK "' >> $@ ;\
+	sed -r -n 's/^\# ?define[ \t]+RLIMIT_([A-Z0-9_]+).*/\L\1/p' $< | \
+	    tr '\n' ' ' | sed -e 's/ $$/"\n/' >> $@
+
+$(obj)/capability.o : $(obj)/capability_names.h
+$(obj)/net.o : $(obj)/net_names.h
+$(obj)/resource.o : $(obj)/rlim_names.h
+$(obj)/capability_names.h : $(srctree)/include/uapi/linux/capability.h \
+			    $(src)/Makefile
+	$(call cmd,make-caps)
+$(obj)/rlim_names.h : $(srctree)/include/uapi/asm-generic/resource.h \
+		      $(src)/Makefile
+	$(call cmd,make-rlim)
+$(obj)/net_names.h : $(srctree)/include/linux/socket.h \
+		     $(srctree)/include/linux/net.h \
+		     $(src)/Makefile
+	$(call cmd,make-af)
+	$(call cmd,make-sock)