Add SUBARCH target for Clang+um (which must go last, not alphabetically, so the other SUBARCHes are assigned). Remove open-coded "DEFINE" macro, instead using linux/kbuild.h's version which was updated to use Clang-friendly assembly in commit cf0c3e68aa81 ("kbuild: fix asm-offset generation to work with clang"). Redefine "DEFINE_LONGS" in terms of "COMMENT" and "DEFINE" so that the intended coment actually has useful content. Add a missed "break" to avoid implicit fall-through warnings.

This lets me run KUnit tests with Clang:

$ ./tools/testing/kunit/kunit.py run --make_options LLVM=1 ...

Cc: Jeff Dike jdike@addtoit.com Cc: Richard Weinberger richard@nod.at Cc: Anton Ivanov anton.ivanov@cambridgegreys.com Cc: Masahiro Yamada masahiroy@kernel.org Cc: Nick Desaulniers ndesaulniers@google.com Cc: Nathan Chancellor nathan@kernel.org Cc: David Gow davidgow@google.com Cc: linux-um@lists.infradead.org Cc: linux-kbuild@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Cc: kunit-dev@googlegroups.com Cc: llvm@lists.linux.dev Reviewed-by: Nathan Chancellor nathan@kernel.org Link: https://lore.kernel.org/lkml/Yg2YubZxvYvx7%2Fnm@dev-arch.archlinux-ax161/ Tested-by: David Gow davidgow@google.com Link: https://lore.kernel.org/lkml/CABVgOSk=oFxsbSbQE-v65VwR2+mXeGXDDjzq8t7FShwjJ3... Signed-off-by: Kees Cook keescook@chromium.org --- v1: https://lore.kernel.org/lkml/20220217002843.2312603-1-keescook@chromium.org v2: https://lore.kernel.org/lkml/20220224055831.1854786-1-keescook@chromium.org v3: - use kbuild.h to avoid duplication (Masahiro) - fix intended comments (Masahiro) - use SUBARCH (Nathan) --- arch/um/os-Linux/execvp.c | 1 + arch/x86/um/user-offsets.c | 9 ++++----- scripts/Makefile.clang | 1 + 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/um/os-Linux/execvp.c b/arch/um/os-Linux/execvp.c index 84a0777c2a45..c09a5fd5e225 100644 --- a/arch/um/os-Linux/execvp.c +++ b/arch/um/os-Linux/execvp.c @@ -93,6 +93,7 @@ int execvp_noalloc(char *buf, const char *file, char *const argv[]) up finding no executable we can use, we want to diagnose that we did find one but were denied access. */ got_eacces = 1; + break; case ENOENT: case ESTALE: case ENOTDIR: diff --git a/arch/x86/um/user-offsets.c b/arch/x86/um/user-offsets.c index bae61554abcc..e54a9814ccf1 100644 --- a/arch/x86/um/user-offsets.c +++ b/arch/x86/um/user-offsets.c @@ -8,12 +8,11 @@ #define __FRAME_OFFSETS #include <linux/ptrace.h> #include <asm/types.h> +#include <linux/kbuild.h>

-#define DEFINE(sym, val) \ - asm volatile("\n->" #sym " %0 " #val : : "i" (val)) - -#define DEFINE_LONGS(sym, val) \ - asm volatile("\n->" #sym " %0 " #val : : "i" (val/sizeof(unsigned long))) +#define DEFINE_LONGS(sym, val) \ + COMMENT(#val " / sizeof(unsigned long)"); \ + DEFINE(sym, val / sizeof(unsigned long))

void foo(void) { diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang index 51fc23e2e9e5..87285b76adb2 100644 --- a/scripts/Makefile.clang +++ b/scripts/Makefile.clang @@ -10,6 +10,7 @@ CLANG_TARGET_FLAGS_powerpc := powerpc64le-linux-gnu CLANG_TARGET_FLAGS_riscv := riscv64-linux-gnu CLANG_TARGET_FLAGS_s390 := s390x-linux-gnu CLANG_TARGET_FLAGS_x86 := x86_64-linux-gnu +CLANG_TARGET_FLAGS_um := $(CLANG_TARGET_FLAGS_$(SUBARCH)) CLANG_TARGET_FLAGS := $(CLANG_TARGET_FLAGS_$(SRCARCH))

ifeq ($(CROSS_COMPILE),)