----- On Apr 29, 2019, at 1:03 PM, ndesaulniers ndesaulniers@xxxxxxxxxx wrote: > On Mon, Apr 29, 2019 at 8:29 AM Mathieu Desnoyers > <mathieu.desnoyers@xxxxxxxxxxxx> wrote: >> >> Ongoing work for asm goto support from clang requires the >> -no-integrated-as compiler flag. >> >> This compiler flag is present in the toplevel kernel Makefile, >> but is not replicated for selftests. Add it specifically for >> the rseq selftest which requires asm goto. >> >> Link: https://reviews.llvm.org/D56571 >> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> >> CC: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> >> CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >> CC: Joel Fernandes <joelaf@xxxxxxxxxx> >> CC: Peter Zijlstra <peterz@xxxxxxxxxxxxx> >> CC: Catalin Marinas <catalin.marinas@xxxxxxx> >> CC: Dave Watson <davejwatson@xxxxxx> >> CC: Will Deacon <will.deacon@xxxxxxx> >> CC: Shuah Khan <shuah@xxxxxxxxxx> >> CC: Andi Kleen <andi@xxxxxxxxxxxxxx> >> CC: linux-kselftest@xxxxxxxxxxxxxxx >> CC: "H . Peter Anvin" <hpa@xxxxxxxxx> >> CC: Chris Lameter <cl@xxxxxxxxx> >> CC: Russell King <linux@xxxxxxxxxxxxxxxx> >> CC: Michael Kerrisk <mtk.manpages@xxxxxxxxx> >> CC: "Paul E . McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> >> CC: Paul Turner <pjt@xxxxxxxxxx> >> CC: Boqun Feng <boqun.feng@xxxxxxxxx> >> CC: Josh Triplett <josh@xxxxxxxxxxxxxxxx> >> CC: Steven Rostedt <rostedt@xxxxxxxxxxx> >> CC: Ben Maurer <bmaurer@xxxxxx> >> CC: linux-api@xxxxxxxxxxxxxxx >> CC: Andy Lutomirski <luto@xxxxxxxxxxxxxx> >> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> >> CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> >> --- >> tools/testing/selftests/rseq/Makefile | 8 +++++++- >> 1 file changed, 7 insertions(+), 1 deletion(-) >> >> diff --git a/tools/testing/selftests/rseq/Makefile >> b/tools/testing/selftests/rseq/Makefile >> index c30c52e1d0d2..d6469535630a 100644 >> --- a/tools/testing/selftests/rseq/Makefile >> +++ b/tools/testing/selftests/rseq/Makefile >> @@ -1,5 +1,11 @@ >> # SPDX-License-Identifier: GPL-2.0+ OR MIT >> -CFLAGS += -O2 -Wall -g -I./ -I../../../../usr/include/ -L./ -Wl,-rpath=./ >> + >> +ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),) >> +CLANG_FLAGS += -no-integrated-as >> +endif >> + >> +CFLAGS += -O2 -Wall -g -I./ -I../../../../usr/include/ -L./ -Wl,-rpath=./ \ >> + $(CLANG_FLAGS) > > The top level Makefile exports $(CLANG_FLAGS), which should contain > `-no-integrated-as`. Is that available here? If so, then you can > just add `$(CLANG_FLAGS)`, no compiler check needed. AFAIU, the makefiles under tools/testing/selftests all end up including tools/testing/selftests/lib.mk, which states: "# This mimics the top-level Makefile. We do it explicitly here so that this # Makefile can operate with or without the kbuild infrastructure." So I don't think it's using any of the definitions from the toplevel Makefile. > If not, maybe the test for CONFIG_CC_IS_CLANG is cleaner? A quick test indicates that the toplevel CONFIG_* definitions are unavailable from the kernel selftests makefiles. > Thanks for the patch, and helping test asm goto in Clang! You're very welcome! Considering that I intend to have rseq widely adopted in user-space, it's only natural to consider that its user-space side needs to be compiled by clang as well. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
