From: Nathan Chancellor <nathan@kernel.org> stable inclusion from stable-v5.10.146 commit 050de2898039560060dc2edca3d032ef62132fc1 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6D0VX Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 8cdd23c23c3d481a43b4aa03dcb5738812831115 ] Commit 97fed779f2a6 ("arm64: bti: Provide Kconfig for kernel mode BTI") disabled CONFIG_ARM64_BTI_KERNEL when CONFIG_GCOV_KERNEL was enabled and compiling with clang because of warnings that were seen with allmodconfig because LLVM was not emitting PAC/BTI instructions for compiler generated functions: | warning: some functions compiled with BTI and some compiled without BTI | warning: not setting BTI in feature flags This dependency was fine for avoiding the warnings with allmodconfig until commit 51c2ee6d121c ("Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR"), which prevents CONFIG_GCOV_KERNEL from being enabled with clang 12.0.0 or older because those versions do not support the no_profile_instrument_function attribute. As a result, CONFIG_ARM64_BTI_KERNEL gets enabled with allmodconfig and there are more warnings like the ones above due to CONFIG_KASAN, which suffers from the same problem as CONFIG_GCOV_KERNEL. This was most likely not noticed at the time because allmodconfig + CONFIG_GCOV_KERNEL=n was not tested. defconfig + CONFIG_KASAN=y is enough to reproduce the same warnings as above. The root cause of the warnings was resolved in LLVM during the 12.0.0 release so rather than play whack-a-mole with the dependencies, just update CONFIG_ARM64_BTI_KERNEL to require clang 12.0.0, which will have all of the issues ironed out. Link: https://github.com/ClangBuiltLinux/linux/issues/1428 Link: https://github.com/ClangBuiltLinux/continuous-integration2/runs/3010034706?c... Link: https://github.com/ClangBuiltLinux/continuous-integration2/runs/3010035725?c... Link: https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc7... Signed-off-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/20210712214636.3134425-1-nathan@kernel.org Signed-off-by: Will Deacon <will@kernel.org> Stable-dep-of: c0a454b9044f ("arm64/bti: Disable in kernel BTI when cross section thunks are broken") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com> --- arch/arm64/Kconfig | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index a0bba8e5426a..36e8cf00dbf9 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1785,7 +1785,8 @@ config ARM64_BTI_KERNEL depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697 depends on !CC_IS_GCC || GCC_VERSION >= 100100 - depends on !(CC_IS_CLANG && GCOV_KERNEL) + # https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc7... + depends on !CC_IS_CLANG || CLANG_VERSION >= 120000 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS) help Build the kernel with Branch Target Identification annotations -- 2.25.1