When __builtin_mul_overflow() has arguments that differ in terms of signedness and width, LLVM may generate a libcall to __muloti4 because it performs the checks in terms of 65-bit multiplication. This issue becomes harder to hit (but still possible) after LLVM 12.0.0, which includes a special case for matching widths but different signs. To gain access to this special case, which the kernel can take advantage of when calls to __muloti4 appear, bump the minimum supported version of LLVM for building the kernel to 13.0.1. 13.0.1 was chosen because there is minimal impact to distribution support while allowing a few more workarounds to be dropped in the kernel source than if 12.0.0 were chosen. Looking at container images of up to date distribution versions: archlinux:latest clang version 16.0.6 debian:oldoldstable-slim clang version 7.0.1-8+deb10u2 (tags/RELEASE_701/final) debian:oldstable-slim Debian clang version 11.0.1-2 debian:stable-slim Debian clang version 14.0.6 debian:testing-slim Debian clang version 16.0.6 (19) debian:unstable-slim Debian clang version 16.0.6 (19) fedora:38 clang version 16.0.6 (Fedora 16.0.6-3.fc38) fedora:latest clang version 17.0.6 (Fedora 17.0.6-1.fc39) fedora:rawhide clang version 17.0.6 (Fedora 17.0.6-1.fc40) opensuse/leap:latest clang version 15.0.7 opensuse/tumbleweed:latest clang version 17.0.6 ubuntu:focal clang version 10.0.0-4ubuntu1 ubuntu:latest Ubuntu clang version 14.0.0-1ubuntu1.1 ubuntu:rolling Ubuntu clang version 16.0.6 (15) ubuntu:devel Ubuntu clang version 17.0.6 (3) The only distribution that gets left behind is Debian Bullseye, as the default version is 11.0.1; other distributions either have a newer version than 13.0.1 or one older than the current minimum of 11.0.0. Debian has easy access to more recent LLVM versions through apt.llvm.org, so this is not as much of a concern. There are also the kernel.org LLVM toolchains, which should work with distributions with glibc 2.28 and newer. Another benefit of slimming up the number of supported versions of LLVM for building the kernel is reducing the build capacity needed to support a matrix that builds with each supported version, which allows a matrix to reallocate the freed up build capacity towards something else, such as more configuration combinations. Closes: https://github.com/ClangBuiltLinux/linux/issues/1975 Link: https://github.com/llvm/llvm-project/issues/38013 Link: https://github.com/llvm/llvm-project/commit/3203143f1356a4e4e3ada231156fc6da6e1a9f9d Link: https://mirrors.edge.kernel.org/pub/tools/llvm/ Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx> --- Documentation/process/changes.rst | 2 +- scripts/min-tool-version.sh | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst index 50b3d1cb1115..d7306b8cad13 100644 --- a/Documentation/process/changes.rst +++ b/Documentation/process/changes.rst @@ -30,7 +30,7 @@ you probably needn't concern yourself with pcmciautils. Program Minimal version Command to check the version ====================== =============== ======================================== GNU C 5.1 gcc --version -Clang/LLVM (optional) 11.0.0 clang --version +Clang/LLVM (optional) 13.0.1 clang --version Rust (optional) 1.74.1 rustc --version bindgen (optional) 0.65.1 bindgen --version GNU make 3.82 make --version diff --git a/scripts/min-tool-version.sh b/scripts/min-tool-version.sh index 9faa4d3d91e3..5d17022ee1f6 100755 --- a/scripts/min-tool-version.sh +++ b/scripts/min-tool-version.sh @@ -29,7 +29,7 @@ llvm) elif [ "$SRCARCH" = loongarch ]; then echo 18.0.0 else - echo 11.0.0 + echo 13.0.1 fi ;; rustc) -- 2.43.0
