kernel/linux.git/arch/um/Makefile, branch v6.19.11

um: Don't rename vmap to kernel_vmap

2025-11-25T09:18:37+00:00

In order to work around the existence of a vmap symbol in libpcap, the UML makefile unconditionally redefines vmap to kernel_vmap. However, this not only affects the actual vmap symbol, but also anything else named vmap, including a number of struct members in DRM. This would not be too much of a problem, since all uses are also updated, except we now have Rust DRM bindings, which expect the corresponding Rust structs to have 'vmap' names. Since the redefinition applies in bindgen, but not to Rust code, we end up with errors such as: error[E0560]: struct `drm_gem_object_funcs` has no fields named `vmap` --> rust/kernel/drm/gem/mod.rs:210:9 Since libpcap support was removed in commit 12b8e7e69aa7 ("um: Remove obsolete pcap driver"), remove the, now unnecessary, define as well. We also take this opportunity to update the comment. Signed-off-by: David Gow Acked-by: Miguel Ojeda Link: https://patch.msgid.link/20251122083213.3996586-1-davidgow@google.com Fixes: 12b8e7e69aa7 ("um: Remove obsolete pcap driver") [adjust commmit message a bit] Signed-off-by: Johannes Berg

Merge tag 'gcc-minimum-version-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2025-05-31T15:16:52+00:00

Pull compiler version requirement update from Arnd Bergmann: "Require gcc-8 and binutils-2.30 x86 already uses gcc-8 as the minimum version, this changes all other architectures to the same version. gcc-8 is used is Debian 10 and Red Hat Enterprise Linux 8, both of which are still supported, and binutils 2.30 is the oldest corresponding version on those. Ubuntu Pro 18.04 and SUSE Linux Enterprise Server 15 both use gcc-7 as the system compiler but additionally include toolchains that remain supported. With the new minimum toolchain versions, a number of workarounds for older versions can be dropped, in particular on x86_64 and arm64. Importantly, the updated compiler version allows removing two of the five remaining gcc plugins, as support for sancov and structeak features is already included in modern compiler versions. I tried collecting the known changes that are possible based on the new toolchain version, but expect that more cleanups will be possible. Since this touches multiple architectures, I merged the patches through the asm-generic tree." * tag 'gcc-minimum-version-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: Makefile.kcov: apply needed compiler option unconditionally in CFLAGS_KCOV Documentation: update binutils-2.30 version reference gcc-plugins: remove SANCOV gcc plugin Kbuild: remove structleak gcc plugin arm64: drop binutils version checks raid6: skip avx512 checks kbuild: require gcc-8 and binutils-2.30

um: let 'make clean' properly clean underlying SUBARCH as well

2025-05-12T06:03:42+00:00

Building the kernel with O= is affected by stale in-tree build artifacts. So, if the source tree is not clean, Kbuild displays the following: $ make ARCH=um O=build defconfig make[1]: Entering directory '/.../linux/build' *** *** The source tree is not clean, please run 'make ARCH=um mrproper' *** in /.../linux *** make[2]: *** [/.../linux/Makefile:673: outputmakefile] Error 1 make[1]: *** [/.../linux/Makefile:248: __sub-make] Error 2 make[1]: Leaving directory '/.../linux/build' make: *** [Makefile:248: __sub-make] Error 2 Usually, running 'make mrproper' is sufficient for cleaning the source tree for out-of-tree builds. However, building UML generates build artifacts not only in arch/um/, but also in the SUBARCH directory (i.e., arch/x86/). If in-tree stale files remain under arch/x86/, Kbuild will reuse them instead of creating new ones under the specified build directory. This commit makes 'make ARCH=um clean' recurse into the SUBARCH directory. Reported-by: Shuah Khan Closes: https://lore.kernel.org/lkml/20250502172459.14175-1-skhan@linuxfoundation.org/ Signed-off-by: Masahiro Yamada Acked-by: Johannes Berg Reviewed-by: David Gow Reviewed-by: Shuah Khan

kbuild: require gcc-8 and binutils-2.30

2025-04-30T19:53:35+00:00

Commit a3e8fe814ad1 ("x86/build: Raise the minimum GCC version to 8.1") raised the minimum compiler version as enforced by Kbuild to gcc-8.1 and clang-15 for x86. This is actually the same gcc version that has been discussed as the minimum for all architectures several times in the past, with little objection. A previous concern was the kernel for SLE15-SP7 needing to be built with gcc-7. As this ended up still using linux-6.4 and there is no plan for an SP8, this is no longer a problem. Change it for all architectures and adjust the documentation accordingly. A few version checks can be removed in the process. The binutils version 2.30 is the lowest version used in combination with gcc-8 on common distros, so use that as the corresponding minimum. Link: https://lore.kernel.org/lkml/20240925150059.3955569-32-ardb+git@google.com/ Link: https://lore.kernel.org/lkml/871q7yxrgv.wl-tiwai@suse.de/ Acked-by: Mark Rutland Signed-off-by: Arnd Bergmann

um: always include kconfig.h and compiler-version.h

2024-11-07T16:36:30+00:00

Since commit a95b37e20db9 ("kbuild: get out of ") we can safely include these files in userspace code. Doing so simplifies matters as options do not need to be exported via asm-offsets.h anymore. Signed-off-by: Benjamin Berg Link: https://patch.msgid.link/20241103150506.1367695-2-benjamin@sipsolutions.net Signed-off-by: Johannes Berg

um: use execveat to create userspace MMs

2024-10-10T11:37:16+00:00

Using clone will not undo features that have been enabled by libc. An example of this already happening is rseq, which could cause the kernel to read/write memory of the userspace process. In the future the standard library might also use mseal by default to protect itself, which would also thwart our attempts at unmapping everything. Solve all this by taking a step back and doing an execve into a tiny static binary that sets up the minimal environment required for the stub without using any standard library. That way we have a clean execution environment that is fully under the control of UML. Note that this changes things a bit as the FDs are not anymore shared with the kernel. Instead, we explicitly share the FDs for the physical memory and all existing iomem regions. Doing this is fine, as iomem regions cannot be added at runtime. Signed-off-by: Benjamin Berg Link: https://patch.msgid.link/20240919124511.282088-3-benjamin@sipsolutions.net [use pipe() instead of pipe2(), remove unneeded close() calls] Signed-off-by: Johannes Berg

um: Makefile: use bash from the environment

2024-04-22T20:17:29+00:00

Set Makefile SHELL to bash instead of /bin/bash for better portability. Some systems do not install binaries to /bin, and therefore do not provide /bin/bash. This includes Linux distros which intentionally avoid implementing the Filesystem Hierarchy Standard (FHS), such as NixOS and Guix System. The recipies inside arch/um/Makefile don't require top-level Bash to build, and setting "SHELL" to "bash" makes Make pick the Bash executable from the environment, hence this patch. Changes since last roll: - Rebase onto a more recent commit on the master branch. - Remove a dangling in-text citation from the change log. - Reword the change log. Signed-off-by: Yueh-Shun Li Reviewed-by: Johannes Berg

um: Fix adding '-no-pie' for clang

2024-01-27T16:13:37+00:00

The kernel builds with -fno-PIE, so commit 883354afbc10 ("um: link vmlinux with -no-pie") added the compiler linker flag '-no-pie' via cc-option because '-no-pie' was only supported in GCC 6.1.0 and newer. While this works for GCC, this does not work for clang because cc-option uses '-c', which stops the pipeline right before linking, so '-no-pie' is unconsumed and clang warns, causing cc-option to fail just as it would if the option was entirely unsupported: $ clang -Werror -no-pie -c -o /dev/null -x c /dev/null clang-16: error: argument unused during compilation: '-no-pie' [-Werror,-Wunused-command-line-argument] A recent version of clang exposes this because it generates a relocation under '-mcmodel=large' that is not supported in PIE mode: /usr/sbin/ld: init/main.o: relocation R_X86_64_32 against symbol `saved_command_line' can not be used when making a PIE object; recompile with -fPIE /usr/sbin/ld: failed to set dynamic section sizes: bad value clang: error: linker command failed with exit code 1 (use -v to see invocation) Remove the cc-option check altogether. It is wasteful to invoke the compiler to check for '-no-pie' because only one supported compiler version does not support it, GCC 5.x (as it is supported with the minimum version of clang and GCC 6.1.0+). Use a combination of the gcc-min-version macro and CONFIG_CC_IS_CLANG to unconditionally add '-no-pie' with CONFIG_LD_SCRIPT_DYN=y, so that it is enabled with all compilers that support this. Furthermore, using gcc-min-version can help turn this back into LINK-$(CONFIG_LD_SCRIPT_DYN) += -no-pie when the minimum version of GCC is bumped past 6.1.0. Cc: stable@vger.kernel.org Closes: https://github.com/ClangBuiltLinux/linux/issues/1982 Signed-off-by: Nathan Chancellor Signed-off-by: Masahiro Yamada

um: use obj-y to descend into arch/um/*/

2023-08-26T20:41:34+00:00

The single build rule does not work with the core-y syntax. [1] Use the standard obj-y syntax. [1]: https://lore.kernel.org/linux-kbuild/d57ba55f-20a3-b836-783d-b49c8a161b6e@kernel.org/T/#m7bc402e1e038f00ebcf2e92ed7fcb8a52fc1ea44 Signed-off-by: Masahiro Yamada Tested-by: Jiri Slaby Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers Signed-off-by: Richard Weinberger

um: Hard-code the result of 'uname -s'

2023-08-26T20:40:37+00:00

We rely on 'uname -s' returning 'Linux' because there are os-Linux/ directories, but no other os-*/. Supporting a non-Linux host is unlikely to happen. Let's hard-code 'Linux'. Signed-off-by: Masahiro Yamada Signed-off-by: Richard Weinberger