kernel/linux.git/arch/um/Makefile, branch v6.12.80

um: Don't rename vmap to kernel_vmap

2025-12-18T12:55:06+00:00

[ Upstream commit a74b6c0e53a6df8e8a096b50c06c4f872906368a ] 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 Signed-off-by: Sasha Levin

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

2025-06-04T12:43:52+00:00

[ Upstream commit ab09da75700e9d25c7dfbc7f7934920beb5e39b9 ] 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 Signed-off-by: Sasha Levin

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

um: Use HOST_DIR for mrproper

2023-06-14T19:27:38+00:00

When HEADER_ARCH was introduced, the MRPROPER_FILES (then MRPROPER_DIRS) list wasn't adjusted, leaving SUBARCH as part of the path argument. This resulted in the "mrproper" target not cleaning up arch/x86/... when SUBARCH was specified. Since HOST_DIR is arch/$(HEADER_ARCH), use it instead to get the correct path. Cc: Richard Weinberger Cc: Anton Ivanov Cc: Johannes Berg Cc: Azeem Shaikh Cc: linux-um@lists.infradead.org Fixes: 7bbe7204e937 ("um: merge Makefile-{i386,x86_64}") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20230606222442.never.807-kees@kernel.org

um: Support LTO

2023-02-13T09:14:31+00:00

Only a handful of changes are necessary to get it to work. Signed-off-by: Peter Foley Signed-off-by: Richard Weinberger

um: Use CFLAGS_vmlinux

2023-02-13T09:14:20+00:00

link-vmlinux.sh doesn't use LDFLAGS_vmlinux when linking the kernel for UML. Move the LDFLAGS_EXESTACK options into CFLAGS_vmlinux so they're actually respected. e.g. /usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../x86_64-pc-linux-gnu/bin/ld: warning: .tmp_vmlinux.kallsyms3.o: missing .note.GNU-stack section implies executable stack /usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../x86_64-pc-linux-gnu/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker /usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../x86_64-pc-linux-gnu/bin/ld: warning: vmlinux has a LOAD segment with RWX permissions Reviewed-by: David Gow Signed-off-by: Peter Foley Signed-off-by: Richard Weinberger

rust: arch/um: Use 'pie' relocation mode under UML

2023-02-10T20:27:32+00:00

UML expects a position independent executable for some reason, so tell rustc to generate pie objects. Otherwise we get a bunch of relocations we can't deal with in libcore. Signed-off-by: David Gow Signed-off-by: Richard Weinberger