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2026-03-21x86/um: fix vDSO installationThomas Weißschuh
The generic vDSO installation logic used by 'make vdso_install' requires that $(vdso-install-y) is defined by the top-level architecture Makefile and that it contains a path relative to the root of the tree. For UML neither of these is satisfied. Move the definition of $(vdso-install-y) to a place which is included by the arch/um/Makefile and use the full relative path. Fixes: f1c2bb8b9964 ("um: implement a x86_64 vDSO") Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://patch.msgid.link/20260318-um-vdso-install-v1-1-26a4ca5c4210@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-10-27x86/um/vdso: Drop VDSO64-y from MakefileThomas Weißschuh
This symbol is unnecessary, remove it. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://patch.msgid.link/20251013-uml-vdso-cleanup-v1-4-a079c7adcc69@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2024-10-23um: vdso: Always reject undefined references in during linkingThomas Weißschuh
Instead of using a custom script to detect and fail on undefined references, use --no-undefined for all VDSO linker invocations. Drop the now unused checkundef.sh script. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Link: https://patch.msgid.link/20241011-vdso-checkundef-v1-2-1a46e0352d20@linutronix.de Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2024-05-14Makefile: remove redundant tool coverage variablesMasahiro Yamada
Now Kbuild provides reasonable defaults for objtool, sanitizers, and profilers. Remove redundant variables. Note: This commit changes the coverage for some objects: - include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV - include arch/sparc/vdso/vdso-image-*.o into UBSAN - include arch/sparc/vdso/vma.o into UBSAN - include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV - include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV - include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV - include arch/x86/entry/vdso/vma.o into GCOV, KCOV - include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV I believe these are positive effects because all of them are kernel space objects. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Roberto Sassu <roberto.sassu@huawei.com>
2024-05-10kbuild: use $(src) instead of $(srctree)/$(src) for source directoryMasahiro Yamada
Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for checked-in source files. It is merely a convention without any functional difference. In fact, $(obj) and $(src) are exactly the same, as defined in scripts/Makefile.build: src := $(obj) When the kernel is built in a separate output directory, $(src) does not accurately reflect the source directory location. While Kbuild resolves this discrepancy by specifying VPATH=$(srctree) to search for source files, it does not cover all cases. For example, when adding a header search path for local headers, -I$(srctree)/$(src) is typically passed to the compiler. This introduces inconsistency between upstream and downstream Makefiles because $(src) is used instead of $(srctree)/$(src) for the latter. To address this inconsistency, this commit changes the semantics of $(src) so that it always points to the directory in the source tree. Going forward, the variables used in Makefiles will have the following meanings: $(obj) - directory in the object tree $(src) - directory in the source tree (changed by this commit) $(objtree) - the top of the kernel object tree $(srctree) - the top of the kernel source tree Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced with $(src). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2023-10-18UML: remove unused cmd_vdso_installMasahiro Yamada
You cannot run this code because arch/um/Makefile does not define the vdso_install target. It appears that this code was blindly copied from another architecture. Remove the dead code. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Richard Weinberger <richard@nod.at>
2023-02-13um: Support LTOPeter Foley
Only a handful of changes are necessary to get it to work. Signed-off-by: Peter Foley <pefoley2@pefoley.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2022-09-21arch: um: Mark the stack non-executable to fix a binutils warningDavid Gow
Since binutils 2.39, ld will print a warning if any stack section is executable, which is the default for stack sections on files without a .note.GNU-stack section. This was fixed for x86 in commit ffcf9c5700e4 ("x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments"), but remained broken for UML, resulting in several warnings: /usr/bin/ld: warning: arch/x86/um/vdso/vdso.o: missing .note.GNU-stack section implies executable stack /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker /usr/bin/ld: warning: .tmp_vmlinux.kallsyms1 has a LOAD segment with RWX permissions /usr/bin/ld: warning: .tmp_vmlinux.kallsyms1.o: missing .note.GNU-stack section implies executable stack /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker /usr/bin/ld: warning: .tmp_vmlinux.kallsyms2 has a LOAD segment with RWX permissions /usr/bin/ld: warning: .tmp_vmlinux.kallsyms2.o: missing .note.GNU-stack section implies executable stack /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker /usr/bin/ld: warning: vmlinux has a LOAD segment with RWX permissions Link both the VDSO and vmlinux with -z noexecstack, fixing the warnings about .note.GNU-stack sections. In addition, pass --no-warn-rwx-segments to dodge the remaining warnings about LOAD segments with RWX permissions in the kallsyms objects. (Note that this flag is apparently not available on lld, so hide it behind a test for BFD, which is what the x86 patch does.) Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ffcf9c5700e49c0aee42dcba9a12ba21338e8136 Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=ba951afb99912da01a6e8434126b8fac7aa75107 Signed-off-by: David Gow <davidgow@google.com> Reviewed-by: Lukas Straub <lukasstraub2@web.de> Tested-by: Lukas Straub <lukasstraub2@web.de> Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested Signed-off-by: Richard Weinberger <richard@nod.at>
2022-07-17UML: add support for KASAN under x86_64Patricia Alfonso
Make KASAN run on User Mode Linux on x86_64. The UML-specific KASAN initializer uses mmap to map the ~16TB of shadow memory to the location defined by KASAN_SHADOW_OFFSET. kasan_init() utilizes constructors to initialize KASAN before main(). The location of the KASAN shadow memory, starting at KASAN_SHADOW_OFFSET, can be configured using the KASAN_SHADOW_OFFSET option. The default location of this offset is 0x100000000000, which keeps it out-of-the-way even on UML setups with more "physical" memory. For low-memory setups, 0x7fff8000 can be used instead, which fits in an immediate and is therefore faster, as suggested by Dmitry Vyukov. There is usually enough free space at this location; however, it is a config option so that it can be easily changed if needed. Note that, unlike KASAN on other architectures, vmalloc allocations still use the shadow memory allocated upfront, rather than allocating and free-ing it per-vmalloc allocation. If another architecture chooses to go down the same path, we should replace the checks for CONFIG_UML with something more generic, such as: - A CONFIG_KASAN_NO_SHADOW_ALLOC option, which architectures could set - or, a way of having architecture-specific versions of these vmalloc and module shadow memory allocation options. Also note that, while UML supports both KASAN in inline mode (CONFIG_KASAN_INLINE) and static linking (CONFIG_STATIC_LINK), it does not support both at the same time. Signed-off-by: Patricia Alfonso <trishalfonso@google.com> Co-developed-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: David Gow <davidgow@google.com> Reviewed-by: Johannes Berg <johannes@sipsolutions.net> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2020-07-07kbuild: remove cc-option test of -fno-stack-protectorMasahiro Yamada
Some Makefiles already pass -fno-stack-protector unconditionally. For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile. No problem report so far about hard-coding this option. So, we can assume all supported compilers know -fno-stack-protector. GCC 4.8 and Clang support this option (https://godbolt.org/z/_HDGzN) Get rid of cc-option from -fno-stack-protector. Remove CONFIG_CC_HAS_STACKPROTECTOR_NONE, which is always 'y'. Note: arch/mips/vdso/Makefile adds -fno-stack-protector twice, first unconditionally, and second conditionally. I removed the second one. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2019-04-24x86/um/vdso: Drop unnecessary cc-ldoptionNick Desaulniers
Towards the goal of removing cc-ldoption, it seems that --hash-style= was added to binutils 2.17.50.0.2 in 2006. The minimal required version of binutils for the kernel according to Documentation/process/changes.rst is 2.20. Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: anton.ivanov@cambridgegreys.com Cc: clang-built-linux@googlegroups.com Cc: jdike@addtoit.com Cc: linux-um@lists.infradead.org Cc: richard@nod.at Link: http://lkml.kernel.org/r/20190423211554.1594-1-ndesaulniers@google.com Link: https://gcc.gnu.org/ml/gcc/2007-01/msg01141.html Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-12-11x86/um/vdso: Drop implicit common-page-size linker flagNick Desaulniers
GNU linker's -z common-page-size's default value is based on the target architecture. arch/x86/um/vdso/Makefile sets it to the architecture default, which is implicit and redundant. Drop it so that one more LLVM build issue gets addressed. Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Richard Weinberger <richard@nod.at> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-um@lists.infradead.org Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20181206191231.192355-1-ndesaulniers@google.com
2018-07-03x86/build/vdso: Remove unused vdso-syms.ldsMasahiro Yamada
This file contains symbol values, and was originally linked into vmlinux, but I have no idea what it was actually used for. Since the following commit: 827880ec260b ("x86/um: thin archives build fix") it is not even linked. Now it is completely orphan, and no problem has been reported. It is a proof that this file was not needed in the first place. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Richard Weinberger <richard@nod.at> Cc: Andy Lutomirski <luto@kernel.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-um@lists.infradead.org Link: http://lkml.kernel.org/r/1530582614-5173-2-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-05-15x86/build/vdso: Put generated linker scripts to $(obj)/Masahiro Yamada
Let's put generated files to $(obj)/ rather than $(src)/ although this is just a matter of taste because both are the same. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: user-mode-linux-devel@lists.sourceforge.net Cc: user-mode-linux-user@lists.sourceforge.net Link: http://lkml.kernel.org/r/1526352744-28229-4-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-05-15x86/build/vdso: Remove unnecessary export in MakefileMasahiro Yamada
CPPFLAGS_vdso.lds is assigned and referenced internally in each Makefile. No need to export it. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: user-mode-linux-devel@lists.sourceforge.net Cc: user-mode-linux-user@lists.sourceforge.net Link: http://lkml.kernel.org/r/1526352744-28229-3-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-30x86/um: thin archives build fixNicholas Piggin
The linker does not like vdso-syms.lds in input archive files. Make it an extra-y instead. Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: user-mode-linux-devel@lists.sourceforge.net Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2016-08-04um: Support kcovVegard Nossum
This adds support for kcov to UML. There is a small problem where UML will randomly segfault during boot; this is because current_thread_info() occasionally returns an invalid (non-NULL) pointer and we try to dereference it in __sanitizer_cov_trace_pc(). I consider this a bug in UML itself and this patch merely exposes it. [v2: disable instrumentation in UML-specific code] Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Meyer <thomas@m3y3r.de> Cc: user-mode-linux-devel <user-mode-linux-devel@lists.sourceforge.net> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: fix gcov build breakageAl Viro
a) exports in gmon_syms.c duplicate kernel/gcov/* ones b) excluding -pg in vdso compile is not enough - -fprofile-arcs and -ftest-coverage also needs to be excluded Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: take arch/um/sys-x86 to arch/x86/umAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>