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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>
2020-01-19Revert "um: Enable CONFIG_CONSTRUCTORS"Johannes Berg
This reverts commit 786b2384bf1c ("um: Enable CONFIG_CONSTRUCTORS"). There are two issues with this commit, uncovered by Anton in tests on some (Debian) systems: 1) I completely forgot to call any constructors if CONFIG_CONSTRUCTORS isn't set. Don't recall now if it just wasn't needed on my system, or if I never tested this case. 2) With that fixed, it works - with CONFIG_CONSTRUCTORS *unset*. If I set CONFIG_CONSTRUCTORS, it fails again, which isn't totally unexpected since whatever wanted to run is likely to have to run before the kernel init etc. that calls the constructors in this case. Basically, some constructors that gcc emits (libc has?) need to run very early during init; the failure mode otherwise was that the ptrace fork test already failed: ---------------------- $ ./linux mem=512M Core dump limits : soft - 0 hard - NONE Checking that ptrace can change system call numbers...check_ptrace : child exited with exitcode 6, while expecting 0; status 0x67f Aborted ---------------------- Thinking more about this, it's clear that we simply cannot support CONFIG_CONSTRUCTORS in UML. All the cases we need now (gcov, kasan) involve not use of the __attribute__((constructor)), but instead some constructor code/entry generated by gcc. Therefore, we cannot distinguish between kernel constructors and system constructors. Thus, revert this commit. Cc: stable@vger.kernel.org [5.4+] Fixes: 786b2384bf1c ("um: Enable CONFIG_CONSTRUCTORS") Reported-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.co.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-11-04vmlinux.lds.h: Replace RODATA with RO_DATAKees Cook
There's no reason to keep the RODATA macro: replace the callers with the expected RO_DATA macro. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: linux-alpha@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: linux-ia64@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Rick Edgecombe <rick.p.edgecombe@intel.com> Cc: Segher Boessenkool <segher@kernel.crashing.org> Cc: Will Deacon <will@kernel.org> Cc: x86-ml <x86@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: https://lkml.kernel.org/r/20191029211351.13243-12-keescook@chromium.org
2019-11-04vmlinux.lds.h: Move NOTES into RO_DATAKees Cook
The .notes section should be non-executable read-only data. As such, move it to the RO_DATA macro instead of being per-architecture defined. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # s390 Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: linux-alpha@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: linux-ia64@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Rick Edgecombe <rick.p.edgecombe@intel.com> Cc: Segher Boessenkool <segher@kernel.crashing.org> Cc: Will Deacon <will@kernel.org> Cc: x86-ml <x86@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: https://lkml.kernel.org/r/20191029211351.13243-11-keescook@chromium.org
2019-09-15um: Enable CONFIG_CONSTRUCTORSJohannes Berg
We do need to call the constructors for *modules*, and at least for KASAN in the future, we must call even the kernel constructors only later when the kernel has been initialized. Instead of relying on libc to call them, emit an empty section for libc and let the kernel's CONSTRUCTORS code do the rest of the job. Tested that it indeed doesn't work in modules, and does work after the fixes in both, with a few functions with __attribute__((constructor)) in both dynamic and static builds. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2018-10-10vmlinux.lds.h: Move LSM_TABLE into INIT_DATAKees Cook
Since the struct lsm_info table is not an initcall, we can just move it into INIT_DATA like all the other tables. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: John Johansen <john.johansen@canonical.com> Reviewed-by: James Morris <james.morris@microsoft.com> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-06-10um: remove uml initcallsAlexander Pateenok
__uml_initcall() is not used and .uml.initcall.init section is empty: $ grep -r '__uml_initcall(' arch/um/include/shared/init.h:#define __uml_initcall(fn) \ $ readelf -s ../umobj/linux | grep __uml_initcall 23214: 00000000603b75d8 0 NOTYPE GLOBAL DEFAULT 32 __uml_initcall_start 25337: 00000000603b75d8 0 NOTYPE GLOBAL DEFAULT 32 __uml_initcall_end So it is unnecessary. Signed-off-by: Alexander Pateenok <pateenoc@gmail.com> Signed-off-by: Richard Weinberger <richard@nod.at>
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>
2017-07-10um: v2: Use generic NOTES macroThomas Meyer
Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Richard Weinberger <richard@nod.at>
2016-08-23um: Don't discard .text.exit sectionAndrey Ryabinin
Commit e41f501d3912 ("vmlinux.lds: account for destructor sections") added '.text.exit' to EXIT_TEXT which is discarded at link time by default. This breaks compilation of UML: `.text.exit' referenced in section `.fini_array' of /usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/libc.a(sdlerror.o): defined in discarded section `.text.exit' of /usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/libc.a(sdlerror.o) Apparently UML doesn't want to discard exit text, so let's place all EXIT_TEXT sections in .exit.text. Fixes: e41f501d3912 ("vmlinux.lds: account for destructor sections") Reported-by: Stefan Traby <stefan@hello-penguin.com> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: <stable@vger.kernel.org> Acked-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2013-07-03UML: normalize global variables exported by vmlinux.ldsJiang Liu
Normalize global variables exported by vmlinux.lds to conform usage guidelines from include/asm-generic/sections.h. 1) Use _text to mark the start of the kernel image including the head text, and _stext to mark the start of the .text section. 2) Export mandatory global variables __bss_stop. 3) Adjust __init_begin and __init_end to avoid acrossing .text and .data sections. Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24percpu: Always align percpu output section to PAGE_SIZETejun Heo
Percpu allocator honors alignment request upto PAGE_SIZE and both the percpu addresses in the percpu address space and the translated kernel addresses should be aligned accordingly. The calculation of the former depends on the alignment of percpu output section in the kernel image. The linker script macros PERCPU_VADDR() and PERCPU() are used to define this output section and the latter takes @align parameter. Several architectures are using @align smaller than PAGE_SIZE breaking percpu memory alignment. This patch removes @align parameter from PERCPU(), renames it to PERCPU_SECTION() and makes it always align to PAGE_SIZE. While at it, add PCPU_SETUP_BUG_ON() checks such that alignment problems are reliably detected and remove percpu alignment comment recently added in workqueue.c as the condition would trigger BUG way before reaching there. For um, this patch raises the alignment of percpu area. As the area is in .init, there shouldn't be any noticeable difference. This problem was discovered by David Howells while debugging boot failure on mn10300. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Mike Frysinger <vapier@gentoo.org> Cc: uclinux-dist-devel@blackfin.uclinux.org Cc: David Howells <dhowells@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: user-mode-linux-devel@lists.sourceforge.net
2011-01-25percpu: align percpu readmostly subsection to cachelineTejun Heo
Currently percpu readmostly subsection may share cachelines with other percpu subsections which may result in unnecessary cacheline bounce and performance degradation. This patch adds @cacheline parameter to PERCPU() and PERCPU_VADDR() linker macros, makes each arch linker scripts specify its cacheline size and use it to align percpu subsections. This is based on Shaohua's x86 only patch. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Shaohua Li <shaohua.li@intel.com>
2009-09-24um: Clean up linker script using standard macros.Tim Abbott
Signed-off-by: Tim Abbott <tabbott@ksplice.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: user-mode-linux-devel@lists.sourceforge.net Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-09linker script: unify usage of discard definitionTejun Heo
Discarded sections in different archs share some commonality but have considerable differences. This led to linker script for each arch implementing its own /DISCARD/ definition, which makes maintaining tedious and adding new entries error-prone. This patch makes all linker scripts to move discard definitions to the end of the linker script and use the common DISCARDS macro. As ld uses the first matching section definition, archs can include default discarded sections by including them earlier in the linker script. ia64 is notable because it first throws away some ia64 specific subsections and then include the rest of the sections into the final image, so those sections must be discarded before the inclusion. defconfig compile tested for x86, x86-64, powerpc, powerpc64, ia64, alpha, sparc, sparc64 and s390. Michal Simek tested microblaze. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Paul Mundt <lethal@linux-sh.org> Acked-by: Mike Frysinger <vapier@gentoo.org> Tested-by: Michal Simek <monstr@monstr.eu> Cc: linux-arch@vger.kernel.org Cc: Michal Simek <monstr@monstr.eu> Cc: microblaze-uclinux@itee.uq.edu.au Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Tony Luck <tony.luck@intel.com>
2008-10-22x86, um: initial part of asm-um moveAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: H. Peter Anvin <hpa@zytor.com>