4 Commits

Author	SHA1	Message	Date
Andi Kleen	742c45c3ec	x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2 ... The kernel needs to explicitly enable FSGSBASE. So, the application needs to know if it can safely use these instructions. Just looking at the CPUID bit is not enough because it may be running in a kernel that does not enable the instructions. One way for the application would be to just try and catch the SIGILL. But that is difficult to do in libraries which may not want to overwrite the signal handlers of the main application. Enumerate the enabled FSGSBASE capability in bit 1 of AT_HWCAP2 in the ELF aux vector. AT_HWCAP2 is already used by PPC for similar purposes. The application can access it open coded or by using the getauxval() function in newer versions of glibc. [ tglx: Massaged changelog ] Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/1557309753-24073-18-git-send-email-chang.seok.bae@intel.com Link: https://lkml.kernel.org/r/20200528201402.1708239-14-sashal@kernel.org	2020-06-18 15:47:05 +02:00
Masahiro Yamada	d9c5252295	treewide: add "WITH Linux-syscall-note" to SPDX tag of uapi headers ... UAPI headers licensed under GPL are supposed to have exception "WITH Linux-syscall-note" so that they can be included into non-GPL user space application code. The exception note is missing in some UAPI headers. Some of them slipped in by the treewide conversion commit b24413180f ("License cleanup: add SPDX GPL-2.0 license identifier to files with no license"). Just run: $ git show --oneline b24413180f -- arch/x86/include/uapi/asm/ I believe they are not intentional, and should be fixed too. This patch was generated by the following script: git grep -l --not -e Linux-syscall-note --and -e SPDX-License-Identifier \ -- :arch/*/include/uapi/asm/*.h :include/uapi/ :^*/Kbuild | while read file do sed -i -e '/[[:space:]]OR[[:space:]]/s/\(GPL-[^[:space:]]*\)/(\1 WITH Linux-syscall-note)/g' \ -e '/[[:space:]]or[[:space:]]/s/\(GPL-[^[:space:]]*\)/(\1 WITH Linux-syscall-note)/g' \ -e '/[[:space:]]OR[[:space:]]/!{/[[:space:]]or[[:space:]]/!s/\(GPL-[^[:space:]]*\)/\1 WITH Linux-syscall-note/g}' $file done After this patch is applied, there are 5 UAPI headers that do not contain "WITH Linux-syscall-note". They are kept untouched since this exception applies only to GPL variants. $ git grep --not -e Linux-syscall-note --and -e SPDX-License-Identifier \ -- :arch/*/include/uapi/asm/*.h :include/uapi/ :^*/Kbuild include/uapi/drm/panfrost_drm.h:/* SPDX-License-Identifier: MIT */ include/uapi/linux/batman_adv.h:/* SPDX-License-Identifier: MIT */ include/uapi/linux/qemu_fw_cfg.h:/* SPDX-License-Identifier: BSD-3-Clause */ include/uapi/linux/vbox_err.h:/* SPDX-License-Identifier: MIT */ include/uapi/linux/virtio_iommu.h:/* SPDX-License-Identifier: BSD-3-Clause */ Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>	2019-07-25 11:05:10 +02:00
Greg Kroah-Hartman	b24413180f	License cleanup: add SPDX GPL-2.0 license identifier to files with no license ... 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>	2017-11-02 11:10:55 +01:00
Grzegorz Andrejczuk	0274f9551e	x86/elf: Add HWCAP2 to expose ring 3 MONITOR/MWAIT ... Introduce ELF_HWCAP2 variable for x86 and reserve its bit 0 to expose the ring 3 MONITOR/MWAIT. HWCAP variables contain bitmasks which can be used by userspace applications to detect which instruction sets are supported by CPU. On x86 architecture information about CPU capabilities can be checked via CPUID instructions, unfortunately presence of ring 3 MONITOR/MWAIT feature cannot be checked this way. ELF_HWCAP cannot be used as well, because on x86 it is set to CPUID[1].EDX which means that all bits are reserved there. HWCAP2 approach was chosen because it reuses existing solution present in other architectures, so only minor modifications are required to the kernel and userspace applications. When ELF_HWCAP2 is defined kernel maps it to AT_HWCAP2 during the start of the application. This way the ring 3 MONITOR/MWAIT feature can be detected using getauxval() API in a simple and fast manner. ELF_HWCAP2 type is u32 to be consistent with x86 ELF_HWCAP type. Signed-off-by: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: Piotr.Luc@intel.com Cc: dave.hansen@linux.intel.com Link: http://lkml.kernel.org/r/1484918557-15481-3-git-send-email-grzegorz.andrejczuk@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>	2017-02-04 08:51:09 +01:00