blackbird-op-linux/arch/powerpc/kernel/vdso32/Makefile, branch master

powerpc/32: Add VDSO version of getcpu on non SMP

2020-01-23T10:31:14+00:00

Commit 18ad51dd342a ("powerpc: Add VDSO version of getcpu") added getcpu() for PPC64 only, by making use of a user readable general purpose SPR. PPC32 doesn't have any such SPR. For non SMP, just return CPU id 0 from the VDSO directly. PPC32 doesn't support CONFIG_NUMA so NUMA node is always 0. Before the patch, vdsotest reported: getcpu: syscall: 1572 nsec/call getcpu: libc: 1787 nsec/call getcpu: vdso: not tested Now, vdsotest reports: getcpu: syscall: 1582 nsec/call getcpu: libc: 502 nsec/call getcpu: vdso: 187 nsec/call Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/eaac4b6494ecff1811220fccc895bf282aab884a.1575273217.git.christophe.leroy@c-s.fr

powerpc/vdso: Drop unnecessary cc-ldoption

2019-05-01T00:49:58+00:00

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 Signed-off-by: Nick Desaulniers Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman

powerpc: Enable kcov

2019-02-23T10:04:32+00:00

kcov provides kernel coverage data that's useful for fuzzing tools like syzkaller. Wire up kcov support on powerpc. Disable kcov instrumentation on the same files where we currently disable gcov and UBSan instrumentation, plus some additional exclusions which appear necessary to boot on book3e machines. Signed-off-by: Andrew Donnellan Acked-by: Dmitry Vyukov Tested-by: Daniel Axtens # e6500 Signed-off-by: Michael Ellerman

powerpc/kbuild: Remove CROSS32 defines from top level powerpc Makefile

2018-06-01T13:08:06+00:00

Switch VDSO32 build over to use CROSS32_COMPILE directly, and have it pass in -m32 after the standard c_flags. This allows endianness overrides to be removed and the endian and bitness flags moved into standard flags variables. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

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 Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

powerpc/vdso: Fix build rules to rebuild vdsos correctly

2016-08-10T13:04:12+00:00

When using if_changed, we need to add FORCE as a dependency (see Documentation/kbuild/makefiles.txt) otherwise we don't get command line change checking amongst other things. This has resulted in vdsos not being rebuilt when switching between big and little endian. The vdso64/32ld commands have to be changed around to avoid pulling FORCE into the linker command line (code copied from x86). Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman

powerpc: enable UBSAN support

2016-01-21T01:09:18+00:00

This hooks up UBSAN support for PowerPC. So far it's found some interesting cases where we don't properly sanitise input to shifts, including one in our futex handling. Nothing critical, but interesting and worth fixing. [valentinrothberg@gmail.com: arch/powerpc/Kconfig: fix typo in select statement] Signed-off-by: Daniel Axtens Cc: Andrey Ryabinin Cc: Benjamin Herrenschmidt Tested-by: Andrew Donnellan Acked-by: Michael Ellerman Signed-off-by: Valentin Rothberg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

powerpc/vdso: Emit GNU & SysV hashes

2015-10-01T06:52:00+00:00

Andy Lutomirski says: Some dynamic loaders may be slightly faster if a GNU hash is available. This is unlikely to have any measurable effect on the time it takes to resolve vdso symbols (since there are so few of them). In some contexts, it can be a win for a different reason: if every DSO has a GNU hash section, then libc can avoid calculating SysV hashes at all. Both musl and glibc appear to have this optimization. Signed-off-by: Michael Ellerman

powerpc: Add VDSO version of getcpu

2012-07-11T04:18:40+00:00

We have a request for a fast method of getting CPU and NUMA node IDs from userspace. This patch implements a getcpu VDSO function, similar to x86. Ben suggested we use SPRG3 which is userspace readable. SPRG3 can be modified by a KVM guest, so we save the SPRG3 value in the paca and restore it when transitioning from the guest to the host. I have a glibc patch that implements sched_getcpu on top of this. Testing on a POWER7: baseline: 538 cycles vdso: 30 cycles Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt

powerpc/Makefiles: Change to new flag variables

2010-10-13T05:19:22+00:00

Replace EXTRA_CFLAGS with ccflags-y and EXTRA_AFLAGS with asflags-y. Signed-off-by: matt mooney Signed-off-by: Benjamin Herrenschmidt