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2020-07-29powerpc/build: vdso linker warning for orphan sectionsNicholas Piggin
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200303012748.4190929-1-npiggin@gmail.com
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>
2013-10-11powerpc: Add ability to build little endian kernelsIan Munsie
This patch allows the kbuild system to successfully compile a kernel for the little endian PowerPC64 architecture. A subsequent patch will add the CONFIG_CPU_LITTLE_ENDIAN kernel config option which must be set to build such a kernel. If cross compiling, CROSS_COMPILE must point to a suitable toolchain (compiled for the powerpc64le-linux and powerpcle-linux targets). Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-04-23powerpc: Add VDSO version of timeAdhemerval Zanella
On 04/18/2013 07:38 PM, Anton Blanchard wrote: > Since you are only reading one long you shouldn't need to check the > update count and loop, you will always see a consistent value. The > system call version of time() just does an unprotected load for example. Fixed. > With the above change and with Michael's comments covered (decent > changelog entry and Signed-off-by): > > Acked-by: Anton Blanchard <anton@samba.org> Thanks for the review, below the updated patch: From: Adhemerval Zanella <azanella@linux.vnet.ibm.com> This patch implement the time syscall as vDSO. The performance speedups are: Baseline PPC32: 380 nsec Baseline PPC64: 350 nsec vdso PPC32: 20 nsec vsdo PPC64: 20 nsec Tested on 64 bit build with both 32 bit and 64 bit userland. Acked-by: Anton Blanchard <anton@samba.org> Signed-off-by: Adhemerval Zanella <azanella@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-11powerpc: Add VDSO version of getcpuAnton Blanchard
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 <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2008-12-21powerpc/mm: Introduce MMU featuresBenjamin Herrenschmidt
We're soon running out of CPU features and I need to add some new ones for various MMU related bits, so this patch separates the MMU features from the CPU features. I moved over the 32-bit MMU related ones, added base features for MMU type families, but didn't move over any 64-bit only feature yet. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-03powerpc: Fixup lwsync at runtimeKumar Gala
To allow for a single kernel image on e500 v1/v2/mc we need to fixup lwsync at runtime. On e500v1/v2 lwsync causes an illop so we need to patch up the code. We default to 'sync' since that is always safe and if the cpu is capable we will replace 'sync' with 'lwsync'. We introduce CPU_FTR_LWSYNC as a way to determine at runtime if this is needed. This flag could be moved elsewhere since we dont really use it for the normal CPU_FTR purpose. Finally we only store the relative offset in the fixup section to keep it as small as possible rather than using a full fixup_entry. Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-01powerpc: Introduce infrastructure for feature sections with alternativesMichael Ellerman
The current feature section logic only supports nop'ing out code, this means if you want to choose at runtime between instruction sequences, one or both cases will have to execute the nop'ed out contents of the other section, eg: BEGIN_FTR_SECTION or 1,1,1 END_FTR_SECTION_IFSET(FOO) BEGIN_FTR_SECTION or 2,2,2 END_FTR_SECTION_IFCLR(FOO) and the resulting code will be either, or 1,1,1 nop or, nop or 2,2,2 For small code segments this is fine, but for larger code blocks and in performance criticial code segments, it would be nice to avoid the nops. This commit starts to implement logic to allow the following: BEGIN_FTR_SECTION or 1,1,1 FTR_SECTION_ELSE or 2,2,2 ALT_FTR_SECTION_END_IFSET(FOO) and the resulting code will be: or 1,1,1 or, or 2,2,2 We achieve this by extending the existing FTR macros. The current feature section semantic just becomes a special case, ie. if the else case is empty we nop out the default case. The key limitation is that the size of the else case must be less than or equal to the size of the default case. If the else case is smaller the remainder of the section is nop'ed. We let the linker put the else case code in with the rest of the text, so that relative branches from the else case are more likley to link, this has the disadvantage that we can't free the unused else cases. This commit introduces the required macro and linker script changes, but does not enable the patching of the alternative sections. We also need to update two hand-made section entries in reg.h and timex.h Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-05-23[POWERPC] Tweak VDSO linker script to avoid upsetting old binutilsRoland McGrath
This works around bugs in older binutils' objcopy. The placement of these sections does not really matter, but it confused the buggy old BFD libraries. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-10-16powerpc64 vDSO: linker script indentationRoland McGrath
This cleans up the formatting in the vDSO linker script, mostly just the use of whitespace. It's intended to approximate the kernel standard conventions for indenting C, treating elements of the linker script about like initialized variable definitions. Signed-off-by: Roland McGrath <roland@redhat.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-10-25[POWERPC] Support feature fixups in vdso'sBenjamin Herrenschmidt
This patch reworks the feature fixup mecanism so vdso's can be fixed up. The main issue was that the construct: .long label (or .llong on 64 bits) will not work in the case of a shared library like the vdso. It will generate an empty placeholder in the fixup table along with a reloc, which is not something we can deal with in the vdso. The idea here (thanks Alan Modra !) is to instead use something like: 1: .long label - 1b That is, the feature fixup tables no longer contain addresses of bits of code to patch, but offsets of such code from the fixup table entry itself. That is properly resolved by ld when building the .so's. I've modified the fixup mecanism generically to use that method for the rest of the kernel as well. Another trick is that the 32 bits vDSO included in the 64 bits kernel need to have a table in the 64 bits format. However, gas does not support 32 bits code with a statement of the form: .llong label - 1b (Or even just .llong label) That is, it cannot emit the right fixup/relocation for the linker to use to assign a 32 bits address to an .llong field. Thus, in the specific case of the 32 bits vdso built as part of the 64 bits kernel, we are using a modified macro that generates: .long 0xffffffff .llong label - 1b Note that is assumes that the value is negative which is enforced by the .lds (those offsets are always negative as the .text is always before the fixup table and gas doesn't support emiting the reloc the other way around). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-07-31[PATCH] vDSO hash-style fixRoland McGrath
The latest toolchains can produce a new ELF section in DSOs and dynamically-linked executables. The new section ".gnu.hash" replaces ".hash", and allows for more efficient runtime symbol lookups by the dynamic linker. The new ld option --hash-style={sysv|gnu|both} controls whether to produce the old ".hash", the new ".gnu.hash", or both. In some new systems such as Fedora Core 6, gcc by default passes --hash-style=gnu to the linker, so that a standard invocation of "gcc -shared" results in producing a DSO with only ".gnu.hash". The new ".gnu.hash" sections need to be dealt with the same way as ".hash" sections in all respects; only the dynamic linker cares about their contents. To work with older dynamic linkers (i.e. preexisting releases of glibc), a binary must have the old ".hash" section. The --hash-style=both option produces binaries that a new dynamic linker can use more efficiently, but an old dynamic linker can still handle. The new section runs afoul of the custom linker scripts used to build vDSO images for the kernel. On ia64, the failure mode for this is a boot-time panic because the vDSO's PT_IA_64_UNWIND segment winds up ill-formed. This patch addresses the problem in two ways. First, it mentions ".gnu.hash" in all the linker scripts alongside ".hash". This produces correct vDSO images with --hash-style=sysv (or old tools), with --hash-style=gnu, or with --hash-style=both. Second, it passes the --hash-style=sysv option when building the vDSO images, so that ".gnu.hash" is not actually produced. This is the most conservative choice for compatibility with any old userland. There is some concern that some ancient glibc builds (though not any known old production system) might choke on --hash-style=both binaries. The optimizations provided by the new style of hash section do not really matter for a DSO with a tiny number of symbols, as the vDSO has. If someone wants to use =gnu or =both for their vDSO builds and worry less about that compatibility, just change the option and the linker script changes will make any choice work fine. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Andi Kleen <ak@muc.de> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-11[PATCH] powerpc: Merge vdso's and add vdso support to 32 bits kernelBenjamin Herrenschmidt
This patch moves the vdso's to arch/powerpc, adds support for the 32 bits vdso to the 32 bits kernel, rename systemcfg (finally !), and adds some new (still untested) routines to both vdso's: clock_gettime() with support for CLOCK_REALTIME and CLOCK_MONOTONIC, clock_getres() (same clocks) and get_tbfreq() for glibc to retreive the timebase frequency. Tom,Steve: The implementation of get_tbfreq() I've done for 32 bits returns a long long (r3, r4) not a long. This is such that if we ever add support for >4Ghz timebases on ppc32, the userland interface won't have to change. I have tested gettimeofday() using some glibc patches in both ppc32 and ppc64 kernels using 32 bits userland (I haven't had a chance to test a 64 bits userland yet, but the implementation didn't change and was tested earlier). I haven't tested yet the new functions. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>