kernel/tools/perf/util/unwind.h, branch linux-4.17.y

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

2017-11-02T10:10:55Z

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

perf unwind: Provide only forward declarations for pointer types

2017-04-20T16:22:43Z

No need to drag the headers, helps in untangling them and reducing build time. Link: http://lkml.kernel.org/n/tip-l8soqph92duyw5jdha0fij8b@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf unwind: Add initialized arg into unwind__prepare_access

2016-07-04T23:27:12Z

Adding initialized arg into unwind__prepare_access to get feedback about the initialization state. It's not possible to get it from error code, because we return 0 even in case we don't recognize dso, which is valid. The 'initialized' value is used in following patch to speedup unwind__prepare_access calls logic in fork path. Signed-off-by: Jiri Olsa Cc: David Ahern Cc: He Kuang Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1467634583-29147-4-git-send-email-jolsa@kernel.org [ Remove ; after static inline function signatures, fixes build break ] Signed-off-by: Arnaldo Carvalho de Melo

perf unwind: Change macro names of perf register

2016-06-23T13:30:17Z

Use macro name prefixed with "LIBUNWIND_ARCH" for better understanding that the regs used by callbacks of libunwind are arch specific. The real regs used should be defined in the wrapper file of "unwind-libunwind-local.c" for each supported arch. Signed-off-by: He Kuang Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: David Ahern Cc: Ekaterina Tumanova Cc: Josh Poimboeuf Cc: Kan Liang Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Pekka Enberg Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Sukadev Bhattiprolu Cc: Wang Nan Link: http://lkml.kernel.org/r/1466578626-92406-2-git-send-email-hekuang@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf unwind: Change fixed name of libunwind__arch_reg_id to macro

2016-06-07T18:11:46Z

For local libunwind, it uses the fixed methods to convert register id according to the host platform, but in remote libunwind, this convert function should be the one for remote architecture. This patch changes the fixed name to macro and code for each remote platform can be compiled indivadually. Signed-off-by: He Kuang Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: David Ahern Cc: Ekaterina Tumanova Cc: Josh Poimboeuf Cc: Kan Liang Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Pekka Enberg Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Sukadev Bhattiprolu Cc: Wang Nan Link: http://lkml.kernel.org/r/1464924803-22214-12-git-send-email-hekuang@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf unwind: Check the target platform before assigning unwind methods

2016-06-07T18:09:36Z

Currently, 'perf script' uses host unwind methods to parse perf.data callchain info without taking the target architecture into account, i.e. assuming the perf.data file was generated on the same machine where the analysis is being performed. So we get wrong result without any warnings when unwinding callchains of x86(32-bit) on x86(64-bit) machine. This patch adds an extra step that checks the target platform before assigning unwind methods. In later patches in this series, we can use this info to assign the right unwind methods for supported platforms. Committer note: After fixing it to register the local unwinder for live mode tools ('perf trace', 'perf top'), i.e. tools that don't use a perf.data file, it works as intended and passes the 'perf test unwind' test: # perf trace -e nanosleep --call dwarf usleep 1 0.328 ( 0.058 ms): usleep/11115 nanosleep(rqtp: 0x7fff083fa480) = 0 __nanosleep_nocancel+0x7 (/usr/lib64/libc-2.22.so) usleep+0x34 (/usr/lib64/libc-2.22.so) main+0x1eb (/usr/bin/usleep) __libc_start_main+0xf0 (/usr/lib64/libc-2.22.so) _start+0x29 (/usr/bin/usleep) # perf test 48 48: Test dwarf unwind : Ok # Signed-off-by: He Kuang Acked-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: David Ahern Cc: Ekaterina Tumanova Cc: Josh Poimboeuf Cc: Kan Liang Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Pekka Enberg Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Sukadev Bhattiprolu Cc: Wang Nan Link: http://lkml.kernel.org/r/1464924803-22214-11-git-send-email-hekuang@huawei.com [ Fixed exit path for 'live' mode tools, where we need to default to local unwinding ] Signed-off-by: Arnaldo Carvalho de Melo

perf unwind: Introduce 'struct unwind_libunwind_ops' for local unwind

2016-06-07T15:08:52Z

Currently, libunwind operations are fixed, and they are chosen according to the host architecture. This will lead to a problem that if a thread is run as x86_32 on a x86_64 machine, perf will use libunwind methods for x86_64 to parse the callchain and get wrong results. This patch changes the fixed methods of libunwind operations to be thread/map related, and each thread can have individual libunwind operations. Local libunwind methods are registered as default value. Signed-off-by: He Kuang Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: David Ahern Cc: Ekaterina Tumanova Cc: Josh Poimboeuf Cc: Kan Liang Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Pekka Enberg Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Sukadev Bhattiprolu Cc: Wang Nan Link: http://lkml.kernel.org/r/1464924803-22214-4-git-send-email-hekuang@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf callchains: Use thread->mg->machine

2014-10-29T12:32:46Z

The unwind__get_entries() already receives the thread parameter, from where it can obtain the matching machine structure, shorten the signature. Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Don Zickus Cc: Frederic Weisbecker Cc: Jean Pihet Cc: Jiri Olsa Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-isjc6bm8mv4612mhi6af64go@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Use global caching provided by libunwind

2014-10-29T12:25:22Z

The libunwind provides two caching policy which are global and per-thread. As perf unwinds callchains in a single thread, it'd sufficient to use global caching. This speeds up my perf report from 14s to 7s on a ~260MB data file. Although the output sometimes contains a slight difference (~0.01% in terms of number of lines printed) on callchains which were not resolved. Signed-off-by: Namhyung Kim Acked-by: Jean Pihet Cc: Arun Sharma Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jean Pihet Cc: Jiri Olsa Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1412556363-26229-4-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Create an address space per thread

2014-10-15T20:38:23Z

The unw_addr_space_t in libunwind represents an address space to be used for stack unwinding. It doesn't need to be create/destory everytime to unwind callchain (as in get_entries) and can have a same lifetime as thread (unless exec called). So move the address space construction/destruction logic to the thread lifetime handling functions. This is a preparation to enable caching in the unwind library. Note that it saves unw_addr_space_t object using thread__set_priv(). It seems currently only used by perf trace and perf kvm stat commands which don't use callchain. Signed-off-by: Namhyung Kim Acked-by: Jean Pihet Acked-by: Jiri Olsa Cc: Arun Sharma Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jean Pihet Cc: Jiri Olsa Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1412556363-26229-3-git-send-email-namhyung@kernel.org [ Fixup unwind-libunwind.c missing CALLCHAIN_DWARF definition, added missing __maybe_unused on unused parameters in stubs at util/unwind.h ] Signed-off-by: Arnaldo Carvalho de Melo