kernel/linux.git/arch/powerpc/include/asm/barrier.h, branch linux-4.16.y

powerpc/64: Fix smp_wmb barrier definition use use lwsync consistently

2018-04-24T07:42:55+00:00

commit 0bfdf598900fd62869659f360d3387ed80eb71cf upstream. asm/barrier.h is not always included after asm/synch.h, which meant it was missing __SUBARCH_HAS_LWSYNC, so in some files smp_wmb() would be eieio when it should be lwsync. kernel/time/hrtimer.c is one case. __SUBARCH_HAS_LWSYNC is only used in one place, so just fold it in to where it's used. Previously with my small simulator config, 377 instances of eieio in the tree. After this patch there are 55. Fixes: 46d075be585e ("powerpc: Optimise smp_wmb") Cc: stable@vger.kernel.org # v2.6.29+ Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

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

locking: Remove smp_mb__before_spinlock()

2017-08-10T10:29:03+00:00

Now that there are no users of smp_mb__before_spinlock() left, remove it entirely. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

powerpc/64: Drop explicit hwsync in context switch

2017-06-15T06:34:39+00:00

The sync (aka. hwsync, aka. heavyweight sync) in the context switch code to prevent MMIO access being reordered from the point of view of a single process if it gets migrated to a different CPU is not required because there is an hwsync performed earlier in the context switch path. Comment this so it's clear enough if anything changes on the scheduler or the powerpc sides. Remove the hwsync from _switch. This improves context switch performance by 2-3% on POWER8. Signed-off-by: Nicholas Piggin Acked-by: Peter Zijlstra (Intel) Signed-off-by: Michael Ellerman

powerpc: define __smp_xxx

2016-01-12T18:46:53+00:00

This defines __smp_xxx barriers for powerpc for use by virtualization. smp_xxx barriers are removed as they are defined correctly by asm-generic/barriers.h This reduces the amount of arch-specific boiler-plate code. Signed-off-by: Michael S. Tsirkin Acked-by: Arnd Bergmann Acked-by: Boqun Feng Acked-by: Peter Zijlstra (Intel)

powerpc: reuse asm-generic/barrier.h

2016-01-12T18:46:48+00:00

On powerpc read_barrier_depends, smp_read_barrier_depends smp_store_mb(), smp_mb__before_atomic and smp_mb__after_atomic match the asm-generic variants exactly. Drop the local definitions and pull in asm-generic/barrier.h instead. This is in preparation to refactoring this code area. Signed-off-by: Michael S. Tsirkin Acked-by: Arnd Bergmann Acked-by: Peter Zijlstra (Intel) Reviewed-by: Paul E. McKenney

lcoking/barriers, arch: Use smp barriers in smp_store_release()

2016-01-12T18:46:46+00:00

With commit b92b8b35a2e ("locking/arch: Rename set_mb() to smp_store_mb()") it was made clear that the context of this call (and thus set_mb) is strictly for CPU ordering, as opposed to IO. As such all archs should use the smp variant of mb(), respecting the semantics and saving a mandatory barrier on UP. Signed-off-by: Davidlohr Bueso Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Andrew Morton Cc: Benjamin Herrenschmidt Cc: Heiko Carstens Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: dave@stgolabs.net Link: http://lkml.kernel.org/r/1445975631-17047-3-git-send-email-dave@stgolabs.net Signed-off-by: Ingo Molnar Reviewed-by: Paul E. McKenney

locking, arch: use WRITE_ONCE()/READ_ONCE() in smp_store_release()/smp_load_acquire()

2015-08-03T08:59:30+00:00

Replace ACCESS_ONCE() macro in smp_store_release() and smp_load_acquire() with WRITE_ONCE() and READ_ONCE() on x86, arm, arm64, ia64, metag, mips, powerpc, s390, sparc and asm-generic since ACCESS_ONCE() does not work reliably on non-scalar types. WRITE_ONCE() and READ_ONCE() were introduced in the following commits: 230fa253df63 ("kernel: Provide READ_ONCE and ASSIGN_ONCE") 43239cbe79fc ("kernel: Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val)") Signed-off-by: Andrey Konovalov Signed-off-by: Peter Zijlstra (Intel) Acked-by: Davidlohr Bueso Acked-by: Michael Ellerman (powerpc) Acked-by: Ralf Baechle Cc: Alexander Duyck Cc: Andre Przywara Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christian Borntraeger Cc: David S. Miller Cc: Davidlohr Bueso Cc: Dmitry Vyukov Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Heiko Carstens Cc: James Hogan Cc: Linus Torvalds Cc: Martin Schwidefsky Cc: Paul E. McKenney Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Russell King Cc: Thomas Gleixner Cc: Tony Luck Cc: Will Deacon Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/1438528264-714-1-git-send-email-andreyknvl@google.com Signed-off-by: Ingo Molnar

Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-06-22T21:54:22+00:00

Pull locking updates from Ingo Molnar: "The main changes are: - 'qspinlock' support, enabled on x86: queued spinlocks - these are now the spinlock variant used by x86 as they outperform ticket spinlocks in every category. (Waiman Long) - 'pvqspinlock' support on x86: paravirtualized variant of queued spinlocks. (Waiman Long, Peter Zijlstra) - 'qrwlock' support, enabled on x86: queued rwlocks. Similar to queued spinlocks, they are now the variant used by x86: CONFIG_ARCH_USE_QUEUED_SPINLOCKS=y CONFIG_QUEUED_SPINLOCKS=y CONFIG_ARCH_USE_QUEUED_RWLOCKS=y CONFIG_QUEUED_RWLOCKS=y - various lockdep fixlets - various locking primitives cleanups, further WRITE_ONCE() propagation" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) locking/lockdep: Remove hard coded array size dependency locking/qrwlock: Don't contend with readers when setting _QW_WAITING lockdep: Do not break user-visible string locking/arch: Rename set_mb() to smp_store_mb() locking/arch: Add WRITE_ONCE() to set_mb() rtmutex: Warn if trylock is called from hard/softirq context arch: Remove __ARCH_HAVE_CMPXCHG locking/rtmutex: Drop usage of __HAVE_ARCH_CMPXCHG locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS locking/pvqspinlock: Rename QUEUED_SPINLOCK to QUEUED_SPINLOCKS locking/pvqspinlock: Replace xchg() by the more descriptive set_mb() locking/pvqspinlock, x86: Enable PV qspinlock for Xen locking/pvqspinlock, x86: Enable PV qspinlock for KVM locking/pvqspinlock, x86: Implement the paravirt qspinlock call patching locking/pvqspinlock: Implement simple paravirt support for the qspinlock locking/qspinlock: Revert to test-and-set on hypervisors locking/qspinlock: Use a simple write to grab the lock locking/qspinlock: Optimize for smaller NR_CPUS locking/qspinlock: Extract out code snippets for the next patch locking/qspinlock: Add pending bit ...

powerpc: Fix smp_mb__before_spinlock()

2015-05-27T19:58:01+00:00

Currently, smp_mb__before_spinlock() is defined to be smp_wmb() in core code, but this is not sufficient on PowerPC. This patch therefore supplies an override for the generic definition to strengthen smp_mb__before_spinlock() to smp_mb(), as is needed on PowerPC. Signed-off-by: Paul E. McKenney Cc: