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2019-01-18s390/kasan: improve string/memory functions checksVasily Gorbik1-0/+28
Avoid using arch specific implementations of string/memory functions with KASAN since gcc cannot instrument asm code memory accesses and many bugs could be missed. Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-10-09s390/kasan: avoid user access code instrumentationVasily Gorbik1-0/+4
Kasan instrumentation adds "store" check for variables marked as modified by inline assembly. With user pointers containing addresses from another address space this produces false positives. static inline unsigned long clear_user_xc(void __user *to, ...) { asm volatile( ... : "+a" (to) ... User space access functions are wrapped by manually instrumented functions in kasan common code, which should be sufficient to catch errors. So, we just disable uaccess.o instrumentation altogether. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-10-09s390/kasan: replace some memory functionsVasily Gorbik1-3/+9
Follow the common kasan approach: "KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in name, so we could call non-instrumented variant if needed." Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-08-07s390/lib: use expoline for all bcr instructionsMartin Schwidefsky1-6/+10
The memove, memset, memcpy, __memset16, __memset32 and __memset64 function have an additional indirect return branch in form of a "bzr" instruction. These need to use expolines as well. Cc: <stable@vger.kernel.org> # v4.17+ Fixes: 97489e0663 ("s390/lib: use expoline for indirect branches") Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-05-09s390: introduce compile time check for empty .bss sectionVasily Gorbik1-0/+3
Introduce compile time check for files which should avoid using .bss section, because of the following reasons: - .bss section has not been zeroed yet, - initrd has not been moved to a safe location and could be overlapping with .bss section. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-05-07s390/lib: use expoline for indirect branchesMartin Schwidefsky1-8/+11
The return from the memmove, memset, memcpy, __memset16, __memset32 and __memset64 functions are done with "br %r14". These are indirect branches as well and need to use execute trampolines for CONFIG_EXPOLINE=y. Cc: stable@vger.kernel.org # 4.16 Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches") Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-12-15s390: fix preemption race in disable_sacf_uaccessMartin Schwidefsky1-1/+1
With CONFIG_PREEMPT=y there is a possible race in disable_sacf_uaccess. The new set_fs value needs to be stored the the task structure first, the control register update needs to be second. Otherwise a preemptive schedule may interrupt the code right after the control register update has been done and the next time the task is scheduled we get an incorrect value in the control register due to the old set_fs setting. Fixes: 0aaba41b58 ("s390: remove all code using the access register mode") Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-14s390/spinlock: fix indentationHeiko Carstens1-3/+4
checkpatch: WARNING: Statements should start on a tabstop #9499: FILE: arch/s390/lib/spinlock.c:231: + return; sparse: arch/s390/lib/spinlock.c:81 arch_load_niai4() warn: inconsistent indenting Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2017-11-14s390: remove all code using the access register modeMartin Schwidefsky1-10/+80
The vdso code for the getcpu() and the clock_gettime() call use the access register mode to access the per-CPU vdso data page with the current code. An alternative to the complicated AR mode is to use the secondary space mode. This makes the vdso faster and quite a bit simpler. The downside is that the uaccess code has to be changed quite a bit. Which instructions are used depends on the machine and what kind of uaccess operation is requested. The instruction dictates which ASCE value needs to be loaded into %cr1 and %cr7. The different cases: * User copy with MVCOS for z10 and newer machines The MVCOS instruction can copy between the primary space (aka user) and the home space (aka kernel) directly. For set_fs(KERNEL_DS) the kernel ASCE is loaded into %cr1. For set_fs(USER_DS) the user space is already loaded in %cr1. * User copy with MVCP/MVCS for older machines To be able to execute the MVCP/MVCS instructions the kernel needs to switch to primary mode. The control register %cr1 has to be set to the kernel ASCE and %cr7 to either the kernel ASCE or the user ASCE dependent on set_fs(KERNEL_DS) vs set_fs(USER_DS). * Data access in the user address space for strnlen / futex To use "normal" instruction with data from the user address space the secondary space mode is used. The kernel needs to switch to primary mode, %cr1 has to contain the kernel ASCE and %cr7 either the user ASCE or the kernel ASCE, dependent on set_fs. To load a new value into %cr1 or %cr7 is an expensive operation, the kernel tries to be lazy about it. E.g. for multiple user copies in a row with MVCP/MVCS the replacement of the vdso ASCE in %cr7 with the user ASCE is done only once. On return to user space a CPU bit is checked that loads the vdso ASCE again. To enable and disable the data access via the secondary space two new functions are added, enable_sacf_uaccess and disable_sacf_uaccess. The fact that a context is in secondary space uaccess mode is stored in the mm_segment_t value for the task. The code of an interrupt may use set_fs as long as it returns to the previous state it got with get_fs with another call to set_fs. The code in finish_arch_post_lock_switch simply has to do a set_fs with the current mm_segment_t value for the task. For CPUs with MVCOS: CPU running in | %cr1 ASCE | %cr7 ASCE | --------------------------------------|-----------|-----------| user space | user | vdso | kernel, USER_DS, normal-mode | user | vdso | kernel, USER_DS, normal-mode, lazy | user | user | kernel, USER_DS, sacf-mode | kernel | user | kernel, KERNEL_DS, normal-mode | kernel | vdso | kernel, KERNEL_DS, normal-mode, lazy | kernel | kernel | kernel, KERNEL_DS, sacf-mode | kernel | kernel | For CPUs without MVCOS: CPU running in | %cr1 ASCE | %cr7 ASCE | --------------------------------------|-----------|-----------| user space | user | vdso | kernel, USER_DS, normal-mode | user | vdso | kernel, USER_DS, normal-mode lazy | kernel | user | kernel, USER_DS, sacf-mode | kernel | user | kernel, KERNEL_DS, normal-mode | kernel | vdso | kernel, KERNEL_DS, normal-mode, lazy | kernel | kernel | kernel, KERNEL_DS, sacf-mode | kernel | kernel | The lines with "lazy" refer to the state after a copy via the secondary space with a delayed reload of %cr1 and %cr7. There are three hardware address spaces that can cause a DAT exception, primary, secondary and home space. The exception can be related to four different fault types: user space fault, vdso fault, kernel fault, and the gmap faults. Dependent on the set_fs state and normal vs. sacf mode there are a number of fault combinations: 1) user address space fault via the primary ASCE 2) gmap address space fault via the primary ASCE 3) kernel address space fault via the primary ASCE for machines with MVCOS and set_fs(KERNEL_DS) 4) vdso address space faults via the secondary ASCE with an invalid address while running in secondary space in problem state 5) user address space fault via the secondary ASCE for user-copy based on the secondary space mode, e.g. futex_ops or strnlen_user 6) kernel address space fault via the secondary ASCE for user-copy with secondary space mode with set_fs(KERNEL_DS) 7) kernel address space fault via the primary ASCE for user-copy with secondary space mode with set_fs(USER_DS) on machines without MVCOS. 8) kernel address space fault via the home space ASCE Replace user_space_fault() with a new function get_fault_type() that can distinguish all four different fault types. With these changes the futex atomic ops from the kernel and the strnlen_user will get a little bit slower, as well as the old style uaccess with MVCP/MVCS. All user accesses based on MVCOS will be as fast as before. On the positive side, the user space vdso code is a lot faster and Linux ceases to use the complicated AR mode. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2017-11-13Merge branch 'locking-core-for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core locking updates from Ingo Molnar: "The main changes in this cycle are: - Another attempt at enabling cross-release lockdep dependency tracking (automatically part of CONFIG_PROVE_LOCKING=y), this time with better performance and fewer false positives. (Byungchul Park) - Introduce lockdep_assert_irqs_enabled()/disabled() and convert open-coded equivalents to lockdep variants. (Frederic Weisbecker) - Add down_read_killable() and use it in the VFS's iterate_dir() method. (Kirill Tkhai) - Convert remaining uses of ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE(). Most of the conversion was Coccinelle driven. (Mark Rutland, Paul E. McKenney) - Get rid of lockless_dereference(), by strengthening Alpha atomics, strengthening READ_ONCE() with smp_read_barrier_depends() and thus being able to convert users of lockless_dereference() to READ_ONCE(). (Will Deacon) - Various micro-optimizations: - better PV qspinlocks (Waiman Long), - better x86 barriers (Michael S. Tsirkin) - better x86 refcounts (Kees Cook) - ... plus other fixes and enhancements. (Borislav Petkov, Juergen Gross, Miguel Bernal Marin)" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits) locking/x86: Use LOCK ADD for smp_mb() instead of MFENCE rcu: Use lockdep to assert IRQs are disabled/enabled netpoll: Use lockdep to assert IRQs are disabled/enabled timers/posix-cpu-timers: Use lockdep to assert IRQs are disabled/enabled sched/clock, sched/cputime: Use lockdep to assert IRQs are disabled/enabled irq_work: Use lockdep to assert IRQs are disabled/enabled irq/timings: Use lockdep to assert IRQs are disabled/enabled perf/core: Use lockdep to assert IRQs are disabled/enabled x86: Use lockdep to assert IRQs are disabled/enabled smp/core: Use lockdep to assert IRQs are disabled/enabled timers/hrtimer: Use lockdep to assert IRQs are disabled/enabled timers/nohz: Use lockdep to assert IRQs are disabled/enabled workqueue: Use lockdep to assert IRQs are disabled/enabled irq/softirqs: Use lockdep to assert IRQs are disabled/enabled locking/lockdep: Add IRQs disabled/enabled assertion APIs: lockdep_assert_irqs_enabled()/disabled() locking/pvqspinlock: Implement hybrid PV queued/unfair locks locking/rwlocks: Fix comments x86/paravirt: Set up the virt_spin_lock_key after static keys get initialized block, locking/lockdep: Assign a lock_class per gendisk used for wait_for_completion() workqueue: Remove now redundant lock acquisitions wrt. workqueue flushes ...
2017-11-13Merge branch 'for-linus' of ↵Linus Torvalds3-168/+267
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 updates from Heiko Carstens: "Since Martin is on vacation you get the s390 pull request for the v4.15 merge window this time from me. Besides a lot of cleanups and bug fixes these are the most important changes: - a new regset for runtime instrumentation registers - hardware accelerated AES-GCM support for the aes_s390 module - support for the new CEX6S crypto cards - support for FORTIFY_SOURCE - addition of missing z13 and new z14 instructions to the in-kernel disassembler - generate opcode tables for the in-kernel disassembler out of a simple text file instead of having to manually maintain those tables - fast memset16, memset32 and memset64 implementations - removal of named saved segment support - hardware counter support for z14 - queued spinlocks and queued rwlocks implementations for s390 - use the stack_depth tracking feature for s390 BPF JIT - a new s390_sthyi system call which emulates the sthyi (store hypervisor information) instruction - removal of the old KVM virtio transport - an s390 specific CPU alternatives implementation which is used in the new spinlock code" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (88 commits) MAINTAINERS: add virtio-ccw.h to virtio/s390 section s390/noexec: execute kexec datamover without DAT s390: fix transactional execution control register handling s390/bpf: take advantage of stack_depth tracking s390: simplify transactional execution elf hwcap handling s390/zcrypt: Rework struct ap_qact_ap_info. s390/virtio: remove unused header file kvm_virtio.h s390: avoid undefined behaviour s390/disassembler: generate opcode tables from text file s390/disassembler: remove insn_to_mnemonic() s390/dasd: avoid calling do_gettimeofday() s390: vfio-ccw: Do not attempt to free no-op, test and tic cda. s390: remove named saved segment support s390/archrandom: Reconsider s390 arch random implementation s390/pci: do not require AIS facility s390/qdio: sanitize put_indicator s390/qdio: use atomic_cmpxchg s390/nmi: avoid using long-displacement facility s390: pass endianness info to sparse s390/decompressor: remove informational messages ...
2017-11-07Merge branch 'linus' into locking/core, to resolve conflictsIngo Molnar9-0/+9
Conflicts: include/linux/compiler-clang.h include/linux/compiler-gcc.h include/linux/compiler-intel.h include/uapi/linux/stddef.h Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman9-0/+9
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>
2017-10-25locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns ↵Mark Rutland1-8/+8
to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-18s390/spinlock: use cpu alternatives to enable niai instructionVasily Gorbik1-6/+3
Enable niai instruction in the spinlock code at run-time for machines on which facility 49 is available (zEC12 and newer). Signed-off-by: Vasily Gorbik <gor@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-10-09s390: cleanup string ops prototypesHeiko Carstens1-14/+14
Just some trivial changes like removing the extern keyword from the header file, renaming arguments to match the man pages, and whitespace removal. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-10-09s390: optimize memset implementationHeiko Carstens1-8/+12
Like for the memset16/32/64 variants avoid that subsequent mvc instructions depend on each other since that might have negative performance impacts. This patch is currently hardly relevant since at least gcc 7.1 generates only inline memset code and not a single memset call. However there is no reason to not provide an optimized version just in case gcc generates memset calls again, like it did in the past. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-10-09s390: implement memset16, memset32 & memset64Heiko Carstens1-0/+44
Provide fast versions of the new memset variants. E.g. the generic memset64 is ten times slower than the optimized version if used on a whole page. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-09-28s390/rwlock: introduce rwlock wait queueingMartin Schwidefsky1-109/+29
Like the common queued rwlock code the s390 implementation uses the queued spinlock code on a spinlock_t embedded in the rwlock_t to achieve the queueing. The encoding of the rwlock_t differs though, the counter field in the rwlock_t is split into two parts. The upper two bytes hold the write bit and the write wait counter, the lower two bytes hold the read counter. The arch_read_lock operation works exactly like the common qrwlock but the enqueue operation for a writer follows a diffent logic. After the failed inline try to get the rwlock in write, the writer first increases the write wait counter, acquires the wait spin_lock for the queueing, and then loops until there are no readers and the write bit is zero. Without the write wait counter a CPU that just released the rwlock could immediately reacquire the lock in the inline code, bypassing all outstanding read and write waiters. For s390 this would cause massive imbalances in favour of writers in case of a contended rwlock. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-09-28s390/spinlock: introduce spinlock wait queueingMartin Schwidefsky1-30/+164
The queued spinlock code for s390 follows the principles of the common code qspinlock implementation but with a few notable differences. The format of the spinlock_t locking word differs, s390 needs to store the logical CPU number of the lock holder in the spinlock_t to be able to use the diagnose 9c directed yield hypervisor call. The inline code sequences for spin_lock and spin_unlock are nice and short. The inline portion of a spin_lock now typically looks like this: lhi %r0,0 # 0 indicates an empty lock l %r1,0x3a0 # CPU number + 1 from lowcore cs %r0,%r1,<some_lock> # lock operation jnz call_wait # on failure call wait function locked: ... call_wait: la %r2,<some_lock> brasl %r14,arch_spin_lock_wait j locked A spin_unlock is as simple as before: lhi %r0,0 sth %r0,2(%r2) # unlock operation After a CPU has queued itself it may not enable interrupts again for the arch_spin_lock_flags() variant. The arch_spin_lock_wait_flags wait function is removed. To improve performance the code implements opportunistic lock stealing. If the wait function finds a spinlock_t that indicates that the lock is free but there are queued waiters, the CPU may steal the lock up to three times without queueing itself. The lock stealing update the steal counter in the lock word to prevent more than 3 steals. The counter is reset at the time the CPU next in the queue successfully takes the lock. While the queued spinlocks improve performance in a system with dedicated CPUs, in a virtualized environment with continuously overcommitted CPUs the queued spinlocks can have a negative effect on performance. This is due to the fact that a queued CPU that is preempted by the hypervisor will block the queue at some point even without holding the lock. With the classic spinlock it does not matter if a CPU is preempted that waits for the lock. Therefore use the queued spinlock code only if the system runs with dedicated CPUs and fall back to classic spinlocks when running with shared CPUs. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-09-28s390/spinlock: use the cpu number +1 as spinlock valueMartin Schwidefsky1-16/+16
The queued spinlock code will come out simpler if the encoding of the CPU that holds the spinlock is (cpu+1) instead of (~cpu). Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-08-29s390/uaccess: avoid mvcos jump labelMartin Schwidefsky1-12/+26
If the kernel is compiled for z10 or later machines the uaccess code inlines the mvcos instruction. The facility bit 27 which indicates the availability of MVCOS has to be set. The have_mvcos jump label will always be true. Make the generation of the have_mvcos jump label conditional on !CONFIG_HAVE_MARCH_Z10_FEATURES. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-07-26s390/spinlock: add niai spinlock hintsMartin Schwidefsky1-36/+51
The z14 machine introduces new mode of the next-instruction-access-intent NIAI instruction. With NIAI-8 it is possible to pin a cache-line on a CPU for a small amount of time, NIAI-7 releases the cache-line again. Finally NIAI-4 can be used to prevent the CPU to speculatively access memory beyond the compare-and-swap instruction to get the lock. Use these instruction in the spinlock code. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-07-26s390/time: add support for the TOD clock epoch extensionMartin Schwidefsky1-1/+1
The TOD epoch extension adds 8 epoch bits to the TOD clock to provide a continuous clock after 2042/09/17. The store-clock-extended (STCKE) instruction will store the epoch index in the first byte of the 16 bytes stored by the instruction. The read_boot_clock64 and the read_presistent_clock64 functions need to take the additional bits into account to give the correct result after 2042/09/17. The clock-comparator register will stay 64 bit wide. The comparison of the clock-comparator with the TOD clock is limited to bytes 1 to 8 of the extended TOD format. To deal with the overflow problem due to an epoch change the clock-comparator sign control in CR0 can be used to switch the comparison of the 64-bit TOD clock with the clock-comparator to a signed comparison. The decision between the signed vs. unsigned clock-comparator comparisons is done at boot time. Only if the TOD clock is in the second half of a 142 year epoch the signed comparison is used. This solves the epoch overflow issue as long as the machine is booted at least once in an epoch. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-05-09s390/uaccess: use sane length for __strncpy_from_user()Heiko Carstens1-2/+2
The average string that is copied from user space to kernel space is rather short. E.g. booting a system involves about 50.000 strncpy_from_user() calls where the NULL terminated string has an average size of 27 bytes. By default our s390 specific strncpy_from_user() implementation however copies up to 4096 bytes, which is a waste of cpu cycles and cache lines. Therefore reduce the default length to L1_CACHE_BYTES (256 bytes), which also reduces the average execution time of strncpy_from_user() by 30-40%. Alternatively we could have switched to the generic strncpy_from_user() implementation, however it turned out that that variant would be slower than the now optimized s390 variant. Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-05-03s390/uprobes: fix compile for !KPROBESHeiko Carstens1-0/+1
Fix the following compile error(s) if CONFIG_KPROBES is disabled: arch/s390/kernel/uprobes.c:79:14: error: implicit declaration of function 'probe_get_fixup_type' arch/s390/kernel/uprobes.c:87:14: error: 'FIXUP_PSW_NORMAL' undeclared (first use in this function) Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-05-02Merge branch 'for-linus' of ↵Linus Torvalds1-55/+29
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 updates from Martin Schwidefsky: - three merges for KVM/s390 with changes for vfio-ccw and cpacf. The patches are included in the KVM tree as well, let git sort it out. - add the new 'trng' random number generator - provide the secure key verification API for the pkey interface - introduce the z13 cpu counters to perf - add a new system call to set up the guarded storage facility - simplify TASK_SIZE and arch_get_unmapped_area - export the raw STSI data related to CPU topology to user space - ... and the usual churn of bug-fixes and cleanups. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (74 commits) s390/crypt: use the correct module alias for paes_s390. s390/cpacf: Introduce kma instruction s390/cpacf: query instructions use unique parameters for compatibility with KMA s390/trng: Introduce s390 TRNG device driver. s390/crypto: Provide s390 specific arch random functionality. s390/crypto: Add new subfunctions to the cpacf PRNO function. s390/crypto: Renaming PPNO to PRNO. s390/pageattr: avoid unnecessary page table splitting s390/mm: simplify arch_get_unmapped_area[_topdown] s390/mm: make TASK_SIZE independent from the number of page table levels s390/gs: add regset for the guarded storage broadcast control block s390/kvm: Add use_cmma field to mm_context_t s390/kvm: Add PGSTE manipulation functions vfio: ccw: improve error handling for vfio_ccw_mdev_remove vfio: ccw: remove unnecessary NULL checks of a pointer s390/spinlock: remove compare and delay instruction s390/spinlock: use atomic primitives for spinlocks s390/cpumf: simplify detection of guest samples s390/pci: remove forward declaration s390/pci: increase the PCI_NR_FUNCTIONS default ...
2017-04-12s390/spinlock: remove compare and delay instructionMartin Schwidefsky1-28/+5
The CAD instruction never worked quite as expected for the spinlock code. It has been disabled by default with git commit 61b0b01686d48220, if the "cad" kernel parameter is specified it is enabled for both user space and the spinlock code. Leave the option to enable the instruction for user space but remove it from the spinlock code. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-04-12s390/spinlock: use atomic primitives for spinlocksMartin Schwidefsky1-38/+35
Add a couple more __atomic_xxx function to atomic_ops.h and use them to replace the compare-and-swap inlines in the spinlock code. This changes the type of the lock value from unsigned int to int. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-03-30s390: get rid of zeroing, switch to RAW_COPY_USERAl Viro1-45/+23
[folded a fix from Martin] Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-02-17s390: replace ACCESS_ONCE with READ_ONCEChristian Borntraeger1-1/+1
Remove the last places of ACCESS_ONCE in s390 code. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-02-17s390: Audit and remove any remaining unnecessary uses of module.hPaul Gortmaker4-4/+5
Historically a lot of these existed because we did not have a distinction between what was modular code and what was providing support to modules via EXPORT_SYMBOL and friends. That changed when we forked out support for the latter into the export.h file. This means we should be able to reduce the usage of module.h in code that is obj-y Makefile or bool Kconfig. The advantage in doing so is that module.h itself sources about 15 other headers; adding significantly to what we feed cpp, and it can obscure what headers we are effectively using. Since module.h was the source for init.h (for __init) and for export.h (for EXPORT_SYMBOL) we consider each change instance for the presence of either and replace as needed. An instance where module_param was used without moduleparam.h was also fixed, as well as implicit use of ptrace.h and string.h headers. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-01-16s390/lib: improve memmove, memset and memcpyHeiko Carstens1-15/+13
Improve the memmove implementation to save one instruction and use better label names. Also use better label names for the memset and memcpy implementations so everything looks consistent. Suggested-by: Jens Remus <jremus@linux.vnet.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-12-14s390/lib: add missing memory barriers to string inline assembliesHeiko Carstens1-6/+6
We have a couple of inline assemblies like memchr() and strlen() that read from memory, but tell the compiler only they need the addresses of the strings they access. This allows the compiler to omit the initialization of such strings and therefore generate broken code. Add the missing memory barrier to all string related inline assemblies to fix this potential issue. It looks like the compiler currently does not generate broken code due to these bugs. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-12-13Merge branch 'for-linus' of ↵Linus Torvalds1-0/+39
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 updates from Martin Schwidefsky: "The main bulk of the s390 patches for the 4.10 merge window: - Add support for the contiguous memory allocator. - The recovery for I/O errors in the dasd device driver is improved, the driver will now remove channel paths that are not working properly. - Additional fields are added to /proc/sysinfo, the extended partition name and the partition UUID. - New naming for PCI devices with system defined UIDs. - The last few remaining alloc_bootmem calls are converted to memblock. - The thread_info structure is stripped down and moved to the task_struct. The only field left in thread_info is the flags field. - Rework of the arch topology code to fix a fake numa issue. - Refactoring of the atomic primitives and add a new preempt_count implementation. - Clocksource steering for the STP sync check offsets. - The s390 specific headers are changed to make them usable with CLANG. - Bug fixes and cleanup" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (70 commits) s390/cpumf: Use configuration level indication for sampling data s390: provide memmove implementation s390: cleanup arch/s390/kernel Makefile s390: fix initrd corruptions with gcov/kcov instrumented kernels s390: exclude early C code from gcov profiling s390/dasd: channel path aware error recovery s390/dasd: extend dasd path handling s390: remove unused labels from entry.S s390/vmlogrdr: fix IUCV buffer allocation s390/crypto: unlock on error in prng_tdes_read() s390/sysinfo: show partition extended name and UUID if available s390/numa: pin all possible cpus to nodes early s390/numa: establish cpu to node mapping early s390/topology: use cpu_topology array instead of per cpu variable s390/smp: initialize cpu_present_mask in setup_arch s390/topology: always use s390 specific sched_domain_topology_level s390/smp: use smp_get_base_cpu() helper function s390/numa: always use logical cpu and core ids s390: Remove VLAIS in ptff() and clear_table() s390: fix machine check panic stack switch ...
2016-12-12s390: provide memmove implementationHeiko Carstens1-0/+39
Provide an s390 specific memmove implementation which is faster than the generic implementation which copies byte-wise. For non-destructive (as defined by the mvc instruction) memmove operations the following table compares the old default implementation versus the new s390 specific implementation: size old new 1 1ns 8ns 2 2ns 8ns 4 4ns 8ns 8 7ns 8ns 16 17ns 8ns 32 35ns 8ns 64 65ns 9ns 128 146ns 10ns 256 298ns 11ns 512 537ns 11ns 1024 1193ns 19ns 2048 2405ns 36ns So only for very small sizes the old implementation is faster. For overlapping memmoves, where the mvc instruction can't be used, the new implementation is as slow as the old one. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-11-22locking/spinlocks, s390: Implement vcpu_is_preempted(cpu)Christian Borntraeger1-17/+8
This implements the s390 version for vcpu_is_preempted(cpu), by reworking the existing smp_vcpu_scheduled() function into arch_vcpu_is_preempted(). We can then also get rid of the local cpu_is_preempted() function by moving the CIF_ENABLED_WAIT test into arch_vcpu_is_preempted(). Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: benh@kernel.crashing.org Cc: boqun.feng@gmail.com Cc: bsingharora@gmail.com Cc: dave@stgolabs.net Cc: jgross@suse.com Cc: kernellwp@gmail.com Cc: konrad.wilk@oracle.com Cc: linuxppc-dev@lists.ozlabs.org Cc: mpe@ellerman.id.au Cc: paulmck@linux.vnet.ibm.com Cc: paulus@samba.org Cc: pbonzini@redhat.com Cc: rkrcmar@redhat.com Cc: virtualization@lists.linux-foundation.org Cc: will.deacon@arm.com Cc: xen-devel-request@lists.xenproject.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1478077718-37424-6-git-send-email-xinhui.pan@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-10-14Merge branch 'kbuild' of ↵Linus Torvalds1-0/+3
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull kbuild updates from Michal Marek: - EXPORT_SYMBOL for asm source by Al Viro. This does bring a regression, because genksyms no longer generates checksums for these symbols (CONFIG_MODVERSIONS). Nick Piggin is working on a patch to fix this. Plus, we are talking about functions like strcpy(), which rarely change prototypes. - Fixes for PPC fallout of the above by Stephen Rothwell and Nick Piggin - fixdep speedup by Alexey Dobriyan. - preparatory work by Nick Piggin to allow architectures to build with -ffunction-sections, -fdata-sections and --gc-sections - CONFIG_THIN_ARCHIVES support by Stephen Rothwell - fix for filenames with colons in the initramfs source by me. * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (22 commits) initramfs: Escape colons in depfile ppc: there is no clear_pages to export powerpc/64: whitelist unresolved modversions CRCs kbuild: -ffunction-sections fix for archs with conflicting sections kbuild: add arch specific post-link Makefile kbuild: allow archs to select link dead code/data elimination kbuild: allow architectures to use thin archives instead of ld -r kbuild: Regenerate genksyms lexer kbuild: genksyms fix for typeof handling fixdep: faster CONFIG_ search ia64: move exports to definitions sparc32: debride memcpy.S a bit [sparc] unify 32bit and 64bit string.h sparc: move exports to definitions ppc: move exports to definitions arm: move exports to definitions s390: move exports to definitions m68k: move exports to definitions alpha: move exports to actual definitions x86: move exports to actual definitions ...
2016-08-16Merge branch 'for-linus' of ↵Linus Torvalds1-9/+7
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 fixes from Martin Schwidefsky: "A couple of bug fixes, minor cleanup and a change to the default config" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390/dasd: fix failing CUIR assignment under LPAR s390/pageattr: handle numpages parameter correctly s390/dasd: fix hanging device after clear subchannel s390/qdio: avoid reschedule of outbound tasklet once killed s390/qdio: remove checks for ccw device internal state s390/qdio: fix double return code evaluation s390/qdio: get rid of spin_lock_irqsave usage s390/cio: remove subchannel_id from ccw_device_private s390/qdio: obtain subchannel_id via ccw_device_get_schid() s390/cio: stop using subchannel_id from ccw_device_private s390/config: make the vector optimized crc function builtin s390/lib: fix memcmp and strstr s390/crc32-vx: Fix checksum calculation for small sizes s390: clarify compressed image code path
2016-08-08Merge tag 'usercopy-v4.8' of ↵Linus Torvalds1-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull usercopy protection from Kees Cook: "Tbhis implements HARDENED_USERCOPY verification of copy_to_user and copy_from_user bounds checking for most architectures on SLAB and SLUB" * tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: mm: SLUB hardened usercopy support mm: SLAB hardened usercopy support s390/uaccess: Enable hardened usercopy sparc/uaccess: Enable hardened usercopy powerpc/uaccess: Enable hardened usercopy ia64/uaccess: Enable hardened usercopy arm64/uaccess: Enable hardened usercopy ARM: uaccess: Enable hardened usercopy x86/uaccess: Enable hardened usercopy mm: Hardened usercopy mm: Implement stack frame object validation mm: Add is_migrate_cma_page
2016-08-08s390/lib: fix memcmp and strstrChristian Borntraeger1-9/+7
if two string compare equal the clcle instruction will update the string addresses to point _after_ the string. This might already be on a different page, so we should not use these pointer to calculate the difference as in that case the calculation of the difference can cause oopses. The return value of memcmp does not need the difference, we can just reuse the condition code and return for CC=1 (All bytes compared, first operand low) -1 and for CC=2 (All bytes compared, first operand high) +1 strstr also does not need the diff. While fixing this, make the common function clcle "correct on its own" by using l1 instead of l2 for the first length. strstr will call this with l2 for both strings. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Fixes: db7f5eef3dc0 ("s390/lib: use basic blocks for inline assemblies") Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-08-07s390: move exports to definitionsAl Viro1-0/+3
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-07-26s390/uaccess: Enable hardened usercopyKees Cook1-0/+2
Enables CONFIG_HARDENED_USERCOPY checks on s390. Signed-off-by: Kees Cook <keescook@chromium.org>
2016-06-28s390/lib: use basic blocks for inline assembliesHeiko Carstens1-24/+26
Use only simple inline assemblies which consist of a single basic block if the register asm construct is being used. Otherwise gcc would generate broken code if the compiler option --sanitize-coverage=trace-pc would be used. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-06-13s390/uaccess: fix whitespace damageHeiko Carstens1-3/+3
Fix some whitespace damage that was introduced by me with a query-replace when removing 31 bit support. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-04-15s390/spinlock: avoid yield to non existent cpuHeiko Carstens1-0/+1
arch_spin_lock_wait_flags() checks if a spinlock is not held before trying a compare and swap instruction. If the lock is unlocked it tries the compare and swap instruction, however if a different cpu grabbed the lock in the meantime the instruction will fail as expected. Subsequently the arch_spin_lock_wait_flags() incorrectly tries to figure out if the cpu that holds the lock is running. However it is using the wrong cpu number for this (-1) and then will also yield the current cpu to the wrong cpu. Fix this by adding a missing continue statement. Fixes: 470ada6b1a1d ("s390/spinlock: refactor arch_spin_lock_wait[_flags]") Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-02-23s390/xor: optimized xor routing using the XC instructionMartin Schwidefsky2-1/+135
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-11-27s390/spinlock: do not yield to a CPU in udelay/mdelayMartin Schwidefsky1-8/+17
It does not make sense to try to relinquish the time slice with diag 0x9c to a CPU in a state that does not allow to schedule the CPU. The scenario where this can happen is a CPU waiting in udelay/mdelay while holding a spin-lock. Add a CIF bit to tag a CPU in enabled wait and use it to detect that the yield of a CPU will not be successful and skip the diagnose call. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-11-27s390/spinlock: avoid diagnose loopMartin Schwidefsky1-9/+19
The spinlock implementation calls the diagnose 0x9c / 0x44 immediately if the SIGP sense running reported the target CPU as not running. The diagnose 0x9c is a hint to the hypervisor to schedule the target CPU in preference to the source CPU that issued the diagnose. It can happen that on return from the diagnose the target CPU has not been scheduled yet, e.g. if the target logical CPU is on another physical CPU and the hypervisor did not want to migrate the logical CPU. Avoid the immediate repeat of the diagnose instruction, instead do the retry loop before the next invocation of diagnose 0x9c. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-10-14s390/bitops: remove 31 bit related commentsHeiko Carstens1-3/+1
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

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