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2016-09-06usercopy: fold builtin_const check into inline functionKees Cook
Instead of having each caller of check_object_size() need to remember to check for a const size parameter, move the check into check_object_size() itself. This actually matches the original implementation in PaX, though this commit cleans up the now-redundant builtin_const() calls in the various architectures. Signed-off-by: Kees Cook <keescook@chromium.org>
2016-08-08Merge tag 'usercopy-v4.8' of ↵Linus Torvalds
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
2016-08-05Merge tag 'rtc-4.8' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux Pull RTC updates from Alexandre Belloni: "RTC for 4.8 Cleanups: - huge cleanup of rtc-generic and char/genrtc this allowed to cleanup rtc-cmos, rtc-sh, rtc-m68k, rtc-powerpc and rtc-parisc - move mn10300 to rtc-cmos Subsystem: - fix wakealarms after hibernate - multiples fixes for rctest - simplify implementations of .read_alarm New drivers: - Maxim MAX6916 Drivers: - ds1307: fix weekday - m41t80: add wakeup support - pcf85063: add support for PCF85063A variant - rv8803: extend i2c fix and other fixes - s35390a: fix alarm reading, this fixes instant reboot after shutdown for QNAP TS-41x - s3c: clock fixes" * tag 'rtc-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (65 commits) rtc: rv8803: Clear V1F when setting the time rtc: rv8803: Stop the clock while setting the time rtc: rv8803: Always apply the I²C workaround rtc: rv8803: Fix read day of week rtc: rv8803: Remove the check for valid time rtc: rv8803: Kconfig: Indicate rx8900 support rtc: asm9260: remove .owner field for driver rtc: at91sam9: Fix missing spin_lock_init() rtc: m41t80: add suspend handlers for alarm IRQ rtc: m41t80: make it a real error message rtc: pcf85063: Add support for the PCF85063A device rtc: pcf85063: fix year range rtc: hym8563: in .read_alarm set .tm_sec to 0 to signal minute accuracy rtc: explicitly set tm_sec = 0 for drivers with minute accurancy rtc: s3c: Add s3c_rtc_{enable/disable}_clk in s3c_rtc_setfreq() rtc: s3c: Remove unnecessary call to disable already disabled clock rtc: abx80x: use devm_add_action_or_reset() rtc: m41t80: use devm_add_action_or_reset() rtc: fix a typo and reduce three empty lines to one rtc: s35390a: improve two comments in .set_alarm ...
2016-08-04sparc: support static_key usage in non-module __exit sectionsJason Baron
The jump table can reference text found in an __exit section. Thus, instead of discarding it at build/link time, include EXIT_TEXT as part of __init and release it at system boot time. Without this patch the link fails with: `.exit.text' referenced in section `__jump_table' of xxx.o: defined in discarded section `.exit.text' of xxx.o Link: http://lkml.kernel.org/r/d822da427ab07a02a394602eca687104ff682f83.1467837322.git.jbaron@akamai.com Signed-off-by: Jason Baron <jbaron@akamai.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Joe Perches <joe@perches.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-04dma-mapping: use unsigned long for dma_attrsKrzysztof Kozlowski
The dma-mapping core and the implementations do not change the DMA attributes passed by pointer. Thus the pointer can point to const data. However the attributes do not have to be a bitfield. Instead unsigned long will do fine: 1. This is just simpler. Both in terms of reading the code and setting attributes. Instead of initializing local attributes on the stack and passing pointer to it to dma_set_attr(), just set the bits. 2. It brings safeness and checking for const correctness because the attributes are passed by value. Semantic patches for this change (at least most of them): virtual patch virtual context @r@ identifier f, attrs; @@ f(..., - struct dma_attrs *attrs + unsigned long attrs , ...) { ... } @@ identifier r.f; @@ f(..., - NULL + 0 ) and // Options: --all-includes virtual patch virtual context @r@ identifier f, attrs; type t; @@ t f(..., struct dma_attrs *attrs); @@ identifier r.f; @@ f(..., - NULL + 0 ) Link: http://lkml.kernel.org/r/1468399300-5399-2-git-send-email-k.kozlowski@samsung.com Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> Acked-by: Robin Murphy <robin.murphy@arm.com> Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> Acked-by: Mark Salter <msalter@redhat.com> [c6x] Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> [cris] Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> [drm] Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Acked-by: Joerg Roedel <jroedel@suse.de> [iommu] Acked-by: Fabien Dessenne <fabien.dessenne@st.com> [bdisp] Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> [vb2-core] Acked-by: David Vrabel <david.vrabel@citrix.com> [xen] Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [xen swiotlb] Acked-by: Joerg Roedel <jroedel@suse.de> [iommu] Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon] Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390] Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org> Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> [avr32] Acked-by: Vineet Gupta <vgupta@synopsys.com> [arc] Acked-by: Robin Murphy <robin.murphy@arm.com> [arm64 and dma-iommu] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge yet more updates from Andrew Morton: - the rest of ocfs2 - various hotfixes, mainly MM - quite a bit of misc stuff - drivers, fork, exec, signals, etc. - printk updates - firmware - checkpatch - nilfs2 - more kexec stuff than usual - rapidio updates - w1 things * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (111 commits) ipc: delete "nr_ipc_ns" kcov: allow more fine-grained coverage instrumentation init/Kconfig: add clarification for out-of-tree modules config: add android config fragments init/Kconfig: ban CONFIG_LOCALVERSION_AUTO with allmodconfig relay: add global mode support for buffer-only channels init: allow blacklisting of module_init functions w1:omap_hdq: fix regression w1: add helper macro module_w1_family w1: remove need for ida and use PLATFORM_DEVID_AUTO rapidio/switches: add driver for IDT gen3 switches powerpc/fsl_rio: apply changes for RIO spec rev 3 rapidio: modify for rev.3 specification changes rapidio: change inbound window size type to u64 rapidio/idt_gen2: fix locking warning rapidio: fix error handling in mbox request/release functions rapidio/tsi721_dma: advance queue processing from transfer submit call rapidio/tsi721: add messaging mbox selector parameter rapidio/tsi721: add PCIe MRRS override parameter rapidio/tsi721_dma: add channel mask and queue size parameters ...
2016-08-02signal: consolidate {TS,TLF}_RESTORE_SIGMASK codeAndy Lutomirski
In general, there's no need for the "restore sigmask" flag to live in ti->flags. alpha, ia64, microblaze, powerpc, sh, sparc (64-bit only), tile, and x86 use essentially identical alternative implementations, placing the flag in ti->status. Replace those optimized implementations with an equally good common implementation that stores it in a bitfield in struct task_struct and drop the custom implementations. Additional architectures can opt in by removing their TIF_RESTORE_SIGMASK defines. Link: http://lkml.kernel.org/r/8a14321d64a28e40adfddc90e18a96c086a6d6f9.1468522723.git.luto@kernel.org Signed-off-by: Andy Lutomirski <luto@kernel.org> Tested-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02Merge tag 'pci-v4.8-changes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci Pull PCI updates from Bjorn Helgaas: "Highlights: - ARM64 support for ACPI host bridges - new drivers for Axis ARTPEC-6 and Marvell Aardvark - new pci_alloc_irq_vectors() interface for MSI-X, MSI, legacy INTx - pci_resource_to_user() cleanup (more to come) Detailed summary: Enumeration: - Move ecam.h to linux/include/pci-ecam.h (Jayachandran C) - Add parent device field to ECAM struct pci_config_window (Jayachandran C) - Add generic MCFG table handling (Tomasz Nowicki) - Refactor pci_bus_assign_domain_nr() for CONFIG_PCI_DOMAINS_GENERIC (Tomasz Nowicki) - Factor DT-specific pci_bus_find_domain_nr() code out (Tomasz Nowicki) Resource management: - Add devm_request_pci_bus_resources() (Bjorn Helgaas) - Unify pci_resource_to_user() declarations (Bjorn Helgaas) - Implement pci_resource_to_user() with pcibios_resource_to_bus() (microblaze, powerpc, sparc) (Bjorn Helgaas) - Request host bridge window resources (designware, iproc, rcar, xgene, xilinx, xilinx-nwl) (Bjorn Helgaas) - Make PCI I/O space optional on ARM32 (Bjorn Helgaas) - Ignore write combining when mapping I/O port space (Bjorn Helgaas) - Claim bus resources on MIPS PCI_PROBE_ONLY set-ups (Bjorn Helgaas) - Remove unicore32 pci=firmware command line parameter handling (Bjorn Helgaas) - Support I/O resources when parsing host bridge resources (Jayachandran C) - Add helpers to request/release memory and I/O regions (Johannes Thumshirn) - Use pci_(request|release)_mem_regions (NVMe, lpfc, GenWQE, ethernet/intel, alx) (Johannes Thumshirn) - Extend pci=resource_alignment to specify device/vendor IDs (Koehrer Mathias (ETAS/ESW5)) - Add generic pci_bus_claim_resources() (Lorenzo Pieralisi) - Claim bus resources on ARM32 PCI_PROBE_ONLY set-ups (Lorenzo Pieralisi) - Remove ARM32 and ARM64 arch-specific pcibios_enable_device() (Lorenzo Pieralisi) - Add pci_unmap_iospace() to unmap I/O resources (Sinan Kaya) - Remove powerpc __pci_mmap_set_pgprot() (Yinghai Lu) PCI device hotplug: - Allow additional bus numbers for hotplug bridges (Keith Busch) - Ignore interrupts during D3cold (Lukas Wunner) Power management: - Enforce type casting for pci_power_t (Andy Shevchenko) - Don't clear d3cold_allowed for PCIe ports (Mika Westerberg) - Put PCIe ports into D3 during suspend (Mika Westerberg) - Power on bridges before scanning new devices (Mika Westerberg) - Runtime resume bridge before rescan (Mika Westerberg) - Add runtime PM support for PCIe ports (Mika Westerberg) - Remove redundant check of pcie_set_clkpm (Shawn Lin) Virtualization: - Add function 1 DMA alias quirk for Marvell 88SE9182 (Aaron Sierra) - Add DMA alias quirk for Adaptec 3805 (Alex Williamson) - Mark Atheros AR9485 and QCA9882 to avoid bus reset (Chris Blake) - Add ACS quirk for Solarflare SFC9220 (Edward Cree) MSI: - Fix PCI_MSI dependencies (Arnd Bergmann) - Add pci_msix_desc_addr() helper (Christoph Hellwig) - Switch msix_program_entries() to use pci_msix_desc_addr() (Christoph Hellwig) - Make the "entries" argument to pci_enable_msix() optional (Christoph Hellwig) - Provide sensible IRQ vector alloc/free routines (Christoph Hellwig) - Spread interrupt vectors in pci_alloc_irq_vectors() (Christoph Hellwig) Error Handling: - Bind DPC to Root Ports as well as Downstream Ports (Keith Busch) - Remove DPC tristate module option (Keith Busch) - Convert Downstream Port Containment driver to use devm_* functions (Mika Westerberg) Generic host bridge driver: - Select IRQ_DOMAIN (Arnd Bergmann) - Claim bus resources on PCI_PROBE_ONLY set-ups (Lorenzo Pieralisi) ACPI host bridge driver: - Add ARM64 acpi_pci_bus_find_domain_nr() (Tomasz Nowicki) - Add ARM64 ACPI support for legacy IRQs parsing and consolidation with DT code (Tomasz Nowicki) - Implement ARM64 AML accessors for PCI_Config region (Tomasz Nowicki) - Support ARM64 ACPI-based PCI host controller (Tomasz Nowicki) Altera host bridge driver: - Check link status before retrain link (Ley Foon Tan) - Poll for link up status after retraining the link (Ley Foon Tan) Axis ARTPEC-6 host bridge driver: - Add PCI_MSI_IRQ_DOMAIN dependency (Arnd Bergmann) - Add DT binding for Axis ARTPEC-6 PCIe controller (Niklas Cassel) - Add Axis ARTPEC-6 PCIe controller driver (Niklas Cassel) Intel VMD host bridge driver: - Use lock save/restore in interrupt enable path (Jon Derrick) - Select device dma ops to override (Keith Busch) - Initialize list item in IRQ disable (Keith Busch) - Use x86_vector_domain as parent domain (Keith Busch) - Separate MSI and MSI-X vector sharing (Keith Busch) Marvell Aardvark host bridge driver: - Add DT binding for the Aardvark PCIe controller (Thomas Petazzoni) - Add Aardvark PCI host controller driver (Thomas Petazzoni) - Add Aardvark PCIe support for Armada 3700 (Thomas Petazzoni) Microsoft Hyper-V host bridge driver: - Fix interrupt cleanup path (Cathy Avery) - Don't leak buffer in hv_pci_onchannelcallback() (Vitaly Kuznetsov) - Handle all pending messages in hv_pci_onchannelcallback() (Vitaly Kuznetsov) NVIDIA Tegra host bridge driver: - Program PADS_REFCLK_CFG* always, not just on legacy SoCs (Stephen Warren) - Program PADS_REFCLK_CFG* registers with per-SoC values (Stephen Warren) - Use lower-case hex consistently for register definitions (Thierry Reding) - Use generic pci_remap_iospace() rather than ARM32-specific one (Thierry Reding) - Stop setting pcibios_min_mem (Thierry Reding) Renesas R-Car host bridge driver: - Drop gen2 dummy I/O port region (Bjorn Helgaas) TI DRA7xx host bridge driver: - Fix return value in case of error (Christophe JAILLET) Xilinx AXI host bridge driver: - Fix return value in case of error (Christophe JAILLET) Miscellaneous: - Make bus_attr_resource_alignment static (Ben Dooks) - Include <asm/dma.h> for isa_dma_bridge_buggy (Ben Dooks) - MAINTAINERS: Add file patterns for PCI device tree bindings (Geert Uytterhoeven) - Make host bridge drivers explicitly non-modular (Paul Gortmaker)" * tag 'pci-v4.8-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (125 commits) PCI: xgene: Make explicitly non-modular PCI: thunder-pem: Make explicitly non-modular PCI: thunder-ecam: Make explicitly non-modular PCI: tegra: Make explicitly non-modular PCI: rcar-gen2: Make explicitly non-modular PCI: rcar: Make explicitly non-modular PCI: mvebu: Make explicitly non-modular PCI: layerscape: Make explicitly non-modular PCI: keystone: Make explicitly non-modular PCI: hisi: Make explicitly non-modular PCI: generic: Make explicitly non-modular PCI: designware-plat: Make it explicitly non-modular PCI: artpec6: Make explicitly non-modular PCI: armada8k: Make explicitly non-modular PCI: artpec: Add PCI_MSI_IRQ_DOMAIN dependency PCI: Add ACS quirk for Solarflare SFC9220 arm64: dts: marvell: Add Aardvark PCIe support for Armada 3700 PCI: aardvark: Add Aardvark PCI host controller driver dt-bindings: add DT binding for the Aardvark PCIe controller PCI: tegra: Program PADS_REFCLK_CFG* registers with per-SoC values ...
2016-08-01Merge branch 'pci/msi-affinity' into nextBjorn Helgaas
Conflicts: drivers/nvme/host/pci.c
2016-07-29sparc64: Trim page tables for 8M hugepagesNitin Gupta
For PMD aligned (8M) hugepages, we currently allocate all four page table levels which is wasteful. We now allocate till PMD level only which saves memory usage from page tables. Also, when freeing page table for 8M hugepage backed region, make sure we don't try to access non-existent PTE level. Orabug: 22630259 Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-28sparc64 mm: Fix base TSB sizing when hugetlb pages are usedMike Kravetz
do_sparc64_fault() calculates both the base and huge page RSS sizes and uses this information in calls to tsb_grow(). The calculation for base page TSB size is not correct if the task uses hugetlb pages. hugetlb pages are not accounted for in RSS, therefore the call to get_mm_rss(mm) does not include hugetlb pages. However, the number of pages based on huge_pte_count (which does include hugetlb pages) is subtracted from this value. This will result in an artificially small and often negative RSS calculation. The base TSB size is then often set to max_tsb_size as the passed RSS is unsigned, so a negative value looks really big. THP pages are also accounted for in huge_pte_count, and THP pages are accounted for in RSS so the calculation in do_sparc64_fault() is correct if a task only uses THP pages. A single huge_pte_count is not sufficient for TSB sizing if both hugetlb and THP pages can be used. Instead of a single counter, use two: one for hugetlb and one for THP. Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-27sparc32: off by ones in BUG_ON()Dan Carpenter
Smatch complains that these tests are off by one, which is true but not life threatening. arch/sparc/kernel/irq_32.c:169 irq_link() error: buffer overflow 'irq_map' 384 <= 384 Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-27sparc: Don't leak context bits into thread->fault_addressDavid S. Miller
On pre-Niagara systems, we fetch the fault address on data TLB exceptions from the TLB_TAG_ACCESS register. But this register also contains the context ID assosciated with the fault in the low 13 bits of the register value. This propagates into current_thread_info()->fault_address and can cause trouble later on. So clear the low 13-bits out of the TLB_TAG_ACCESS value in the cases where it matters. Reported-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-26mm: do not pass mm_struct into handle_mm_faultKirill A. Shutemov
We always have vma->vm_mm around. Link: http://lkml.kernel.org/r/1466021202-61880-8-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26sparc/uaccess: Enable hardened usercopyKees Cook
Enables CONFIG_HARDENED_USERCOPY checks on sparc. Based on code from PaX and grsecurity. Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-25Merge branch 'irq-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq updates from Thomas Gleixner: "The irq department delivers: - new core infrastructure to allow better management of multi-queue devices (interrupt spreading, node aware descriptor allocation ...) - a new interrupt flow handler to support the new fangled Intel VMD devices. - yet another new interrupt controller driver. - a series of fixes which addresses sparse warnings, missing includes, missing static declarations etc from Ben Dooks. - a fix for the error handling in the hierarchical domain allocation code. - the usual pile of small updates to core and driver code" * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits) genirq: Fix missing irq allocation affinity hint irqdomain: Fix irq_domain_alloc_irqs_recursive() error handling irq/Documentation: Correct result of echnoing 5 to smp_affinity MAINTAINERS: Remove Jiang Liu from irq domains genirq/msi: Fix broken debug output genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectors genirq/msi: Make use of affinity aware allocations genirq: Use affinity hint in irqdesc allocation genirq: Add affinity hint to irq allocation genirq: Introduce IRQD_AFFINITY_MANAGED flag genirq/msi: Remove unused MSI_FLAG_IDENTITY_MAP irqchip/s3c24xx: Fixup IO accessors for big endian irqchip/exynos-combiner: Fix usage of __raw IO irqdomain: Fix disposal of mappings for interrupt hierarchies irqchip/aspeed-vic: Add irq controller for Aspeed doc/devicetree: Add Aspeed VIC bindings x86/PCI/VMD: Use untracked irq handler genirq: Add untracked irq handler irqchip/mips-gic: Populate irq_domain names irqchip/gicv3-its: Implement two-level(indirect) device table support ...
2016-07-25Merge branch 'locking-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "The locking tree was busier in this cycle than the usual pattern - a couple of major projects happened to coincide. The main changes are: - implement the atomic_fetch_{add,sub,and,or,xor}() API natively across all SMP architectures (Peter Zijlstra) - add atomic_fetch_{inc/dec}() as well, using the generic primitives (Davidlohr Bueso) - optimize various aspects of rwsems (Jason Low, Davidlohr Bueso, Waiman Long) - optimize smp_cond_load_acquire() on arm64 and implement LSE based atomic{,64}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() on arm64 (Will Deacon) - introduce smp_acquire__after_ctrl_dep() and fix various barrier mis-uses and bugs (Peter Zijlstra) - after discovering ancient spin_unlock_wait() barrier bugs in its implementation and usage, strengthen its semantics and update/fix usage sites (Peter Zijlstra) - optimize mutex_trylock() fastpath (Peter Zijlstra) - ... misc fixes and cleanups" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (67 commits) locking/atomic: Introduce inc/dec variants for the atomic_fetch_$op() API locking/barriers, arch/arm64: Implement LDXR+WFE based smp_cond_load_acquire() locking/static_keys: Fix non static symbol Sparse warning locking/qspinlock: Use __this_cpu_dec() instead of full-blown this_cpu_dec() locking/atomic, arch/tile: Fix tilepro build locking/atomic, arch/m68k: Remove comment locking/atomic, arch/arc: Fix build locking/Documentation: Clarify limited control-dependency scope locking/atomic, arch/rwsem: Employ atomic_long_fetch_add() locking/atomic, arch/qrwlock: Employ atomic_fetch_add_acquire() locking/atomic, arch/mips: Convert to _relaxed atomics locking/atomic, arch/alpha: Convert to _relaxed atomics locking/atomic: Remove the deprecated atomic_{set,clear}_mask() functions locking/atomic: Remove linux/atomic.h:atomic_fetch_or() locking/atomic: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() locking/atomic: Fix atomic64_relaxed() bits locking/atomic, arch/xtensa: Implement atomic_fetch_{add,sub,and,or,xor}() locking/atomic, arch/x86: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() locking/atomic, arch/tile: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() locking/atomic, arch/sparc: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() ...
2016-07-04genirq: Add affinity hint to irq allocationThomas Gleixner
Add an extra argument to the irq(domain) allocation functions, so we can hand down affinity hints to the allocator. Thats necessary to implement proper support for multiqueue devices. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Christoph Hellwig <hch@lst.de> Cc: linux-block@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: linux-nvme@lists.infradead.org Cc: axboe@fb.com Cc: agordeev@redhat.com Link: http://lkml.kernel.org/r/1467621574-8277-4-git-send-email-hch@lst.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-06-24sparc: get rid of superfluous __GFP_REPEATMichal Hocko
__GFP_REPEAT has a rather weak semantic but since it has been introduced around 2.6.12 it has been ignored for low order allocations. {pud,pmd}_alloc_one is using __GFP_REPEAT but it always allocates from pgtable_cache which is initialzed to PAGE_SIZE objects. This means that this flag has never been actually useful here because it has always been used only for PAGE_ALLOC_COSTLY requests. Link: http://lkml.kernel.org/r/1464599699-30131-13-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-24tree wide: get rid of __GFP_REPEAT for order-0 allocations part IMichal Hocko
This is the third version of the patchset previously sent [1]. I have basically only rebased it on top of 4.7-rc1 tree and dropped "dm: get rid of superfluous gfp flags" which went through dm tree. I am sending it now because it is tree wide and chances for conflicts are reduced considerably when we want to target rc2. I plan to send the next step and rename the flag and move to a better semantic later during this release cycle so we will have a new semantic ready for 4.8 merge window hopefully. Motivation: While working on something unrelated I've checked the current usage of __GFP_REPEAT in the tree. It seems that a majority of the usage is and always has been bogus because __GFP_REPEAT has always been about costly high order allocations while we are using it for order-0 or very small orders very often. It seems that a big pile of them is just a copy&paste when a code has been adopted from one arch to another. I think it makes some sense to get rid of them because they are just making the semantic more unclear. Please note that GFP_REPEAT is documented as * __GFP_REPEAT: Try hard to allocate the memory, but the allocation attempt * _might_ fail. This depends upon the particular VM implementation. while !costly requests have basically nofail semantic. So one could reasonably expect that order-0 request with __GFP_REPEAT will not loop for ever. This is not implemented right now though. I would like to move on with __GFP_REPEAT and define a better semantic for it. $ git grep __GFP_REPEAT origin/master | wc -l 111 $ git grep __GFP_REPEAT | wc -l 36 So we are down to the third after this patch series. The remaining places really seem to be relying on __GFP_REPEAT due to large allocation requests. This still needs some double checking which I will do later after all the simple ones are sorted out. I am touching a lot of arch specific code here and I hope I got it right but as a matter of fact I even didn't compile test for some archs as I do not have cross compiler for them. Patches should be quite trivial to review for stupid compile mistakes though. The tricky parts are usually hidden by macro definitions and thats where I would appreciate help from arch maintainers. [1] http://lkml.kernel.org/r/1461849846-27209-1-git-send-email-mhocko@kernel.org This patch (of 19): __GFP_REPEAT has a rather weak semantic but since it has been introduced around 2.6.12 it has been ignored for low order allocations. Yet we have the full kernel tree with its usage for apparently order-0 allocations. This is really confusing because __GFP_REPEAT is explicitly documented to allow allocation failures which is a weaker semantic than the current order-0 has (basically nofail). Let's simply drop __GFP_REPEAT from those places. This would allow to identify place which really need allocator to retry harder and formulate a more specific semantic for what the flag is supposed to do actually. Link: http://lkml.kernel.org/r/1464599699-30131-2-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> [for tile] Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: John Crispin <blogic@openwrt.org> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Ley Foon Tan <lftan@altera.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-17sparc/PCI: Implement pci_resource_to_user() with pcibios_resource_to_bus()Bjorn Helgaas
"User" addresses are shown in /sys/devices/pci.../.../resource and /proc/bus/pci/devices and used as mmap offsets for /proc/bus/pci/BB/DD.F files. On sparc, these are PCI bus addresses, i.e., raw BAR values. Previously pci_resource_to_user() computed the user address by subtracting either pbm->io_space.start or pbm->mem_space.start from the resource start. We've already told the PCI core about those offsets here: pci_scan_one_pbm() pci_add_resource_offset(&resources, &pbm->io_space, pbm->io_space.start); pci_add_resource_offset(&resources, &pbm->mem_space, pbm->mem_space.start); pci_add_resource_offset(&resources, &pbm->mem64_space, pbm->mem_space.start); so pcibios_resource_to_bus() knows how to do that translation. No functional change intended. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Yinghai Lu <yinghai@kernel.org>
2016-06-17PCI: Unify pci_resource_to_user() declarationsBjorn Helgaas
Replace the pci_resource_to_user() declarations in each arch that defines HAVE_ARCH_PCI_RESOURCE_TO_USER with a single one in linux/pci.h. Change the MIPS static inline implementation to a non-inline version so the static inline doesn't conflict with the new non-static linux/pci.h declaration. No functional change intended. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2016-06-16locking/atomic: Remove linux/atomic.h:atomic_fetch_or()Peter Zijlstra
Since all architectures have this implemented now natively, remove this dead code. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-16locking/atomic, arch/sparc: Implement atomic{,64}_fetch_{add,sub,and,or,xor}()Peter Zijlstra
Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: James Y Knight <jyknight@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: sparclinux@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-14locking/spinlock, arch: Update and fix spin_unlock_wait() implementationsPeter Zijlstra
This patch updates/fixes all spin_unlock_wait() implementations. The update is in semantics; where it previously was only a control dependency, we now upgrade to a full load-acquire to match the store-release from the spin_unlock() we waited on. This ensures that when spin_unlock_wait() returns, we're guaranteed to observe the full critical section we waited on. This fixes a number of spin_unlock_wait() users that (not unreasonably) rely on this. I also fixed a number of ticket lock versions to only wait on the current lock holder, instead of for a full unlock, as this is sufficient. Furthermore; again for ticket locks; I added an smp_rmb() in between the initial ticket load and the spin loop testing the current value because I could not convince myself the address dependency is sufficient, esp. if the loads are of different sizes. I'm more than happy to remove this smp_rmb() again if people are certain the address dependency does indeed work as expected. Note: PPC32 will be fixed independently Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: chris@zankel.net Cc: cmetcalf@mellanox.com Cc: davem@davemloft.net Cc: dhowells@redhat.com Cc: james.hogan@imgtec.com Cc: jejb@parisc-linux.org Cc: linux@armlinux.org.uk Cc: mpe@ellerman.id.au Cc: ralf@linux-mips.org Cc: realmz6@gmail.com Cc: rkuo@codeaurora.org Cc: rth@twiddle.net Cc: schwidefsky@de.ibm.com Cc: tony.luck@intel.com Cc: vgupta@synopsys.com Cc: ysato@users.sourceforge.jp Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-04sparc32: remove stale RTC_PORT definitionArnd Bergmann
sparc32:allmodconfig fails to build in next-20160602 as follows. In file included from drivers/block/floppy.c:185:0: include/linux/mc146818rtc.h: In function 'mc146818_is_updating': include/linux/mc146818rtc.h:138:9: error: 'rtc_port' undeclared (first use in this function) include/linux/mc146818rtc.h:138:9: note: each undeclared identifier is reported only once for each function it appears in include/linux/mc146818rtc.h: In function 'mc146818_get_time': include/linux/mc146818rtc.h:172:17: error: 'rtc_port' undeclared (first use in this function) include/linux/mc146818rtc.h: In function 'mc146818_set_time': include/linux/mc146818rtc.h:278:8: error: 'rtc_port' undeclared (first use in this function) scripts/Makefile.build:295: recipe for target 'drivers/block/floppy.o' failed The reason is a duplicate definition of the RTC_PORT macro. The one in arch/sparc/include/asm/io_32.h was apparently used a long time ago for the drivers/char/rtc.c driver that is not available on SPARC any more, since we now select 'RTC_CLASS' unconditionally. Removing the macro fixes the build problem, and for consistency, this also removes the RTC_ALWAYS_BCD macro and the comment for both. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reported-by: Guenter Roeck <linux@roeck-us.net> Fixes: fd09cc80165c ("rtc: cmos: move mc146818rtc code out of asm-generic/rtc.h") Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-05-31Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparcLinus Torvalds
Pull sparc fixes from David Miller: "sparc64 mmu context allocation and trap return bug fixes" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc: sparc64: Fix return from trap window fill crashes. sparc: Harden signal return frame checks. sparc64: Take ctx_alloc_lock properly in hugetlb_setup().
2016-05-29sparc64: Fix return from trap window fill crashes.David S. Miller
We must handle data access exception as well as memory address unaligned exceptions from return from trap window fill faults, not just normal TLB misses. Otherwise we can get an OOPS that looks like this: ld-linux.so.2(36808): Kernel bad sw trap 5 [#1] CPU: 1 PID: 36808 Comm: ld-linux.so.2 Not tainted 4.6.0 #34 task: fff8000303be5c60 ti: fff8000301344000 task.ti: fff8000301344000 TSTATE: 0000004410001601 TPC: 0000000000a1a784 TNPC: 0000000000a1a788 Y: 00000002 Not tainted TPC: <do_sparc64_fault+0x5c4/0x700> g0: fff8000024fc8248 g1: 0000000000db04dc g2: 0000000000000000 g3: 0000000000000001 g4: fff8000303be5c60 g5: fff800030e672000 g6: fff8000301344000 g7: 0000000000000001 o0: 0000000000b95ee8 o1: 000000000000012b o2: 0000000000000000 o3: 0000000200b9b358 o4: 0000000000000000 o5: fff8000301344040 sp: fff80003013475c1 ret_pc: 0000000000a1a77c RPC: <do_sparc64_fault+0x5bc/0x700> l0: 00000000000007ff l1: 0000000000000000 l2: 000000000000005f l3: 0000000000000000 l4: fff8000301347e98 l5: fff8000024ff3060 l6: 0000000000000000 l7: 0000000000000000 i0: fff8000301347f60 i1: 0000000000102400 i2: 0000000000000000 i3: 0000000000000000 i4: 0000000000000000 i5: 0000000000000000 i6: fff80003013476a1 i7: 0000000000404d4c I7: <user_rtt_fill_fixup+0x6c/0x7c> Call Trace: [0000000000404d4c] user_rtt_fill_fixup+0x6c/0x7c The window trap handlers are slightly clever, the trap table entries for them are composed of two pieces of code. First comes the code that actually performs the window fill or spill trap handling, and then there are three instructions at the end which are for exception processing. The userland register window fill handler is: add %sp, STACK_BIAS + 0x00, %g1; \ ldxa [%g1 + %g0] ASI, %l0; \ mov 0x08, %g2; \ mov 0x10, %g3; \ ldxa [%g1 + %g2] ASI, %l1; \ mov 0x18, %g5; \ ldxa [%g1 + %g3] ASI, %l2; \ ldxa [%g1 + %g5] ASI, %l3; \ add %g1, 0x20, %g1; \ ldxa [%g1 + %g0] ASI, %l4; \ ldxa [%g1 + %g2] ASI, %l5; \ ldxa [%g1 + %g3] ASI, %l6; \ ldxa [%g1 + %g5] ASI, %l7; \ add %g1, 0x20, %g1; \ ldxa [%g1 + %g0] ASI, %i0; \ ldxa [%g1 + %g2] ASI, %i1; \ ldxa [%g1 + %g3] ASI, %i2; \ ldxa [%g1 + %g5] ASI, %i3; \ add %g1, 0x20, %g1; \ ldxa [%g1 + %g0] ASI, %i4; \ ldxa [%g1 + %g2] ASI, %i5; \ ldxa [%g1 + %g3] ASI, %i6; \ ldxa [%g1 + %g5] ASI, %i7; \ restored; \ retry; nop; nop; nop; nop; \ b,a,pt %xcc, fill_fixup_dax; \ b,a,pt %xcc, fill_fixup_mna; \ b,a,pt %xcc, fill_fixup; And the way this works is that if any of those memory accesses generate an exception, the exception handler can revector to one of those final three branch instructions depending upon which kind of exception the memory access took. In this way, the fault handler doesn't have to know if it was a spill or a fill that it's handling the fault for. It just always branches to the last instruction in the parent trap's handler. For example, for a regular fault, the code goes: winfix_trampoline: rdpr %tpc, %g3 or %g3, 0x7c, %g3 wrpr %g3, %tnpc done All window trap handlers are 0x80 aligned, so if we "or" 0x7c into the trap time program counter, we'll get that final instruction in the trap handler. On return from trap, we have to pull the register window in but we do this by hand instead of just executing a "restore" instruction for several reasons. The largest being that from Niagara and onward we simply don't have enough levels in the trap stack to fully resolve all possible exception cases of a window fault when we are already at trap level 1 (which we enter to get ready to return from the original trap). This is executed inline via the FILL_*_RTRAP handlers. rtrap_64.S's code branches directly to these to do the window fill by hand if necessary. Now if you look at them, we'll see at the end: ba,a,pt %xcc, user_rtt_fill_fixup; ba,a,pt %xcc, user_rtt_fill_fixup; ba,a,pt %xcc, user_rtt_fill_fixup; And oops, all three cases are handled like a fault. This doesn't work because each of these trap types (data access exception, memory address unaligned, and faults) store their auxiliary info in different registers to pass on to the C handler which does the real work. So in the case where the stack was unaligned, the unaligned trap handler sets up the arg registers one way, and then we branched to the fault handler which expects them setup another way. So the FAULT_TYPE_* value ends up basically being garbage, and randomly would generate the backtrace seen above. Reported-by: Nick Alcock <nix@esperi.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-29sparc: Harden signal return frame checks.David S. Miller
All signal frames must be at least 16-byte aligned, because that is the alignment we explicitly create when we build signal return stack frames. All stack pointers must be at least 8-byte aligned. Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-25Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf updates from Ingo Molnar: "Mostly tooling and PMU driver fixes, but also a number of late updates such as the reworking of the call-chain size limiting logic to make call-graph recording more robust, plus tooling side changes for the new 'backwards ring-buffer' extension to the perf ring-buffer" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits) perf record: Read from backward ring buffer perf record: Rename variable to make code clear perf record: Prevent reading invalid data in record__mmap_read perf evlist: Add API to pause/resume perf trace: Use the ptr->name beautifier as default for "filename" args perf trace: Use the fd->name beautifier as default for "fd" args perf report: Add srcline_from/to branch sort keys perf evsel: Record fd into perf_mmap perf evsel: Add overwrite attribute and check write_backward perf tools: Set buildid dir under symfs when --symfs is provided perf trace: Only auto set call-graph to "dwarf" when syscalls are being traced perf annotate: Sort list of recognised instructions perf annotate: Fix identification of ARM blt and bls instructions perf tools: Fix usage of max_stack sysctl perf callchain: Stop validating callchains by the max_stack sysctl perf trace: Fix exit_group() formatting perf top: Use machine->kptr_restrict_warned perf trace: Warn when trying to resolve kernel addresses with kptr_restrict=1 perf machine: Do not bail out if not managing to read ref reloc symbol perf/x86/intel/p4: Trival indentation fix, remove space ...
2016-05-25sparc64: Take ctx_alloc_lock properly in hugetlb_setup().David S. Miller
On cheetahplus chips we take the ctx_alloc_lock in order to modify the TLB lookup parameters for the indexed TLBs, which are stored in the context register. This is called with interrupts disabled, however ctx_alloc_lock is an IRQ safe lock, therefore we must take acquire/release it properly with spin_{lock,unlock}_irq(). Reported-by: Meelis Roos <mroos@linux.ee> Tested-by: Meelis Roos <mroos@linux.ee> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparcLinus Torvalds
Pull sparc updates from David Miller: "Some 32-bit kgdb cleanups from Sam Ravnborg, and a hugepage TLB flush overhead fix on 64-bit from Nitin Gupta" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc: sparc64: Reduce TLB flushes during hugepte changes aeroflex/greth: fix warning about unused variable openprom: fix warning sparc32: drop superfluous cast in calls to __nocache_pa() sparc32: fix build with STRICT_MM_TYPECHECKS sparc32: use proper prototype for trapbase sparc32: drop local prototype in kgdb_32 sparc32: drop hardcoding trap_level in kgdb_trap
2016-05-20sparc64: Reduce TLB flushes during hugepte changesNitin Gupta
During hugepage map/unmap, TSB and TLB flushes are currently issued at every PAGE_SIZE'd boundary which is unnecessary. We now issue the flush at REAL_HPAGE_SIZE boundaries only. Without this patch workloads which unmap a large hugepage backed VMA region get CPU lockups due to excessive TLB flush calls. Orabug: 22365539, 22643230, 22995196 Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-20lib/GCD.c: use binary GCD algorithm instead of EuclideanZhaoxiu Zeng
The binary GCD algorithm is based on the following facts: 1. If a and b are all evens, then gcd(a,b) = 2 * gcd(a/2, b/2) 2. If a is even and b is odd, then gcd(a,b) = gcd(a/2, b) 3. If a and b are all odds, then gcd(a,b) = gcd((a-b)/2, b) = gcd((a+b)/2, b) Even on x86 machines with reasonable division hardware, the binary algorithm runs about 25% faster (80% the execution time) than the division-based Euclidian algorithm. On platforms like Alpha and ARMv6 where division is a function call to emulation code, it's even more significant. There are two variants of the code here, depending on whether a fast __ffs (find least significant set bit) instruction is available. This allows the unpredictable branches in the bit-at-a-time shifting loop to be eliminated. If fast __ffs is not available, the "even/odd" GCD variant is used. I use the following code to benchmark: #include <stdio.h> #include <stdlib.h> #include <stdint.h> #include <string.h> #include <time.h> #include <unistd.h> #define swap(a, b) \ do { \ a ^= b; \ b ^= a; \ a ^= b; \ } while (0) unsigned long gcd0(unsigned long a, unsigned long b) { unsigned long r; if (a < b) { swap(a, b); } if (b == 0) return a; while ((r = a % b) != 0) { a = b; b = r; } return b; } unsigned long gcd1(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; b >>= __builtin_ctzl(b); for (;;) { a >>= __builtin_ctzl(a); if (a == b) return a << __builtin_ctzl(r); if (a < b) swap(a, b); a -= b; } } unsigned long gcd2(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; r &= -r; while (!(b & r)) b >>= 1; for (;;) { while (!(a & r)) a >>= 1; if (a == b) return a; if (a < b) swap(a, b); a -= b; a >>= 1; if (a & r) a += b; a >>= 1; } } unsigned long gcd3(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; b >>= __builtin_ctzl(b); if (b == 1) return r & -r; for (;;) { a >>= __builtin_ctzl(a); if (a == 1) return r & -r; if (a == b) return a << __builtin_ctzl(r); if (a < b) swap(a, b); a -= b; } } unsigned long gcd4(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; r &= -r; while (!(b & r)) b >>= 1; if (b == r) return r; for (;;) { while (!(a & r)) a >>= 1; if (a == r) return r; if (a == b) return a; if (a < b) swap(a, b); a -= b; a >>= 1; if (a & r) a += b; a >>= 1; } } static unsigned long (*gcd_func[])(unsigned long a, unsigned long b) = { gcd0, gcd1, gcd2, gcd3, gcd4, }; #define TEST_ENTRIES (sizeof(gcd_func) / sizeof(gcd_func[0])) #if defined(__x86_64__) #define rdtscll(val) do { \ unsigned long __a,__d; \ __asm__ __volatile__("rdtsc" : "=a" (__a), "=d" (__d)); \ (val) = ((unsigned long long)__a) | (((unsigned long long)__d)<<32); \ } while(0) static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long), unsigned long a, unsigned long b, unsigned long *res) { unsigned long long start, end; unsigned long long ret; unsigned long gcd_res; rdtscll(start); gcd_res = gcd(a, b); rdtscll(end); if (end >= start) ret = end - start; else ret = ~0ULL - start + 1 + end; *res = gcd_res; return ret; } #else static inline struct timespec read_time(void) { struct timespec time; clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time); return time; } static inline unsigned long long diff_time(struct timespec start, struct timespec end) { struct timespec temp; if ((end.tv_nsec - start.tv_nsec) < 0) { temp.tv_sec = end.tv_sec - start.tv_sec - 1; temp.tv_nsec = 1000000000ULL + end.tv_nsec - start.tv_nsec; } else { temp.tv_sec = end.tv_sec - start.tv_sec; temp.tv_nsec = end.tv_nsec - start.tv_nsec; } return temp.tv_sec * 1000000000ULL + temp.tv_nsec; } static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long), unsigned long a, unsigned long b, unsigned long *res) { struct timespec start, end; unsigned long gcd_res; start = read_time(); gcd_res = gcd(a, b); end = read_time(); *res = gcd_res; return diff_time(start, end); } #endif static inline unsigned long get_rand() { if (sizeof(long) == 8) return (unsigned long)rand() << 32 | rand(); else return rand(); } int main(int argc, char **argv) { unsigned int seed = time(0); int loops = 100; int repeats = 1000; unsigned long (*res)[TEST_ENTRIES]; unsigned long long elapsed[TEST_ENTRIES]; int i, j, k; for (;;) { int opt = getopt(argc, argv, "n:r:s:"); /* End condition always first */ if (opt == -1) break; switch (opt) { case 'n': loops = atoi(optarg); break; case 'r': repeats = atoi(optarg); break; case 's': seed = strtoul(optarg, NULL, 10); break; default: /* You won't actually get here. */ break; } } res = malloc(sizeof(unsigned long) * TEST_ENTRIES * loops); memset(elapsed, 0, sizeof(elapsed)); srand(seed); for (j