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2013-06-20ARM: kernel: build MPIDR hash function data structureLorenzo Pieralisi
On ARM SMP systems, cores are identified by their MPIDR register. The MPIDR guidelines in the ARM ARM do not provide strict enforcement of MPIDR layout, only recommendations that, if followed, split the MPIDR on ARM 32 bit platforms in three affinity levels. In multi-cluster systems like big.LITTLE, if the affinity guidelines are followed, the MPIDR can not be considered an index anymore. This means that the association between logical CPU in the kernel and the HW CPU identifier becomes somewhat more complicated requiring methods like hashing to associate a given MPIDR to a CPU logical index, in order for the look-up to be carried out in an efficient and scalable way. This patch provides a function in the kernel that starting from the cpu_logical_map, implement collision-free hashing of MPIDR values by checking all significative bits of MPIDR affinity level bitfields. The hashing can then be carried out through bits shifting and ORing; the resulting hash algorithm is a collision-free though not minimal hash that can be executed with few assembly instructions. The mpidr is filtered through a mpidr mask that is built by checking all bits that toggle in the set of MPIDRs corresponding to possible CPUs. Bits that do not toggle do not carry information so they do not contribute to the resulting hash. Pseudo code: /* check all bits that toggle, so they are required */ for (i = 1, mpidr_mask = 0; i < num_possible_cpus(); i++) mpidr_mask |= (cpu_logical_map(i) ^ cpu_logical_map(0)); /* * Build shifts to be applied to aff0, aff1, aff2 values to hash the mpidr * fls() returns the last bit set in a word, 0 if none * ffs() returns the first bit set in a word, 0 if none */ fs0 = mpidr_mask[7:0] ? ffs(mpidr_mask[7:0]) - 1 : 0; fs1 = mpidr_mask[15:8] ? ffs(mpidr_mask[15:8]) - 1 : 0; fs2 = mpidr_mask[23:16] ? ffs(mpidr_mask[23:16]) - 1 : 0; ls0 = fls(mpidr_mask[7:0]); ls1 = fls(mpidr_mask[15:8]); ls2 = fls(mpidr_mask[23:16]); bits0 = ls0 - fs0; bits1 = ls1 - fs1; bits2 = ls2 - fs2; aff0_shift = fs0; aff1_shift = 8 + fs1 - bits0; aff2_shift = 16 + fs2 - (bits0 + bits1); u32 hash(u32 mpidr) { u32 l0, l1, l2; u32 mpidr_masked = mpidr & mpidr_mask; l0 = mpidr_masked & 0xff; l1 = mpidr_masked & 0xff00; l2 = mpidr_masked & 0xff0000; return (l0 >> aff0_shift | l1 >> aff1_shift | l2 >> aff2_shift); } The hashing algorithm relies on the inherent properties set in the ARM ARM recommendations for the MPIDR. Exotic configurations, where for instance the MPIDR values at a given affinity level have large holes, can end up requiring big hash tables since the compression of values that can be achieved through shifting is somewhat crippled when holes are present. Kernel warns if the number of buckets of the resulting hash table exceeds the number of possible CPUs by a factor of 4, which is a symptom of a very sparse HW MPIDR configuration. The hash algorithm is quite simple and can easily be implemented in assembly code, to be used in code paths where the kernel virtual address space is not set-up (ie cpu_resume) and instruction and data fetches are strongly ordered so code must be compact and must carry out few data accesses. Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Colin Cross <ccross@android.com> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Amit Kucheria <amit.kucheria@linaro.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Nicolas Pitre <nico@linaro.org> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Kevin Hilman <khilman@linaro.org> Tested-by: Stephen Warren <swarren@wwwdotorg.org>
2013-06-20Merge tag 'imx-soc-3.11' of git://git.linaro.org/people/shawnguo/linux-2.6 ↵Arnd Bergmann
into next/soc From Shawn Guo: imx soc changes for 3.11: * New SoCs i.MX6 Sololite and Vybrid VF610 support * imx5 and imx6 clock fixes and additions * Update clock driver to use of_clk_init() function * Refactor restart routine mxc_restart() to get it work for DT boot as well * Clean up mxc specific ulpi access ops * imx defconfig updates * tag 'imx-soc-3.11' of git://git.linaro.org/people/shawnguo/linux-2.6: (29 commits) ARM: imx_v6_v7_defconfig: Enable Vybrid VF610 ARM: imx_v6_v7_defconfig: Enable imx-wm8962 by default ARM: clk-imx6qdl: Add clko1 configuration for imx6qdl-sabresd ARM: imx_v6_v7_defconfig: Enable PWM and backlight options ARM: imx: Remove mxc specific ulpi access ops ARM: imx: add initial support for VF610 ARM: imx: add VF610 clock support ARM: imx_v6_v7_defconfig: enable parallel display ARM: imx: clk: No need to initialize phandle struct ARM: imx: irq-common: Include header to avoid sparse warning ARM: imx: Enable mx6 solo-lite support ARM: imx6: use common of_clk_init() call to initialize clocks ARM: imx6q: call of_clk_init() to register fixed rate clocks ARM: imx: imx_v6_v7_defconfig: Select CONFIG_DRM_IMX_TVE ARM: i.MX6: clk: add different DualLite MLB clock config ARM i.MX5: Add S/PDIF clocks ARM i.MX53: Add SATA clock ARM: imx6q: clk: add the eim_slow clock ARM: imx: remove MLB PLL from pllv3 ARM: imx: disable pll8_mlb in mx6q_clks ... Conflicts: arch/arm/Kconfig.debug (simple add/add conflict) Includes an update to 3.10-rc6 Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2013-06-20Merge tag 'integrator-pci-for-arm-soc' of ↵Arnd Bergmann
git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator into next/soc From Linus Walleij: This is a patch series that: - Pulls the Integrator/AP PCI bridge driver into one file - Adds full device tree support for it - Keeps ATAG support around for the time being * tag 'integrator-pci-for-arm-soc' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator: ARM: integrator: basic PCIv3 device tree support ARM: integrator: move static ioremapping into PCIv3 driver ARM: integrator: move VGA base assignment ARM: integrator: remap PCIv3 base dynamically ARM: integrator: move V3 register definitions into driver ARM: integrator: move PCI base address grab to probe ARM: integrator: grab PCI error IRQ in probe() ARM: integrator: convert PCIv3 bridge to platform device ARM: integrator: merge PCIv3 driver into one file ARM: pci: create pci_common_init_dev() Documentation/devicetree: add a small note on PCI Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2013-06-18Merge branch 'for-rmk/arch-timer-cleanups' of git://linux-arm.org/linux-mr ↵Russell King
into devel-stable Please pull these arch_timer cleanups I've been holding onto for a while. They're the same as my last posting [1], but have been rebased to v3.10-rc3. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2013-May/170602.html -- Mark Rutland
2013-06-18Merge branch 'for-rmk/lpae' of ↵Russell King
git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into devel-stable Conflicts: arch/arm/kernel/smp.c Please pull these miscellaneous LPAE fixes I've been collecting for a while now for 3.11. They've been tested and reviewed by quite a few people, and most of the patches are pretty trivial. -- Will Deacon.
2013-06-18Merge branch 'for-rmk/hugepages' of ↵Russell King
git://git.linaro.org/people/stevecapper/linux into devel-stable These changes bring both HugeTLB support and Transparent HugePage (THP) support to ARM. Only long descriptors (LPAE) are supported in this series. The code has been tested on an Arndale board (Exynos 5250).
2013-06-17Merge 3.10-rc6 into driver-core-nextGreg Kroah-Hartman
We want these fixes here too. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-06-17ARM: 7759/1: decouple CPU offlining from reboot/shutdownStephen Warren
Add comments to machine_shutdown()/halt()/power_off()/restart() that describe their purpose and/or requirements re: CPUs being active/not. In machine_shutdown(), replace the call to smp_send_stop() with a call to disable_nonboot_cpus(). This completely disables all but one CPU, thus satisfying the requirement that only a single CPU be active for kexec. Adjust Kconfig dependencies for this change. In machine_halt()/power_off()/restart(), call smp_send_stop() directly, rather than via machine_shutdown(); these functions don't need to completely de-activate all CPUs using hotplug, but rather just quiesce them. Remove smp_kill_cpus(), and its call from smp_send_stop(). smp_kill_cpus() was indirectly calling smp_ops.cpu_kill() without calling smp_ops.cpu_die() on the target CPUs first. At least some implementations of smp_ops had issues with this; it caused cpu_kill() to hang on Tegra, for example. Since smp_send_stop() is only used for shutdown, halt, and power-off, there is no need to attempt any kind of CPU hotplug here. Adjust Kconfig to reflect that machine_shutdown() (and hence kexec) relies upon disable_nonboot_cpus(). However, this alone doesn't guarantee that hotplug will work, or even that hotplug is implemented for a particular piece of HW that a multi-platform zImage runs on. Hence, add error-checking to machine_kexec() to determine whether it did work. Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Stephen Warren <swarren@nvidia.com> Acked-by: Will Deacon <will.deacon@arm.com> Tested-by: Zhangfei Gao <zhangfei.gao@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-06-17Merge branch 'ja-nommu-for-rmk-v2' of git://linux-arm.org/linux-ja into ↵Russell King
devel-stable This includes the following series sent earlier to the list: - nommu-fixes - R7 Support - MPU support I've left out the ARCH_MULTIPLATFORM/!MMU stuff that Arnd and I were discussing today until we've reached a conclusion/that's had some more review. This is rebased (and re-tested) on your devel-stable branch because otherwise there were going to be conflicts with Uwe's V7M work now that you've merged that. I've included the fix for limiting MPU to CPU_V7.
2013-06-17ARM: mpu: protect the vectors page with an MPU regionJonathan Austin
Without an MMU it is possible for userspace programs to start executing code in places that they have no business executing. The MPU allows some level of protection against this. This patch protects the vectors page from access by userspace processes. Userspace tasks that dereference a null pointer are already protected by an svc at 0x0 that kills them. However when tasks use an offset from a null pointer (eg a function in a null struct) they miss this carefully placed svc and enter the exception vectors in user mode, ending up in the kernel. This patch causes programs that do this to receive a SEGV instead of happily entering the kernel in user-mode, and hence avoid a 'Bad Mode' panic. As part of this change it is necessary to make sigreturn happen via the stack when there is not an sa_restorer function. This change is invisible to userspace, and irrelevant to code compiled using a uClibc toolchain, which always uses an sa_restorer function. Because we don't get to remap the vectors in !MMU kuser_helpers are not in a defined location, and hence aren't usable. This means we don't need to worry about keeping them accessible from PL0 Signed-off-by: Jonathan Austin <jonathan.austin@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> CC: Nicolas Pitre <nico@linaro.org> CC: Catalin Marinas <catalin.marinas@arm.com>
2013-06-17ARM: 7748/1: oabi: handle faults when loading swi instruction from userspaceWill Deacon
Running an OABI_COMPAT kernel on an SMP platform can lead to fun and games with page aging. If one CPU issues a swi instruction immediately before another CPU decides to mkold the page containing the swi instruction, then we will fault attempting to load the instruction during the vector_swi handler in order to retrieve its immediate field. Since this fault is not currently dealt with by our exception tables, this results in a panic: Unable to handle kernel paging request at virtual address 4020841c pgd = c490c000 [4020841c] *pgd=84451831, *pte=bf05859d, *ppte=00000000 Internal error: Oops: 17 [#1] PREEMPT SMP ARM Modules linked in: hid_sony(O) CPU: 1 Tainted: G W O (3.4.0-perf-gf496dca-01162-gcbcc62b #1) PC is at vector_swi+0x28/0x88 LR is at 0x40208420 This patch wraps all of the swi instruction loads with the USER macro and provides a shared exception table entry which simply rewinds the saved user PC and returns from the system call (without setting tbl, so there's no worries with tracing or syscall restarting). Returning to userspace will re-enter the page fault handler, from where we will probably send SIGSEGV to the current task. Reported-by: Wang, Yalin <yalin.wang@sonymobile.com> Reviewed-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-06-12sched_clock: Make ARM's sched_clock generic for all architecturesStephen Boyd
Nothing about the sched_clock implementation in the ARM port is specific to the architecture. Generalize the code so that other architectures can use it by selecting GENERIC_SCHED_CLOCK. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> [jstultz: Merge minor collisions with other patches in my tree] Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-06-12ARM: sched_clock: Return suspended count earlierStephen Boyd
If we're suspended and sched_clock() is called we're going to read the hardware one more time and throw away that value and return back the cached value we saved during the suspend callback. This is wasteful. Let's short circuit all that and return the cached value as early as possible if we're suspended. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-06-12ARM: sched_clock: Remove unused needs_suspend memberStephen Boyd
The needs_suspend member is unused now that we always do the suspend/resume handling (see 6a4dae5 (ARM: 7565/1: sched: stop sched_clock() during suspend, 2012-10-23)). Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-06-07ARM: mpu: add MPU initialisation for secondary coresJonathan Austin
The MPU initialisation on the primary core is performed in two stages, one minimal stage to ensure the CPU can boot and a second one after sanity_check_meminfo. As the memory configuration is known by the time we boot secondary cores only a single step is necessary, provided the values for DRSR are passed to secondaries. This patch implements this arrangement. The configuration generated for the MPU regions is made available to the secondary core, which can then use the asm MPU intialisation code to program a complete region configuration. This is necessary for SMP configurations without an MMU, as the MPU initialisation is the only way to ensure that memory is specified as 'shared'. Signed-off-by: Jonathan Austin <jonathan.austin@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> CC: Nicolas Pitre <nico@linaro.org>
2013-06-07ARM: mpu: add early bring-up code for the ARMv7 PMSA-compliant MPUJonathan Austin
This patch adds initial support for using the MPU, which is necessary for SMP operation on PMSAv7 processors because it is the only way to ensure memory is shared. This is an initial patch and full SMP support is added later in this series. The setup of the MPU is performed in a way analagous to that for the MMU: Very early initialisation before the C environment is brought up, followed by a sanity check and more complete initialisation in C. This patch provides the simplest possible memory region configuration: MPU_PROBE_REGION: Reserved for probing MPU details, not enabled MPU_BG_REGION: A 'background' region that specifies all memory strongly ordered MPU_RAM_REGION: A single shared, cacheable, normal region for the valid RAM. In this early initialisation code we simply map the whole of the address space with the BG_REGION and (at least) the kernel with the RAM_REGION. The MPU has region alignment constraints that require us to round past the end of the kernel. As region 2 has a higher priority than region 1, it overrides the strongly- ordered behaviour for RAM only. Subsequent patches will add more complete initialisation from the C-world and support for bringing up secondary CPUs. Signed-off-by: Jonathan Austin <jonathan.austin@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> CC: Hyok S. Choi <hyok.choi@samsung.com>
2013-06-07ARM: nommu: Don't build smp_tlb.c for !CONFIG_MMUJonathan Austin
Without an MMU we don't need to do any TLB maintenance. Until the addition of 93dc68876b60 (ARM: 7684/1: errata: Workaround for Cortex-A15 erratum 798181 (TLBI/DSB operations)) building the tlb maintenance ops in smp_tlb.c worked, though none of the contents were used. Since that commit, however, SMP NOMMU has not been able to build. This patch restores that ability by making the building of smp_tlb.c dependent on MMU. Signed-off-by: Jonathan Austin <jonathan.austin@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> CC: Will Deacon <will.deacon@arm.com>
2013-06-07ARM: suspend: fix CPU suspend code for !CONFIG_MMU configurationsWill Deacon
The ARM CPU suspend code can be selected even for a !CONFIG_MMU configuration. The resulting kernel will not compile and, even if it did, would access undefined co-processor registers when executing. This patch fixes the v6 and v7 CPU suspend code for the nommu case. Signed-off-by: Will Deacon <will.deacon@arm.com> Tested-by: Jonathan Austin <jonathan.austin@arm.com> CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> (commit_signer:1/3=33%) CC: Santosh Shilimkar <santosh.shilimkar@ti.com> (commit_signer:1/3=33%) CC: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2013-06-07ARM: nommu: do not initialise page tables in secondary_data structureWill Deacon
nommu systems do not require any page tables, so don't try to initialise them when bringing up secondary cores. Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-06-07ARM: nommu: add entry point for secondary CPUs to head-nommu.SWill Deacon
This patch adds a secondary_startup entry point to head-nommu.S so that we can boot secondary CPUs on an SMP nommu configuration. Signed-off-by: Will Deacon <will.deacon@arm.com> CC: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> CC: Nicolas Pitre <nico@linaro.org>
2013-06-07ARM: arch_timer: stop virtual timer when booted in HYP modeMarc Zyngier
When booting the kernel, a bootloader could have left the virtual timer ticking away, potentially generating interrupts. This could be troublesome if the user of the virtual timer is not careful when enabling the interrupt. In order to avoid any surprise, stop the virtual timer from interrupting us when booted in HYP mode, as we'll use the physical timer in this case. Reported-by: Giridhar Maruthy <giridhar.m@samsung.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: Dave Martin <dave.martin@linaro.org>
2013-06-07ARM: hyp: initialize CNTVOFF to zeroMarc Zyngier
In order to be able to use the virtual counter in a safe way, make sure it is initialized to zero before dropping to SVC. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: Dave Martin <dave.martin@linaro.org>
2013-06-05ARM: 7745/1: psci: fix building without HOTPLUG_CPUArnd Bergmann
The cpu_die field in smp_operations is not valid with CONFIG_HOTPLUG_CPU, so we must enclose it in #ifdef, but at least that lets us remove two other lines. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-06-05ARM: 7742/1: topology: export cpu_topologyArnd Bergmann
The cpu_topology symbol is required by any driver using the topology interfaces, which leads to a couple of build errors: ERROR: "cpu_topology" [drivers/net/ethernet/sfc/sfc.ko] undefined! ERROR: "cpu_topology" [drivers/cpufreq/arm_big_little.ko] undefined! ERROR: "cpu_topology" [drivers/block/mtip32xx/mtip32xx.ko] undefined! The obvious solution is to export this symbol. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Will Deacon <will.deacon@arm.com> Cc: stable@vger.kernel.org Cc: Nicolas Pitre <nico@linaro.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-06-03Finally eradicate CONFIG_HOTPLUGStephen Rothwell
Ever since commit 45f035ab9b8f ("CONFIG_HOTPLUG should be always on"), it has been basically impossible to build a kernel with CONFIG_HOTPLUG turned off. Remove all the remaining references to it. Cc: Russell King <linux@arm.linux.org.uk> Cc: Doug Thompson <dougthompson@xmission.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-06-03ARM: pci: create pci_common_init_dev()Linus Walleij
When working with device tree support for PCI on ARM you run into a problem when mapping IRQs from the device tree irqmaps: doing this the code in drivers/of/of_pci_irq.c will try to find the OF node on the root bridge and this fails, because bus->dev.of_node is NULL, and that in turn boils down to the fact that pci_set_bus_of_node() has called pcibios_get_phb_of_node() from drivers/pci/of.c to obtain the OF node of the bridge or its parent and none is set and thus NULL is returned. Fix this by adding an additional parent argument API for registering PCI bridges on the ARM architecture called pci_common_init_dev(), and pass along this parent to pci_scan_root_bus() called from pcibios_init_hw() in bios32.c and voila: the IRQ mappings start working: the OF node can be retrieved from the parent. Create the old pci_common_init() as a wrapper around the new call. Cc: Mike Rapoport <mike@compulab.co.il> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmitt <benh@kernel.crashing.org> Reviewed-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-05-31Merge branch 'depends/rmk-devel-stable' into next/socOlof Johansson
Pulling in base dependencies from rmk's devel-stable branch needed by the CCI patches for vexpress. Signed-off-by: Olof Johansson <olof@lixom.net> * depends/rmk-devel-stable: ARM: Enable selection of SMP operations at boot time arm: introduce psci_smp_ops ARM: ARMv7-M: implement read_cpuid_ext ARM: ARMv7-M: Allow the building of new kernel port ARM: ARMv7-M: Add support for exception handling ARM: Add base support for ARMv7-M
2013-05-30ARM: elf: add new hwcap for identifying atomic ldrd/strd instructionsWill Deacon
CPUs implementing LPAE have atomic ldrd/strd instructions, meaning that userspace software can avoid having to use the exclusive variants of these instructions if they wish. This patch advertises the atomicity of these instructions via the hwcaps, so userspace can detect this CPU feature. Reported-by: Vladimir Danushevsky <vladimir.danushevsky@oracle.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-05-30ARM: LPAE: accomodate >32-bit addresses for page table baseCyril Chemparathy
This patch redefines the early boot time use of the R4 register to steal a few low order bits (ARCH_PGD_SHIFT bits) on LPAE systems. This allows for up to 38-bit physical addresses. Signed-off-by: Cyril Chemparathy <cyril@ti.com> Signed-off-by: Vitaly Andrianov <vitalya@ti.com> Acked-by: Nicolas Pitre <nico@linaro.org> Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Subash Patel <subash.rp@samsung.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-05-25Merge branch 'fixes' of git://git.linaro.org/people/rmk/linux-armLinus Torvalds
Pull ARM fixes from Russell King: "Just three this time, all really quite small" * 'fixes' of git://git.linaro.org/people/rmk/linux-arm: ARM: 7729/1: vfp: ensure VFP_arch is non-zero when VFP is not supported ARM: 7727/1: remove the .vm_mm value from gate_vma ARM: 7723/1: crypto: sha1-armv4-large.S: fix SP handling
2013-05-22ARM: 7727/1: remove the .vm_mm value from gate_vmaSteven Capper
If one reads /proc/$PID/smaps, the mmap_sem belonging to the address space of the task being examined is locked for reading. All the pages of the vmas belonging to the task's address space are then walked with this lock held. If a gate_vma is present in the architecture, it too is examined by the fs/proc/task_mmu.c code. As gate_vma doesn't belong to the address space of the task though, its pages are not walked. A recent cleanup (commit f6604efe) of the gate_vma initialisation code set the vm_mm value to &init_mm. Unfortunately a non-NULL vm_mm value in the gate_vma will cause the task_mmu code to attempt to walk the pages of the gate_vma (with no mmap-sem lock held). If one enables Transparent Huge Page support and vm debugging, this will then cause OOPses as pmd_trans_huge_lock is called without mmap_sem being locked. This patch removes the .vm_mm value from gate_vma, restoring the original behaviour of the task_mmu code. Signed-off-by: Steve Capper <steve.capper@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-05-22Merge tag '3.10-rc2-psci-ops-11-tag' of ↵Russell King
git://git.kernel.org/pub/scm/linux/kernel/git/sstabellini/xen into devel-stable Pull psci_smp_ops support from Stefano Stabellini: It contains the generic PSCI patch and the smp_init patch that we discussed so much about. I think it would be helpful for other people if you could create a stable branch with these patches so that SoC devs can base their work on it.
2013-05-22Merge branch 'for-next' of git://git.pengutronix.de/git/ukl/linux into ↵Russell King
devel-stable Pull ARM-v7M support from Uwe Kleine-König: "All but the last patch were in next since next-20130418 without issues. The last patch fixes a problem in combination with 8164f7a (ARM: 7680/1: Detect support for SDIV/UDIV from ISAR0 register) which triggers a WARN_ON without an implemented read_cpuid_ext. The branch merges fine into v3.10-rc1 and I'd be happy if you pulled it for 3.11-rc1. The only missing piece to be able to run a Cortex-M3 is the irqchip driver that will go in via Thomas Gleixner and platform specific stuff."
2013-05-21ARM: smp: Drop RCU_NONIDLE usage in cpu_die()Stephen Boyd
Before f7b861b7a6d9 ("arm: Use generic idle loop") ARM would kill the CPU within the rcu idle section. Now that the rcu_idle_enter()/exit() pair have been pushed lower down in the idle loop this is no longer true and so using RCU_NONIDLE here is no longer necessary and also harmful because RCU is not actually idle at this point. Cc: Russell King <linux@arm.linux.org.uk> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-21ARM: Enable selection of SMP operations at boot timeJon Medhurst
Add a new 'smp_init' hook to machine_desc so platforms can specify a function to be used to setup smp ops instead of having a statically defined value. The hook must return true when smp_ops are initialized. If false the static mdesc->smp_ops will be used by default. Add the definition of "bool" by including the linux/types.h file to asm/mach/arch.h and make it self-contained. Signed-off-by: Jon Medhurst <tixy@linaro.org> Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
2013-05-21arm: introduce psci_smp_opsStefano Stabellini
Rename virt_smp_ops to psci_smp_ops and move them to arch/arm/kernel/psci_smp.c. Remove mach-virt/platsmp.c, now unused. Compile psci_smp if CONFIG_ARM_PSCI and CONFIG_SMP. Add a cpu_die smp_op based on psci_ops.cpu_off. Initialize PSCI before setting smp_ops in setup_arch. If PSCI is available on the platform, prefer psci_smp_ops over the platform smp_ops. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Will Deacon <will.deacon@arm.com> CC: arnd@arndb.de CC: marc.zyngier@arm.com CC: linux@arm.linux.org.uk CC: nico@linaro.org CC: rob.herring@calxeda.com
2013-05-15ARM: 7669/1: keep __my_cpu_offset consistent with generic oneMing Lei
Commit 14318efb(ARM: 7587/1: implement optimized percpu variable access) introduces arm's __my_cpu_offset to optimize percpu vaiable access, which really works well on hackbench, but will cause __my_cpu_offset to return garbage value before it is initialized in cpu_init() called by setup_arch, so accessing percpu variable before setup_arch may cause kernel hang. But generic __my_cpu_offset always returns zero before percpu area is brought up, and won't hang kernel. So the patch tries to clear __my_cpu_offset on boot CPU early to avoid boot hang. At least now percpu variable is accessed by lockdep before setup_arch(), and enabling CONFIG_LOCK_STAT or CONFIG_DEBUG_LOCKDEP can trigger kernel hang. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-05-09Merge branch 'late/fixes' into fixesOlof Johansson
* late/fixes: ARM: OMAP2+: Fix unmet direct dependencies for SERIAL_OMAP ARM: ux500: always select ABX500_CORE ARM: SIRF: select SMP_ON_UP only on SMP builds ARM: SPEAr: conditionalize l2x0 support ARM: imx: build CPU suspend code only when needed ARM: OMAP: build SMP code only for OMAP4/5 ARM: tegra: Tegra114 needs CPU_FREQ_TABLE ARM: default machine descriptor for multiplatform Signed-off-by: Olof Johansson <olof@lixom.net>
2013-05-07Merge tag 'cleanup-for-linus-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc Pull ARM SoC late cleanups from Arnd Bergmann: "These are cleanups and smaller changes that either depend on earlier feature branches or came in late during the development cycle. We normally try to get all cleanups early, so these are the exceptions: - A follow-up on the clocksource reworks, hopefully the last time we need to merge clocksource subsystem changes through arm-soc. A first set of patches was part of the original 3.10 arm-soc cleanup series because of interdependencies with timer drivers now moved out of arch/arm. - Migrating the SPEAr13xx platform away from using auxdata for DMA channel descriptions towards using information in device tree, based on the earlier SPEAr multiplatform series - A few follow-ups on the Atmel SAMA5 support and other changes for Atmel at91 based on the larger at91 reworks. - Moving the armada irqchip implementation to drivers/irqchip - Several OMAP cleanups following up on the larger series already merged in 3.10." * tag 'cleanup-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (50 commits) ARM: OMAP4: change the device names in usb_bind_phy ARM: OMAP2+: Fix mismerge for timer.c between ff931c82 and da4a686a ARM: SPEAr: conditionalize SMP code ARM: arch_timer: Silence debug preempt warnings ARM: OMAP: remove unused variable serial: amba-pl011: fix !CONFIG_DMA_ENGINE case ata: arasan: remove the need for platform_data ARM: at91/sama5d34ek.dts: remove not needed compatibility string ARM: at91: dts: add MCI DMA support ARM: at91: dts: add i2c dma support ARM: at91: dts: set #dma-cells to the correct value ARM: at91: suspend both memory controllers on at91sam9263 irqchip: armada-370-xp: slightly cleanup irq controller driver irqchip: armada-370-xp: move IRQ handler to avoid forward declaration irqchip: move IRQ driver for Armada 370/XP ARM: mvebu: move L2 cache initialization in init_early() devtree: add binding documentation for sp804 ARM: integrator-cp: convert use CLKSRC_OF for timer init ARM: versatile: use OF init for sp804 timer ARM: versatile: add versatile dtbs to dtbs target ...
2013-05-06Merge branch 'late/clksrc' into late/cleanupArnd Bergmann
There is no reason to keep the clksrc cleanups separate from the other cleanups, and this resolves some merge conflicts. Conflicts: arch/arm/mach-spear/spear13xx.c drivers/irqchip/Makefile
2013-05-05Merge tag 'kvm-3.10-1' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull kvm updates from Gleb Natapov: "Highlights of the updates are: general: - new emulated device API - legacy device assignment is now optional - irqfd interface is more generic and can be shared between arches x86: - VMCS shadow support and other nested VMX improvements - APIC virtualization and Posted Interrupt hardware support - Optimize mmio spte zapping ppc: - BookE: in-kernel MPIC emulation with irqfd support - Book3S: in-kernel XICS emulation (incomplete) - Book3S: HV: migration fixes - BookE: more debug support preparation - BookE: e6500 support ARM: - reworking of Hyp idmaps s390: - ioeventfd for virtio-ccw And many other bug fixes, cleanups and improvements" * tag 'kvm-3.10-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (204 commits) kvm: Add compat_ioctl for device control API KVM: x86: Account for failing enable_irq_window for NMI window request KVM: PPC: Book3S: Add API for in-kernel XICS emulation kvm/ppc/mpic: fix missing unlock in set_base_addr() kvm/ppc: Hold srcu lock when calling kvm_io_bus_read/write kvm/ppc/mpic: remove users kvm/ppc/mpic: fix mmio region lists when multiple guests used kvm/ppc/mpic: remove default routes from documentation kvm: KVM_CAP_IOMMU only available with device assignment ARM: KVM: iterate over all CPUs for CPU compatibility check KVM: ARM: Fix spelling in error message ARM: KVM: define KVM_ARM_MAX_VCPUS unconditionally KVM: ARM: Fix API documentation for ONE_REG encoding ARM: KVM: promote vfp_host pointer to generic host cpu context ARM: KVM: add architecture specific hook for capabilities ARM: KVM: perform HYP initilization for hotplugged CPUs ARM: KVM: switch to a dual-step HYP init code ARM: KVM: rework HYP page table freeing ARM: KVM: enforce maximum size for identity mapped code ARM: KVM: move to a KVM provided HYP idmap ...
2013-05-05arm: single_open() leaksAl Viro
Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-05-03Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-armLinus Torvalds
Pull ARM updates from Russell King: "The major items included in here are: - MCPM, multi-cluster power management, part of the infrastructure required for ARMs big.LITTLE support. - A rework of the ARM KVM code to allow re-use by ARM64. - Error handling cleanups of the IS_ERR_OR_NULL() madness and fixes of that stuff for arch/arm - Preparatory patches for Cortex-M3 support from Uwe Kleine-König. There is also a set of three patches in here from Hugh/Catalin to address freeing of inappropriate page tables on LPAE. You already have these from akpm, but they were already part of my tree at the time he sent them, so unfortunately they'll end up with duplicate commits" * 'for-linus' of git://git.linaro.org/people/rmk/linux-arm: (77 commits) ARM: EXYNOS: remove unnecessary use of IS_ERR_VALUE() ARM: IMX: remove unnecessary use of IS_ERR_VALUE() ARM: OMAP: use consistent error checking ARM: cleanup: OMAP hwmod error checking ARM: 7709/1: mcpm: Add explicit AFLAGS to support v6/v7 multiplatform kernels ARM: 7700/2: Make cpu_init() notrace ARM: 7702/1: Set the page table freeing ceiling to TASK_SIZE ARM: 7701/1: mm: Allow arch code to control the user page table ceiling ARM: 7703/1: Disable preemption in broadcast_tlb*_a15_erratum() ARM: mcpm: provide an interface to set the SMP ops at run time ARM: mcpm: generic SMP secondary bringup and hotplug support ARM: mcpm_head.S: vlock-based first man election ARM: mcpm: Add baremetal voting mutexes ARM: mcpm: introduce helpers for platform coherency exit/setup ARM: mcpm: introduce the CPU/cluster power API ARM: multi-cluster PM: secondary kernel entry code ARM: cacheflush: add synchronization helpers for mixed cache state accesses ARM: cpu hotplug: remove majority of cache flushing from platforms ARM: smp: flush L1 cache in cpu_die() ARM: tegra: remove tegra specific cpu_disable() ...
2013-05-02Merge branch 'cleanup' into for-linusRussell King
Conflicts: arch/arm/plat-omap/dmtimer.c
2013-05-02Merge branches 'devel-stable', 'entry', 'fixes', 'mach-types', 'misc' and ↵Russell King
'smp-hotplug' into for-linus
2013-05-02Merge tag 'cleanup-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc Pull ARM SoC cleanup from Olof Johansson: "Here is a collection of cleanup patches. Among the pieces that stand out are: - The deletion of h720x platforms - Split of at91 non-dt platforms to their own Kconfig file to keep them separate - General cleanups and refactoring of i.MX and MXS platforms - Some restructuring of clock tables for OMAP - Convertion of PMC driver for Tegra to dt-only - Some renames of sunxi -> sun4i (Allwinner A10) - ... plus a bunch of other stuff that I haven't mentioned" * tag 'cleanup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (119 commits) ARM: i.MX: remove unused ARCH_* configs ARM i.MX53: remove platform ahci support ARM: sunxi: Rework the restart code irqchip: sunxi: Rename sunxi to sun4i irqchip: sunxi: Make use of the IRQCHIP_DECLARE macro clocksource: sunxi: Rename sunxi to sun4i clocksource: sunxi: make use of CLKSRC_OF clocksource: sunxi: Cleanup the timer code ARM: at91: remove trailing semicolon from macros ARM: at91/setup: fix trivial typos ARM: EXYNOS: remove "config EXYNOS_DEV_DRM" ARM: EXYNOS: change the name of USB ohci header ARM: SAMSUNG: Remove unnecessary code for dma ARM: S3C24XX: Remove unused GPIO drive strength register definitions ARM: OMAP4+: PM: Restore CPU power state to ON with clockdomain force wakeup method ARM: S3C24XX: Removed unneeded dependency on CPU_S3C2412 ARM: S3C24XX: Removed unneeded dependency on CPU_S3C2410 ARM: S3C24XX: Removed unneeded dependency on ARCH_S3C24XX for boards ARM: SAMSUNG: Fix typo "CONFIG_SAMSUNG_DEV_RTC" ARM: S5P64X0: Fix typo "CONFIG_S5P64X0_SETUP_SDHCI" ...
2013-05-01Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull VFS updates from Al Viro, Misc cleanups all over the place, mainly wrt /proc interfaces (switch create_proc_entry to proc_create(), get rid of the deprecated create_proc_read_entry() in favor of using proc_create_data() and seq_file etc). 7kloc removed. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits) don't bother with deferred freeing of fdtables proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h proc: Make the PROC_I() and PDE() macros internal to procfs proc: Supply a function to remove a proc entry by PDE take cgroup_open() and cpuset_open() to fs/proc/base.c ppc: Clean up scanlog ppc: Clean up rtas_flash driver somewhat hostap: proc: Use remove_proc_subtree() drm: proc: Use remove_proc_subtree() drm: proc: Use minor->index to label things, not PDE->name drm: Constify drm_proc_list[] zoran: Don't print proc_dir_entry data in debug reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show() proc: Supply an accessor for getting the data from a PDE's parent airo: Use remove_proc_subtree() rtl8192u: Don't need to save device proc dir PDE rtl8187se: Use a dir under /proc/net/r8180/ proc: Add proc_mkdir_data() proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h} proc: Move PDE_NET() to fs/proc/proc_net.c ...
2013-04-30ARM/etm/sysrq: fix inconstistent help message of sysrq keyzhangwei(Jovi)
Currently help message of /proc/sysrq-trigger highlights its upper-case characters, like below: SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) ... this would confuse user trigger sysrq by upper-case character, which is inconsistent with the real lower-case character registed key. This inconsistent help message will also lead more confused when 26 upper-case letters put into use in future. This patch fix arm etm sysrq key: "etm-buffer-dump(v)" (This patch also add "-" to separate each sysrq key help word, instead of spaces) Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30dump_stack: unify debug information printed by show_regs()Tejun Heo
show_regs() is inherently arch-dependent but it does make sense to print generic debug information and some archs already do albeit in slightly different forms. This patch introduces a generic function to print debug information from show_regs() so that different archs print out the same information and it's much easier to modify what's printed. show_regs_print_info() prints out the same debug info as dump_stack() does plus task and thread_info pointers. * Archs which didn't print debug info now do. alpha, arc, blackfin, c6x, cris, frv, h8300, hexagon, ia64, m32r, metag, microblaze, mn10300, openrisc, parisc, score, sh64, sparc, um, xtensa * Already prints debug info. Replaced with show_regs_print_info(). The printed information is superset of what used to be there. arm, arm64, avr32, mips, powerpc, sh32, tile, unicore32, x86 * s390 is special in that it used to print arch-specific information along with generic debug info. Heiko and Martin think that the arch-specific extra isn't worth keeping s390 specfic implementation. Converted to use the generic version. Note that now all archs print the debug info before actual register dumps. An example BUG() dump follows. kernel BUG at /work/os/work/kernel/workqueue.c:4841! invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #7 Hardware name: empty empty/S3992, BIOS 080011 10/26/2007 task: ffff88007c85e040 ti: ffff88007c860000 task.ti: ffff88007c860000 RIP: 0010:[<ffffffff8234a07e>] [<ffffffff8234a07e>] init_workqueues+0x4/0x6 RSP: 0000:ffff88007c861ec8 EFLAGS: 00010246 RAX: ffff88007c861fd8 RBX: ffffffff824466a8 RCX: 0000000000000001 RDX: 0000000000000046 RSI: 0000000000000001 RDI: ffffffff8234a07a RBP: ffff88007c861ec8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8234a07a R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88007dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: ffff88015f7ff000 CR3: 00000000021f1000 CR4: 00000000000007f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Stack: ffff88007c861ef8 ffffffff81000312 ffffffff824466a8 ffff88007c85e650 0000000000000003 0000000000000000 ffff88007c861f38 ffffffff82335e5d ffff88007c862080 ffffffff8223d8c0 ffff88007c862080 ffffffff81c47760 Call Trace: [<ffffffff81000312>] do_one_initcall+0x122/0x170 [<ffffffff82335e5d>] kernel_init_freeable+0x9b/0x1c8 [<ffffffff81c47760>] ? rest_init+0x140/0x140 [<ffffffff81c4776e>] kernel_init+0xe/0xf0 [<ffffffff81c6be9c>] ret_from_fork+0x7c/0xb0 [<ffffffff81c47760>] ? rest_init+0x140/0x140 ... v2: Typo fix in x86-32. v3: CPU number dropped from show_regs_print_info() as dump_stack_print_info() has been updated to print it. s390 specific implementation dropped as requested by s390 maintainers. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Sam Ravnborg <sam@ravnborg.org> Acked-by: Chris Metcalf <cmetcalf@tilera.com> [tile bits] Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon bits] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30dump_stack: consolidate dump_stack() implementations and unify their behaviorsTejun Heo
Both dump_stack() and show_stack() are currently implemented by each architecture. show_stack(NULL, NULL) dumps the backtrace for the current task as does dump_stack(). On some archs, dump_stack() prints extra information - pid, utsname and so on - in addition to the backtrace while the two are identical on other archs. The usages in arch-independent code of the two functions indicate show_stack(NULL, NULL) should print out bare backtrace while dump_stack() is used for debugging purposes when something went wrong, so it does make sense to print additional information on the task which triggered dump_stack(). There's no reason to require archs to implement two separate but mostly identical functions. It leads to unnecessary subtle information. This patch expands the dummy fallback dump_stack() implementation in lib/dump_stack.c such that it prints out debug information (taken from x86) and invokes show_stack(NULL, NULL) and drops arch-specific dump_stack() implementations in all archs except blackfin. Blackfin's dump_stack() does something wonky that I don't understand. Debug information can be printed separately by calling dump_stack_print_info() so that arch-specific dump_stack() implementation can still emit the same debug information. This is used in blackfin. This patch brings the following behavior changes. * On some archs, an extra level in backtrace for show_stack() could be printed. This is because the top frame was determined in dump_stack() on those archs while generic dump_stack() can't do that reliably. It can be compensated by inlining dump_stack() but not sure whether that'd be necessary. * Most archs didn't use to print debug info on dump_stack(). They do now. An example WARN dump follows. WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505() Hardware name: empty Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #9 0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48 ffffffff8108f50f ffffffff82228240 0000000000000040 ffffffff8234a03c 0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58 Call Trace: [<ffffffff81c614dc>] dump_stack+0x19/0x1b [<ffffffff8108f50f>] warn_slowpath_common+0x7f/0xc0 [<ffffffff8108f56a>] warn_slowpath_null+0x1a/0x20 [<ffffffff8234a071>] init_workqueues+0x35/0x505 ... v2: CPU number added to the generic debug info as requested by s390 folks and dropped the s390 specific dump_stack(). This loses %ksp from the debug message which the maintainers think isn't important enough to keep the s390-specific dump_stack() implementation. dump_stack_print_info() is moved to kernel/printk.c from lib/dump_stack.c. Because linkage is per objecct file, dump_stack_print_info() living in the same lib file as generic dump_stack() means that archs which implement custom dump_stack() - at this point, only blackfin - can't use dump_stack_print_info() as that will bring in the generic version of dump_stack() too. v1 The v1 patch broke build on blackfin due to this issue. The build breakage was reported by Fengguang Wu. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Vineet Gupta <vgupta@synopsys.com> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [s390 bits] Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Sam Ravnborg <sam@ravnborg.org> Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon bits] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>