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* arm64: kexec: have own crash_smp_send_stop() for crash dump for nonpanic coresHoeun Ryu2017-08-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 0ee5941 : (x86/panic: replace smp_send_stop() with kdump friendly version in panic path) introduced crash_smp_send_stop() which is a weak function and can be overridden by architecture codes to fix the side effect caused by commit f06e515 : (kernel/panic.c: add "crash_kexec_post_ notifiers" option). ARM64 architecture uses the weak version function and the problem is that the weak function simply calls smp_send_stop() which makes other CPUs offline and takes away the chance to save crash information for nonpanic CPUs in machine_crash_shutdown() when crash_kexec_post_notifiers kernel option is enabled. Calling smp_send_crash_stop() in machine_crash_shutdown() is useless because all nonpanic CPUs are already offline by smp_send_stop() in this case and smp_send_crash_stop() only works against online CPUs. The result is that secondary CPUs registers are not saved by crash_save_cpu() and the vmcore file misreports these CPUs as being offline. crash_smp_send_stop() is implemented to fix this problem by replacing the existing smp_send_crash_stop() and adding a check for multiple calling to the function. The function (strong symbol version) saves crash information for nonpanic CPUs and machine_crash_shutdown() tries to save crash information for nonpanic CPUs only when crash_kexec_post_notifiers kernel option is disabled. * crash_kexec_post_notifiers : false panic() __crash_kexec() machine_crash_shutdown() crash_smp_send_stop() <= save crash dump for nonpanic cores * crash_kexec_post_notifiers : true panic() crash_smp_send_stop() <= save crash dump for nonpanic cores __crash_kexec() machine_crash_shutdown() crash_smp_send_stop() <= just return. Signed-off-by: Hoeun Ryu <hoeun.ryu@gmail.com> Reviewed-by: James Morse <james.morse@arm.com> Tested-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: kdump: implement machine_crash_shutdown()AKASHI Takahiro2017-04-051-0/+3
| | | | | | | | | | | | | | | | Primary kernel calls machine_crash_shutdown() to shut down non-boot cpus and save registers' status in per-cpu ELF notes before starting crash dump kernel. See kernel_kexec(). Even if not all secondary cpus have shut down, we do kdump anyway. As we don't have to make non-boot(crashed) cpus offline (to preserve correct status of cpus at crash dump) before shutting down, this patch also adds a variant of smp_send_stop(). Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Reviewed-by: James Morse <james.morse@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: smp: Prevent raw_smp_processor_id() recursionRobin Murphy2016-12-021-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Under CONFIG_DEBUG_PREEMPT=y, this_cpu_ptr() ends up calling back into raw_smp_processor_id(), resulting in some hilariously catastrophic infinite recursion. In the normal case, we have: #define this_cpu_ptr(ptr) raw_cpu_ptr(ptr) and everything is dandy. However for CONFIG_DEBUG_PREEMPT, this_cpu_ptr() is defined in terms of my_cpu_offset, wherein the fun begins: #define my_cpu_offset per_cpu_offset(smp_processor_id()) ... #define smp_processor_id() debug_smp_processor_id() ... notrace unsigned int debug_smp_processor_id(void) { return check_preemption_disabled("smp_processor_id", ""); ... notrace static unsigned int check_preemption_disabled(const char *what1, const char *what2) { int this_cpu = raw_smp_processor_id(); and bang. Use raw_cpu_ptr() directly to avoid that. Fixes: 57c82954e77f ("arm64: make cpu number a percpu variable") Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Robin Murphy <robin.murphy@arm.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: split thread_info from task stackMark Rutland2016-11-111-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch moves arm64's struct thread_info from the task stack into task_struct. This protects thread_info from corruption in the case of stack overflows, and makes its address harder to determine if stack addresses are leaked, making a number of attacks more difficult. Precise detection and handling of overflow is left for subsequent patches. Largely, this involves changing code to store the task_struct in sp_el0, and acquire the thread_info from the task struct. Core code now implements current_thread_info(), and as noted in <linux/sched.h> this relies on offsetof(task_struct, thread_info) == 0, enforced by core code. This change means that the 'tsk' register used in entry.S now points to a task_struct, rather than a thread_info as it used to. To make this clear, the TI_* field offsets are renamed to TSK_TI_*, with asm-offsets appropriately updated to account for the structural change. Userspace clobbers sp_el0, and we can no longer restore this from the stack. Instead, the current task is cached in a per-cpu variable that we can safely access from early assembly as interrupts are disabled (and we are thus not preemptible). Both secondary entry and idle are updated to stash the sp and task pointer separately. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Laura Abbott <labbott@redhat.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: James Morse <james.morse@arm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: make cpu number a percpu variableMark Rutland2016-11-111-1/+10
| | | | | | | | | | | | | | | | | | | | | | In the absence of CONFIG_THREAD_INFO_IN_TASK, core code maintains thread_info::cpu, and low-level architecture code can access this to build raw_smp_processor_id(). With CONFIG_THREAD_INFO_IN_TASK, core code maintains task_struct::cpu, which for reasons of hte header soup is not accessible to low-level arch code. Instead, we can maintain a percpu variable containing the cpu number. For both the old and new implementation of raw_smp_processor_id(), we read a syreg into a GPR, add an offset, and load the result. As the offset is now larger, it may not be folded into the load, but otherwise the assembly shouldn't change much. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Laura Abbott <labbott@redhat.com> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: smp: Add function to determine if cpus are stuck in the kernelJames Morse2016-06-221-0/+12
| | | | | | | | | | | | | | | | | | | | | kernel/smp.c has a fancy counter that keeps track of the number of CPUs it marked as not-present and left in cpu_park_loop(). If there are any CPUs spinning in here, features like kexec or hibernate may release them by overwriting this memory. This problem also occurs on machines using spin-tables to release secondary cores. After commit 44dbcc93ab67 ("arm64: Fix behavior of maxcpus=N") we bring all known cpus into the secondary holding pen, meaning this memory can't be re-used by kexec or hibernate. Add a function cpus_are_stuck_in_kernel() to determine if either of these cases have occurred. Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
* arm64: Add cpu_panic_kernel helperSuzuki K Poulose2016-04-151-0/+11
| | | | | | | | | | | | | | | During the activation of a secondary CPU, we could report serious configuration issues and hence request to crash the kernel. We do this for CPU ASID bit check now. We will need it also for handling mismatched exception levels for the CPUs with VHE. Hence, add a helper to do the same for reusability. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
* arm64: Handle early CPU boot failuresSuzuki K Poulose2016-02-251-0/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A secondary CPU could fail to come online due to insufficient capabilities and could simply die or loop in the kernel. e.g, a CPU with no support for the selected kernel PAGE_SIZE loops in kernel with MMU turned off. or a hotplugged CPU which doesn't have one of the advertised system capability will die during the activation. There is no way to synchronise the status of the failing CPU back to the master. This patch solves the issue by adding a field to the secondary_data which can be updated by the failing CPU. If the secondary CPU fails even before turning the MMU on, it updates the status in a special variable reserved in the head.txt section to make sure that the update can be cache invalidated safely without possible sharing of cache write back granule. Here are the possible states : -1. CPU_MMU_OFF - Initial value set by the master CPU, this value indicates that the CPU could not turn the MMU on, hence the status could not be reliably updated in the secondary_data. Instead, the CPU has updated the status @ __early_cpu_boot_status. 0. CPU_BOOT_SUCCESS - CPU has booted successfully. 1. CPU_KILL_ME - CPU has invoked cpu_ops->die, indicating the master CPU to synchronise by issuing a cpu_ops->cpu_kill. 2. CPU_STUCK_IN_KERNEL - CPU couldn't invoke die(), instead is looping in the kernel. This information could be used by say, kexec to check if it is really safe to do a kexec reboot. 3. CPU_PANIC_KERNEL - CPU detected some serious issues which requires kernel to crash immediately. The secondary CPU cannot call panic() until it has initialised the GIC. This flag can be used to instruct the master to do so. Cc: Mark Rutland <mark.rutland@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> [catalin.marinas@arm.com: conflict resolution] [catalin.marinas@arm.com: converted "status" from int to long] [catalin.marinas@arm.com: updated update_early_cpu_boot_status to use str_l] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: Move cpu_die_early to smp.cSuzuki K Poulose2016-02-241-0/+1
| | | | | | | | | | | This patch moves cpu_die_early to smp.c, where it fits better. No functional changes, except for adding the necessary checks for CONFIG_HOTPLUG_CPU. Cc: Mark Rutland <mark.rutland@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: Add a helper for parking CPUs in a loopSuzuki K Poulose2016-02-241-0/+8
| | | | | | | | | | Adds a routine which can be used to park CPUs (spinning in kernel) when they can't be killed. Cc: Mark Rutland <mark.rutland@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: kernel: implement ACPI parking protocolLorenzo Pieralisi2016-02-161-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The SBBR and ACPI specifications allow ACPI based systems that do not implement PSCI (eg systems with no EL3) to boot through the ACPI parking protocol specification[1]. This patch implements the ACPI parking protocol CPU operations, and adds code that eases parsing the parking protocol data structures to the ARM64 SMP initializion carried out at the same time as cpus enumeration. To wake-up the CPUs from the parked state, this patch implements a wakeup IPI for ARM64 (ie arch_send_wakeup_ipi_mask()) that mirrors the ARM one, so that a specific IPI is sent for wake-up purpose in order to distinguish it from other IPI sources. Given the current ACPI MADT parsing API, the patch implements a glue layer that helps passing MADT GICC data structure from SMP initialization code to the parking protocol implementation somewhat overriding the CPU operations interfaces. This to avoid creating a completely trasparent DT/ACPI CPU operations layer that would require creating opaque structure handling for CPUs data (DT represents CPU through DT nodes, ACPI through static MADT table entries), which seems overkill given that ACPI on ARM64 mandates only two booting protocols (PSCI and parking protocol), so there is no need for further protocol additions. Based on the original work by Mark Salter <msalter@redhat.com> [1] https://acpica.org/sites/acpica/files/MP%20Startup%20for%20ARM%20platforms.docx Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Tested-by: Loc Ho <lho@apm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Hanjun Guo <hanjun.guo@linaro.org> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mark Salter <msalter@redhat.com> Cc: Al Stone <ahs3@redhat.com> [catalin.marinas@arm.com: Added WARN_ONCE(!acpi_parking_protocol_valid() on the IPI] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: force CONFIG_SMP=y and remove redundant #ifdefsWill Deacon2015-07-271-4/+0
| | | | | | | | | | | Nobody seems to be producing !SMP systems anymore, so this is just becoming a source of kernel bugs, particularly if people want to use coherent DMA with non-shared pages. This patch forces CONFIG_SMP=y for arm64, removing a modest amount of code in the process. Signed-off-by: Will Deacon <will.deacon@arm.com>
* ARM64: kernel: unify ACPI and DT cpus initializationLorenzo Pieralisi2015-05-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | The code that initializes cpus on arm64 is currently split in two different code paths that carry out DT and ACPI cpus initialization. Most of the code executing SMP initialization is common and should be merged to reduce discrepancies between ACPI and DT initialization and to have code initializing cpus in a single common place in the kernel. This patch refactors arm64 SMP cpus initialization code to merge ACPI and DT boot paths in a common file and to create sanity checks that can be reused by both boot methods. Current code assumes PSCI is the only available boot method when arm64 boots with ACPI; this can be easily extended if/when the ACPI parking protocol is merged into the kernel. Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by: Hanjun Guo <hanjun.guo@linaro.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Hanjun Guo <hanjun.guo@linaro.org> Tested-by: Mark Rutland <mark.rutland@arm.com> [DT] Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* ARM64 / ACPI: Parse MADT for SMP initializationHanjun Guo2015-03-251-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | MADT contains the information for MPIDR which is essential for SMP initialization, parse the GIC cpu interface structures to get the MPIDR value and map it to cpu_logical_map(), and add enabled cpu with valid MPIDR into cpu_possible_map. ACPI 5.1 only has two explicit methods to boot up SMP, PSCI and Parking protocol, but the Parking protocol is only specified for ARMv7 now, so make PSCI as the only way for the SMP boot protocol before some updates for the ACPI spec or the Parking protocol spec. Parking protocol patches for SMP boot will be sent to upstream when the new version of Parking protocol is ready. CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> CC: Catalin Marinas <catalin.marinas@arm.com> CC: Will Deacon <will.deacon@arm.com> CC: Mark Rutland <mark.rutland@arm.com> Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> Tested-by: Yijing Wang <wangyijing@huawei.com> Tested-by: Mark Langsdorf <mlangsdo@redhat.com> Tested-by: Jon Masters <jcm@redhat.com> Tested-by: Timur Tabi <timur@codeaurora.org> Tested-by: Robert Richter <rrichter@cavium.com> Acked-by: Robert Richter <rrichter@cavium.com> Acked-by: Olof Johansson <olof@lixom.net> Reviewed-by: Grant Likely <grant.likely@linaro.org> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
* arm64: Tell irq work about self IPI supportFrederic Weisbecker2014-09-131-0/+2
| | | | | | | | | | | | | | | | | ARM64 irq work self-IPI support depends on __smp_cross_call to point to some relevant IRQ controller operations. This information should be available after the call to init_IRQ(). Lets implement arch_irq_work_has_interrupt() accordingly. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* arm64: add CPU_HOTPLUG infrastructureMark Rutland2013-10-251-0/+5
| | | | | | | | | This patch adds the basic infrastructure necessary to support CPU_HOTPLUG on arm64, based on the arm implementation. Actual hotplug support will depend on an implementation's cpu_operations (e.g. PSCI). Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: factor out spin-table boot methodMark Rutland2013-10-251-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The arm64 kernel has an internal holding pen, which is necessary for some systems where we can't bring CPUs online individually and must hold multiple CPUs in a safe area until the kernel is able to handle them. The current SMP infrastructure for arm64 is closely coupled to this holding pen, and alternative boot methods must launch CPUs into the pen, where they sit before they are launched into the kernel proper. With PSCI (and possibly other future boot methods), we can bring CPUs online individually, and need not perform the secondary_holding_pen dance. Instead, this patch factors the holding pen management code out to the spin-table boot method code, as it is the only boot method requiring the pen. A new entry point for secondaries, secondary_entry is added for other boot methods to use, which bypasses the holding pen and its associated overhead when bringing CPUs online. The smp.pen.text section is also removed, as the pen can live in head.text without problem. The cpu_operations structure is extended with two new functions, cpu_boot and cpu_postboot, for bringing a cpu into the kernel and performing any post-boot cleanup required by a bootmethod (e.g. resetting the secondary_holding_pen_release to INVALID_HWID). Documentation is added for cpu_operations. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: reorganise smp_enable_opsMark Rutland2013-10-251-11/+0
| | | | | | | | | | | | | | | | | For hotplug support, we're going to want a place to store operations that do more than bring CPUs online, and it makes sense to group these with our current smp_enable_ops. For cpuidle support, we'll want to group additional functions, and we may want them even for UP kernels. This patch renames smp_enable_ops to the more general cpu_operations, and pulls the definitions out of smp code such that they can be used in UP kernels. While we're at it, fix up instances of the cpu parameter to be an unsigned int, drop the init markings and rename the *_cpu functions to cpu_* to reduce future churn when cpu_operations is extended. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: SMP: enable PSCI boot methodMarc Zyngier2013-01-291-0/+1
| | | | | | | | Wire the PSCI implementation into the SMP secondary startup code. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: SMP: rework the SMP code to be enabling method agnosticMarc Zyngier2013-01-291-0/+10
| | | | | | | | | | | In order to introduce PSCI support, let the SMP code handle multiple enabling methods. This also allow CPUs to be booted using different methods (though this feels a bit weird...). In the process, move the spin-table code to its own file. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: SMP supportCatalin Marinas2012-09-171-0/+69
This patch adds SMP initialisation and spinlocks implementation for AArch64. The spinlock support uses the new load-acquire/store-release instructions to avoid explicit barriers. The architecture also specifies that an event is automatically generated when clearing the exclusive monitor state to wake up processors in WFE, so there is no need for an explicit DSB/SEV instruction sequence. The SEVL instruction is used to set the exclusive monitor locally as there is no conditional WFE and a branch is more expensive. For the SMP booting protocol, see Documentation/arm64/booting.txt. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Olof Johansson <olof@lixom.net> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
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