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| * | arm64: KGDB: Add step debugging supportVijaya Kumar K2014-02-261-8/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add KGDB software step debugging support for EL1 debug in AArch64 mode. KGDB registers step debug handler with debug monitor. On receiving 'step' command from GDB tool, target enables software step debugging and step address is updated in ELR. Software Step debugging is disabled when 'continue' command is received Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * | arm64: KGDB: Add Basic KGDB supportVijaya Kumar K2014-02-262-0/+289
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add KGDB debug support for kernel debugging. With this patch, basic KGDB debugging is possible.GDB register layout is updated and GDB tool can establish connection with target and can set/clear breakpoints. Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * | arm64: Add macros to manage processor debug stateVijaya Kumar K2014-02-261-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add macros to enable and disable to manage PSTATE.D for debugging. The macros local_dbg_save and local_dbg_restore are moved to irqflags.h file KGDB boot tests fail because of PSTATE.D is masked. unmask it for debugging support Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* | | Merge branch 'sched/urgent' into sched/coreIngo Molnar2014-03-111-1/+5
|\ \ \ | | |/ | |/| | | | | | | | | | Pick up fixes before queueing up new changes. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | ARM64: unwind: Fix PC calculationOlof Johansson2014-02-171-1/+5
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The frame PC value in the unwind code used to just take the saved LR value and use that. That's incorrect as a stack trace, since it shows the return path stack, not the call path stack. In particular, it shows faulty information in case the bl is done as the very last instruction of one label, since the return point will be in the next label. That can easily be seen with tail calls to panic(), which is marked __noreturn and thus doesn't have anything useful after it. Easiest here is to just correct the unwind code and do a -4, to get the actual call site for the backtrace instead of the return site. Signed-off-by: Olof Johansson <olof@lixom.net> Cc: stable@vger.kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* / cpuidle/arm64: Remove redundant cpuidle_idle_call()Nicolas Pitre2014-02-221-5/+2
|/ | | | | | | | | | | | | | | | | | The core idle loop now takes care of it. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Deepthi Dharwar <deepthi@linux.vnet.ibm.com> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: linux-pm@vger.kernel.org Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/n/tip-wk9vpc8dsn46s12pl602ljpo@git.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* arm64: atomics: fix use of acquire + release for full barrier semanticsWill Deacon2014-02-071-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Linux requires a number of atomic operations to provide full barrier semantics, that is no memory accesses after the operation can be observed before any accesses up to and including the operation in program order. On arm64, these operations have been incorrectly implemented as follows: // A, B, C are independent memory locations <Access [A]> // atomic_op (B) 1: ldaxr x0, [B] // Exclusive load with acquire <op(B)> stlxr w1, x0, [B] // Exclusive store with release cbnz w1, 1b <Access [C]> The assumption here being that two half barriers are equivalent to a full barrier, so the only permitted ordering would be A -> B -> C (where B is the atomic operation involving both a load and a store). Unfortunately, this is not the case by the letter of the architecture and, in fact, the accesses to A and C are permitted to pass their nearest half barrier resulting in orderings such as Bl -> A -> C -> Bs or Bl -> C -> A -> Bs (where Bl is the load-acquire on B and Bs is the store-release on B). This is a clear violation of the full barrier requirement. The simple way to fix this is to implement the same algorithm as ARMv7 using explicit barriers: <Access [A]> // atomic_op (B) dmb ish // Full barrier 1: ldxr x0, [B] // Exclusive load <op(B)> stxr w1, x0, [B] // Exclusive store cbnz w1, 1b dmb ish // Full barrier <Access [C]> but this has the undesirable effect of introducing *two* full barrier instructions. A better approach is actually the following, non-intuitive sequence: <Access [A]> // atomic_op (B) 1: ldxr x0, [B] // Exclusive load <op(B)> stlxr w1, x0, [B] // Exclusive store with release cbnz w1, 1b dmb ish // Full barrier <Access [C]> The simple observations here are: - The dmb ensures that no subsequent accesses (e.g. the access to C) can enter or pass the atomic sequence. - The dmb also ensures that no prior accesses (e.g. the access to A) can pass the atomic sequence. - Therefore, no prior access can pass a subsequent access, or vice-versa (i.e. A is strictly ordered before C). - The stlxr ensures that no prior access can pass the store component of the atomic operation. The only tricky part remaining is the ordering between the ldxr and the access to A, since the absence of the first dmb means that we're now permitting re-ordering between the ldxr and any prior accesses. From an (arbitrary) observer's point of view, there are two scenarios: 1. We have observed the ldxr. This means that if we perform a store to [B], the ldxr will still return older data. If we can observe the ldxr, then we can potentially observe the permitted re-ordering with the access to A, which is clearly an issue when compared to the dmb variant of the code. Thankfully, the exclusive monitor will save us here since it will be cleared as a result of the store and the ldxr will retry. Notice that any use of a later memory observation to imply observation of the ldxr will also imply observation of the access to A, since the stlxr/dmb ensure strict ordering. 2. We have not observed the ldxr. This means we can perform a store and influence the later ldxr. However, that doesn't actually tell us anything about the access to [A], so we've not lost anything here either when compared to the dmb variant. This patch implements this solution for our barriered atomic operations, ensuring that we satisfy the full barrier requirements where they are needed. Cc: <stable@vger.kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: vdso: update wtm fields for CLOCK_MONOTONIC_COARSENathan Lynch2014-02-051-2/+2
| | | | | | | | | | | Update wall-to-monotonic fields in the VDSO data page unconditionally. These are used to service CLOCK_MONOTONIC_COARSE, which is not guarded by use_syscall. Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: vdso: fix coarse clock handlingNathan Lynch2014-02-051-1/+6
| | | | | | | | | | | | | | | | | | | | | | | When __kernel_clock_gettime is called with a CLOCK_MONOTONIC_COARSE or CLOCK_REALTIME_COARSE clock id, it returns incorrectly to whatever the caller has placed in x2 ("ret x2" to return from the fast path). Fix this by saving x30/LR to x2 only in code that will call __do_get_tspec, restoring x30 afterward, and using a plain "ret" to return from the routine. Also: while the resulting tv_nsec value for CLOCK_REALTIME and CLOCK_MONOTONIC must be computed using intermediate values that are left-shifted by cs_shift (x12, set by __do_get_tspec), the results for coarse clocks should be calculated using unshifted values (xtime_coarse_nsec is in units of actual nanoseconds). The current code shifts intermediate values by x12 unconditionally, but x12 is uninitialized when servicing a coarse clock. Fix this by setting x12 to 0 once we know we are dealing with a coarse clock id. Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: vdso: prevent ld from aligning PT_LOAD segments to 64kWill Deacon2014-02-041-1/+1
| | | | | | | | | | | | | | | | | | | Whilst the text segment for our VDSO is marked as PT_LOAD in the ELF headers, it is mapped by the kernel and not actually subject to demand-paging. ld doesn't realise this, and emits a p_align field of 64k (the maximum supported page size), which conflicts with the load address picked by the kernel on 4k systems, which will be 4k aligned. This causes GDB to fail with "Failed to read a valid object file image from memory" when attempting to load the VDSO. This patch passes the -n option to ld, which prevents it from aligning PT_LOAD segments to the maximum page size. Cc: <stable@vger.kernel.org> Reported-by: Kyle McMartin <kyle@redhat.com> Acked-by: Kyle McMartin <kyle@redhat.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* Merge tag 'arm64-upstream' of ↵Linus Torvalds2014-01-313-8/+8
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pyll ARM64 patches from Catalin Marinas: - Build fix with DMA_CMA enabled - Introduction of PTE_WRITE to distinguish between writable but clean and truly read-only pages - FIQs enabling/disabling clean-up (they aren't used on arm64) - CPU resume fix for the per-cpu offset restoring - Code comment typos * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: mm: Introduce PTE_WRITE arm64: mm: Remove PTE_BIT_FUNC macro arm64: FIQs are unused arm64: mm: fix the function name in comment of cpu_do_switch_mm arm64: fix build error if DMA_CMA is enabled arm64: kernel: fix per-cpu offset restore on resume arm64: mm: fix the function name in comment of __flush_dcache_area arm64: mm: use ubfm for dcache_line_size
| * arm64: FIQs are unusedNicolas Pitre2014-01-302-8/+0
| | | | | | | | | | | | | | | | | | | | So any FIQ handling is superfluous at the moment. The functions to disable/enable FIQs is kept around if ever someone needs them in the future, but existing calling sites including arch_cpu_idle_prepare() may go for now. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * arm64: kernel: fix per-cpu offset restore on resumeLorenzo Pieralisi2014-01-241-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The introduction of percpu offset optimisation through tpidr_el1 in: Commit id :7158627686f02319c50c8d9d78f75d4c8 "arm64: percpu: implement optimised pcpu access using tpidr_el1" requires cpu_{suspend/resume} to restore the tpidr_el1 register upon resume so that percpu variables can be addressed correctly when a CPU comes out of reset from warm-boot. This patch fixes cpu_{suspend}/{resume} tpidr_el1 restoration on resume, by calling the set_my_cpu_offset C API, as it is done on primary and secondary CPUs on cold boot, so that, even if the register used to store the percpu offset is changed, the save and restore of general purpose registers does not have to be updated. Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* | Merge tag 'arm64-upstream' of ↵Linus Torvalds2014-01-2019-239/+1229
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull ARM64 updates from Catalin Marinas: - CPU suspend support on top of PSCI (firmware Power State Coordination Interface) - jump label support - CMA can now be enabled on arm64 - HWCAP bits for crypto and CRC32 extensions - optimised percpu using tpidr_el1 register - code cleanup * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (42 commits) arm64: fix typo in entry.S arm64: kernel: restore HW breakpoint registers in cpu_suspend jump_label: use defined macros instead of hard-coding for better readability arm64, jump label: optimize jump label implementation arm64, jump label: detect %c support for ARM64 arm64: introduce aarch64_insn_gen_{nop|branch_imm}() helper functions arm64: move encode_insn_immediate() from module.c to insn.c arm64: introduce interfaces to hotpatch kernel and module code arm64: introduce basic aarch64 instruction decoding helpers arm64: dts: Reduce size of virtio block device for foundation model arm64: Remove unused __data_loc variable arm64: Enable CMA arm64: Warn on NULL device structure for dma APIs arm64: Add hwcaps for crypto and CRC32 extensions. arm64: drop redundant macros from read_cpuid() arm64: Remove outdated comment arm64: cmpxchg: update macros to prevent warnings arm64: support single-step and breakpoint handler hooks ARM64: fix framepointer check in unwind_frame ARM64: check stack pointer in get_wchan ...
| * arm64: fix typo in entry.SNeil Zhang2014-01-131-1/+1
| | | | | | | | | | | | | | | | | | Commit 64681787 (arm64: let the core code deal with preempt_count) changed the code, but left the comments unchanged, fix it. Signed-off-by: Neil Zhang <zhangwm@marvell.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * arm64: kernel: restore HW breakpoint registers in cpu_suspendLorenzo Pieralisi2014-01-102-23/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a CPU resumes from low-power, it restores HW breakpoint and watchpoint slots through a CPU PM notifier. Since we want to enable debugging as early as possible in the resume path, the mdscr content is restored along the general purpose registers in the cpu_suspend API and debug exceptions are reenabled when cpu_suspend returns. Since the CPU PM notifier is run after a CPU has been resumed, we cannot expect HW breakpoint registers to contain sane values till the notifier is run, since the HW breakpoints registers content is unknown at reset; this means that the CPU might run with debug exceptions enabled, mdscr restored but HW breakpoint registers containing junk values that can trigger spurious debug exceptions. This patch fixes current HW breakpoints restore by moving the HW breakpoints registers restoration to the cpu_suspend API, before the debug exceptions are enabled. This way, as soon as the cpu_suspend function returns the kernel can resume debugging with sane values in HW breakpoint registers. Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * arm64, jump label: optimize jump label implementationJiang Liu2014-01-082-0/+59
| | | | | | | | | | | | | | | | | | Optimize jump label implementation for ARM64 by dynamically patching kernel text. Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * arm64: introduce aarch64_insn_gen_{nop|branch_imm}() helper functionsJiang Liu2014-01-081-0/+40
| | | | | | | | | | | | | | | | | | Introduce aarch64_insn_gen_{nop|branch_imm}() helper functions, which will be used to implement jump label on ARM64. Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * arm64: move encode_insn_immediate() from module.c to insn.cJiang Liu2014-01-082-110/+101
| | | | | | | | | | | | | | | | | | | | Function encode_insn_immediate() will be used by other instruction manipulate related functions, so move it into insn.c and rename it as aarch64_insn_encode_immediate(). Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * arm64: introduce interfaces to hotpatch kernel and module codeJiang Liu2014-01-081-0/+119
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce three interfaces to patch kernel and module code: aarch64_insn_patch_text_nosync(): patch code without synchronization, it's caller's responsibility to synchronize all CPUs if needed. aarch64_insn_patch_text_sync(): patch code and always synchronize with stop_machine() aarch64_insn_patch_text(): patch code and synchronize with stop_machine() if needed Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * arm64: introduce basic aarch64 instruction decoding helpersJiang Liu2014-01-082-1/+92
| | | | | | | | | | | | | | | | | | Introduce basic aarch64 instruction decoding helper aarch64_get_insn_class() and aarch64_insn_hotpatch_safe(). Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * arm64: Remove unused __data_loc variableGeoff Levand2013-12-202-12/+0
| | | | | | | | | | | | | | | | The __data_loc variable is an unused left over from the 32 bit arm implementation. Remove that variable and adjust the __mmap_switched startup routine accordingly. Signed-off-by: Geoff Levand <geoff@infradead.org> for Huawei, Linaro Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * Merge tag 'arm64-suspend' of git://linux-arm.org/linux-2.6-lp into upstreamCatalin Marinas2013-12-199-69/+587
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * tag 'arm64-suspend' of git://linux-arm.org/linux-2.6-lp: arm64: add CPU power management menu/entries arm64: kernel: add PM build infrastructure arm64: kernel: add CPU idle call arm64: enable generic clockevent broadcast arm64: kernel: implement HW breakpoints CPU PM notifier arm64: kernel: refactor code to install/uninstall breakpoints arm: kvm: implement CPU PM notifier arm64: kernel: implement fpsimd CPU PM notifier arm64: kernel: cpu_{suspend/resume} implementation arm64: kernel: suspend/resume registers save/restore arm64: kernel: build MPIDR_EL1 hash function data structure arm64: kernel: add MPIDR_EL1 accessors macros Conflicts: arch/arm64/Kconfig
| | * arm64: kernel: add PM build infrastructureLorenzo Pieralisi2013-12-161-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds the required makefile and kconfig entries to enable PM for arm64 systems. The kernel relies on the cpu_{suspend}/{resume} infrastructure to properly save the context for a CPU and put it to sleep, hence this patch adds the config option required to enable cpu_{suspend}/{resume} API. In order to rely on the CPU PM implementation for saving and restoring of CPU subsystems like GIC and PMU, the arch Kconfig must be also augmented to select the CONFIG_CPU_PM option when SUSPEND or CPU_IDLE kernel implementations are selected. Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
| | * arm64: kernel: add CPU idle callLorenzo Pieralisi2013-12-161-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When CPU idle is enabled, the architectural idle call should go through the idle subsystem to allow CPUs to enter idle states defined by the platform CPU idle back-end operations. This patch, mirroring other archs behaviour, adds the CPU idle call to the architectural arch_cpu_idle implementation for arm64. Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
| | * arm64: enable generic clockevent broadcastLorenzo Pieralisi2013-12-161-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On platforms with power management capabilities, timers that are shut down when a CPU enters deep C-states must be emulated using an always-on timer and a timer IPI to relay the timer IRQ to target CPUs on an SMP system. This patch enables the generic clockevents broadcast infrastructure for arm64, by providing the required Kconfig entries and adding the timer IPI infrastructure. Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
| | * arm64: kernel: implement HW breakpoints CPU PM notifierLorenzo Pieralisi2013-12-161-13/+66
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a CPU is shutdown either through CPU idle or suspend to RAM, the content of HW breakpoint registers must be reset or restored to proper values when CPU resume from low power states. This patch adds debug register restore operations to the HW breakpoint control function and implements a CPU PM notifier that allows to restore the content of HW breakpoint registers to allow proper suspend/resume operations. Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
| | * arm64: kernel: refactor code to install/uninstall breakpointsLorenzo Pieralisi2013-12-161-54/+88
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most of the code executed to install and uninstall breakpoints is common and can be factored out in a function that through a runtime operations type provides the requested implementation. This patch creates a common function that can be used to install/uninstall breakpoints and defines the set of operations that can be carried out through it. Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
| | * arm64: kernel: implement fpsimd CPU PM notifierLorenzo Pieralisi2013-12-161-0/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a CPU enters a low power state, its FP register content is lost. This patch adds a notifier to save the FP context on CPU shutdown and restore it on CPU resume. The context is saved and restored only if the suspending thread is not a kernel thread, mirroring the current context switch behaviour. Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
| | * arm64: kernel: cpu_{suspend/resume} implementationLorenzo Pieralisi2013-12-163-0/+304
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Kernel subsystems like CPU idle and suspend to RAM require a generic mechanism to suspend a processor, save its context and put it into a quiescent state. The cpu_{suspend}/{resume} implementation provides such a framework through a kernel interface allowing to save/restore registers, flush the context to DRAM and suspend/resume to/from low-power states where processor context may be lost. The CPU suspend implementation relies on the suspend protocol registered in CPU operations to carry out a suspend request after context is saved and flushed to DRAM. The cpu_suspend interface: int cpu_suspend(unsigned long arg); allows to pass an opaque parameter that is handed over to the suspend CPU operations back-end so that it can take action according to the semantics attached to it. The arg parameter allows suspend to RAM and CPU idle drivers to communicate to suspend protocol back-ends; it requires standardization so that the interface can be reused seamlessly across systems, paving the way for generic drivers. Context memory is allocated on the stack, whose address is stashed in a per-cpu variable to keep track of it and passed to core functions that save/restore the registers required by the architecture. Even though, upon successful execution, the cpu_suspend function shuts down the suspending processor, the warm boot resume mechanism, based on the cpu_resume function, makes the resume path operate as a cpu_suspend function return, so that cpu_suspend can be treated as a C function by the caller, which simplifies coding the PM drivers that rely on the cpu_suspend API. Upon context save, the minimal amount of memory is flushed to DRAM so that it can be retrieved when the MMU is off and caches are not searched. The suspend CPU operation, depending on the required operations (eg CPU vs Cluster shutdown) is in charge of flushing the cache hierarchy either implicitly (by calling firmware implementations like PSCI) or explicitly by executing the required cache maintainance functions. Debug exceptions are disabled during cpu_{suspend}/{resume} operations so that debug registers can be saved and restored properly preventing preemption from debug agents enabled in the kernel. Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
| | * arm64: kernel: build MPIDR_EL1 hash function data structureLorenzo Pieralisi2013-12-161-0/+70
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On ARM64 SMP systems, cores are identified by their MPIDR_EL1 register. The MPIDR_EL1 guidelines in the ARM ARM do not provide strict enforcement of MPIDR_EL1 layout, only recommendations that, if followed, split the MPIDR_EL1 on ARM 64 bit platforms in four affinity levels. In multi-cluster systems like big.LITTLE, if the affinity guidelines are followed, the MPIDR_EL1 can not be considered a linear index. 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_EL1 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_EL1 values by checking all significative bits of MPIDR_EL1 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_el1 is filtered through a mpidr mask that is built by checking all bits that toggle in the set of MPIDR_EL1s 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_el1_mask = 0; i < num_possible_cpus(); i++) mpidr_el1_mask |= (cpu_logical_map(i) ^ cpu_logical_map(0)); /* * Build shifts to be applied to aff0, aff1, aff2, aff3 values to hash the * mpidr_el1 * 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_el1_mask[7:0] ? ffs(mpidr_el1_mask[7:0]) - 1 : 0; fs1 = mpidr_el1_mask[15:8] ? ffs(mpidr_el1_mask[15:8]) - 1 : 0; fs2 = mpidr_el1_mask[23:16] ? ffs(mpidr_el1_mask[23:16]) - 1 : 0; fs3 = mpidr_el1_mask[39:32] ? ffs(mpidr_el1_mask[39:32]) - 1 : 0; ls0 = fls(mpidr_el1_mask[7:0]); ls1 = fls(mpidr_el1_mask[15:8]); ls2 = fls(mpidr_el1_mask[23:16]); ls3 = fls(mpidr_el1_mask[39:32]); bits0 = ls0 - fs0; bits1 = ls1 - fs1; bits2 = ls2 - fs2; bits3 = ls3 - fs3; aff0_shift = fs0; aff1_shift = 8 + fs1 - bits0; aff2_shift = 16 + fs2 - (bits0 + bits1); aff3_shift = 32 + fs3 - (bits0 + bits1 + bits2); u32 hash(u64 mpidr_el1) { u32 l[4]; u64 mpidr_el1_masked = mpidr_el1 & mpidr_el1_mask; l[0] = mpidr_el1_masked & 0xff; l[1] = mpidr_el1_masked & 0xff00; l[2] = mpidr_el1_masked & 0xff0000; l[3] = mpidr_el1_masked & 0xff00000000; return (l[0] >> aff0_shift | l[1] >> aff1_shift | l[2] >> aff2_shift | l[3] >> aff3_shift); } The hashing algorithm relies on the inherent properties set in the ARM ARM recommendations for the MPIDR_EL1. Exotic configurations, where for instance the MPIDR_EL1 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_EL1 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. Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
| * | arm64: Add hwcaps for crypto and CRC32 extensions.Steve Capper2013-12-191-0/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Advertise the optional cryptographic and CRC32 instructions to user space where present. Several hwcap bits [3-7] are allocated. Signed-off-by: Steve Capper <steve.capper@linaro.org> [bit 2 is taken now so use bits 3-7 instead] Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * | arm64: Remove outdated commentLiviu Dudau2013-12-191-5/+0
| | | | | | | | | | | | | | | | | | | | | Code referenced in the comment has moved to arch/arm64/kernel/cputable.c Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * | arm64: support single-step and breakpoint handler hooksSandeepa Prabhu2013-12-192-1/+89
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | AArch64 Single Steping and Breakpoint debug exceptions will be used by multiple debug framworks like kprobes & kgdb. This patch implements the hooks for those frameworks to register their own handlers for handling breakpoint and single step events. Reworked the debug exception handler in entry.S: do_dbg to route software breakpoint (BRK64) exception to do_debug_exception() Signed-off-by: Sandeepa Prabhu <sandeepa.prabhu@linaro.org> Signed-off-by: Deepak Saxena <dsaxena@linaro.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * | ARM64: fix framepointer check in unwind_frameKonstantin Khlebnikov2013-12-191-1/+1
| | | | | | | | | | | | | | | | | | | | | We need at least 24 bytes above frame pointer. Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * | ARM64: check stack pointer in get_wchanKonstantin Khlebnikov2013-12-191-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | get_wchan() is lockless. Task may wakeup at any time and change its own stack, thus each next stack frame may be overwritten and filled with random stuff. Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * | arm64: use generic strnlen_user and strncpy_from_user functionsWill Deacon2013-12-191-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements the word-at-a-time interface for arm64 using the same algorithm as ARM. We use the fls64 macro, which expands to a clz instruction via a compiler builtin. Big-endian configurations make use of the implementation from asm-generic. With this implemented, we can replace our byte-at-a-time strnlen_user and strncpy_from_user functions with the optimised generic versions. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * | arm64: percpu: implement optimised pcpu access using tpidr_el1Will Deacon2013-12-192-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | This patch implements optimised percpu variable accesses using the el1 r/w thread register (tpidr_el1) along the same lines as arch/arm/. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * | arm64: perf: add support for percpu pmu interruptVinayak Kale2013-12-191-30/+78
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add support for irq registration when pmu interrupt is percpu. Signed-off-by: Vinayak Kale <vkale@apm.com> Signed-off-by: Tuan Phan <tphan@apm.com> [will: tidied up cross-calling to pass &irq] Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| * | arm64: vmlinux.lds.S: drop redundant .commentMark Rutland2013-12-191-1/+0
| |/ | | | | | | | | | | | | | | | | | | | | We currently try to emit .comment twice, once in STABS_DEBUG, and once in the line immediately following it. As the two section definitions are identical, the latter is redundant and can be dropped. This patch drops the redundant .comment section definition. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* / arm64: ptrace: avoid using HW_BREAKPOINT_EMPTY for disabled eventsWill Deacon2013-12-191-20/+18
|/ | | | | | | | | | | | | | | | | | | | | | | | | Commit 8f34a1da35ae ("arm64: ptrace: use HW_BREAKPOINT_EMPTY type for disabled breakpoints") fixed an issue with GDB trying to zero breakpoint control registers. The problem there is that the arch hw_breakpoint code will attempt to create a (disabled), execute breakpoint of length 0. This will fail validation and report unexpected failure to GDB. To avoid this, we treated disabled breakpoints as HW_BREAKPOINT_EMPTY, but that seems to have broken with recent kernels, causing watchpoints to be treated as TYPE_INST in the core code and returning ENOSPC for any further breakpoints. This patch fixes the problem by prioritising the `enable' field of the breakpoint: if it is cleared, we simply update the perf_event_attr to indicate that the thing is disabled and don't bother changing either the type or the length. This reinforces the behaviour that the breakpoint control register is essentially read-only apart from the enable bit when disabling a breakpoint. Cc: <stable@vger.kernel.org> Reported-by: Aaron Liu <liucy214@gmail.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: kernel: add code to set cpu boot mode to secondary_entry shimLorenzo Pieralisi2013-12-061-1/+2
| | | | | | | | | | | | | | The refactoring of el2_setup split code setting up EL2 and detecting the CPU boot mode in separate chunks. This allows the code that sets up EL2 to run in an endian independent way - ie before the endianess is set up in the respective sctlr registers. This patch brings secondary_entry up-to-date so that CPUs entering the kernel through this code path set-up EL2 and the cpu boot mode properly. Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by: Mark Rutland <mark.rutand@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: debug: make aarch32 bkpt checking endian cleanMatthew Leach2013-11-281-8/+12
| | | | | | | | | | The current breakpoint instruction checking code for A32 is not endian clean. Fix this with appropriate byte-swapping when retrieving instructions. Signed-off-by: Matthew Leach <matthew.leach@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: ptrace: fix compat registes get/set to be endian cleanMatthew Leach2013-11-281-21/+19
| | | | | | | | | | | | | On a BE system the wrong half of the X registers is retrieved/written when attempting to get/set the value of aarch32 registers through ptrace. Ensure that types are the correct width so that the relevant casting occurs. Signed-off-by: Matthew Leach <matthew.leach@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: Unmask asynchronous aborts when in kernel modeCatalin Marinas2013-11-252-0/+6
| | | | | | | | | The asynchronous aborts are generally fatal for the kernel but they can be masked via the pstate A bit. If a system error happens while in kernel mode, it won't be visible until returning to user space. This patch enables this kind of abort early to help identifying the cause. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: let the core code deal with preempt_countMarc Zyngier2013-11-251-22/+7
| | | | | | | | | | | | | | | | | | Commit f27dde8deef3 (sched: Add NEED_RESCHED to the preempt_count) introduced the use of bit 31 in preempt_count for obscure scheduling purposes. This causes interrupts taken from EL0 to hit the (open coded) BUG when this flag is flipped while handling the interrupt (we compare the values before and after, and kill the kernel if they are different). The fix is to stop messing with the preempt count entirely, as this is already being dealt with in the generic code (irq_enter/irq_exit). Tested on a dual A53 FPGA running cyclictest. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-armLinus Torvalds2013-11-143-20/+19
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull ARM updates from Russell King: "Included in this series are: 1. BE8 (modern big endian) changes for ARM from Ben Dooks 2. big.Little support from Nicolas Pitre and Dave Martin 3. support for LPAE systems with all system memory above 4GB 4. Perf updates from Will Deacon 5. Additional prefetching and other performance improvements from Will. 6. Neon-optimised AES implementation fro Ard. 7. A number of smaller fixes scattered around the place. There is a rather horrid merge conflict in tools/perf - I was never notified of the conflict because it originally occurred between Will's tree and other stuff. Consequently I have a resolution which Will forwarded me, which I'll forward on immediately after sending this mail. The other notable thing is I'm expecting some build breakage in the crypto stuff on ARM only with Ard's AES patches. These were merged into a stable git branch which others had already pulled, so there's little I can do about this. The problem is caused because these patches have a dependency on some code in the crypto git tree - I tried requesting a branch I can pull to resolve these, and all I got each time from the crypto people was "we'll revert our patches then" which would only make things worse since I still don't have the dependent patches. I've no idea what's going on there or how to resolve that, and since I can't split these patches from the rest of this pull request, I'm rather stuck with pushing this as-is or reverting Ard's patches. Since it should "come out in the wash" I've left them in - the only build problems they seem to cause at the moment are with randconfigs, and since it's a new feature anyway. However, if by -rc1 the dependencies aren't in, I think it'd be best to revert Ard's patches" I resolved the perf conflict roughly as per the patch sent by Russell, but there may be some differences. Any errors are likely mine. Let's see how the crypto issues work out.. * 'for-linus' of git://git.linaro.org/people/rmk/linux-arm: (110 commits) ARM: 7868/1: arm/arm64: remove atomic_clear_mask() in "include/asm/atomic.h" ARM: 7867/1: include: asm: use 'int' instead of 'unsigned long' for 'oldval' in atomic_cmpxchg(). ARM: 7866/1: include: asm: use 'long long' instead of 'u64' within atomic.h ARM: 7871/1: amba: Extend number of IRQS ARM: 7887/1: Don't smp_cross_call() on UP devices in arch_irq_work_raise() ARM: 7872/1: Support arch_irq_work_raise() via self IPIs ARM: 7880/1: Clear the IT state independent of the Thumb-2 mode ARM: 7878/1: nommu: Implement dummy early_paging_init() ARM: 7876/1: clear Thumb-2 IT state on exception handling ARM: 7874/2: bL_switcher: Remove cpu_hotplug_driver_{lock,unlock}() ARM: footbridge: fix build warnings for netwinder ARM: 7873/1: vfp: clear vfp_current_hw_state for dying cpu ARM: fix misplaced arch_virt_to_idmap() ARM: 7848/1: mcpm: Implement cpu_kill() to synchronise on powerdown ARM: 7847/1: mcpm: Factor out logical-to-physical CPU translation ARM: 7869/1: remove unused XSCALE_PMU Kconfig param ARM: 7864/1: Handle 64-bit memory in case of 32-bit phys_addr_t ARM: 7863/1: Let arm_add_memory() always use 64-bit arguments ARM: 7862/1: pcpu: replace __get_cpu_var_uses ARM: 7861/1: cacheflush: consolidate single-CPU ARMv7 cache disabling code ...
| * ARM: 7862/1: pcpu: replace __get_cpu_var_usesChristoph Lameter2013-10-293-20/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is the ARM part of Christoph's patchset cleaning up the various uses of __get_cpu_var across the tree. The idea is to convert __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and fewer registers are used when code is generated. [will: fixed debug ref counting checks and pcpu array accesses] Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* | Merge branch 'akpm' (patches from Andrew Morton)Linus Torvalds2013-11-131-1/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge first patch-bomb from Andrew Morton: "Quite a lot of other stuff is banked up awaiting further next->mainline merging, but this batch contains: - Lots of random misc patches - OCFS2 - Most of MM - backlight updates - lib/ updates - printk updates - checkpatch updates - epoll tweaking - rtc updates - hfs - hfsplus - documentation - procfs - update gcov to gcc-4.7 format - IPC" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (269 commits) ipc, msg: fix message length check for negative values ipc/util.c: remove unnecessary work pending test devpts: plug the memory leak in kill_sb ./Makefile: export initial ramdisk compression config option init/Kconfig: add option to disable kernel compression drivers: w1: make w1_slave::flags long to avoid memory corruption drivers/w1/masters/ds1wm.cuse dev_get_platdata() drivers/memstick/core/ms_block.c: fix unreachable state in h_msb_read_page() drivers/memstick/core/mspro_block.c: fix attributes array allocation drivers/pps/clients/pps-gpio.c: remove redundant of_match_ptr kernel/panic.c: reduce 1 byte usage for print tainted buffer gcov: reuse kbasename helper kernel/gcov/fs.c: use pr_warn() kernel/module.c: use pr_foo() gcov: compile specific gcov implementation based on gcc version gcov: add support for gcc 4.7 gcov format gcov: move gcov structs definitions to a gcc version specific file kernel/taskstats.c: return -ENOMEM when alloc memory fails in add_del_listener() kernel/taskstats.c: add nla_nest_cancel() for failure processing between nla_nest_start() and nla_nest_end() kernel/sysctl_binary.c: use scnprintf() instead of snprintf() ...
| * | mm/arch: use NUMA_NO_NODEJianguo Wu2013-11-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | Use more appropriate NUMA_NO_NODE instead of -1 in all archs' module_alloc() Signed-off-by: Jianguo Wu <wujianguo@huawei.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>