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2015-10-06arm64: replace read_lock to rcu lock in call_break_hookYang Shi
BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 in_atomic(): 0, irqs_disabled(): 128, pid: 342, name: perf 1 lock held by perf/342: #0: (break_hook_lock){+.+...}, at: [<ffffffc0000851ac>] call_break_hook+0x34/0xd0 irq event stamp: 62224 hardirqs last enabled at (62223): [<ffffffc00010b7bc>] __call_rcu.constprop.59+0x104/0x270 hardirqs last disabled at (62224): [<ffffffc0000fbe20>] vprintk_emit+0x68/0x640 softirqs last enabled at (0): [<ffffffc000097928>] copy_process.part.8+0x428/0x17f8 softirqs last disabled at (0): [< (null)>] (null) CPU: 0 PID: 342 Comm: perf Not tainted 4.1.6-rt5 #4 Hardware name: linux,dummy-virt (DT) Call trace: [<ffffffc000089968>] dump_backtrace+0x0/0x128 [<ffffffc000089ab0>] show_stack+0x20/0x30 [<ffffffc0007030d0>] dump_stack+0x7c/0xa0 [<ffffffc0000c878c>] ___might_sleep+0x174/0x260 [<ffffffc000708ac8>] __rt_spin_lock+0x28/0x40 [<ffffffc000708db0>] rt_read_lock+0x60/0x80 [<ffffffc0000851a8>] call_break_hook+0x30/0xd0 [<ffffffc000085a70>] brk_handler+0x30/0x98 [<ffffffc000082248>] do_debug_exception+0x50/0xb8 Exception stack(0xffffffc00514fe30 to 0xffffffc00514ff50) fe20: 00000000 00000000 c1594680 0000007f fe40: ffffffff ffffffff 92063940 0000007f 0550dcd8 ffffffc0 00000000 00000000 fe60: 0514fe70 ffffffc0 000be1f8 ffffffc0 0514feb0 ffffffc0 0008948c ffffffc0 fe80: 00000004 00000000 0514fed0 ffffffc0 ffffffff ffffffff 9282a948 0000007f fea0: 00000000 00000000 9282b708 0000007f c1592820 0000007f 00083914 ffffffc0 fec0: 00000000 00000000 00000010 00000000 00000064 00000000 00000001 00000000 fee0: 005101e0 00000000 c1594680 0000007f c1594740 0000007f ffffffd8 ffffff80 ff00: 00000000 00000000 00000000 00000000 c1594770 0000007f c1594770 0000007f ff20: 00665e10 00000000 7f7f7f7f 7f7f7f7f 01010101 01010101 00000000 00000000 ff40: 928e4cc0 0000007f 91ff11e8 0000007f call_break_hook is called in atomic context (hard irq disabled), so replace the sleepable lock to rcu lock, replace relevant list operations to rcu version and call synchronize_rcu() in unregister_break_hook(). And, replace write lock to spinlock in {un}register_break_hook. Signed-off-by: Yang Shi <yang.shi@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-10-05arm64: debug: Fix typo in debug-monitors.cYang Shi
Fix comment typo: s/handers/handlers/ Signed-off-by: Yang Shi <yang.shi@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-09-17arm64: cpu hotplug: ensure we mask out CPU_TASKS_FROZEN in notifiersWill Deacon
We have a couple of CPU hotplug notifiers for resetting the CPU debug state to a sane value when a CPU comes online. This patch ensures that we mask out CPU_TASKS_FROZEN so that we don't miss any online events occuring due to suspend/resume. Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-07-27arm64: debug: rename enum debug_el to avoid symbol collisionWill Deacon
lib/list_sort.c defines a 'struct debug_el', where "el" is assumedly a a contraction of "element". This conflicts with 'enum debug_el' in our asm/debug-monitors.h header file, where "el" stands for Exception Level. The result is build failure when targetting allmodconfig, so rename our enum to 'dbg_active_el' to be slightly more explicit about what it is. Signed-off-by: Will Deacon <will.deacon@arm.com>
2014-08-05Merge tag 'kvm-arm-for-3.17' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm KVM/ARM New features for 3.17 include: - Fixes and code refactoring for stage2 kvm MMU unmap_range - Support unmapping IPAs on deleting memslots for arm and arm64 - Support MMIO mappings in stage2 faults - KVM VGIC v2 emulation on GICv3 hardware - Big-Endian support for arm/arm64 (guest and host) - Debug Architecture support for arm64 (arm32 is on Christoffer's todo list) Conflicts: virt/kvm/arm/vgic.c [last minute cherry-pick from 3.17 to 3.16]
2014-07-31arm64: don't call break hooks for BRK exceptions from EL0Will Deacon
Our break hooks are used to handle brk exceptions from kgdb (and potentially kprobes if that code ever resurfaces), so don't bother calling them if the BRK exception comes from userspace. This prevents userspace from trapping to a kdb shell on systems where kgdb is enabled and active. Cc: <stable@vger.kernel.org> Reported-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2014-07-11arm64: move DBG_MDSCR_* to asm/debug-monitors.hMarc Zyngier
In order to be able to use the DBG_MDSCR_* macros from the KVM code, move the relevant definitions to the obvious include file. Also move the debug_el enum to a portion of the file that is guarded by #ifndef __ASSEMBLY__ in order to use that file from assembly code. Acked-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Anup Patel <anup.patel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-04-25arm64: debug: remove noisy, pointless warningWill Deacon
Sending a SIGTRAP to a user task after execution of a BRK instruction at EL0 is fundamental to the way in which software breakpoints work and doesn't deserve a warning to be logged in dmesg. Whilst the warning can be justified from EL1, do_debug_exception will already do the right thing, so simply remove the code altogether. Cc: Sandeepa Prabhu <sandeepa.prabhu@linaro.org> Reported-by: Kyrylo Tkachov <kyrylo.tkachov@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-04-07Merge tag 'cpu-hotplug-3.15-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull CPU hotplug notifiers registration fixes from Rafael Wysocki: "The purpose of this single series of commits from Srivatsa S Bhat (with a small piece from Gautham R Shenoy) touching multiple subsystems that use CPU hotplug notifiers is to provide a way to register them that will not lead to deadlocks with CPU online/offline operations as described in the changelog of commit 93ae4f978ca7f ("CPU hotplug: Provide lockless versions of callback registration functions"). The first three commits in the series introduce the API and document it and the rest simply goes through the users of CPU hotplug notifiers and converts them to using the new method" * tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (52 commits) net/iucv/iucv.c: Fix CPU hotplug callback registration net/core/flow.c: Fix CPU hotplug callback registration mm, zswap: Fix CPU hotplug callback registration mm, vmstat: Fix CPU hotplug callback registration profile: Fix CPU hotplug callback registration trace, ring-buffer: Fix CPU hotplug callback registration xen, balloon: Fix CPU hotplug callback registration hwmon, via-cputemp: Fix CPU hotplug callback registration hwmon, coretemp: Fix CPU hotplug callback registration thermal, x86-pkg-temp: Fix CPU hotplug callback registration octeon, watchdog: Fix CPU hotplug callback registration oprofile, nmi-timer: Fix CPU hotplug callback registration intel-idle: Fix CPU hotplug callback registration clocksource, dummy-timer: Fix CPU hotplug callback registration drivers/base/topology.c: Fix CPU hotplug callback registration acpi-cpufreq: Fix CPU hotplug callback registration zsmalloc: Fix CPU hotplug callback registration scsi, fcoe: Fix CPU hotplug callback registration scsi, bnx2fc: Fix CPU hotplug callback registration scsi, bnx2i: Fix CPU hotplug callback registration ...
2014-03-20arm64, debug-monitors: Fix CPU hotplug callback registrationSrivatsa S. Bhat
Subsystems that want to register CPU hotplug callbacks, as well as perform initialization for the CPUs that are already online, often do it as shown below: get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); This is wrong, since it is prone to ABBA deadlocks involving the cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently with CPU hotplug operations). Instead, the correct and race-free way of performing the callback registration is: cpu_notifier_register_begin(); for_each_online_cpu(cpu) init_cpu(cpu); /* Note the use of the double underscored version of the API */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_notifier_register_done(); Fix the debug-monitors code in arm64 by using this latter form of callback registration. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Ingo Molnar <mingo@kernel.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-13arm64: debug: make local symbols staticJingoo Han
Make local symbols static, because these are used only in this file. Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-02-26arm64: enable processor debug state for secondary cpusVijaya Kumar K
processor debug state PSTATE.D is unmasked in smp call clear_os_lock for secondary cpus. So debug state is still masked in normal kernel context. With this patch, unmask debug state on secondary boot for the cpus in normal kernel context. Now kgdb tests passed with multicore. 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>
2014-02-26arm64: Add macros to manage processor debug stateVijaya Kumar K
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>
2013-12-19arm64: support single-step and breakpoint handler hooksSandeepa Prabhu
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>
2013-11-28arm64: debug: make aarch32 bkpt checking endian cleanMatthew Leach
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>
2013-10-29ARM: 7862/1: pcpu: replace __get_cpu_var_usesChristoph Lameter
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>
2013-07-14arm64: delete __cpuinit usage from all usersPaul Gortmaker
The __cpuinit type of throwaway sections might have made sense some time ago when RAM was more constrained, but now the savings do not offset the cost and complications. For example, the fix in commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time") is a good example of the nasty type of bugs that can be created with improper use of the various __init prefixes. After a discussion on LKML[1] it was decided that cpuinit should go the way of devinit and be phased out. Once all the users are gone, we can then finally remove the macros themselves from linux/init.h. Note that some harmless section mismatch warnings may result, since notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c) are flagged as __cpuinit -- so if we remove the __cpuinit from arch specific callers, we will also get section mismatch warnings. As an intermediate step, we intend to turn the linux/init.h cpuinit content into no-ops as early as possible, since that will get rid of these warnings. In any case, they are temporary and harmless. This removes all the arch/arm64 uses of the __cpuinit macros from all C files. Currently arm64 does not have any __CPUINIT used in assembly files. [1] https://lkml.org/lkml/2013/5/20/589 Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2013-06-12arm64: debug: consolidate software breakpoint handlersWill Deacon
The software breakpoint handlers are hooked in directly from ptrace, which makes it difficult to add additional handlers for things like kprobes and kgdb. This patch moves the handling code into debug-monitors.c, where we can dispatch to different debug subsystems more easily. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2013-05-13arm64: debug: clear mdscr_el1 instead of taking the OS lockWill Deacon
During boot, we take the debug OS lock before interrupts are enabled. This is required to prevent clearing of PSTATE.D on the interrupt entry path, which could result in spurious debug exceptions before we've got round to resetting things like the hardware breakpoints registers to a sane state. A problem with this approach is that taking the OS lock prevents an external JTAG debugger from debugging the system, which is especially irritating during boot, where JTAG debugging can be most useful. This patch clears mdscr_el1 rather than taking the lock, clearing the MDE and KDE bits and preventing self-hosted hardware debug exceptions from occurring. Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: stable@vger.kernel.org
2012-09-17arm64: Debugging supportWill Deacon
This patch adds ptrace, debug monitors and hardware breakpoints support. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 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>