/* * Context tracking: Probe on high level context boundaries such as kernel * and userspace. This includes syscalls and exceptions entry/exit. * * This is used by RCU to remove its dependency on the timer tick while a CPU * runs in userspace. * * Started by Frederic Weisbecker: * * Copyright (C) 2012 Red Hat, Inc., Frederic Weisbecker * * Many thanks to Gilad Ben-Yossef, Paul McKenney, Ingo Molnar, Andrew Morton, * Steven Rostedt, Peter Zijlstra for suggestions and improvements. * */ #include #include #include #include #include #include #define CREATE_TRACE_POINTS #include DEFINE_STATIC_KEY_FALSE(context_tracking_enabled); EXPORT_SYMBOL_GPL(context_tracking_enabled); DEFINE_PER_CPU(struct context_tracking, context_tracking); EXPORT_SYMBOL_GPL(context_tracking); static bool context_tracking_recursion_enter(void) { int recursion; recursion = __this_cpu_inc_return(context_tracking.recursion); if (recursion == 1) return true; WARN_ONCE((recursion < 1), "Invalid context tracking recursion value %d\n", recursion); __this_cpu_dec(context_tracking.recursion); return false; } static void context_tracking_recursion_exit(void) { __this_cpu_dec(context_tracking.recursion); } /** * context_tracking_enter - Inform the context tracking that the CPU is going * enter user or guest space mode. * * This function must be called right before we switch from the kernel * to user or guest space, when it's guaranteed the remaining kernel * instructions to execute won't use any RCU read side critical section * because this function sets RCU in extended quiescent state. */ void __context_tracking_enter(enum ctx_state state) { /* Kernel threads aren't supposed to go to userspace */ WARN_ON_ONCE(!current->mm); if (!context_tracking_recursion_enter()) return; if ( __this_cpu_read(context_tracking.state) != state) { if (__this_cpu_read(context_tracking.active)) { /* * At this stage, only low level arch entry code remains and * then we'll run in userspace. We can assume there won't be * any RCU read-side critical section until the next call to * user_exit() or rcu_irq_enter(). Let's remove RCU's dependency * on the tick. */ if (state == CONTEXT_USER) { trace_user_enter(0); vtime_user_enter(current); } rcu_user_enter(); } /* * Even if context tracking is disabled on this CPU, because it's outside * the full dynticks mask for example, we still have to keep track of the * context transitions and states to prevent inconsistency on those of * other CPUs. * If a task triggers an exception in userspace, sleep on the exception * handler and then migrate to another CPU, that new CPU must know where * the exception returns by the time we call exception_exit(). * This information can only be provided by the previous CPU when it called * exception_enter(). * OTOH we can spare the calls to vtime and RCU when context_tracking.active * is false because we know that CPU is not tickless. */ __this_cpu_write(context_tracking.state, state); } context_tracking_recursion_exit(); } NOKPROBE_SYMBOL(__context_tracking_enter); EXPORT_SYMBOL_GPL(__context_tracking_enter); void context_tracking_enter(enum ctx_state state) { unsigned long flags; /* * Some contexts may involve an exception occuring in an irq, * leading to that nesting: * rcu_irq_enter() rcu_user_exit() rcu_user_exit() rcu_irq_exit() * This would mess up the dyntick_nesting count though. And rcu_irq_*() * helpers are enough to protect RCU uses inside the exception. So * just return immediately if we detect we are in an IRQ. */ if (in_interrupt()) return; local_irq_save(flags); __context_tracking_enter(state); local_irq_restore(flags); } NOKPROBE_SYMBOL(context_tracking_enter); EXPORT_SYMBOL_GPL(context_tracking_enter); void context_tracking_user_enter(void) { user_enter(); } NOKPROBE_SYMBOL(context_tracking_user_enter); /** * context_tracking_exit - Inform the context tracking that the CPU is * exiting user or guest mode and entering the kernel. * * This function must be called after we entered the kernel from user or * guest space before any use of RCU read side critical section. This * potentially include any high level kernel code like syscalls, exceptions, * signal handling, etc... * * This call supports re-entrancy. This way it can be called from any exception * handler without needing to know if we came from userspace or not. */ void __context_tracking_exit(enum ctx_state state) { if (!context_tracking_recursion_enter()) return; if (__this_cpu_read(context_tracking.state) == state) { if (__this_cpu_read(context_tracking.active)) { /* * We are going to run code that may use RCU. Inform * RCU core about that (ie: we may need the tick again). */ rcu_user_exit(); if (state == CONTEXT_USER) { vtime_user_exit(current); trace_user_exit(0); } } __this_cpu_write(context_tracking.state, CONTEXT_KERNEL); } context_tracking_recursion_exit(); } NOKPROBE_SYMBOL(__context_tracking_exit); EXPORT_SYMBOL_GPL(__context_tracking_exit); void context_tracking_exit(enum ctx_state state) { unsigned long flags; if (in_interrupt()) return; local_irq_save(flags); __context_tracking_exit(state); local_irq_restore(flags); } NOKPROBE_SYMBOL(context_tracking_exit); EXPORT_SYMBOL_GPL(context_tracking_exit); void context_tracking_user_exit(void) { user_exit(); } NOKPROBE_SYMBOL(context_tracking_user_exit); void __init context_tracking_cpu_set(int cpu) { static __initdata bool initialized = false; if (!per_cpu(context_tracking.active, cpu)) { per_cpu(context_tracking.active, cpu) = true; static_branch_inc(&context_tracking_enabled); } if (initialized) return; /* * Set TIF_NOHZ to init/0 and let it propagate to all tasks through fork * This assumes that init is the only task at this early boot stage. */ set_tsk_thread_flag(&init_task, TIF_NOHZ); WARN_ON_ONCE(!tasklist_empty()); initialized = true; } #ifdef CONFIG_CONTEXT_TRACKING_FORCE void __init context_tracking_init(void) { int cpu; for_each_possible_cpu(cpu) context_tracking_cpu_set(cpu); } #endif ultz (missing genl module alias, clear IP DF on transmit). 2) Netfilter needs to reflect the fwmark when sending resets, from Pau Espin Pedrol. 3) nftable dump OOPS fix from Liping Zhang. 4) Fix erroneous setting of VIRTIO_NET_HDR_F_DATA_VALID on transmit, from Rolf Neugebauer. 5) Fix build error of ipt_CLUSTERIP when procfs is disabled, from Arnd Bergmann. 6) Fix regression in handling of NETIF_F_SG in harmonize_features(), from Eric Dumazet. 7) Fix RTNL deadlock wrt. lwtunnel module loading, from David Ahern. 8) tcp_fastopen_create_child() needs to setup tp->max_window, from Alexey Kodanev. 9) Missing kmemdup() failure check in ipv6 segment routing code, from Eric Dumazet. 10) Don't execute unix_bind() under the bindlock, otherwise we deadlock with splice. From WANG Cong. 11) ip6_tnl_parse_tlv_enc_lim() potentially reallocates the skb buffer, therefore callers must reload cached header pointers into that skb. Fix from Eric Dumazet. 12) Fix various bugs in legacy IRQ fallback handling in alx driver, from Tobias Regnery. 13) Do not allow lwtunnel drivers to be unloaded while they are referenced by active instances, from Robert Shearman. 14) Fix truncated PHY LED trigger names, from Geert Uytterhoeven. 15) Fix a few regressions from virtio_net XDP support, from John Fastabend and Jakub Kicinski. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (102 commits) ISDN: eicon: silence misleading array-bounds warning net: phy: micrel: add support for KSZ8795 gtp: fix cross netns recv on gtp socket gtp: clear DF bit on GTP packet tx gtp: add genl family modules alias tcp: don't annotate mark on control socket from tcp_v6_send_response() ravb: unmap descriptors when freeing rings virtio_net: reject XDP programs using header adjustment virtio_net: use dev_kfree_skb for small buffer XDP receive r8152: check rx after napi is enabled r8152: re-schedule napi for tx r8152: avoid start_xmit to schedule napi when napi is disabled r8152: avoid start_xmit to call napi_schedule during autosuspend net: dsa: Bring back device detaching in dsa_slave_suspend() net: phy: leds: Fix truncated LED trigger names net: phy: leds: Break dependency of phy.h on phy_led_triggers.h net: phy: leds: Clear phy_num_led_triggers on failure to avoid crash net-next: ethernet: mediatek: change the compatible string Documentation: devicetree: change the mediatek ethernet compatible string bnxt_en: Fix RTNL lock usage on bnxt_get_port_module_status(). ...
Diffstat (limited to 'net/bluetooth/leds.h')