diff options
Diffstat (limited to 'ANDROID_3.4.5/arch/x86/kernel/nmi.c')
| -rw-r--r-- | ANDROID_3.4.5/arch/x86/kernel/nmi.c | 539 |
1 files changed, 0 insertions, 539 deletions
diff --git a/ANDROID_3.4.5/arch/x86/kernel/nmi.c b/ANDROID_3.4.5/arch/x86/kernel/nmi.c deleted file mode 100644 index 32856fa4..00000000 --- a/ANDROID_3.4.5/arch/x86/kernel/nmi.c +++ /dev/null @@ -1,539 +0,0 @@ -/* - * Copyright (C) 1991, 1992 Linus Torvalds - * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs - * Copyright (C) 2011 Don Zickus Red Hat, Inc. - * - * Pentium III FXSR, SSE support - * Gareth Hughes <gareth@valinux.com>, May 2000 - */ - -/* - * Handle hardware traps and faults. - */ -#include <linux/spinlock.h> -#include <linux/kprobes.h> -#include <linux/kdebug.h> -#include <linux/nmi.h> -#include <linux/delay.h> -#include <linux/hardirq.h> -#include <linux/slab.h> -#include <linux/export.h> - -#include <linux/mca.h> - -#if defined(CONFIG_EDAC) -#include <linux/edac.h> -#endif - -#include <linux/atomic.h> -#include <asm/traps.h> -#include <asm/mach_traps.h> -#include <asm/nmi.h> -#include <asm/x86_init.h> - -#define NMI_MAX_NAMELEN 16 -struct nmiaction { - struct list_head list; - nmi_handler_t handler; - unsigned int flags; - char *name; -}; - -struct nmi_desc { - spinlock_t lock; - struct list_head head; -}; - -static struct nmi_desc nmi_desc[NMI_MAX] = -{ - { - .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[0].lock), - .head = LIST_HEAD_INIT(nmi_desc[0].head), - }, - { - .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[1].lock), - .head = LIST_HEAD_INIT(nmi_desc[1].head), - }, - -}; - -struct nmi_stats { - unsigned int normal; - unsigned int unknown; - unsigned int external; - unsigned int swallow; -}; - -static DEFINE_PER_CPU(struct nmi_stats, nmi_stats); - -static int ignore_nmis; - -int unknown_nmi_panic; -/* - * Prevent NMI reason port (0x61) being accessed simultaneously, can - * only be used in NMI handler. - */ -static DEFINE_RAW_SPINLOCK(nmi_reason_lock); - -static int __init setup_unknown_nmi_panic(char *str) -{ - unknown_nmi_panic = 1; - return 1; -} -__setup("unknown_nmi_panic", setup_unknown_nmi_panic); - -#define nmi_to_desc(type) (&nmi_desc[type]) - -static int notrace __kprobes nmi_handle(unsigned int type, struct pt_regs *regs, bool b2b) -{ - struct nmi_desc *desc = nmi_to_desc(type); - struct nmiaction *a; - int handled=0; - - rcu_read_lock(); - - /* - * NMIs are edge-triggered, which means if you have enough - * of them concurrently, you can lose some because only one - * can be latched at any given time. Walk the whole list - * to handle those situations. - */ - list_for_each_entry_rcu(a, &desc->head, list) - handled += a->handler(type, regs); - - rcu_read_unlock(); - - /* return total number of NMI events handled */ - return handled; -} - -static int __setup_nmi(unsigned int type, struct nmiaction *action) -{ - struct nmi_desc *desc = nmi_to_desc(type); - unsigned long flags; - - spin_lock_irqsave(&desc->lock, flags); - - /* - * most handlers of type NMI_UNKNOWN never return because - * they just assume the NMI is theirs. Just a sanity check - * to manage expectations - */ - WARN_ON_ONCE(type == NMI_UNKNOWN && !list_empty(&desc->head)); - - /* - * some handlers need to be executed first otherwise a fake - * event confuses some handlers (kdump uses this flag) - */ - if (action->flags & NMI_FLAG_FIRST) - list_add_rcu(&action->list, &desc->head); - else - list_add_tail_rcu(&action->list, &desc->head); - - spin_unlock_irqrestore(&desc->lock, flags); - return 0; -} - -static struct nmiaction *__free_nmi(unsigned int type, const char *name) -{ - struct nmi_desc *desc = nmi_to_desc(type); - struct nmiaction *n; - unsigned long flags; - - spin_lock_irqsave(&desc->lock, flags); - - list_for_each_entry_rcu(n, &desc->head, list) { - /* - * the name passed in to describe the nmi handler - * is used as the lookup key - */ - if (!strcmp(n->name, name)) { - WARN(in_nmi(), - "Trying to free NMI (%s) from NMI context!\n", n->name); - list_del_rcu(&n->list); - break; - } - } - - spin_unlock_irqrestore(&desc->lock, flags); - synchronize_rcu(); - return (n); -} - -int register_nmi_handler(unsigned int type, nmi_handler_t handler, - unsigned long nmiflags, const char *devname) -{ - struct nmiaction *action; - int retval = -ENOMEM; - - if (!handler) - return -EINVAL; - - action = kzalloc(sizeof(struct nmiaction), GFP_KERNEL); - if (!action) - goto fail_action; - - action->handler = handler; - action->flags = nmiflags; - action->name = kstrndup(devname, NMI_MAX_NAMELEN, GFP_KERNEL); - if (!action->name) - goto fail_action_name; - - retval = __setup_nmi(type, action); - - if (retval) - goto fail_setup_nmi; - - return retval; - -fail_setup_nmi: - kfree(action->name); -fail_action_name: - kfree(action); -fail_action: - - return retval; -} -EXPORT_SYMBOL_GPL(register_nmi_handler); - -void unregister_nmi_handler(unsigned int type, const char *name) -{ - struct nmiaction *a; - - a = __free_nmi(type, name); - if (a) { - kfree(a->name); - kfree(a); - } -} - -EXPORT_SYMBOL_GPL(unregister_nmi_handler); - -static notrace __kprobes void -pci_serr_error(unsigned char reason, struct pt_regs *regs) -{ - pr_emerg("NMI: PCI system error (SERR) for reason %02x on CPU %d.\n", - reason, smp_processor_id()); - - /* - * On some machines, PCI SERR line is used to report memory - * errors. EDAC makes use of it. - */ -#if defined(CONFIG_EDAC) - if (edac_handler_set()) { - edac_atomic_assert_error(); - return; - } -#endif - - if (panic_on_unrecovered_nmi) - panic("NMI: Not continuing"); - - pr_emerg("Dazed and confused, but trying to continue\n"); - - /* Clear and disable the PCI SERR error line. */ - reason = (reason & NMI_REASON_CLEAR_MASK) | NMI_REASON_CLEAR_SERR; - outb(reason, NMI_REASON_PORT); -} - -static notrace __kprobes void -io_check_error(unsigned char reason, struct pt_regs *regs) -{ - unsigned long i; - - pr_emerg( - "NMI: IOCK error (debug interrupt?) for reason %02x on CPU %d.\n", - reason, smp_processor_id()); - show_registers(regs); - - if (panic_on_io_nmi) - panic("NMI IOCK error: Not continuing"); - - /* Re-enable the IOCK line, wait for a few seconds */ - reason = (reason & NMI_REASON_CLEAR_MASK) | NMI_REASON_CLEAR_IOCHK; - outb(reason, NMI_REASON_PORT); - - i = 20000; - while (--i) { - touch_nmi_watchdog(); - udelay(100); - } - - reason &= ~NMI_REASON_CLEAR_IOCHK; - outb(reason, NMI_REASON_PORT); -} - -static notrace __kprobes void -unknown_nmi_error(unsigned char reason, struct pt_regs *regs) -{ - int handled; - - /* - * Use 'false' as back-to-back NMIs are dealt with one level up. - * Of course this makes having multiple 'unknown' handlers useless - * as only the first one is ever run (unless it can actually determine - * if it caused the NMI) - */ - handled = nmi_handle(NMI_UNKNOWN, regs, false); - if (handled) { - __this_cpu_add(nmi_stats.unknown, handled); - return; - } - - __this_cpu_add(nmi_stats.unknown, 1); - -#ifdef CONFIG_MCA - /* - * Might actually be able to figure out what the guilty party - * is: - */ - if (MCA_bus) { - mca_handle_nmi(); - return; - } -#endif - pr_emerg("Uhhuh. NMI received for unknown reason %02x on CPU %d.\n", - reason, smp_processor_id()); - - pr_emerg("Do you have a strange power saving mode enabled?\n"); - if (unknown_nmi_panic || panic_on_unrecovered_nmi) - panic("NMI: Not continuing"); - - pr_emerg("Dazed and confused, but trying to continue\n"); -} - -static DEFINE_PER_CPU(bool, swallow_nmi); -static DEFINE_PER_CPU(unsigned long, last_nmi_rip); - -static notrace __kprobes void default_do_nmi(struct pt_regs *regs) -{ - unsigned char reason = 0; - int handled; - bool b2b = false; - - /* - * CPU-specific NMI must be processed before non-CPU-specific - * NMI, otherwise we may lose it, because the CPU-specific - * NMI can not be detected/processed on other CPUs. - */ - - /* - * Back-to-back NMIs are interesting because they can either - * be two NMI or more than two NMIs (any thing over two is dropped - * due to NMI being edge-triggered). If this is the second half - * of the back-to-back NMI, assume we dropped things and process - * more handlers. Otherwise reset the 'swallow' NMI behaviour - */ - if (regs->ip == __this_cpu_read(last_nmi_rip)) - b2b = true; - else - __this_cpu_write(swallow_nmi, false); - - __this_cpu_write(last_nmi_rip, regs->ip); - - handled = nmi_handle(NMI_LOCAL, regs, b2b); - __this_cpu_add(nmi_stats.normal, handled); - if (handled) { - /* - * There are cases when a NMI handler handles multiple - * events in the current NMI. One of these events may - * be queued for in the next NMI. Because the event is - * already handled, the next NMI will result in an unknown - * NMI. Instead lets flag this for a potential NMI to - * swallow. - */ - if (handled > 1) - __this_cpu_write(swallow_nmi, true); - return; - } - - /* Non-CPU-specific NMI: NMI sources can be processed on any CPU */ - raw_spin_lock(&nmi_reason_lock); - reason = x86_platform.get_nmi_reason(); - - if (reason & NMI_REASON_MASK) { - if (reason & NMI_REASON_SERR) - pci_serr_error(reason, regs); - else if (reason & NMI_REASON_IOCHK) - io_check_error(reason, regs); -#ifdef CONFIG_X86_32 - /* - * Reassert NMI in case it became active - * meanwhile as it's edge-triggered: - */ - reassert_nmi(); -#endif - __this_cpu_add(nmi_stats.external, 1); - raw_spin_unlock(&nmi_reason_lock); - return; - } - raw_spin_unlock(&nmi_reason_lock); - - /* - * Only one NMI can be latched at a time. To handle - * this we may process multiple nmi handlers at once to - * cover the case where an NMI is dropped. The downside - * to this approach is we may process an NMI prematurely, - * while its real NMI is sitting latched. This will cause - * an unknown NMI on the next run of the NMI processing. - * - * We tried to flag that condition above, by setting the - * swallow_nmi flag when we process more than one event. - * This condition is also only present on the second half - * of a back-to-back NMI, so we flag that condition too. - * - * If both are true, we assume we already processed this - * NMI previously and we swallow it. Otherwise we reset - * the logic. - * - * There are scenarios where we may accidentally swallow - * a 'real' unknown NMI. For example, while processing - * a perf NMI another perf NMI comes in along with a - * 'real' unknown NMI. These two NMIs get combined into - * one (as descibed above). When the next NMI gets - * processed, it will be flagged by perf as handled, but - * noone will know that there was a 'real' unknown NMI sent - * also. As a result it gets swallowed. Or if the first - * perf NMI returns two events handled then the second - * NMI will get eaten by the logic below, again losing a - * 'real' unknown NMI. But this is the best we can do - * for now. - */ - if (b2b && __this_cpu_read(swallow_nmi)) - __this_cpu_add(nmi_stats.swallow, 1); - else - unknown_nmi_error(reason, regs); -} - -/* - * NMIs can hit breakpoints which will cause it to lose its - * NMI context with the CPU when the breakpoint does an iret. - */ -#ifdef CONFIG_X86_32 -/* - * For i386, NMIs use the same stack as the kernel, and we can - * add a workaround to the iret problem in C. Simply have 3 states - * the NMI can be in. - * - * 1) not running - * 2) executing - * 3) latched - * - * When no NMI is in progress, it is in the "not running" state. - * When an NMI comes in, it goes into the "executing" state. - * Normally, if another NMI is triggered, it does not interrupt - * the running NMI and the HW will simply latch it so that when - * the first NMI finishes, it will restart the second NMI. - * (Note, the latch is binary, thus multiple NMIs triggering, - * when one is running, are ignored. Only one NMI is restarted.) - * - * If an NMI hits a breakpoint that executes an iret, another - * NMI can preempt it. We do not want to allow this new NMI - * to run, but we want to execute it when the first one finishes. - * We set the state to "latched", and the first NMI will perform - * an cmpxchg on the state, and if it doesn't successfully - * reset the state to "not running" it will restart the next - * NMI. - */ -enum nmi_states { - NMI_NOT_RUNNING, - NMI_EXECUTING, - NMI_LATCHED, -}; -static DEFINE_PER_CPU(enum nmi_states, nmi_state); - -#define nmi_nesting_preprocess(regs) \ - do { \ - if (__get_cpu_var(nmi_state) != NMI_NOT_RUNNING) { \ - __get_cpu_var(nmi_state) = NMI_LATCHED; \ - return; \ - } \ - nmi_restart: \ - __get_cpu_var(nmi_state) = NMI_EXECUTING; \ - } while (0) - -#define nmi_nesting_postprocess() \ - do { \ - if (cmpxchg(&__get_cpu_var(nmi_state), \ - NMI_EXECUTING, NMI_NOT_RUNNING) != NMI_EXECUTING) \ - goto nmi_restart; \ - } while (0) -#else /* x86_64 */ -/* - * In x86_64 things are a bit more difficult. This has the same problem - * where an NMI hitting a breakpoint that calls iret will remove the - * NMI context, allowing a nested NMI to enter. What makes this more - * difficult is that both NMIs and breakpoints have their own stack. - * When a new NMI or breakpoint is executed, the stack is set to a fixed - * point. If an NMI is nested, it will have its stack set at that same - * fixed address that the first NMI had, and will start corrupting the - * stack. This is handled in entry_64.S, but the same problem exists with - * the breakpoint stack. - * - * If a breakpoint is being processed, and the debug stack is being used, - * if an NMI comes in and also hits a breakpoint, the stack pointer - * will be set to the same fixed address as the breakpoint that was - * interrupted, causing that stack to be corrupted. To handle this case, - * check if the stack that was interrupted is the debug stack, and if - * so, change the IDT so that new breakpoints will use the current stack - * and not switch to the fixed address. On return of the NMI, switch back - * to the original IDT. - */ -static DEFINE_PER_CPU(int, update_debug_stack); - -static inline void nmi_nesting_preprocess(struct pt_regs *regs) -{ - /* - * If we interrupted a breakpoint, it is possible that - * the nmi handler will have breakpoints too. We need to - * change the IDT such that breakpoints that happen here - * continue to use the NMI stack. - */ - if (unlikely(is_debug_stack(regs->sp))) { - debug_stack_set_zero(); - this_cpu_write(update_debug_stack, 1); - } -} - -static inline void nmi_nesting_postprocess(void) -{ - if (unlikely(this_cpu_read(update_debug_stack))) { - debug_stack_reset(); - this_cpu_write(update_debug_stack, 0); - } -} -#endif - -dotraplinkage notrace __kprobes void -do_nmi(struct pt_regs *regs, long error_code) -{ - nmi_nesting_preprocess(regs); - - nmi_enter(); - - inc_irq_stat(__nmi_count); - - if (!ignore_nmis) - default_do_nmi(regs); - - nmi_exit(); - - /* On i386, may loop back to preprocess */ - nmi_nesting_postprocess(); -} - -void stop_nmi(void) -{ - ignore_nmis++; -} - -void restart_nmi(void) -{ - ignore_nmis--; -} - -/* reset the back-to-back NMI logic */ -void local_touch_nmi(void) -{ - __this_cpu_write(last_nmi_rip, 0); -} |