diff options
Diffstat (limited to 'arch/x86/kernel/nmi.c')
| -rw-r--r-- | arch/x86/kernel/nmi.c | 37 |
1 files changed, 35 insertions, 2 deletions
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 60308053fdb2..ba77ebc2c353 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -14,6 +14,7 @@ #include <linux/kprobes.h> #include <linux/kdebug.h> #include <linux/nmi.h> +#include <linux/debugfs.h> #include <linux/delay.h> #include <linux/hardirq.h> #include <linux/slab.h> @@ -29,6 +30,9 @@ #include <asm/nmi.h> #include <asm/x86_init.h> +#define CREATE_TRACE_POINTS +#include <trace/events/nmi.h> + struct nmi_desc { spinlock_t lock; struct list_head head; @@ -82,6 +86,15 @@ __setup("unknown_nmi_panic", setup_unknown_nmi_panic); #define nmi_to_desc(type) (&nmi_desc[type]) +static u64 nmi_longest_ns = 1 * NSEC_PER_MSEC; +static int __init nmi_warning_debugfs(void) +{ + debugfs_create_u64("nmi_longest_ns", 0644, + arch_debugfs_dir, &nmi_longest_ns); + return 0; +} +fs_initcall(nmi_warning_debugfs); + static int __kprobes nmi_handle(unsigned int type, struct pt_regs *regs, bool b2b) { struct nmi_desc *desc = nmi_to_desc(type); @@ -96,8 +109,28 @@ static int __kprobes nmi_handle(unsigned int type, struct pt_regs *regs, bool b2 * 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); + list_for_each_entry_rcu(a, &desc->head, list) { + u64 before, delta, whole_msecs; + int remainder_ns, decimal_msecs, thishandled; + + before = local_clock(); + thishandled = a->handler(type, regs); + handled += thishandled; + delta = local_clock() - before; + trace_nmi_handler(a->handler, (int)delta, thishandled); + + if (delta < nmi_longest_ns) + continue; + + nmi_longest_ns = delta; + whole_msecs = delta; + remainder_ns = do_div(whole_msecs, (1000 * 1000)); + decimal_msecs = remainder_ns / 1000; + printk_ratelimited(KERN_INFO + "INFO: NMI handler (%ps) took too long to run: " + "%lld.%03d msecs\n", a->handler, whole_msecs, + decimal_msecs); + } rcu_read_unlock(); |