diff options
Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r-- | kernel/trace/trace.c | 63 |
1 files changed, 61 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9bad237..f6d026f 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -32,6 +32,8 @@ unsigned long __read_mostly tracing_max_latency = (cycle_t)ULONG_MAX; unsigned long __read_mostly tracing_thresh; +static int tracing_disabled = 1; + static long notrace ns2usecs(cycle_t nsec) { @@ -217,11 +219,48 @@ int register_tracer(struct tracer *type) } } +#ifdef CONFIG_FTRACE_STARTUP_TEST + if (type->selftest) { + struct tracer *saved_tracer = current_trace; + struct trace_array_cpu *data; + struct trace_array *tr = &global_trace; + int saved_ctrl = tr->ctrl; + int i; + /* + * Run a selftest on this tracer. + * Here we reset the trace buffer, and set the current + * tracer to be this tracer. The tracer can then run some + * internal tracing to verify that everything is in order. + * If we fail, we do not register this tracer. + */ + for_each_possible_cpu(i) { + if (!data->trace) + continue; + data = tr->data[i]; + tracing_reset(data); + } + current_trace = type; + tr->ctrl = 0; + /* the test is responsible for initializing and enabling */ + pr_info("Testing tracer %s: ", type->name); + ret = type->selftest(type, tr); + /* the test is responsible for resetting too */ + current_trace = saved_tracer; + tr->ctrl = saved_ctrl; + if (ret) { + printk(KERN_CONT "FAILED!\n"); + goto out; + } + printk(KERN_CONT "PASSED\n"); + } +#endif + type->next = trace_types; trace_types = type; len = strlen(type->name); if (len > max_tracer_type_len) max_tracer_type_len = len; + out: mutex_unlock(&trace_types_lock); @@ -985,6 +1024,11 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) { struct trace_iterator *iter; + if (tracing_disabled) { + *ret = -ENODEV; + return NULL; + } + iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) { *ret = -ENOMEM; @@ -1023,6 +1067,9 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) int tracing_open_generic(struct inode *inode, struct file *filp) { + if (tracing_disabled) + return -ENODEV; + filp->private_data = inode->i_private; return 0; } @@ -1128,6 +1175,9 @@ static int show_traces_open(struct inode *inode, struct file *file) { int ret; + if (tracing_disabled) + return -ENODEV; + ret = seq_open(file, &show_traces_seq_ops); if (!ret) { struct seq_file *m = file->private_data; @@ -1452,6 +1502,11 @@ struct dentry *tracing_init_dentry(void) return d_tracer; } +#ifdef CONFIG_FTRACE_SELFTEST +/* Let selftest have access to static functions in this file */ +#include "trace_selftest.c" +#endif + static __init void tracer_init_debugfs(void) { struct dentry *d_tracer; @@ -1585,6 +1640,7 @@ __init static int tracer_alloc_buffers(void) void *array; struct page *page; int pages = 0; + int ret = -ENOMEM; int i; /* Allocate the first page for all buffers */ @@ -1650,6 +1706,9 @@ __init static int tracer_alloc_buffers(void) register_tracer(&no_tracer); current_trace = &no_tracer; + /* All seems OK, enable tracing */ + tracing_disabled = 0; + return 0; free_buffers: @@ -1678,7 +1737,7 @@ __init static int tracer_alloc_buffers(void) } #endif } - return -ENOMEM; + return ret; } -device_initcall(tracer_alloc_buffers); +fs_initcall(tracer_alloc_buffers); |