diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/Makefile | 1 | ||||
| -rw-r--r-- | kernel/trace/Kconfig | 5 | ||||
| -rw-r--r-- | kernel/trace/Makefile | 3 | ||||
| -rw-r--r-- | kernel/trace/ftrace.c | 138 |
4 files changed, 147 insertions, 0 deletions
diff --git a/kernel/Makefile b/kernel/Makefile index 1c9938addb9..fa05f6d8bdb 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -69,6 +69,7 @@ obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o obj-$(CONFIG_MARKERS) += marker.o obj-$(CONFIG_LATENCYTOP) += latencytop.o +obj-$(CONFIG_FTRACE) += trace/ ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y) # According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig new file mode 100644 index 00000000000..8185c91417b --- /dev/null +++ b/kernel/trace/Kconfig @@ -0,0 +1,5 @@ +# +# Architectures that offer an FTRACE implementation should select HAVE_FTRACE: +# +config HAVE_FTRACE + bool diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile new file mode 100644 index 00000000000..bf4fd215a6a --- /dev/null +++ b/kernel/trace/Makefile @@ -0,0 +1,3 @@ +obj-$(CONFIG_FTRACE) += libftrace.o + +libftrace-y := ftrace.o diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c new file mode 100644 index 00000000000..b6a80b98a3f --- /dev/null +++ b/kernel/trace/ftrace.c @@ -0,0 +1,138 @@ +/* + * Infrastructure for profiling code inserted by 'gcc -pg'. + * + * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> + * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com> + * + * Originally ported from the -rt patch by: + * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com> + * + * Based on code in the latency_tracer, that is: + * + * Copyright (C) 2004-2006 Ingo Molnar + * Copyright (C) 2004 William Lee Irwin III + */ + +#include <linux/module.h> +#include <linux/ftrace.h> + +static DEFINE_SPINLOCK(ftrace_func_lock); +static struct ftrace_ops ftrace_list_end __read_mostly = +{ + .func = ftrace_stub, +}; + +static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end; +ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; + +/* mcount is defined per arch in assembly */ +EXPORT_SYMBOL(mcount); + +notrace void ftrace_list_func(unsigned long ip, unsigned long parent_ip) +{ + struct ftrace_ops *op = ftrace_list; + + /* in case someone actually ports this to alpha! */ + read_barrier_depends(); + + while (op != &ftrace_list_end) { + /* silly alpha */ + read_barrier_depends(); + op->func(ip, parent_ip); + op = op->next; + }; +} + +/** + * register_ftrace_function - register a function for profiling + * @ops - ops structure that holds the function for profiling. + * + * Register a function to be called by all functions in the + * kernel. + * + * Note: @ops->func and all the functions it calls must be labeled + * with "notrace", otherwise it will go into a + * recursive loop. + */ +int register_ftrace_function(struct ftrace_ops *ops) +{ + unsigned long flags; + + spin_lock_irqsave(&ftrace_func_lock, flags); + ops->next = ftrace_list; + /* + * We are entering ops into the ftrace_list but another + * CPU might be walking that list. We need to make sure + * the ops->next pointer is valid before another CPU sees + * the ops pointer included into the ftrace_list. + */ + smp_wmb(); + ftrace_list = ops; + /* + * For one func, simply call it directly. + * For more than one func, call the chain. + */ + if (ops->next == &ftrace_list_end) + ftrace_trace_function = ops->func; + else + ftrace_trace_function = ftrace_list_func; + spin_unlock_irqrestore(&ftrace_func_lock, flags); + + return 0; +} + +/** + * unregister_ftrace_function - unresgister a function for profiling. + * @ops - ops structure that holds the function to unregister + * + * Unregister a function that was added to be called by ftrace profiling. + */ +int unregister_ftrace_function(struct ftrace_ops *ops) +{ + unsigned long flags; + struct ftrace_ops **p; + int ret = 0; + + spin_lock_irqsave(&ftrace_func_lock, flags); + + /* + * If we are the only function, then the ftrace pointer is + * pointing directly to that function. + */ + if (ftrace_list == ops && ops->next == &ftrace_list_end) { + ftrace_trace_function = ftrace_stub; + ftrace_list = &ftrace_list_end; + goto out; + } + + for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next) + if (*p == ops) + break; + + if (*p != ops) { + ret = -1; + goto out; + } + + *p = (*p)->next; + + /* If we only have one func left, then call that directly */ + if (ftrace_list->next == &ftrace_list_end) + ftrace_trace_function = ftrace_list->func; + + out: + spin_unlock_irqrestore(&ftrace_func_lock, flags); + + return 0; +} + +/** + * clear_ftrace_function - reset the ftrace function + * + * This NULLs the ftrace function and in essence stops + * tracing. There may be lag + */ +void clear_ftrace_function(void) +{ + ftrace_trace_function = ftrace_stub; +} |