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ftrace: Replace uses of _ftrace_direct APIs with _ftrace_direct_multi
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The _multi API requires that users keep their own ops but can enforce
that an op is only associated to one direct call.

Link: https://lkml.kernel.org/r/[email protected]

Signed-off-by: Florent Revest <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Tested-by: Mark Rutland <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
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FlorentRevest authored and rostedt committed Mar 21, 2023
1 parent 5949574 commit 23edf48
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Showing 4 changed files with 28 additions and 18 deletions.
10 changes: 6 additions & 4 deletions kernel/trace/trace_selftest.c
Original file line number Diff line number Diff line change
Expand Up @@ -785,6 +785,7 @@ static struct fgraph_ops fgraph_ops __initdata = {
};

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
static struct ftrace_ops direct;
#ifndef CALL_DEPTH_ACCOUNT
#define CALL_DEPTH_ACCOUNT ""
#endif
Expand Down Expand Up @@ -870,8 +871,8 @@ trace_selftest_startup_function_graph(struct tracer *trace,
* Register direct function together with graph tracer
* and make sure we get graph trace.
*/
ret = register_ftrace_direct((unsigned long) DYN_FTRACE_TEST_NAME,
(unsigned long) trace_direct_tramp);
ftrace_set_filter_ip(&direct, (unsigned long)DYN_FTRACE_TEST_NAME, 0, 0);
ret = register_ftrace_direct_multi(&direct, (unsigned long)trace_direct_tramp);
if (ret)
goto out;

Expand All @@ -891,8 +892,9 @@ trace_selftest_startup_function_graph(struct tracer *trace,

unregister_ftrace_graph(&fgraph_ops);

ret = unregister_ftrace_direct((unsigned long) DYN_FTRACE_TEST_NAME,
(unsigned long) trace_direct_tramp);
ret = unregister_ftrace_direct_multi(&direct,
(unsigned long) trace_direct_tramp,
true);
if (ret)
goto out;

Expand Down
12 changes: 8 additions & 4 deletions samples/ftrace/ftrace-direct-modify.c
Original file line number Diff line number Diff line change
Expand Up @@ -96,6 +96,8 @@ asm (

#endif /* CONFIG_S390 */

static struct ftrace_ops direct;

static unsigned long my_tramp = (unsigned long)my_tramp1;
static unsigned long tramps[2] = {
(unsigned long)my_tramp1,
Expand All @@ -114,7 +116,7 @@ static int simple_thread(void *arg)
if (ret)
continue;
t ^= 1;
ret = modify_ftrace_direct(my_ip, my_tramp, tramps[t]);
ret = modify_ftrace_direct_multi(&direct, tramps[t]);
if (!ret)
my_tramp = tramps[t];
WARN_ON_ONCE(ret);
Expand All @@ -129,7 +131,9 @@ static int __init ftrace_direct_init(void)
{
int ret;

ret = register_ftrace_direct(my_ip, my_tramp);
ftrace_set_filter_ip(&direct, (unsigned long) my_ip, 0, 0);
ret = register_ftrace_direct_multi(&direct, my_tramp);

if (!ret)
simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn");
return ret;
Expand All @@ -138,12 +142,12 @@ static int __init ftrace_direct_init(void)
static void __exit ftrace_direct_exit(void)
{
kthread_stop(simple_tsk);
unregister_ftrace_direct(my_ip, my_tramp);
unregister_ftrace_direct_multi(&direct, my_tramp, true);
}

module_init(ftrace_direct_init);
module_exit(ftrace_direct_exit);

MODULE_AUTHOR("Steven Rostedt");
MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct()");
MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct_multi()");
MODULE_LICENSE("GPL");
12 changes: 7 additions & 5 deletions samples/ftrace/ftrace-direct-too.c
Original file line number Diff line number Diff line change
Expand Up @@ -70,21 +70,23 @@ asm (

#endif /* CONFIG_S390 */

static struct ftrace_ops direct;

static int __init ftrace_direct_init(void)
{
return register_ftrace_direct((unsigned long)handle_mm_fault,
(unsigned long)my_tramp);
ftrace_set_filter_ip(&direct, (unsigned long) handle_mm_fault, 0, 0);

return register_ftrace_direct_multi(&direct, (unsigned long) my_tramp);
}

static void __exit ftrace_direct_exit(void)
{
unregister_ftrace_direct((unsigned long)handle_mm_fault,
(unsigned long)my_tramp);
unregister_ftrace_direct_multi(&direct, (unsigned long)my_tramp, true);
}

module_init(ftrace_direct_init);
module_exit(ftrace_direct_exit);

MODULE_AUTHOR("Steven Rostedt");
MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct()");
MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct_multi()");
MODULE_LICENSE("GPL");
12 changes: 7 additions & 5 deletions samples/ftrace/ftrace-direct.c
Original file line number Diff line number Diff line change
Expand Up @@ -63,21 +63,23 @@ asm (

#endif /* CONFIG_S390 */

static struct ftrace_ops direct;

static int __init ftrace_direct_init(void)
{
return register_ftrace_direct((unsigned long)wake_up_process,
(unsigned long)my_tramp);
ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);

return register_ftrace_direct_multi(&direct, (unsigned long) my_tramp);
}

static void __exit ftrace_direct_exit(void)
{
unregister_ftrace_direct((unsigned long)wake_up_process,
(unsigned long)my_tramp);
unregister_ftrace_direct_multi(&direct, (unsigned long)my_tramp, true);
}

module_init(ftrace_direct_init);
module_exit(ftrace_direct_exit);

MODULE_AUTHOR("Steven Rostedt");
MODULE_DESCRIPTION("Example use case of using register_ftrace_direct()");
MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()");
MODULE_LICENSE("GPL");

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