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| author | Jiri Olsa <jolsa@redhat.com> | 2021-10-08 11:13:36 +0200 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2021-10-21 20:19:00 +0200 |
| commit | 5fae941b9a6f95773df644e7cf304bf199707876 (patch) | |
| tree | 696dd6956ef422502ccf37fa2735374157cd2f08 /samples | |
| parent | ftrace: Add multi direct modify interface (diff) | |
| download | linux-5fae941b9a6f95773df644e7cf304bf199707876.tar.xz linux-5fae941b9a6f95773df644e7cf304bf199707876.zip | |
ftrace/samples: Add multi direct interface test module
Adding simple module that uses multi direct interface:
register_ftrace_direct_multi
unregister_ftrace_direct_multi
The init function registers trampoline for 2 functions,
and exit function unregisters them.
Link: https://lkml.kernel.org/r/20211008091336.33616-9-jolsa@kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'samples')
| -rw-r--r-- | samples/ftrace/Makefile | 1 | ||||
| -rw-r--r-- | samples/ftrace/ftrace-direct-multi.c | 52 |
2 files changed, 53 insertions, 0 deletions
diff --git a/samples/ftrace/Makefile b/samples/ftrace/Makefile index 4ce896e10b2e..ab1d1c05c288 100644 --- a/samples/ftrace/Makefile +++ b/samples/ftrace/Makefile @@ -3,6 +3,7 @@ obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct.o obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct-too.o obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct-modify.o +obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct-multi.o CFLAGS_sample-trace-array.o := -I$(src) obj-$(CONFIG_SAMPLE_TRACE_ARRAY) += sample-trace-array.o diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c new file mode 100644 index 000000000000..2a5b1fb7ac14 --- /dev/null +++ b/samples/ftrace/ftrace-direct-multi.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <linux/module.h> + +#include <linux/mm.h> /* for handle_mm_fault() */ +#include <linux/ftrace.h> +#include <linux/sched/stat.h> + +void my_direct_func(unsigned long ip) +{ + trace_printk("ip %lx\n", ip); +} + +extern void my_tramp(void *); + +asm ( +" .pushsection .text, \"ax\", @progbits\n" +" .type my_tramp, @function\n" +" .globl my_tramp\n" +" my_tramp:" +" pushq %rbp\n" +" movq %rsp, %rbp\n" +" pushq %rdi\n" +" movq 8(%rbp), %rdi\n" +" call my_direct_func\n" +" popq %rdi\n" +" leave\n" +" ret\n" +" .size my_tramp, .-my_tramp\n" +" .popsection\n" +); + +static struct ftrace_ops direct; + +static int __init ftrace_direct_multi_init(void) +{ + ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0); + ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0); + + return register_ftrace_direct_multi(&direct, (unsigned long) my_tramp); +} + +static void __exit ftrace_direct_multi_exit(void) +{ + unregister_ftrace_direct_multi(&direct, (unsigned long) my_tramp); +} + +module_init(ftrace_direct_multi_init); +module_exit(ftrace_direct_multi_exit); + +MODULE_AUTHOR("Jiri Olsa"); +MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()"); +MODULE_LICENSE("GPL"); |