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authorJiri Olsa <jolsa@redhat.com>2021-10-08 11:13:36 +0200
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-10-21 20:19:00 +0200
commit5fae941b9a6f95773df644e7cf304bf199707876 (patch)
tree696dd6956ef422502ccf37fa2735374157cd2f08 /samples/ftrace
parentftrace: Add multi direct modify interface (diff)
downloadlinux-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/ftrace')
-rw-r--r--samples/ftrace/Makefile1
-rw-r--r--samples/ftrace/ftrace-direct-multi.c52
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");