From 5fae941b9a6f95773df644e7cf304bf199707876 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Fri, 8 Oct 2021 11:13:36 +0200 Subject: 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 Signed-off-by: Steven Rostedt (VMware) --- samples/ftrace/Makefile | 1 + samples/ftrace/ftrace-direct-multi.c | 52 ++++++++++++++++++++++++++++++++++++ 2 files changed, 53 insertions(+) create mode 100644 samples/ftrace/ftrace-direct-multi.c (limited to 'samples') 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 + +#include /* for handle_mm_fault() */ +#include +#include + +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"); -- cgit v1.2.3-58-ga151 From f76fbbbb5061fe14824ba5807c44bd7400a6b4e1 Mon Sep 17 00:00:00 2001 From: Tiezhu Yang Date: Tue, 26 Oct 2021 09:51:28 +0800 Subject: samples/kretprobes: Fix return value if register_kretprobe() failed Use the actual return value instead of always -1 if register_kretprobe() failed. E.g. without this patch: # insmod samples/kprobes/kretprobe_example.ko func=no_such_func insmod: ERROR: could not insert module samples/kprobes/kretprobe_example.ko: Operation not permitted With this patch: # insmod samples/kprobes/kretprobe_example.ko func=no_such_func insmod: ERROR: could not insert module samples/kprobes/kretprobe_example.ko: Unknown symbol in module Link: https://lkml.kernel.org/r/1635213091-24387-2-git-send-email-yangtiezhu@loongson.cn Fixes: 804defea1c02 ("Kprobes: move kprobe examples to samples/") Signed-off-by: Tiezhu Yang Acked-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- samples/kprobes/kretprobe_example.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'samples') diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c index 5dc1bf3baa98..228321ecb161 100644 --- a/samples/kprobes/kretprobe_example.c +++ b/samples/kprobes/kretprobe_example.c @@ -86,7 +86,7 @@ static int __init kretprobe_init(void) ret = register_kretprobe(&my_kretprobe); if (ret < 0) { pr_err("register_kretprobe failed, returned %d\n", ret); - return -1; + return ret; } pr_info("Planted return probe at %s: %p\n", my_kretprobe.kp.symbol_name, my_kretprobe.kp.addr); -- cgit v1.2.3-58-ga151