Re: [PATCH v7 21/36] function_graph: Add selftest for passing local variables
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2024-02-15 15:01:22
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On Wed, 7 Feb 2024 00:11:22 +0900 "Masami Hiramatsu (Google)" [off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: Steven Rostedt (VMware) <rostedt@goodmis.org> Add boot up selftest that passes variables from a function entry to a function exit, and make sure that they do get passed around. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> --- Changes in v2: - Add reserved size test. - Use pr_*() instead of printk(KERN_*). --- kernel/trace/trace_selftest.c | 169 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 169 insertions(+)diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index f0758afa2f7d..4d86cd4c8c8c 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c@@ -756,6 +756,173 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr) #ifdef CONFIG_FUNCTION_GRAPH_TRACER +#ifdef CONFIG_DYNAMIC_FTRACE + +#define BYTE_NUMBER 123 +#define SHORT_NUMBER 12345 +#define WORD_NUMBER 1234567890 +#define LONG_NUMBER 1234567890123456789LL + +static int fgraph_store_size __initdata; +static const char *fgraph_store_type_name __initdata; +static char *fgraph_error_str __initdata; +static char fgraph_error_str_buf[128] __initdata; + +static __init int store_entry(struct ftrace_graph_ent *trace, + struct fgraph_ops *gops) +{ + const char *type = fgraph_store_type_name; + int size = fgraph_store_size; + void *p; + + p = fgraph_reserve_data(gops->idx, size); + if (!p) { + snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf), + "Failed to reserve %s\n", type); + fgraph_error_str = fgraph_error_str_buf; + return 0; + } + + switch (fgraph_store_size) { + case 1: + *(char *)p = BYTE_NUMBER; + break; + case 2: + *(short *)p = SHORT_NUMBER; + break; + case 4: + *(int *)p = WORD_NUMBER; + break; + case 8: + *(long long *)p = LONG_NUMBER; + break; + } +
What would be an interesting test is to run all versions together. That is, to attach a callback that stores a byte, a callback that stores a short, a callback that stores a word and a callback that stores a long, and attach them all to the same function. I guess we can add that as a separate patch. -- Steve
+ return 1; +} +