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| author |   Adrian Hunter <adrian.hunter@intel.com> | 2020-05-12 15:19:13 +0300 |
|---|---|---|
| committer |   Peter Zijlstra <peterz@infradead.org> | 2020-06-15 14:09:49 +0200 |
| commit | fc0ea795f53c8d7040fa42471f74fe51d78d0834 (patch) | |
| tree | ddf3830f325d6540366e8ef1cc934b7ccb7d081c /kernel/kallsyms.c | |
| parent | perf/x86: Add perf text poke events for kprobes (diff) | |
| download | linux-dev-fc0ea795f53c8d7040fa42471f74fe51d78d0834.tar.xz linux-dev-fc0ea795f53c8d7040fa42471f74fe51d78d0834.zip | |
ftrace: Add symbols for ftrace trampolines
Symbols are needed for tools to describe instruction addresses. Pages
allocated for ftrace's purposes need symbols to be created for them.
Add such symbols to be visible via /proc/kallsyms.
Example on x86 with CONFIG_DYNAMIC_FTRACE=y
# echo function > /sys/kernel/debug/tracing/current_tracer
# cat /proc/kallsyms | grep '\[__builtin__ftrace\]'
ffffffffc0238000 t ftrace_trampoline [__builtin__ftrace]
Note: This patch adds "__builtin__ftrace" as a module name in /proc/kallsyms for
symbols for pages allocated for ftrace's purposes, even though "__builtin__ftrace"
is not a module.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200512121922.8997-7-adrian.hunter@intel.com
Diffstat (limited to '')
| -rw-r--r-- | kernel/kallsyms.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index c6cc293c0e67..834bfdc43235 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -482,6 +482,11 @@ static int get_ksymbol_mod(struct kallsym_iter *iter) return 1; } +/* + * ftrace_mod_get_kallsym() may also get symbols for pages allocated for ftrace + * purposes. In that case "__builtin__ftrace" is used as a module name, even + * though "__builtin__ftrace" is not a module. + */ static int get_ksymbol_ftrace_mod(struct kallsym_iter *iter) { int ret = ftrace_mod_get_kallsym(iter->pos - iter->pos_mod_end, |