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| author | Steven Rostedt <rostedt@goodmis.org> | 2025-07-04 10:48:38 -0400 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2025-07-22 20:15:56 -0400 |
| commit | 4d6d0a6263babf7c43faa55de4fa3c6637dec624 (patch) | |
| tree | 17c2a7509f4ddd4c9844a65750bb44b899a2b6c7 /Documentation/trace | |
| parent | 9b4d5d330fcd40bbc38a1e6ed3d617e674d651fa (diff) | |
| download | linux-4d6d0a6263babf7c43faa55de4fa3c6637dec624.tar.gz linux-4d6d0a6263babf7c43faa55de4fa3c6637dec624.tar.bz2 linux-4d6d0a6263babf7c43faa55de4fa3c6637dec624.zip | |
tracing: Remove redundant config HAVE_FTRACE_MCOUNT_RECORD
Ftrace is tightly coupled with architecture specific code because it
requires the use of trampolines written in assembly. This means that when
a new feature or optimization is made, it must be done for all
architectures. To simplify the approach, CONFIG_HAVE_FTRACE_* configs are
added to denote which architecture has the new enhancement so that other
architectures can still function until they too have been updated.
The CONFIG_HAVE_FTRACE_MCOUNT was added to help simplify the
DYNAMIC_FTRACE work, but now every architecture that implements
DYNAMIC_FTRACE also has HAVE_FTRACE_MCOUNT set too, making it redundant
with the HAVE_DYNAMIC_FTRACE.
Remove the HAVE_FTRACE_MCOUNT config and use DYNAMIC_FTRACE directly where
applicable.
Link: https://lore.kernel.org/all/20250703154916.48e3ada7@gandalf.local.home/
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/20250704104838.27a18690@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'Documentation/trace')
| -rw-r--r-- | Documentation/trace/ftrace-design.rst | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/Documentation/trace/ftrace-design.rst b/Documentation/trace/ftrace-design.rst index dc82d64b3a44..8f4fab3f9324 100644 --- a/Documentation/trace/ftrace-design.rst +++ b/Documentation/trace/ftrace-design.rst @@ -238,19 +238,15 @@ You need very few things to get the syscalls tracing in an arch. - Tag this arch as HAVE_SYSCALL_TRACEPOINTS. -HAVE_FTRACE_MCOUNT_RECORD -------------------------- +HAVE_DYNAMIC_FTRACE +------------------- See scripts/recordmcount.pl for more info. Just fill in the arch-specific details for how to locate the addresses of mcount call sites via objdump. This option doesn't make much sense without also implementing dynamic ftrace. - -HAVE_DYNAMIC_FTRACE -------------------- - -You will first need HAVE_FTRACE_MCOUNT_RECORD and HAVE_FUNCTION_TRACER, so -scroll your reader back up if you got over eager. +You will first need HAVE_FUNCTION_TRACER, so scroll your reader back up if you +got over eager. Once those are out of the way, you will need to implement: - asm/ftrace.h: |