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| author | Borislav Petkov <bp@suse.de> | 2019-10-21 17:18:23 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2019-10-25 10:52:22 +0200 |
| commit | 0f42c1ad44d437f75b840b572376fd538fbb9643 (patch) | |
| tree | b86501365601e861b13c80f35ea0487d3cab0d0b /Documentation/asm-annotations.rst | |
| parent | 13fbe784ef6e58d0267a6e183f90ce7826d7d885 (diff) | |
| download | lwn-0f42c1ad44d437f75b840b572376fd538fbb9643.tar.gz lwn-0f42c1ad44d437f75b840b572376fd538fbb9643.zip | |
x86/ftrace: Get rid of function_hook
History lesson courtesy of Steve:
"When ftrace first was introduced to the kernel, it used gcc's
mcount profiling mechanism. The mcount mechanism would add a call to
"mcount" at the start of every function but after the stack frame was
set up. Later, in gcc 4.6, gcc introduced -mfentry, that would create a
call to "__fentry__" instead of "mcount", before the stack frame was
set up. In order to handle both cases, ftrace defined a macro
"function_hook" that would be either "mcount" or "__fentry__" depending
on which one was being used.
The Linux kernel no longer supports the "mcount" method, thus there's
no reason to keep the "function_hook" define around. Simply use
"__fentry__", as there is no ambiguity to the name anymore."
Drop it everywhere.
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20191018124800.0a7006bb@gandalf.local.home
Diffstat (limited to 'Documentation/asm-annotations.rst')
| -rw-r--r-- | Documentation/asm-annotations.rst | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/Documentation/asm-annotations.rst b/Documentation/asm-annotations.rst index 29ccd6e61fe5..f55c2bb74d00 100644 --- a/Documentation/asm-annotations.rst +++ b/Documentation/asm-annotations.rst @@ -117,9 +117,9 @@ This section covers ``SYM_FUNC_*`` and ``SYM_CODE_*`` enumerated above. So in most cases, developers should write something like in the following example, having some asm instructions in between the macros, of course:: - SYM_FUNC_START(function_hook) + SYM_FUNC_START(memset) ... asm insns ... - SYM_FUNC_END(function_hook) + SYM_FUNC_END(memset) In fact, this kind of annotation corresponds to the now deprecated ``ENTRY`` and ``ENDPROC`` macros. |