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authorBorislav Petkov <bp@suse.de>2019-10-21 17:18:23 +0200
committerBorislav Petkov <bp@suse.de>2019-10-25 10:52:22 +0200
commit0f42c1ad44d437f75b840b572376fd538fbb9643 (patch)
treeb86501365601e861b13c80f35ea0487d3cab0d0b /Documentation/asm-annotations.rst
parent13fbe784ef6e58d0267a6e183f90ce7826d7d885 (diff)
downloadlwn-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
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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.