[PATCH] x86: Detect CFI support in the assembler at runtime
... instead of using a CONFIG option. The config option still controls
if the resulting executable actually has unwind information.
This is useful to prevent compilation errors when users select
CONFIG_STACK_UNWIND on old binutils and also allows to use
CFI in the future for non kernel debugging applications.
Cc: jbeulich@novell.com
Cc: sam@ravnborg.org
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index b7d6abb..e2cbd59 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -421,6 +421,11 @@
The second argument is optional, and if supplied will be used
if first argument is not supported.
+ as-instr
+ as-instr checks if the assembler reports a specific instruction
+ and then outputs either option1 or option2
+ C escapes are supported in the test instruction
+
cc-option
cc-option is used to check if $(CC) supports a given option, and not
supported to use an optional second option.
