[aarch64] Add support for pointer authentication B key

[deliverable/binutils-gdb.git] / gas / doc / c-aarch64.texi

diff --git a/gas/doc/c-aarch64.texi b/gas/doc/c-aarch64.texi
index f38fdf591a23c9c70f1b8e5fc5f183b5a21840e2..ca84c9d766fc28e67008f3764710dfe44c6b630a 100644 (file)
--- a/gas/doc/c-aarch64.texi
+++ b/gas/doc/c-aarch64.texi
@@ -435,6 +435,14 @@ as the @code{.dword} directive.
 @c YYYYYYYYYYYYYYYYYYYYYYYYYY
 @c ZZZZZZZZZZZZZZZZZZZZZZZZZZ
 
+@cindex @code{.cfi_b_key_frame} directive, AArch64
+@item  @code{.cfi_b_key_frame}
+The @code{.cfi_b_key_frame} directive inserts a 'B' character into the CIE
+corresponding to the current frame's FDE, meaning that its return address has
+been signed with the B-key.  If two frames are signed with differing keys then
+they will not share the same CIE.  This information is intended to be used by
+the stack unwinder in order to properly authenticate return addresses.
+
 @end table
 
 @node AArch64 Opcodes