From e1e18ea0defe9e1ee35abbbe5279028ecf786957 Mon Sep 17 00:00:00 2001 From: Wilco Dijkstra Date: Tue, 26 Sep 2023 16:27:38 +0100 Subject: [PATCH] AArch64: Remove BTI from outline atomics The outline atomic functions have hidden visibility and can only be called directly. Therefore we can remove the BTI at function entry. This improves security by reducing the number of indirect entry points in a binary. The BTI markings on the objects are still emitted. libgcc/ChangeLog: * config/aarch64/lse.S (BTI_C): Remove define. --- libgcc/config/aarch64/lse.S | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/libgcc/config/aarch64/lse.S b/libgcc/config/aarch64/lse.S index dde3a28e07b1..f64a3e98bfae 100644 --- a/libgcc/config/aarch64/lse.S +++ b/libgcc/config/aarch64/lse.S @@ -46,6 +46,9 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see * direct branch. The choice of LSE vs non-LSE is done via one byte load * followed by a well-predicted direct branch. The functions are compiled * separately to minimize code size. + * + * Since these functions have hidden visibility and are never called + * indirectly, they do not need to start with a BTI instruction. */ #include "auto-target.h" @@ -161,8 +164,6 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see #define tmp1 17 #define tmp2 15 -#define BTI_C hint 34 - /* Start and end a function. */ .macro STARTFN name .text @@ -172,7 +173,6 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see .type \name, %function .cfi_startproc \name: - BTI_C .endm .macro ENDFN name -- 2.47.2