Re: [PATCH 1/2] arm: add arm bti pass

[Andrea Corallo via Gcc-patches]

Andrea Corallo via Gcc-patches  writes:

> Hi all,
>
> this patch is part of a series that enables Armv8.1-M in GCC and adds
> Branch Target Identification Mechanism [1].
>
> This patch moves and generalize the Aarch64 "bti" pass so it can be
> used also by the Arm backend.
>
> The pass iterates through the instructions and adds the necessary BTI
> instructions at the beginning of every function and at every landing
> pads targeted by indirect jumps.
>
> Regressioned and bootstraped on arm-linux-gnu aarch64-linux-gnu.
>
> Best Regards
>
>   Andrea
>
> [1] 
> 

Ping

Best Regards

  Andrea

[PATCH 1/2] arm: add arm bti pass

[Andrea Corallo via Gcc-patches]

Hi all,

this patch is part of a series that enables Armv8.1-M in GCC and adds
Branch Target Identification Mechanism [1].

This patch moves and generalize the Aarch64 "bti" pass so it can be
used also by the Arm backend.

The pass iterates through the instructions and adds the necessary BTI
instructions at the beginning of every function and at every landing
pads targeted by indirect jumps.

Regressioned and bootstraped on arm-linux-gnu aarch64-linux-gnu.

Best Regards

  Andrea

[1] 
<https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/armv8-1-m-pointer-authentication-and-branch-target-identification-extension>

>From 94ee67dbc78c5ea15dde7114d7bffc18a5843cb7 Mon Sep 17 00:00:00 2001
From: Andrea Corallo 
Date: Wed, 28 Jul 2021 15:49:16 +0200
Subject: [PATCH 1/2] arm: add arm bti pass

gcc/ChangeLog

2021-09-15  Andrea Corallo  

* config/arm/unspecs.md (UNSPECV_BTI): Add unspec.

* config/arm/t-arm (aarch-bti-insert.o): Add rule.

* config/arm/arm.md (bti): New pattern.

* config/arm/arm.c (aarch_bti_enabled, aarch_bti_j_insn_p)
(aarch_pac_insn_p, aarch_gen_bti_c, aarch_gen_bti_j): New
functions.

* config/arm/arm-protos.h (make_pass_insert_bti): Add proto.

* config/arm/arm-passes.def: New file.

* config/arm/aarch-common-protos.h (aarch_bti_enabled)
(aarch_bti_j_insn_p, aarch_pac_insn_p, aarch_gen_bti_c)
(aarch_gen_bti_j): Add protos.

* config/arm/aarch-bti-insert.c: New file, rename from
'gcc/config/aarch64/aarch64-bti-insert.c' and generalize.

* config/aarch64/t-aarch64 (aarch-bti-insert.o): Rename from
'aarch64-bti-insert.o' and account for new folder.

* config/aarch64/aarch64.c (aarch_bti_enabled)
(aarch_bti_j_insn_p, aarch_pac_insn_p, aarch_gen_bti_c)
(aarch_gen_bti_j): New functions.
(aarch64_output_mi_thunk)
(aarch64_print_patchable_function_entry)
(aarch64_file_end_indicate_exec_stack): Rename 'aarch64_bti_enabled'
=> 'aarch_bti_enabled'.

* config/aarch64/aarch64-protos.h: Remove 'aarch64_bti_enabled'.

* config/aarch64/aarch64-c.c (aarch64_update_cpp_builtins): Rename
'aarch64_bti_enabled' into 'aarch_bti_enabled'.

* config.gcc (aarch64*-*-*): Rename 'aarch64-bti-insert.o' into
'aarch-bti-insert.o'.
(arm*-*-*): Add 'aarch-bti-insert.o'.

gcc/testsuite/ChangeLog

2021-09-15  Andrea Corallo  

* gcc.target/arm/bti1.c: New testcase.

* gcc.target/arm/bti2.c: Likewise.
---
 gcc/config.gcc|  4 +-
 gcc/config/aarch64/aarch64-c.c|  2 +-
 gcc/config/aarch64/aarch64-protos.h   |  1 -
 gcc/config/aarch64/aarch64.c  | 58 ++--
 gcc/config/aarch64/t-aarch64  |  4 +-
 .../aarch-bti-insert.c}   | 66 ---
 gcc/config/arm/aarch-common-protos.h  |  5 ++
 gcc/config/arm/arm-passes.def | 21 ++
 gcc/config/arm/arm-protos.h   |  2 +
 gcc/config/arm/arm.c  | 35 ++
 gcc/config/arm/arm.md |  6 ++
 gcc/config/arm/t-arm  | 10 +++
 gcc/config/arm/unspecs.md |  1 +
 gcc/testsuite/gcc.target/arm/bti1.c   | 12 
 gcc/testsuite/gcc.target/arm/bti2.c   | 58 
 15 files changed, 222 insertions(+), 63 deletions(-)
 rename gcc/config/{aarch64/aarch64-bti-insert.c => arm/aarch-bti-insert.c} 
(80%)
 create mode 100644 gcc/config/arm/arm-passes.def
 create mode 100644 gcc/testsuite/gcc.target/arm/bti1.c
 create mode 100644 gcc/testsuite/gcc.target/arm/bti2.c

diff --git a/gcc/config.gcc b/gcc/config.gcc
index d9bfbfdc0d2..648cf28e105 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -322,7 +322,7 @@ aarch64*-*-*)
c_target_objs="aarch64-c.o"
cxx_target_objs="aarch64-c.o"
d_target_objs="aarch64-d.o"
-   extra_objs="aarch64-builtins.o aarch-common.o aarch64-sve-builtins.o 
aarch64-sve-builtins-shapes.o aarch64-sve-builtins-base.o 
aarch64-sve-builtins-sve2.o cortex-a57-fma-steering.o aarch64-speculation.o 
falkor-tag-collision-avoidance.o aarch64-bti-insert.o aarch64-cc-fusion.o"
+   extra_objs="aarch64-builtins.o aarch-common.o aarch64-sve-builtins.o 
aarch64-sve-builtins-shapes.o aarch64-sve-builtins-base.o 
aarch64-sve-builtins-sve2.o cortex-a57-fma-steering.o aarch64-speculation.o 
falkor-tag-collision-avoidance.o aarch-bti-insert.o aarch64-cc-fusion.o"
target_gtfiles="\$(srcdir)/config/aarch64/aarch64-builtins.c 
\$(srcdir)/config/aarch64/aarch64-sve-builtins.h 
\$(srcdir)/config/aarch64/aarch64-sve-builtins.cc"
tar