[gcc r12-6763] arm: Add option for mitigating against Cortex-A CPU erratum for AES

[gcc r12-6763] arm: Add option for mitigating against Cortex-A CPU erratum for AES

[Richard Earnshaw]

https://gcc.gnu.org/g:facbc2368c8f373a596e7665beb29b96c894bae2

commit r12-6763-gfacbc2368c8f373a596e7665beb29b96c894bae2
Author: Richard Earnshaw <rearnsha@arm.com>
Date:   Thu Oct 21 16:20:49 2021 +0100

    arm: Add option for mitigating against Cortex-A CPU erratum for AES
    
    Add a new option -mfix-cortex-a-aes for enabling the Cortex-A AES
    erratum work-around and enable it automatically for the affected
    products (Cortex-A57 and Cortex-A72).
    
    gcc/ChangeLog:
    
            * config/arm/arm-cpus.in (quirk_aes_1742098): New quirk feature
            (ALL_QUIRKS): Add it.
            (cortex-a57, cortex-a72): Enable it.
            (cortex-a57.cortex-a53, cortex-a72.cortex-a53): Likewise.
            * config/arm/arm.opt (mfix-cortex-a57-aes-1742098): New command-line
            option.
            (mfix-cortex-a72-aes-1655431): New option alias.
            * config/arm/arm.cc (arm_option_override): Handle default settings
            for AES erratum switch.
            * doc/invoke.texi (Arm Options): Document new options.

Diff:
---
 gcc/config/arm/arm-cpus.in |  9 ++++++++-
 gcc/config/arm/arm.cc      |  9 +++++++++
 gcc/config/arm/arm.opt     | 10 ++++++++++
 gcc/doc/invoke.texi        | 11 +++++++++++
 4 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/gcc/config/arm/arm-cpus.in b/gcc/config/arm/arm-cpus.in
index 499e82d790d..0d3082b569f 100644
--- a/gcc/config/arm/arm-cpus.in
+++ b/gcc/config/arm/arm-cpus.in
@@ -192,6 +192,9 @@ define feature quirk_cm3_ldrd
 # v8-m/v8.1-m VLLDM errata.
 define feature quirk_vlldm
 
+# AES errata on some Cortex-A parts
+define feature quirk_aes_1742098
+
 # Don't use .cpu assembly directive
 define feature quirk_no_asmcpu
 
@@ -329,7 +332,7 @@ define implied vfp_base MVE MVE_FP ALL_FP
 # architectures.
 # xscale isn't really a 'quirk', but it isn't an architecture either and we
 # need to ignore it for matching purposes.
-define fgroup ALL_QUIRKS   quirk_no_volatile_ce quirk_armv6kz quirk_cm3_ldrd quirk_vlldm xscale quirk_no_asmcpu
+define fgroup ALL_QUIRKS   quirk_no_volatile_ce quirk_armv6kz quirk_cm3_ldrd quirk_vlldm xscale quirk_no_asmcpu quirk_aes_1742098
 
 define fgroup IGNORE_FOR_MULTILIB cdecp0 cdecp1 cdecp2 cdecp3 cdecp4 cdecp5 cdecp6 cdecp7
 
@@ -1342,6 +1345,7 @@ begin cpu cortex-a57
  cname cortexa57
  tune flags LDSCHED
  architecture armv8-a+crc+simd
+ isa quirk_aes_1742098
  option crypto add FP_ARMv8 CRYPTO
  costs cortex_a57
  vendor 41
@@ -1353,6 +1357,7 @@ begin cpu cortex-a72
  tune for cortex-a57
  tune flags LDSCHED
  architecture armv8-a+crc+simd
+ isa quirk_aes_1742098
  option crypto add FP_ARMv8 CRYPTO
  costs cortex_a57
  vendor 41
@@ -1391,6 +1396,7 @@ begin cpu cortex-a57.cortex-a53
  tune for cortex-a53
  tune flags LDSCHED
  architecture armv8-a+crc+simd
+ isa quirk_aes_1742098
  option crypto add FP_ARMv8 CRYPTO
  costs cortex_a57
 end cpu cortex-a57.cortex-a53
@@ -1400,6 +1406,7 @@ begin cpu cortex-a72.cortex-a53
  tune for cortex-a53
  tune flags LDSCHED
  architecture armv8-a+crc+simd
+ isa quirk_aes_1742098
  option crypto add FP_ARMv8 CRYPTO
  costs cortex_a57
 end cpu cortex-a72.cortex-a53
diff --git a/gcc/config/arm/arm.cc b/gcc/config/arm/arm.cc
index 7825e364c01..04354b36606 100644
--- a/gcc/config/arm/arm.cc
+++ b/gcc/config/arm/arm.cc
@@ -3638,6 +3638,15 @@ arm_option_override (void)
 	fix_vlldm = 0;
     }
 
+  /* Enable fix_aes by default if required.  */
+  if (fix_aes_erratum_1742098 == 2)
+    {
+      if (bitmap_bit_p (arm_active_target.isa, isa_bit_quirk_aes_1742098))
+	fix_aes_erratum_1742098 = 1;
+      else
+	fix_aes_erratum_1742098 = 0;
+    }
+
   /* Hot/Cold partitioning is not currently supported, since we can't
      handle literal pool placement in that case.  */
   if (flag_reorder_blocks_and_partition)
diff --git a/gcc/config/arm/arm.opt b/gcc/config/arm/arm.opt
index 587fc932f96..2a4f165033a 100644
--- a/gcc/config/arm/arm.opt
+++ b/gcc/config/arm/arm.opt
@@ -272,6 +272,16 @@ mfix-cmse-cve-2021-35465
 Target Var(fix_vlldm) Init(2)
 Mitigate issues with VLLDM on some M-profile devices (CVE-2021-35465).
 
+mfix-cortex-a57-aes-1742098
+Target Var(fix_aes_erratum_1742098) Init(2) Save
+Mitigate issues with AES instructions on Cortex-A57 and Cortex-A72.
+Arm erratum #1742098
+
+mfix-cortex-a72-aes-1655431
+Target Alias(mfix-cortex-a57-aes-1742098)
+Mitigate issues with AES instructions on Cortex-A57 and Cortex-A72.
+Arm erratum #1655431
+
 munaligned-access
 Target Var(unaligned_access) Init(2) Save
 Enable unaligned word and halfword accesses to packed data.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 58751c48b8e..67693d6c5cf 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -812,6 +812,8 @@ Objective-C and Objective-C++ Dialects}.
 -mtp=@var{name}  -mtls-dialect=@var{dialect} @gol
 -mword-relocations @gol
 -mfix-cortex-m3-ldrd @gol
+-mfix-cortex-a57-aes-1742098 @gol
+-mfix-cortex-a72-aes-1655431 @gol
 -munaligned-access @gol
 -mneon-for-64bits @gol
 -mslow-flash-data @gol
@@ -21281,6 +21283,15 @@ with overlapping destination and base registers are used.  This option avoids
 generating these instructions.  This option is enabled by default when
 @option{-mcpu=cortex-m3} is specified.
 
+@item -mfix-cortex-a57-aes-1742098
+@itemx -mno-fix-cortex-a57-aes-1742098
+@itemx -mfix-cortex-a72-aes-1655431
+@itemx -mno-fix-cortex-a72-aes-1655431
+Enable (disable) mitigation for an erratum on Cortex-A57 and
+Cortex-A72 that affects the AES cryptographic instructions.  This
+option is enabled by default when either @option{-mcpu=cortex-a57} or
+@option{-mcpu=cortex-a72} is specified.
+
 @item -munaligned-access
 @itemx -mno-unaligned-access
 @opindex munaligned-access