[v1] Implement Most ARMv8.3 Pointer Authentication Features

[PATCH 3/7] target/arm: Implement v8.3 EnhancedPAC

Posted by Aaron Lindsay 2 years, 3 months ago

Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
---
 target/arm/pauth_helper.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/target/arm/pauth_helper.c b/target/arm/pauth_helper.c
index f525ef7fad..a83956652f 100644
--- a/target/arm/pauth_helper.c
+++ b/target/arm/pauth_helper.c
@@ -347,11 +347,15 @@ static uint64_t pauth_addpac(CPUARMState *env, uint64_t ptr, uint64_t modifier,
      */
     test = sextract64(ptr, bot_bit, top_bit - bot_bit);
     if (test != 0 && test != -1) {
-        /*
-         * Note that our top_bit is one greater than the pseudocode's
-         * version, hence "- 2" here.
-         */
-        pac ^= MAKE_64BIT_MASK(top_bit - 2, 1);
+        if (cpu_isar_feature(aa64_pauth_epac, env_archcpu(env))) {
+            pac = 0;
+        } else {
+            /*
+             * Note that our top_bit is one greater than the pseudocode's
+             * version, hence "- 2" here.
+             */
+            pac ^= MAKE_64BIT_MASK(top_bit - 2, 1);
+        }
     }
 
     /*
-- 
2.25.1

Re: [PATCH 3/7] target/arm: Implement v8.3 EnhancedPAC

Posted by Peter Maydell 2 years, 2 months ago

On Thu, 2 Feb 2023 at 21:12, Aaron Lindsay <aaron@os.amperecomputing.com> wrote:
>
> Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
> ---
>  target/arm/pauth_helper.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/target/arm/pauth_helper.c b/target/arm/pauth_helper.c
> index f525ef7fad..a83956652f 100644
> --- a/target/arm/pauth_helper.c
> +++ b/target/arm/pauth_helper.c
> @@ -347,11 +347,15 @@ static uint64_t pauth_addpac(CPUARMState *env, uint64_t ptr, uint64_t modifier,
>       */
>      test = sextract64(ptr, bot_bit, top_bit - bot_bit);
>      if (test != 0 && test != -1) {
> -        /*
> -         * Note that our top_bit is one greater than the pseudocode's
> -         * version, hence "- 2" here.
> -         */
> -        pac ^= MAKE_64BIT_MASK(top_bit - 2, 1);
> +        if (cpu_isar_feature(aa64_pauth_epac, env_archcpu(env))) {
> +            pac = 0;
> +        } else {
> +            /*
> +             * Note that our top_bit is one greater than the pseudocode's
> +             * version, hence "- 2" here.
> +             */
> +            pac ^= MAKE_64BIT_MASK(top_bit - 2, 1);
> +        }
>      }

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM