qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [RFC PATCH] target/arm: properly document FEAT_CRC32


From: Philippe Mathieu-Daudé
Subject: Re: [RFC PATCH] target/arm: properly document FEAT_CRC32
Date: Fri, 24 Feb 2023 11:28:28 +0100
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.8.0

On 24/2/23 00:27, Richard Henderson wrote:
On 2/23/23 13:22, Philippe Mathieu-Daudé wrote:
On 24/2/23 00:01, Richard Henderson wrote:
On 2/22/23 01:01, Alex Bennée wrote:
This is a mandatory feature for Armv8.1 architectures but we don't
state the feature clearly in our emulation list. While checking verify
our cortex-a76 model matches up with the current TRM by breaking out
the long form isar into a more modern readable FIELD_DP code.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
  docs/system/arm/emulation.rst |  1 +
  target/arm/cpu64.c            | 29 ++++++++++++++++++++++++++---
  target/arm/cpu_tcg.c          |  2 +-
  3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/docs/system/arm/emulation.rst b/docs/system/arm/emulation.rst
index 2062d71261..2c4fde5eef 100644
--- a/docs/system/arm/emulation.rst
+++ b/docs/system/arm/emulation.rst
@@ -14,6 +14,7 @@ the following architecture extensions:
  - FEAT_BBM at level 2 (Translation table break-before-make levels)
  - FEAT_BF16 (AArch64 BFloat16 instructions)
  - FEAT_BTI (Branch Target Identification)
+- FEAT_CRC32 (CRC32 instruction)
  - FEAT_CSV2 (Cache speculation variant 2)
  - FEAT_CSV2_1p1 (Cache speculation variant 2, version 1.1)
  - FEAT_CSV2_1p2 (Cache speculation variant 2, version 1.2)
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 4066950da1..12e1a532ab 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -912,6 +912,8 @@ static void aarch64_a72_initfn(Object *obj)
  static void aarch64_a76_initfn(Object *obj)
  {
      ARMCPU *cpu = ARM_CPU(obj);
+    uint64_t t;
+    uint32_t u;
      cpu->dtb_compatible = "arm,cortex-a76";
      set_feature(&cpu->env, ARM_FEATURE_V8);
@@ -928,7 +930,18 @@ static void aarch64_a76_initfn(Object *obj)
      cpu->ctr = 0x8444C004;
      cpu->dcz_blocksize = 4;
      cpu->isar.id_aa64dfr0  = 0x0000000010305408ull;
-    cpu->isar.id_aa64isar0 = 0x0000100010211120ull;
+
+    /* per r4p1 of the Cryptographic Extension TRM */
+    t = cpu->isar.id_aa64isar0;
+    t = FIELD_DP64(t, ID_AA64ISAR0, AES, 2);      /* FEAT_PMULL */
+    t = FIELD_DP64(t, ID_AA64ISAR0, SHA1, 1);     /* FEAT_SHA1 */
+    t = FIELD_DP64(t, ID_AA64ISAR0, SHA2, 1);     /* FEAT_SHA512 */
+    t = FIELD_DP64(t, ID_AA64ISAR0, CRC32, 1);    /* FEAT_CRC32 */
+    t = FIELD_DP64(t, ID_AA64ISAR0, ATOMIC, 2);   /* FEAT_LSE */
+    t = FIELD_DP64(t, ID_AA64ISAR0, RDM, 1);      /* FEAT_RDM */
+    t = FIELD_DP64(t, ID_AA64ISAR0, DP, 1);       /* FEAT_DotProd */

Maybe:

         assert(t == 0x0000100010211120ull);

But why bother to break it out then?

To keep everybody happy :) For example Alex can grep which cores
implement FEAT_CRC32...



reply via email to

[Prev in Thread] Current Thread [Next in Thread]