[v2,04/17] target/arm: Add isar_feature_aa64_fp_simd, isar_feature_aa32_vfp

Message ID 20200224222232.13807-5-richard.henderson@linaro.org
State New
Headers show
Series
  • target/arm: vfp feature and decodetree cleanup
Related show

Commit Message

Richard Henderson Feb. 24, 2020, 10:22 p.m.
We cannot easily create "any" functions for these, because the
ID_AA64PFR0 fields for FP and SIMD signal "enabled" with zero.
Which means that an aarch32-only cpu will return incorrect results
when testing the aarch64 registers.

To use these, we must either have context or additionally test
vs ARM_FEATURE_AARCH64.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 target/arm/cpu.h     | 11 +++++++++++
 target/arm/cpu.c     |  9 ++++++---
 target/arm/machine.c |  5 +++--
 3 files changed, 20 insertions(+), 5 deletions(-)

-- 
2.20.1

Comments

Peter Maydell Feb. 25, 2020, 1:20 p.m. | #1
On Mon, 24 Feb 2020 at 22:22, Richard Henderson
<richard.henderson@linaro.org> wrote:
>

> We cannot easily create "any" functions for these, because the

> ID_AA64PFR0 fields for FP and SIMD signal "enabled" with zero.

> Which means that an aarch32-only cpu will return incorrect results

> when testing the aarch64 registers.

>

> To use these, we must either have context or additionally test

> vs ARM_FEATURE_AARCH64.

>

> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

> ---

>  target/arm/cpu.h     | 11 +++++++++++

>  target/arm/cpu.c     |  9 ++++++---

>  target/arm/machine.c |  5 +++--

>  3 files changed, 20 insertions(+), 5 deletions(-)


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


thanks
-- PMM

Patch

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index f7a90f512e..b94d2a5ace 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -3494,6 +3494,11 @@  static inline bool isar_feature_aa32_fpdp_v3(const ARMISARegisters *id)
     return FIELD_EX32(id->mvfr0, MVFR0, FPDP) >= 2;
 }
 
+static inline bool isar_feature_aa32_vfp(const ARMISARegisters *id)
+{
+    return isar_feature_aa32_fpsp_v2(id) || isar_feature_aa32_fpdp_v2(id);
+}
+
 /*
  * We always set the FP and SIMD FP16 fields to indicate identical
  * levels of support (assuming SIMD is implemented at all), so
@@ -3696,6 +3701,12 @@  static inline bool isar_feature_aa64_dcpodp(const ARMISARegisters *id)
     return FIELD_EX64(id->id_aa64isar1, ID_AA64ISAR1, DPB) >= 2;
 }
 
+static inline bool isar_feature_aa64_fp_simd(const ARMISARegisters *id)
+{
+    /* We always set the AdvSIMD and FP fields identically.  */
+    return FIELD_EX64(id->id_aa64pfr0, ID_AA64PFR0, FP) != 0xf;
+}
+
 static inline bool isar_feature_aa64_fp16(const ARMISARegisters *id)
 {
     /* We always set the AdvSIMD and FP fields identically wrt FP16.  */
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index be4c2a1253..5be4c25809 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -1260,7 +1260,9 @@  void arm_cpu_post_init(Object *obj)
      * KVM does not currently allow us to lie to the guest about its
      * ID/feature registers, so the guest always sees what the host has.
      */
-    if (arm_feature(&cpu->env, ARM_FEATURE_VFP)) {
+    if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)
+        ? cpu_isar_feature(aa64_fp_simd, cpu)
+        : cpu_isar_feature(aa32_vfp, cpu)) {
         cpu->has_vfp = true;
         if (!kvm_enabled()) {
             qdev_property_add_static(DEVICE(obj), &arm_cpu_has_vfp_property);
@@ -1636,8 +1638,9 @@  static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
      * We rely on no XScale CPU having VFP so we can use the same bits in the
      * TB flags field for VECSTRIDE and XSCALE_CPAR.
      */
-    assert(!(arm_feature(env, ARM_FEATURE_VFP) &&
-             arm_feature(env, ARM_FEATURE_XSCALE)));
+    assert(arm_feature(&cpu->env, ARM_FEATURE_AARCH64) ||
+           !cpu_isar_feature(aa32_vfp_simd, cpu) ||
+           !arm_feature(env, ARM_FEATURE_XSCALE));
 
     if (arm_feature(env, ARM_FEATURE_V7) &&
         !arm_feature(env, ARM_FEATURE_M) &&
diff --git a/target/arm/machine.c b/target/arm/machine.c
index 241890ac8c..c5a2114f51 100644
--- a/target/arm/machine.c
+++ b/target/arm/machine.c
@@ -9,9 +9,10 @@ 
 static bool vfp_needed(void *opaque)
 {
     ARMCPU *cpu = opaque;
-    CPUARMState *env = &cpu->env;
 
-    return arm_feature(env, ARM_FEATURE_VFP);
+    return (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)
+            ? cpu_isar_feature(aa64_fp_simd, cpu)
+            : cpu_isar_feature(aa32_vfp_simd, cpu));
 }
 
 static int get_fpscr(QEMUFile *f, void *opaque, size_t size,