[PATCH 1/1] target/arm: adjust CPTR_EL2 according to HCR_EL2.E2H

[PATCH 1/1] target/arm: adjust CPTR_EL2 according to HCR_EL2.E2H

[LIU Zhiwei]

From DDI0487Fc_armv8_arm.pdf, the CPTR_EL2 has two kinds
of layouts according to HCR_EL2.E2H.

When HCR_EL2.E2H is 1, fp_exception_el should refer to
HCR_EL2.FPEN and sve_exception_el should refer to HCR_EL2.ZEN.

Change-Id: If1c8f88db9fb505c36211ceafbf25e838ed96ec0
Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
---
 target/arm/helper.c | 53 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 45 insertions(+), 8 deletions(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 8ef0fb478f..19b74b25e4 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -6116,11 +6116,29 @@ int sve_exception_el(CPUARMState *env, int el)
      * they will be zero when EL2 is not present.
      */
     if (el <= 2 && !arm_is_secure_below_el3(env)) {
-        if (env->cp15.cptr_el[2] & CPTR_TZ) {
-            return 2;
-        }
-        if (env->cp15.cptr_el[2] & CPTR_TFP) {
-            return 0;
+        if ((arm_hcr_el2_eff(env) & HCR_E2H) == HCR_E2H) {
+            int zen = extract32(env->cp15.cptr_el[2], 16, 2);
+            switch (zen) {
+            case 0:
+            case 2:
+                return 2;
+            case 1:
+                if ((arm_hcr_el2_eff(env) & HCR_TGE) == HCR_TGE) {
+                    if (el == 0) {
+                        return 2;
+                    }
+                }
+                break;
+            case 3:
+                break;
+            }
+        } else {
+            if (env->cp15.cptr_el[2] & CPTR_TZ) {
+                return 2;
+            }
+            if (env->cp15.cptr_el[2] & CPTR_TFP) {
+                return 0;
+            }
         }
     }
 
@@ -12492,10 +12510,29 @@ int fp_exception_el(CPUARMState *env, int cur_el)
      */
 
     /* CPTR_EL2 : present in v7VE or v8 */
-    if (cur_el <= 2 && extract32(env->cp15.cptr_el[2], 10, 1)
-        && !arm_is_secure_below_el3(env)) {
+    if ((cur_el <= 2) && !arm_is_secure_below_el3(env)) {
         /* Trap FP ops at EL2, NS-EL1 or NS-EL0 to EL2 */
-        return 2;
+        if ((arm_hcr_el2_eff(env) & HCR_E2H) == HCR_E2H) {
+            int fpen = extract32(env->cp15.cptr_el[2], 20, 2);
+            switch (fpen) {
+            case 0:
+            case 2:
+                return 2;
+            case 1:
+                if ((arm_hcr_el2_eff(env) & HCR_TGE) == HCR_TGE) {
+                    if (cur_el == 0) {
+                        return 2;
+                    }
+                }
+                break;
+            case 3:
+                break;
+            }
+        } else {
+            if (extract32(env->cp15.cptr_el[2], 10, 1)) {
+                return 2;
+            }
+        }
     }
 
     /* CPTR_EL3 : present in v8 */
-- 
2.23.0

Re: [PATCH 1/1] target/arm: adjust CPTR_EL2 according to HCR_EL2.E2H

[Richard Henderson]

On 8/10/20 11:07 PM, LIU Zhiwei wrote:
>      if (el <= 2 && !arm_is_secure_below_el3(env)) {
> -        if (env->cp15.cptr_el[2] & CPTR_TZ) {
> -            return 2;
> -        }
> -        if (env->cp15.cptr_el[2] & CPTR_TFP) {
> -            return 0;
> +        if ((arm_hcr_el2_eff(env) & HCR_E2H) == HCR_E2H) {
> +            int zen = extract32(env->cp15.cptr_el[2], 16, 2);
> +            switch (zen) {
> +            case 0:
> +            case 2:
> +                return 2;
> +            case 1:
> +                if ((arm_hcr_el2_eff(env) & HCR_TGE) == HCR_TGE) {

Since the outer if checks that we're in non-secure state, and (by nature of
sve) we know we're in aarch64 mode, then we don't need to use arm_hcr_el2_eff
and can just use env->cp15.hcr_el2.

Add a comment

>     /* Since we exclude secure first, we may read HCR_EL2 directly. */

like we do in vae1_tlbmask.

You do not need to write

    if ((x & bit) == bit)

just use

    if (x & bit)

here.

With those changes,
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~