[Qemu-devel] [PATCH v4 15/33] target-arm: add NSACR register

[greg . bellows]

From: Fabian Aggeler <address@hidden>

Implements NSACR register with corresponding read/write functions
for ARMv7 and ARMv8.

Signed-off-by: Sergey Fedorov <address@hidden>
Signed-off-by: Fabian Aggeler <address@hidden>
Signed-off-by: Greg Bellows <address@hidden>
---
 target-arm/cpu.h    |  6 +++++
 target-arm/helper.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index 1e8d5ee..4625088 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -182,6 +182,7 @@ typedef struct CPUARMState {
         uint64_t c1_coproc; /* Coprocessor access register.  */
         uint32_t c1_xscaleauxcr; /* XScale auxiliary control register.  */
         uint32_t c1_scr; /* secure config register.  */
+        uint32_t c1_nsacr; /* Non-secure access control register. */
         uint64_t ttbr0_el1; /* MMU translation table base 0. */
         uint64_t ttbr1_el1; /* MMU translation table base 1. */
         uint64_t c2_control; /* MMU translation table base control.  */
@@ -609,6 +610,11 @@ static inline void xpsr_write(CPUARMState *env, uint32_t 
val, uint32_t mask)
 #define SCR_RES1_MASK (3U << 4)
 #define SCR_MASK      (0x3fff & ~SCR_RES1_MASK)
 
+#define NSACR_NSTRCDIS (1U << 20)
+#define NSACR_RFR      (1U << 19)
+#define NSACR_NSASEDIS (1U << 15)
+#define NSACR_NSD32DIS (1U << 14)
+
 /* Return the current FPSCR value.  */
 uint32_t vfp_get_fpscr(CPUARMState *env);
 void vfp_set_fpscr(CPUARMState *env, uint32_t val);
diff --git a/target-arm/helper.c b/target-arm/helper.c
index e43545a..6342dbf 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -489,7 +489,19 @@ static void cpacr_write(CPUARMState *env, const 
ARMCPRegInfo *ri,
             /* VFP coprocessor: cp10 & cp11 [23:20] */
             mask |= (1 << 31) | (1 << 30) | (0xf << 20);
 
-            if (!arm_feature(env, ARM_FEATURE_NEON)) {
+            if (arm_feature(env, ARM_FEATURE_NEON)) {
+                /* NSACR can disable non-secure writes to
+                 * ASEDIS [31] or D32DIS [30]
+                 */
+                if (arm_feature(env, ARM_FEATURE_EL3) && !arm_is_secure(env)) {
+                    if ((env->cp15.c1_nsacr & NSACR_NSASEDIS)) {
+                        mask &= ~(1 << 31);
+                    }
+                    if ((env->cp15.c1_nsacr & NSACR_NSD32DIS)) {
+                        mask &= ~(1 << 30);
+                    }
+                }
+            } else {
                 /* ASEDIS [31] bit is RAO/WI */
                 value |= (1 << 31);
             }
@@ -501,6 +513,7 @@ static void cpacr_write(CPUARMState *env, const 
ARMCPRegInfo *ri,
                     !arm_feature(env, ARM_FEATURE_VFP3)) {
                 /* D32DIS [30] is RAO/WI if D16-31 are not implemented. */
                 value |= (1 << 30);
+                mask |= (1 << 30);
             }
         }
         value &= mask;
@@ -2195,6 +2208,55 @@ static void scr_write(CPUARMState *env, const 
ARMCPRegInfo *ri, uint64_t value)
     raw_write(env, ri, value);
 }
 
+static void nsacr_write(CPUARMState *env, const ARMCPRegInfo *ri,
+                      uint64_t value)
+{
+    uint32_t mask = 0;
+
+    /* Pre ARMv8 some bits are RAO or UNK/SBZP */
+    if (!arm_feature(env, ARM_FEATURE_V8)) {
+
+        if (arm_feature(env, ARM_FEATURE_VFP)) {
+            mask |= NSACR_NSASEDIS | NSACR_NSD32DIS;
+
+            if (!arm_feature(env, ARM_FEATURE_NEON)) {
+                /* NSASEDIS are RAO/WI */
+                value |= NSACR_NSASEDIS;
+            }
+
+            /* VFPv3 and upwards with NEON implement 32 double precision
+             * registers (D0-D31).
+             */
+            if (!arm_feature(env, ARM_FEATURE_NEON) ||
+                    !arm_feature(env, ARM_FEATURE_VFP3)) {
+                /* NSD32DIS is RAO/WI if D16-31 are not implemented. */
+                value |= NSACR_NSD32DIS;
+            }
+        }
+
+        /* cpn bits [13:0] */
+        mask = 0x3fff;
+
+        value &= mask;
+    }
+
+    raw_write(env, ri, value);
+}
+
+static uint64_t nsacr_read(CPUARMState *env, const ARMCPRegInfo *ri)
+{
+    uint64_t ret = raw_read(env, ri);
+
+    if (arm_feature(env, ARM_FEATURE_V8)) {
+        if (!arm_feature(env, ARM_FEATURE_EL3) || (
+                arm_el_is_aa64(env, 3) && !is_a64(env) &&
+                arm_current_pl(env) != 3)) {
+            ret = 0x0000C00;
+        }
+    }
+    return ret;
+}
+
 static const ARMCPRegInfo v8_el3_cp_reginfo[] = {
     { .name = "ELR_EL3", .state = ARM_CP_STATE_AA64,
       .type = ARM_CP_NO_MIGRATE,
@@ -2228,6 +2290,10 @@ static const ARMCPRegInfo v7_el3_cp_reginfo[] = {
     { .name = "SCR", .cp = 15, .crn = 1, .crm = 1, .opc1 = 0, .opc2 = 0,
       .access = PL3_RW, .fieldoffset = offsetof(CPUARMState, cp15.scr_el3),
       .resetvalue = 0, },
+    { .name = "NSACR", .cp = 15, .crn = 1, .crm = 1, .opc1 = 0, .opc2 = 2,
+      .access = PL3_RW | PL1_R, .resetvalue = 0,
+      .writefn = nsacr_write, .readfn = nsacr_read,
+      .fieldoffset = offsetof(CPUARMState, cp15.c1_nsacr) },
     REGINFO_SENTINEL
 };
 
-- 
1.8.3.2