[Qemu-devel] [PATCH v3 1/2] nvic: Handle ARMv6-M SCS reserved registers

[Julia Suvorova <jusual@mail.ru>]

Handle SCS reserved registers listed in ARMv6-M ARM D3.6.1.
All reserved registers are RAZ/WI. ARM_FEATURE_M_MAIN is used for the
checks, because these registers are reserved in ARMv8-M Baseline too.

Signed-off-by: Julia Suvorova <jusual@mail.ru>
---
 hw/intc/armv7m_nvic.c | 51 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 49 insertions(+), 2 deletions(-)

diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c
index aba4510c70..7f71b336bd 100644
--- a/hw/intc/armv7m_nvic.c
+++ b/hw/intc/armv7m_nvic.c
@@ -865,6 +865,9 @@ static uint32_t nvic_readl(NVICState *s, uint32_t offset, MemTxAttrs attrs)
         }
         return val;
     case 0xd10: /* System Control.  */
+        if (!arm_feature(&cpu->env, ARM_FEATURE_V7)) {
+            goto bad_offset;
+        }
         return cpu->env.v7m.scr[attrs.secure];
     case 0xd14: /* Configuration Control.  */
         /* The BFHFNMIGN bit is the only non-banked bit; we
@@ -986,12 +989,21 @@ static uint32_t nvic_readl(NVICState *s, uint32_t offset, MemTxAttrs attrs)
         }
         return val;
     case 0xd2c: /* Hard Fault Status.  */
+        if (!arm_feature(&cpu->env, ARM_FEATURE_M_MAIN)) {
+            goto bad_offset;
+        }
         return cpu->env.v7m.hfsr;
     case 0xd30: /* Debug Fault Status.  */
         return cpu->env.v7m.dfsr;
     case 0xd34: /* MMFAR MemManage Fault Address */
+        if (!arm_feature(&cpu->env, ARM_FEATURE_M_MAIN)) {
+            goto bad_offset;
+        }
         return cpu->env.v7m.mmfar[attrs.secure];
     case 0xd38: /* Bus Fault Address.  */
+        if (!arm_feature(&cpu->env, ARM_FEATURE_M_MAIN)) {
+            goto bad_offset;
+        }
         return cpu->env.v7m.bfar;
     case 0xd3c: /* Aux Fault Status.  */
         /* TODO: Implement fault status registers.  */
@@ -1287,6 +1299,9 @@ static void nvic_writel(NVICState *s, uint32_t offset, uint32_t value,
         }
         break;
     case 0xd10: /* System Control.  */
+        if (!arm_feature(&cpu->env, ARM_FEATURE_V7)) {
+            goto bad_offset;
+        }
         /* We don't implement deep-sleep so these bits are RAZ/WI.
          * The other bits in the register are banked.
          * QEMU's implementation ignores SEVONPEND and SLEEPONEXIT, which
@@ -1388,15 +1403,24 @@ static void nvic_writel(NVICState *s, uint32_t offset, uint32_t value,
         nvic_irq_update(s);
         break;
     case 0xd2c: /* Hard Fault Status.  */
+        if (!arm_feature(&cpu->env, ARM_FEATURE_M_MAIN)) {
+            goto bad_offset;
+        }
         cpu->env.v7m.hfsr &= ~value; /* W1C */
         break;
     case 0xd30: /* Debug Fault Status.  */
         cpu->env.v7m.dfsr &= ~value; /* W1C */
         break;
     case 0xd34: /* Mem Manage Address.  */
+        if (!arm_feature(&cpu->env, ARM_FEATURE_M_MAIN)) {
+            goto bad_offset;
+        }
         cpu->env.v7m.mmfar[attrs.secure] = value;
         return;
     case 0xd38: /* Bus Fault Address.  */
+        if (!arm_feature(&cpu->env, ARM_FEATURE_M_MAIN)) {
+            goto bad_offset;
+        }
         cpu->env.v7m.bfar = value;
         return;
     case 0xd3c: /* Aux Fault Status.  */
@@ -1626,6 +1650,11 @@ static void nvic_writel(NVICState *s, uint32_t offset, uint32_t value,
     case 0xf00: /* Software Triggered Interrupt Register */
     {
         int excnum = (value & 0x1ff) + NVIC_FIRST_IRQ;
+
+        if (!arm_feature(&cpu->env, ARM_FEATURE_M_MAIN)) {
+            goto bad_offset;
+        }
+
         if (excnum < s->num_irq) {
             armv7m_nvic_set_pending(s, excnum, false);
         }
@@ -1775,7 +1804,13 @@ static MemTxResult nvic_sysreg_read(void *opaque, hwaddr addr,
             }
         }
         break;
-    case 0xd18 ... 0xd23: /* System Handler Priority (SHPR1, SHPR2, SHPR3) */
+    case 0xd18: /* System Handler Priority (SHPR1) */
+        if (!arm_feature(&s->cpu->env, ARM_FEATURE_M_MAIN)) {
+            val = 0;
+            break;
+        }
+        /* fall through */
+    case 0xd1c ... 0xd23: /* System Handler Priority (SHPR2, SHPR3) */
         val = 0;
         for (i = 0; i < size; i++) {
             unsigned hdlidx = (offset - 0xd14) + i;
@@ -1788,6 +1823,10 @@ static MemTxResult nvic_sysreg_read(void *opaque, hwaddr addr,
         }
         break;
     case 0xd28 ... 0xd2b: /* Configurable Fault Status (CFSR) */
+        if (!arm_feature(&s->cpu->env, ARM_FEATURE_M_MAIN)) {
+            val = 0;
+            break;
+        };
         /* The BFSR bits [15:8] are shared between security states
          * and we store them in the NS copy
          */
@@ -1882,7 +1921,12 @@ static MemTxResult nvic_sysreg_write(void *opaque, hwaddr addr,
         }
         nvic_irq_update(s);
         return MEMTX_OK;
-    case 0xd18 ... 0xd23: /* System Handler Priority (SHPR1, SHPR2, SHPR3) */
+    case 0xd18: /* System Handler Priority (SHPR1) */
+        if (!arm_feature(&s->cpu->env, ARM_FEATURE_M_MAIN)) {
+            return MEMTX_OK;
+        }
+        /* fall through */
+    case 0xd1c ... 0xd23: /* System Handler Priority (SHPR2, SHPR3) */
         for (i = 0; i < size; i++) {
             unsigned hdlidx = (offset - 0xd14) + i;
             int newprio = extract32(value, i * 8, 8);
@@ -1896,6 +1940,9 @@ static MemTxResult nvic_sysreg_write(void *opaque, hwaddr addr,
         nvic_irq_update(s);
         return MEMTX_OK;
     case 0xd28 ... 0xd2b: /* Configurable Fault Status (CFSR) */
+        if (!arm_feature(&s->cpu->env, ARM_FEATURE_M_MAIN)) {
+            return MEMTX_OK;
+        }
         /* All bits are W1C, so construct 32 bit value with 0s in
          * the parts not written by the access size
          */
-- 
2.17.1