[Qemu-devel] [PATCH v2 09/26] armv7m: implement CFSR, HFSR, BFAR, and MMFAR

[Michael Davidsaver <mdavidsaver@gmail.com>]

Add the Configurable, HardFault, BusFault and MemManage Status registers.
Note undefined instructions, violations, and escalations.

No BusFaults are raised at this point.
---
 hw/intc/armv7m_nvic.c | 28 ++++++++++++++++++++++------
 target-arm/cpu.h      |  4 ++++
 target-arm/helper.c   |  3 +++
 target-arm/machine.c  |  8 ++++++--
 4 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c
index ca9bd4c..619c320 100644
--- a/hw/intc/armv7m_nvic.c
+++ b/hw/intc/armv7m_nvic.c
@@ -333,6 +333,7 @@ void armv7m_nvic_set_pending(void *opaque, int irq)
             irq = ARMV7M_EXCP_HARD;
             vec = &s->vectors[irq];
 
+            s->cpu->env.v7m.hfsr |= 1<<30; /* FORCED */
             DPRINTF(0, "Escalate %d to HardFault\n", oldirq);
         }
     }
@@ -548,16 +549,20 @@ static uint32_t nvic_readl(NVICState *s, uint32_t offset)
         if (s->vectors[ARMV7M_EXCP_USAGE].enabled) val |= (1 << 18);
         return val;
     case 0xd28: /* Configurable Fault Status.  */
-        /* TODO: Implement Fault Status.  */
-        qemu_log_mask(LOG_UNIMP, "Configurable Fault Status unimplemented\n");
-        return 0;
+        return cpu->env.v7m.cfsr;
     case 0xd2c: /* Hard Fault Status.  */
+        return cpu->env.v7m.hfsr;
     case 0xd30: /* Debug Fault Status.  */
-    case 0xd34: /* Mem Manage Address.  */
+        qemu_log_mask(LOG_UNIMP, "Debug Fault status register unimplemented\n");
+        return 0;
+    case 0xd34: /* MMFAR MemManage Fault Address */
+        return cpu->env.v7m.mmfar;
     case 0xd38: /* Bus Fault Address.  */
+        return cpu->env.v7m.bfar;
     case 0xd3c: /* Aux Fault Status.  */
         /* TODO: Implement fault status registers.  */
-        qemu_log_mask(LOG_UNIMP, "Fault status registers unimplemented\n");
+        qemu_log_mask(LOG_UNIMP,
+                      "Aux Fault status registers unimplemented\n");
         return 0;
     case 0xd40: /* PFR0.  */
         return 0x00000030;
@@ -690,13 +695,24 @@ static void nvic_writel(NVICState *s, uint32_t offset, uint32_t value)
          */
         break;
     case 0xd28: /* Configurable Fault Status.  */
+        cpu->env.v7m.cfsr &= ~value; /* W1C */
+        break;
     case 0xd2c: /* Hard Fault Status.  */
+        cpu->env.v7m.hfsr &= ~value; /* W1C */
+        break;
     case 0xd30: /* Debug Fault Status.  */
+        qemu_log_mask(LOG_UNIMP,
+                      "NVIC: debug fault status register unimplemented\n");
+        break;
     case 0xd34: /* Mem Manage Address.  */
+        cpu->env.v7m.mmfar = value;
+        return;
     case 0xd38: /* Bus Fault Address.  */
+        cpu->env.v7m.bfar = value;
+        return;
     case 0xd3c: /* Aux Fault Status.  */
         qemu_log_mask(LOG_UNIMP,
-                      "NVIC: fault status registers unimplemented\n");
+                      "NVIC: Aux fault status registers unimplemented\n");
         break;
     case 0xf00: /* Software Triggered Interrupt Register */
         if ((value & 0x1ff) < NVIC_MAX_IRQ) {
diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index 4b7f78e..4262efc 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -396,6 +396,10 @@ typedef struct CPUARMState {
         uint32_t vecbase;
         uint32_t basepri;
         uint32_t control;
+        uint32_t cfsr; /* Configurable Fault Status */
+        uint32_t hfsr; /* HardFault Status */
+        uint32_t mmfar; /* MemManage Fault Address */
+        uint32_t bfar; /* BusFault Address */
         int current_sp;
         int exception;
         int exception_prio;
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 4490b74..d1ca011 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -5454,6 +5454,7 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs)
     switch (cs->exception_index) {
     case EXCP_UDEF:
         armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE);
+        env->v7m.cfsr |= 1<<16; /* UNDEFINSTR */
         break;
     case EXCP_SWI:
         /* The PC already points to the next instruction.  */
@@ -5465,6 +5466,8 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs)
          * should set the MMFAR, etc from exception.fsr and exception.vaddress.
          */
         armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_MEM);
+        env->v7m.mmfar = env->exception.vaddress;
+        env->v7m.cfsr = (1<<1)|(1<<7); /* DACCVIOL and MMARVALID */
         break;
     case EXCP_BKPT:
         if (semihosting_enabled()) {
diff --git a/target-arm/machine.c b/target-arm/machine.c
index 36a0d15..14a4882 100644
--- a/target-arm/machine.c
+++ b/target-arm/machine.c
@@ -92,14 +92,18 @@ static bool m_needed(void *opaque)
 
 static const VMStateDescription vmstate_m = {
     .name = "cpu/m",
-    .version_id = 1,
-    .minimum_version_id = 1,
+    .version_id = 2,
+    .minimum_version_id = 2,
     .needed = m_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(env.v7m.other_sp, ARMCPU),
         VMSTATE_UINT32(env.v7m.vecbase, ARMCPU),
         VMSTATE_UINT32(env.v7m.basepri, ARMCPU),
         VMSTATE_UINT32(env.v7m.control, ARMCPU),
+        VMSTATE_UINT32(env.v7m.cfsr, ARMCPU),
+        VMSTATE_UINT32(env.v7m.hfsr, ARMCPU),
+        VMSTATE_UINT32(env.v7m.mmfar, ARMCPU),
+        VMSTATE_UINT32(env.v7m.bfar, ARMCPU),
         VMSTATE_INT32(env.v7m.current_sp, ARMCPU),
         VMSTATE_INT32(env.v7m.exception, ARMCPU),
         VMSTATE_END_OF_LIST()
-- 
2.1.4