ARM: Implement a stub of CPACR.

This register controls access to the coprocessors. This doesn't actually
implement it, it allows writes which don't turn anything off. In other words,
it allows the simulated program to ask for what it already has.

1 files changed, 16 insertions, 1 deletions

diff --git a/src/arch/arm/isa.hh b/src/arch/arm/isa.hh
index 67ee56537..dd80976bb 100644
--- a/src/arch/arm/isa.hh
+++ b/src/arch/arm/isa.hh
@@ -106,6 +106,12 @@ namespace ArmISA
             sctlr.rao4 = 1;
             miscRegs[MISCREG_SCTLR] = sctlr;
 
+            /*
+             * Technically this should be 0, but we don't support those
+             * settings.
+             */
+            miscRegs[MISCREG_CPACR] = 0x0fffffff;
+
             //XXX We need to initialize the rest of the state.
         }
 
@@ -200,6 +206,7 @@ namespace ArmISA
         void
         setMiscReg(int misc_reg, const MiscReg &val, ThreadContext *tc)
         {
+            MiscReg newVal = val;
             if (misc_reg == MISCREG_CPSR) {
                 updateRegMap(val);
                 CPSR cpsr = val;
@@ -216,7 +223,15 @@ namespace ArmISA
                 panic("Unimplemented CP15 register %s wrote with %#x.\n",
                       miscRegName[misc_reg], val);
             }
-            return setMiscRegNoEffect(misc_reg, val);
+            switch (misc_reg) {
+              case MISCREG_CPACR:
+                newVal = bits(val, 27, 0);
+                if (newVal != 0x0fffffff) {
+                    panic("Disabling coprocessors isn't implemented.\n");
+                }
+                break;
+            }
+            return setMiscRegNoEffect(misc_reg, newVal);
         }
 
         int