target-arm: add MVBAR support

Use MVBAR register as exception vector base address for
exceptions taken to CPU monitor mode.

Signed-off-by: Sergey Fedorov <s.fedorov@samsung.com>
Signed-off-by: Fabian Aggeler <aggelerf@ethz.ch>
Signed-off-by: Greg Bellows <greg.bellows@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1416242878-876-13-git-send-email-greg.bellows@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 10 insertions, 6 deletions

diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index 12bd6ec048..cdf2dd7349 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -211,6 +211,7 @@ typedef struct CPUARMState {
         uint32_t c9_pminten; /* perf monitor interrupt enables */
         uint64_t mair_el1;
         uint64_t vbar_el[4]; /* vector base address register */
+        uint32_t mvbar; /* (monitor) vector base address register */
         uint32_t c13_fcse; /* FCSE PID.  */
         uint64_t contextidr_el1; /* Context ID.  */
         uint64_t tpidr_el0; /* User RW Thread register.  */
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 0d4948911c..412c465345 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -2356,6 +2356,9 @@ static const ARMCPRegInfo el3_cp_reginfo[] = {
     { .name = "NSACR", .cp = 15, .opc1 = 0, .crn = 1, .crm = 1, .opc2 = 2,
       .access = PL3_W | PL1_R, .resetvalue = 0,
       .fieldoffset = offsetof(CPUARMState, cp15.nsacr) },
+    { .name = "MVBAR", .cp = 15, .opc1 = 0, .crn = 12, .crm = 0, .opc2 = 1,
+      .access = PL3_RW, .writefn = vbar_write, .resetvalue = 0,
+      .fieldoffset = offsetof(CPUARMState, cp15.mvbar) },
     REGINFO_SENTINEL
 };
 
@@ -4272,16 +4275,16 @@ void arm_cpu_do_interrupt(CPUState *cs)
         cpu_abort(cs, "Unhandled exception 0x%x\n", cs->exception_index);
         return; /* Never happens.  Keep compiler happy.  */
     }
-    /* High vectors.  */
-    if (env->cp15.c1_sys & SCTLR_V) {
-        /* when enabled, base address cannot be remapped.  */
+
+    if (new_mode == ARM_CPU_MODE_MON) {
+        addr += env->cp15.mvbar;
+    } else if (env->cp15.c1_sys & SCTLR_V) {
+        /* High vectors. When enabled, base address cannot be remapped. */
         addr += 0xffff0000;
     } else {
         /* ARM v7 architectures provide a vector base address register to remap
          * the interrupt vector table.
-         * This register is only followed in non-monitor mode, and has a secure
-         * and un-secure copy. Since the cpu is always in a un-secure operation
-         * and is never in monitor mode this feature is always active.
+         * This register is only followed in non-monitor mode, and is banked.
          * Note: only bits 31:5 are valid.
          */
         addr += env->cp15.vbar_el[1];