target/openrisc: Implement EVBAR register

Exception Vector Base Address Register (EVBAR) - This optional register
can be used to apply an offset to the exception vector addresses.

The significant bits (31-12) of the vector offset address for each
exception depend on the setting of the Supervision Register (SR)'s EPH
bit and the Exception Vector Base Address Register (EVBAR).

Its presence is indicated by the EVBARP bit in the CPU Configuration
Register (CPUCFGR).

Signed-off-by: Tim 'mithro' Ansell <mithro@mithis.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

diff --git a/target/openrisc/cpu.c b/target/openrisc/cpu.c
index 7fd2b9a2167f37d672bcbbbe42f8a78db43a3723..1524ed981ae917c922d0505944b4470005bd7721 100644 (file)
--- a/target/openrisc/cpu.c
+++ b/target/openrisc/cpu.c
@@ -134,6 +134,7 @@ static void or1200_initfn(Object *obj)
 
     set_feature(cpu, OPENRISC_FEATURE_OB32S);
     set_feature(cpu, OPENRISC_FEATURE_OF32S);
+    set_feature(cpu, OPENRISC_FEATURE_EVBAR);
 }
 
 static void openrisc_any_initfn(Object *obj)
@@ -141,6 +142,7 @@ static void openrisc_any_initfn(Object *obj)
     OpenRISCCPU *cpu = OPENRISC_CPU(obj);
 
     set_feature(cpu, OPENRISC_FEATURE_OB32S);
+    set_feature(cpu, OPENRISC_FEATURE_EVBAR);
 }
 
 typedef struct OpenRISCCPUInfo {

diff --git a/target/openrisc/cpu.h b/target/openrisc/cpu.h
index 418a0e6960c7236cf730e15cf616b92c6fbd2c9b..1958b72718cce0291abed9610370f193e8ee402d 100644 (file)
--- a/target/openrisc/cpu.h
+++ b/target/openrisc/cpu.h
@@ -111,6 +111,11 @@ enum {
     CPUCFGR_OF32S = (1 << 7),
     CPUCFGR_OF64S = (1 << 8),
     CPUCFGR_OV64S = (1 << 9),
+    /* CPUCFGR_ND = (1 << 10), */
+    /* CPUCFGR_AVRP = (1 << 11), */
+    CPUCFGR_EVBARP = (1 << 12),
+    /* CPUCFGR_ISRP = (1 << 13), */
+    /* CPUCFGR_AECSRP = (1 << 14), */
 };
 
 /* DMMU configure register */
@@ -200,6 +205,7 @@ enum {
     OPENRISC_FEATURE_OF32S = (1 << 7),
     OPENRISC_FEATURE_OF64S = (1 << 8),
     OPENRISC_FEATURE_OV64S = (1 << 9),
+    OPENRISC_FEATURE_EVBAR = (1 << 12),
 };
 
 /* Tick Timer Mode Register */
@@ -289,6 +295,7 @@ typedef struct CPUOpenRISCState {
     uint32_t dmmucfgr;        /* DMMU configure register */
     uint32_t immucfgr;        /* IMMU configure register */
     uint32_t esr;             /* Exception supervisor register */
+    uint32_t evbar;           /* Exception vector base address register */
     uint32_t fpcsr;           /* Float register */
     float_status fp_status;
 

diff --git a/target/openrisc/interrupt.c b/target/openrisc/interrupt.c
index a2eec6fb32928671e753e289421cd123c236228d..78f0ba942192c9c268943f7e4ee5f0226db210cf 100644 (file)
--- a/target/openrisc/interrupt.c
+++ b/target/openrisc/interrupt.c
@@ -65,7 +65,11 @@ void openrisc_cpu_do_interrupt(CPUState *cs)
     env->lock_addr = -1;
 
     if (cs->exception_index > 0 && cs->exception_index < EXCP_NR) {
-        env->pc = (cs->exception_index << 8);
+        hwaddr vect_pc = cs->exception_index << 8;
+        if (env->cpucfgr & CPUCFGR_EVBARP) {
+            vect_pc |= env->evbar;
+        }
+        env->pc = vect_pc;
     } else {
         cpu_abort(cs, "Unhandled exception 0x%x\n", cs->exception_index);
     }

diff --git a/target/openrisc/sys_helper.c b/target/openrisc/sys_helper.c
index 60c31936562f03330a1548a51d87a11dfb4f5dfa..6ba816249b39d7e3fd39349659bdef8d002c013c 100644 (file)
--- a/target/openrisc/sys_helper.c
+++ b/target/openrisc/sys_helper.c
@@ -39,6 +39,10 @@ void HELPER(mtspr)(CPUOpenRISCState *env,
         env->vr = rb;
         break;
 
+    case TO_SPR(0, 11): /* EVBAR */
+        env->evbar = rb;
+        break;
+
     case TO_SPR(0, 16): /* NPC */
         cpu_restore_state(cs, GETPC());
         /* ??? Mirror or1ksim in not trashing delayed branch state
@@ -206,6 +210,9 @@ target_ulong HELPER(mfspr)(CPUOpenRISCState *env,
     case TO_SPR(0, 4): /* IMMUCFGR */
         return env->immucfgr;
 
+    case TO_SPR(0, 11): /* EVBAR */
+        return env->evbar;
+
     case TO_SPR(0, 16): /* NPC (equals PC) */
         cpu_restore_state(cs, GETPC());
         return env->pc;