target-arm: A64: Emulate the SMC insn

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 1411718914-6608-10-git-send-email-edgar.iglesias@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target-arm/cpu.h

@@ -53,6 +53,7 @@
 #define EXCP_STREX          10
 #define EXCP_HVC            11   /* HyperVisor Call */
 #define EXCP_HYP_TRAP       12
+#define EXCP_SMC            13   /* Secure Monitor Call */
 
 #define ARMV7M_EXCP_RESET   1
 #define ARMV7M_EXCP_NMI     2

target-arm/helper-a64.c

@@ -478,6 +478,7 @@ void aarch64_cpu_do_interrupt(CPUState *cs)
     case EXCP_SWI:
     case EXCP_HVC:
     case EXCP_HYP_TRAP:
+    case EXCP_SMC:
         env->cp15.esr_el[new_el] = env->exception.syndrome;
         break;
     case EXCP_IRQ:

target-arm/helper.c

@@ -3784,6 +3784,9 @@ unsigned int arm_excp_target_el(CPUState *cs, unsigned int excp_idx)
     case EXCP_HYP_TRAP:
         target_el = 2;
         break;
+    case EXCP_SMC:
+        target_el = 3;
+        break;
     default:
         target_el = MAX(cur_el, 1);
         break;

target-arm/helper.h

@@ -51,6 +51,7 @@ DEF_HELPER_3(exception_with_syndrome, void, env, i32, i32)
 DEF_HELPER_1(wfi, void, env)
 DEF_HELPER_1(wfe, void, env)
 DEF_HELPER_1(pre_hvc, void, env)
+DEF_HELPER_2(pre_smc, void, env, i32)
 
 DEF_HELPER_3(cpsr_write, void, env, i32, i32)
 DEF_HELPER_1(cpsr_read, i32, env)

target-arm/internals.h

@@ -55,6 +55,7 @@ static const char * const excnames[] = {
     [EXCP_STREX] = "QEMU intercept of STREX",
     [EXCP_HVC] = "Hypervisor Call",
     [EXCP_HYP_TRAP] = "Hypervisor Trap",
+    [EXCP_SMC] = "Secure Monitor Call",
 };
 
 static inline void arm_log_exception(int idx)
@@ -222,6 +223,11 @@ static inline uint32_t syn_aa64_hvc(uint32_t imm16)
     return (EC_AA64_HVC << ARM_EL_EC_SHIFT) | ARM_EL_IL | (imm16 & 0xffff);
 }
 
+static inline uint32_t syn_aa64_smc(uint32_t imm16)
+{
+    return (EC_AA64_SMC << ARM_EL_EC_SHIFT) | ARM_EL_IL | (imm16 & 0xffff);
+}
+
 static inline uint32_t syn_aa32_svc(uint32_t imm16, bool is_thumb)
 {
     return (EC_AA32_SVC << ARM_EL_EC_SHIFT) | (imm16 & 0xffff)

target-arm/op_helper.c

@@ -416,6 +416,32 @@ void HELPER(pre_hvc)(CPUARMState *env)
     }
 }
 
+void HELPER(pre_smc)(CPUARMState *env, uint32_t syndrome)
+{
+    int cur_el = arm_current_pl(env);
+    /* FIXME: Use real secure state.  */
+    bool secure = false;
+    bool smd = env->cp15.scr_el3 & SCR_SMD;
+    /* On ARMv8 AArch32, SMD only applies to NS state.
+     * On ARMv7 SMD only applies to NS state and only if EL2 is available.
+     * For ARMv7 non EL2, we force SMD to zero so we don't need to re-check
+     * the EL2 condition here.
+     */
+    bool undef = is_a64(env) ? smd : (!secure && smd);
+
+    /* In NS EL1, HCR controlled routing to EL2 has priority over SMD.  */
+    if (!secure && cur_el == 1 && (env->cp15.hcr_el2 & HCR_TSC)) {
+        env->exception.syndrome = syndrome;
+        raise_exception(env, EXCP_HYP_TRAP);
+    }
+
+    /* We've already checked that EL3 exists at translation time.  */
+    if (undef) {
+        env->exception.syndrome = syn_uncategorized();
+        raise_exception(env, EXCP_UDEF);
+    }
+}
+
 void HELPER(exception_return)(CPUARMState *env)
 {
     int cur_el = arm_current_pl(env);

target-arm/translate-a64.c

@@ -1470,6 +1470,7 @@ static void disas_exc(DisasContext *s, uint32_t insn)
     int opc = extract32(insn, 21, 3);
     int op2_ll = extract32(insn, 0, 5);
     int imm16 = extract32(insn, 5, 16);
+    TCGv_i32 tmp;
 
     switch (opc) {
     case 0:
@@ -1496,6 +1497,18 @@ static void disas_exc(DisasContext *s, uint32_t insn)
             gen_ss_advance(s);
             gen_exception_insn(s, 0, EXCP_HVC, syn_aa64_hvc(imm16));
             break;
+        case 3:
+            if (!arm_dc_feature(s, ARM_FEATURE_EL3) || s->current_pl == 0) {
+                unallocated_encoding(s);
+                break;
+            }
+            gen_a64_set_pc_im(s->pc - 4);
+            tmp = tcg_const_i32(syn_aa64_smc(imm16));
+            gen_helper_pre_smc(cpu_env, tmp);
+            tcg_temp_free_i32(tmp);
+            gen_ss_advance(s);
+            gen_exception_insn(s, 0, EXCP_SMC, syn_aa64_smc(imm16));
+            break;
         default:
             unallocated_encoding(s);
             break;