[Qemu-devel] [PATCH v5 06/33] target-arm: A32: Emulate the SMC instruction

[Greg Bellows]

From: Fabian Aggeler <address@hidden>

Implements SMC instruction in Aarch32 using the A32 syndrome. When executing
SMC instruction from monitor CPU mode SCR.NS bit is reset.

Signed-off-by: Sergey Fedorov <address@hidden>
Signed-off-by: Fabian Aggeler <address@hidden>
Signed-off-by: Greg Bellows <address@hidden>

----------
v4 -> v5
- Merge pre_smc upstream changes and incorporated ss_advance
---
 target-arm/helper.c    | 11 +++++++++++
 target-arm/internals.h |  7 ++++++-
 target-arm/op_helper.c |  3 +--
 target-arm/translate.c | 39 +++++++++++++++++++++++++++++----------
 4 files changed, 47 insertions(+), 13 deletions(-)

diff --git a/target-arm/helper.c b/target-arm/helper.c
index 2381e6f..7f3f049 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -4090,6 +4090,12 @@ void arm_cpu_do_interrupt(CPUState *cs)
         mask = CPSR_A | CPSR_I | CPSR_F;
         offset = 4;
         break;
+    case EXCP_SMC:
+        new_mode = ARM_CPU_MODE_MON;
+        addr = 0x08;
+        mask = CPSR_A | CPSR_I | CPSR_F;
+        offset = 0;
+        break;
     default:
         cpu_abort(cs, "Unhandled exception 0x%x\n", cs->exception_index);
         return; /* Never happens.  Keep compiler happy.  */
@@ -4108,6 +4114,11 @@ void arm_cpu_do_interrupt(CPUState *cs)
          */
         addr += env->cp15.vbar_el[1];
     }
+
+    if ((env->uncached_cpsr & CPSR_M) == ARM_CPU_MODE_MON) {
+        env->cp15.scr_el3 &= ~SCR_NS;
+    }
+
     switch_mode (env, new_mode);
     /* For exceptions taken to AArch32 we must clear the SS bit in both
      * PSTATE and in the old-state value we save to SPSR_<mode>, so zero it 
now.
diff --git a/target-arm/internals.h b/target-arm/internals.h
index fd69a83..43a2e7d 100644
--- a/target-arm/internals.h
+++ b/target-arm/internals.h
@@ -236,7 +236,12 @@ static inline uint32_t syn_aa32_svc(uint32_t imm16, bool 
is_thumb)
         | (is_thumb ? 0 : ARM_EL_IL);
 }
 
-static inline uint32_t syn_aa64_bkpt(uint32_t imm16)
+static inline uint32_t syn_aa32_smc(void)
+{
+    return (EC_AA32_SMC << ARM_EL_EC_SHIFT) | ARM_EL_IL;
+}
+
+static inline uint32_t syn_aa64_bkpt(uint16_t imm16)
 {
     return (EC_AA64_BKPT << ARM_EL_EC_SHIFT) | ARM_EL_IL | (imm16 & 0xffff);
 }
diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
index 0809d63..8ed8ee9 100644
--- a/target-arm/op_helper.c
+++ b/target-arm/op_helper.c
@@ -419,8 +419,7 @@ void HELPER(pre_hvc)(CPUARMState *env)
 void HELPER(pre_smc)(CPUARMState *env, uint32_t syndrome)
 {
     int cur_el = arm_current_el(env);
-    /* FIXME: Use real secure state.  */
-    bool secure = false;
+    bool secure = arm_is_secure(env);;
     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.
diff --git a/target-arm/translate.c b/target-arm/translate.c
index f6404be..3f3ddfb 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -7872,15 +7872,27 @@ static void disas_arm_insn(CPUARMState * env, 
DisasContext *s)
         case 7:
         {
             int imm16 = extract32(insn, 0, 4) | (extract32(insn, 8, 12) << 4);
-            /* SMC instruction (op1 == 3)
-               and undefined instructions (op1 == 0 || op1 == 2)
-               will trap */
-            if (op1 != 1) {
+            if (op1 == 1) {
+                /* bkpt */
+                ARCH(5);
+                gen_exception_insn(s, 4, EXCP_BKPT,
+                        syn_aa32_bkpt(imm16, false));
+            } else if (op1 == 3) {
+                /* smi/smc */
+                if (!arm_dc_feature(s, ARM_FEATURE_EL3) ||
+                        s->current_pl == 0) {
+                    goto illegal_op;
+                }
+                gen_set_pc_im(s, s->pc);
+                tmp = tcg_const_i32(syn_aa32_smc());
+                gen_helper_pre_smc(cpu_env, tmp);
+                tcg_temp_free_i32(tmp);
+                gen_ss_advance(s);
+                gen_exception_insn(s, 0, EXCP_SMC, syn_aa32_smc());
+                break;
+            } else {
                 goto illegal_op;
             }
-            /* bkpt */
-            ARCH(5);
-            gen_exception_insn(s, 4, EXCP_BKPT, syn_aa32_bkpt(imm16, false));
             break;
         }
         case 0x8: /* signed multiply */
@@ -9711,9 +9723,16 @@ static int disas_thumb2_insn(CPUARMState *env, 
DisasContext *s, uint16_t insn_hw
 
                 if (insn & (1 << 26)) {
                     /* Secure monitor call (v6Z) */
-                    qemu_log_mask(LOG_UNIMP,
-                                  "arm: unimplemented secure monitor call\n");
-                    goto illegal_op; /* not implemented.  */
+                    if (!arm_dc_feature(s, ARM_FEATURE_EL3) ||
+                            s->current_pl == 0) {
+                        goto illegal_op;
+                    }
+                    gen_set_pc_im(s, s->pc);
+                    tmp = tcg_const_i32(syn_aa32_smc());
+                    gen_helper_pre_smc(cpu_env, tmp);
+                    tcg_temp_free_i32(tmp);
+                    gen_ss_advance(s);
+                    gen_exception_insn(s, 0, EXCP_SMC, syn_aa32_smc());
                 } else {
                     op = (insn >> 20) & 7;
                     switch (op) {
-- 
1.8.3.2