armv7m: Report no-coprocessor faults correctly

For v7M attempts to access a nonexistent coprocessor are reported
differently from plain undefined instructions (as UsageFaults of type
NOCP rather than type UNDEFINSTR).  Split them out into a new
EXCP_NOCP so we can report the FSR value correctly.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 1485285380-10565-8-git-send-email-peter.maydell@linaro.org

diff --git a/linux-user/main.c b/linux-user/main.c
index f5c85574f987913fa22d2207f045ba9363efda68..30049581ef8dee8dddea23713492ee0f9fd1ef3e 100644 (file)
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -573,6 +573,7 @@ void cpu_loop(CPUARMState *env)
 
         switch(trapnr) {
         case EXCP_UDEF:
+        case EXCP_NOCP:
             {
                 TaskState *ts = cs->opaque;
                 uint32_t opcode;

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 4b062d20f31e9dda13065c695cd8fcfd47f7dc8b..39bff86dafac689e9c476773ad72891850de97a1 100644 (file)
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -53,6 +53,7 @@
 #define EXCP_VIRQ           14
 #define EXCP_VFIQ           15
 #define EXCP_SEMIHOST       16   /* semihosting call */
+#define EXCP_NOCP           17   /* v7M NOCP UsageFault */
 
 #define ARMV7M_EXCP_RESET   1
 #define ARMV7M_EXCP_NMI     2

diff --git a/target/arm/helper.c b/target/arm/helper.c
index e6b1c36a95595c1432f8c887bfc61dd320052ce9..c23df1b133499ba5a955442b5e22104db7d31176 100644 (file)
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -6074,6 +6074,10 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs)
         armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE);
         env->v7m.cfsr |= R_V7M_CFSR_UNDEFINSTR_MASK;
         return;
+    case EXCP_NOCP:
+        armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE);
+        env->v7m.cfsr |= R_V7M_CFSR_NOCP_MASK;
+        return;
     case EXCP_SWI:
         /* The PC already points to the next instruction.  */
         armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SVC);

diff --git a/target/arm/translate.c b/target/arm/translate.c
index a7c2abeffef42cb7ea2396613b139213b008acfa..493c627bcf990fecffe039ecf54a4fe0efdcf577 100644 (file)
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -10217,6 +10217,14 @@ static int disas_thumb2_insn(CPUARMState *env, DisasContext *s, uint16_t insn_hw
         break;
     case 6: case 7: case 14: case 15:
         /* Coprocessor.  */
+        if (arm_dc_feature(s, ARM_FEATURE_M)) {
+            /* We don't currently implement M profile FP support,
+             * so this entire space should give a NOCP fault.
+             */
+            gen_exception_insn(s, 4, EXCP_NOCP, syn_uncategorized(),
+                               default_exception_el(s));
+            break;
+        }
         if (((insn >> 24) & 3) == 3) {
             /* Translate into the equivalent ARM encoding.  */
             insn = (insn & 0xe2ffffff) | ((insn & (1 << 28)) >> 4) | (1 << 28);