hw/intc/armv7m_nvic: Fix ICSR PENDNMISET/CLR handling

The PENDNMISET/CLR bits in the ICSR should be RAZ/WI from
NonSecure state if the AIRCR.BFHFNMINS bit is zero. We had
misimplemented this as making the bits RAZ/WI from both
Secure and NonSecure states. Fix this bug by checking
attrs.secure so that Secure code can pend and unpend NMIs.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180209165810.6668-3-peter.maydell@linaro.org

hw/intc/armv7m_nvic.c

@@ -830,8 +830,8 @@ static uint32_t nvic_readl(NVICState *s, uint32_t offset, MemTxAttrs attrs)
             }
         }
         /* NMIPENDSET */
-        if ((cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) &&
-            s->vectors[ARMV7M_EXCP_NMI].pending) {
+        if ((attrs.secure || (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK))
+            && s->vectors[ARMV7M_EXCP_NMI].pending) {
             val |= (1 << 31);
         }
         /* ISRPREEMPT: RES0 when halting debug not implemented */
@@ -1193,7 +1193,7 @@ static void nvic_writel(NVICState *s, uint32_t offset, uint32_t value,
         break;
     }
     case 0xd04: /* Interrupt Control State (ICSR) */
-        if (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) {
+        if (attrs.secure || cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) {
             if (value & (1 << 31)) {
                 armv7m_nvic_set_pending(s, ARMV7M_EXCP_NMI, false);
             } else if (value & (1 << 30) &&