ARC: fix build warnings

| arch/arc/mm/tlb.c:914:2: warning: variable length array 'pd0' is used [-Wvla]
| arch/arc/include/asm/cmpxchg.h:95:29: warning: value computed is not used [-Wunused-value]
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/include/asm/cmpxchg.h

@@ -92,8 +92,11 @@ __cmpxchg(volatile void *ptr, unsigned long expected, unsigned long new)
 
 #endif /* CONFIG_ARC_HAS_LLSC */
 
-#define cmpxchg(ptr, o, n) ((typeof(*(ptr)))__cmpxchg((ptr), \
-				(unsigned long)(o), (unsigned long)(n)))
+#define cmpxchg(ptr, o, n) ({				\
+	(typeof(*(ptr)))__cmpxchg((ptr),		\
+				  (unsigned long)(o),	\
+				  (unsigned long)(n));	\
+})
 
 /*
  * atomic_cmpxchg is same as cmpxchg
@@ -198,8 +201,11 @@ static inline unsigned long __xchg(unsigned long val, volatile void *ptr,
 	return __xchg_bad_pointer();
 }
 
-#define xchg(ptr, with) ((typeof(*(ptr)))__xchg((unsigned long)(with), (ptr), \
-						 sizeof(*(ptr))))
+#define xchg(ptr, with) ({				\
+	(typeof(*(ptr)))__xchg((unsigned long)(with),	\
+			       (ptr),			\
+			       sizeof(*(ptr)));		\
+})
 
 #endif /* CONFIG_ARC_PLAT_EZNPS */
 

arch/arc/mm/tlb.c

@@ -911,9 +911,11 @@ void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
 			  struct pt_regs *regs)
 {
 	struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
-	unsigned int pd0[mmu->ways];
 	unsigned long flags;
-	int set;
+	int set, n_ways = mmu->ways;
+
+	n_ways = min(n_ways, 4);
+	BUG_ON(mmu->ways > 4);
 
 	local_irq_save(flags);
 
@@ -921,9 +923,10 @@ void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
 	for (set = 0; set < mmu->sets; set++) {
 
 		int is_valid, way;
+		unsigned int pd0[4];
 
 		/* read out all the ways of current set */
-		for (way = 0, is_valid = 0; way < mmu->ways; way++) {
+		for (way = 0, is_valid = 0; way < n_ways; way++) {
 			write_aux_reg(ARC_REG_TLBINDEX,
 					  SET_WAY_TO_IDX(mmu, set, way));
 			write_aux_reg(ARC_REG_TLBCOMMAND, TLBRead);
@@ -937,14 +940,14 @@ void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
 			continue;
 
 		/* Scan the set for duplicate ways: needs a nested loop */
-		for (way = 0; way < mmu->ways - 1; way++) {
+		for (way = 0; way < n_ways - 1; way++) {
 
 			int n;
 
 			if (!pd0[way])
 				continue;
 
-			for (n = way + 1; n < mmu->ways; n++) {
+			for (n = way + 1; n < n_ways; n++) {
 				if (pd0[way] != pd0[n])
 					continue;