[SPARC64] mm: don't re-evaluate *ptep

sparc64 prom_callback and new_setup_frame32 each operates on a user page
table without holding lock, and no doubt they've good reason.  But I'd
feel more confident if they were to do a "pte = *ptep" and then operate
on pte, rather than re-evaluating *ptep.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc64/kernel/setup.c

@@ -154,6 +154,7 @@ int prom_callback(long *args)
 			pud_t *pudp;
 			pmd_t *pmdp;
 			pte_t *ptep;
+			pte_t pte;
 
 			for_each_process(p) {
 				mm = p->mm;
@@ -178,8 +179,9 @@ int prom_callback(long *args)
 			 * being called from inside OBP.
 			 */
 			ptep = pte_offset_map(pmdp, va);
-			if (pte_present(*ptep)) {
+			pte = *ptep;
-				tte = pte_val(*ptep);
+			if (pte_present(pte)) {
+				tte = pte_val(pte);
 				res = PROM_TRUE;
 			}
 			pte_unmap(ptep);
@@ -218,6 +220,7 @@ int prom_callback(long *args)
 			pud_t *pudp;
 			pmd_t *pmdp;
 			pte_t *ptep;
+			pte_t pte;
 			int error;
 
 			if ((va >= LOW_OBP_ADDRESS) && (va < HI_OBP_ADDRESS)) {
@@ -240,8 +243,9 @@ int prom_callback(long *args)
 			 * being called from inside OBP.
 			 */
 			ptep = pte_offset_kernel(pmdp, va);
-			if (pte_present(*ptep)) {
+			pte = *ptep;
-				tte = pte_val(*ptep);
+			if (pte_present(pte)) {
+				tte = pte_val(pte);
 				res = PROM_TRUE;
 			}
 			goto done;

arch/sparc64/kernel/signal32.c

@@ -863,6 +863,7 @@ static void new_setup_frame32(struct k_sigaction *ka, struct pt_regs *regs,
 		pud_t *pudp = pud_offset(pgdp, address);
 		pmd_t *pmdp = pmd_offset(pudp, address);
 		pte_t *ptep;
+		pte_t pte;
 
 		regs->u_regs[UREG_I7] = (unsigned long) (&(sf->insns[0]) - 2);
 	
@@ -873,9 +874,10 @@ static void new_setup_frame32(struct k_sigaction *ka, struct pt_regs *regs,
 
 		preempt_disable();
 		ptep = pte_offset_map(pmdp, address);
-		if (pte_present(*ptep)) {
+		pte = *ptep;
+		if (pte_present(pte)) {
 			unsigned long page = (unsigned long)
-				page_address(pte_page(*ptep));
+				page_address(pte_page(pte));
 
 			wmb();
 			__asm__ __volatile__("flush	%0 + %1"