[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>

2 files changed, 12 insertions, 6 deletions

diff --git a/arch/sparc64/kernel/setup.c b/arch/sparc64/kernel/setup.c
index c1f34237cdf2..bf1849dd9c49 100644
--- a/arch/sparc64/kernel/setup.c
+++ b/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)) {
-                                tte = pte_val(*ptep);
+                        pte = *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)) {
-                                tte = pte_val(*ptep);
+                        pte = *ptep;
+                        if (pte_present(pte)) {
+                                tte = pte_val(pte);
                                 res = PROM_TRUE;
                         }
                         goto done;
diff --git a/arch/sparc64/kernel/signal32.c b/arch/sparc64/kernel/signal32.c
index aecccd0df1d1..009a86e5ded4 100644
--- a/arch/sparc64/kernel/signal32.c
+++ b/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"