sh: TLB fast path optimizations for load/store exceptions.

This only bothers with the TLB entry flush in the case of the initial
page write exception, as it is unecessary in the case of the load/store
exceptions.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 13 insertions, 13 deletions

diff --git a/arch/sh/mm/fault_32.c b/arch/sh/mm/fault_32.c
index 41840647f65f..f1c93c880ed4 100644
--- a/arch/sh/mm/fault_32.c
+++ b/arch/sh/mm/fault_32.c
@@ -327,7 +327,6 @@ handle_tlbmiss(struct pt_regs *regs, unsigned long writeaccess,
         pmd_t *pmd;
         pte_t *pte;
         pte_t entry;
-        int ret = 1;
 
         /*
          * We don't take page faults for P1, P2, and parts of P4, these
@@ -338,40 +337,41 @@ handle_tlbmiss(struct pt_regs *regs, unsigned long writeaccess,
                 pgd = pgd_offset_k(address);
         } else {
                 if (unlikely(address >= TASK_SIZE || !current->mm))
-                        goto out;
+                        return 1;
 
                 pgd = pgd_offset(current->mm, address);
         }
 
         pud = pud_offset(pgd, address);
         if (pud_none_or_clear_bad(pud))
-                goto out;
+                return 1;
         pmd = pmd_offset(pud, address);
         if (pmd_none_or_clear_bad(pmd))
-                goto out;
+                return 1;
         pte = pte_offset_kernel(pmd, address);
         entry = *pte;
         if (unlikely(pte_none(entry) || pte_not_present(entry)))
-                goto out;
+                return 1;
         if (unlikely(writeaccess && !pte_write(entry)))
-                goto out;
+                return 1;
 
         if (writeaccess)
                 entry = pte_mkdirty(entry);
         entry = pte_mkyoung(entry);
 
+        set_pte(pte, entry);
+
 #if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SMP)
         /*
-         * ITLB is not affected by "ldtlb" instruction.
-         * So, we need to flush the entry by ourselves.
+         * SH-4 does not set MMUCR.RC to the corresponding TLB entry in
+         * the case of an initial page write exception, so we need to
+         * flush it in order to avoid potential TLB entry duplication.
          */
-        local_flush_tlb_one(get_asid(), address & PAGE_MASK);
+        if (writeaccess == 2)
+                local_flush_tlb_one(get_asid(), address & PAGE_MASK);
 #endif
 
-        set_pte(pte, entry);
         update_mmu_cache(NULL, address, entry);
 
-        ret = 0;
-out:
-        return ret;
+        return 0;
 }