sh: Kill off UTLB flush in fast-path.

The __do_page_fault() fast-path contains a UTLB flush in order to
force an ITLB reload, this isn't needed in practice as the ITLB is
auto-reloaded from the UTLB anyways, which is already displaced by
the manual 'ldtlb' in the update_mmu_cache() path.

This provides a measurable speed up in the TLB miss fast-path.

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

diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
index f33cedb..c56a5fa 100644 (file)
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -304,14 +304,6 @@ asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs,
                entry = pte_mkdirty(entry);
        entry = pte_mkyoung(entry);
 
-#ifdef CONFIG_CPU_SH4
-       /*
-        * ITLB is not affected by "ldtlb" instruction.
-        * So, we need to flush the entry by ourselves.
-        */
-       local_flush_tlb_one(get_asid(), address & PAGE_MASK);
-#endif
-
        set_pte(pte, entry);
        update_mmu_cache(NULL, address, entry);
        ret = 0;