sh: NO_CONTEXT ASID optimizations for SH-4 cache flush.

This optimizes for the cases when a CPU does not yet have a valid ASID
context associated with it, as in this case there is no work for any of
flush_cache_mm()/flush_cache_page()/flush_cache_range() to do. Based on
the the MIPS implementation.

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

diff --git a/arch/sh/mm/cache-sh4.c b/arch/sh/mm/cache-sh4.c
index dfc1d0379479f7a01e9e411d4386bbb1a5846682..92f87a460a81e0c9c970d1877284140216cc804e 100644 (file)
--- a/arch/sh/mm/cache-sh4.c
+++ b/arch/sh/mm/cache-sh4.c
@@ -330,6 +330,9 @@ loop_exit:
  */
 void flush_cache_mm(struct mm_struct *mm)
 {
+       if (cpu_context(smp_processor_id(), mm) == NO_CONTEXT)
+               return;
+
        /*
         * If cache is only 4k-per-way, there are never any 'aliases'.  Since
         * the cache is physically tagged, the data can just be left in there.
@@ -371,6 +374,9 @@ void flush_cache_page(struct vm_area_struct *vma, unsigned long address,
        unsigned long phys = pfn << PAGE_SHIFT;
        unsigned int alias_mask;
 
+       if (cpu_context(smp_processor_id(), vma->vm_mm) == NO_CONTEXT)
+               return;
+
        alias_mask = boot_cpu_data.dcache.alias_mask;
 
        /* We only need to flush D-cache when we have alias */
@@ -413,6 +419,9 @@ void flush_cache_page(struct vm_area_struct *vma, unsigned long address,
 void flush_cache_range(struct vm_area_struct *vma, unsigned long start,
                       unsigned long end)
 {
+       if (cpu_context(smp_processor_id(), vma->vm_mm) == NO_CONTEXT)
+               return;
+
        /*
         * If cache is only 4k-per-way, there are never any 'aliases'.  Since
         * the cache is physically tagged, the data can just be left in there.