introduce two APIs for page attribute

Introduce two APIs for page attribute. flushing tlb/cache in every page
attribute is expensive. AGP gart usually will do a lot of operations to
change a page to uc, new APIs can reduce flush.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: airlied@linux.ie
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 50 insertions, 8 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 65c6e46bf059..2c5c18c2464d 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -752,12 +752,12 @@ static inline int cache_attr(pgprot_t attr)
                 (_PAGE_PAT | _PAGE_PAT_LARGE | _PAGE_PWT | _PAGE_PCD);
 }
 
-static int change_page_attr_set_clr(unsigned long addr, int numpages,
+static int do_change_page_attr_set_clr(unsigned long addr, int numpages,
                                     pgprot_t mask_set, pgprot_t mask_clr,
-                                    int force_split)
+                                    int force_split, int *tlb_flush)
 {
         struct cpa_data cpa;
-        int ret, cache, checkalias;
+        int ret, checkalias;
 
         /*
          * Check, if we are requested to change a not supported
@@ -792,9 +792,22 @@ static int change_page_attr_set_clr(unsigned long addr, int numpages,
         /*
          * Check whether we really changed something:
          */
-        if (!cpa.flushtlb)
-                goto out;
+        *tlb_flush = cpa.flushtlb;
+        cpa_fill_pool(NULL);
+
+        return ret;
+}
+
+static int change_page_attr_set_clr(unsigned long addr, int numpages,
+                                    pgprot_t mask_set, pgprot_t mask_clr,
+                                    int force_split)
+{
+        int cache, flush_cache = 0, ret;
 
+        ret = do_change_page_attr_set_clr(addr, numpages, mask_set, mask_clr,
+                force_split, &flush_cache);
+        if (!flush_cache)
+                goto out;
         /*
          * No need to flush, when we did not set any of the caching
          * attributes:
@@ -811,10 +824,7 @@ static int change_page_attr_set_clr(unsigned long addr, int numpages,
                 cpa_flush_range(addr, numpages, cache);
         else
                 cpa_flush_all(cache);
-
 out:
-        cpa_fill_pool(NULL);
-
         return ret;
 }
 
@@ -852,6 +862,30 @@ int set_memory_uc(unsigned long addr, int numpages)
 }
 EXPORT_SYMBOL(set_memory_uc);
 
+int set_memory_uc_noflush(unsigned long addr, int numpages)
+{
+        int flush;
+        /*
+         * for now UC MINUS. see comments in ioremap_nocache()
+         */
+        if (reserve_memtype(addr, addr + numpages * PAGE_SIZE,
+                            _PAGE_CACHE_UC_MINUS, NULL))
+                return -EINVAL;
+        /*
+         * for now UC MINUS. see comments in ioremap_nocache()
+         */
+        return do_change_page_attr_set_clr(addr, numpages,
+                                    __pgprot(_PAGE_CACHE_UC_MINUS),
+                                        __pgprot(0), 0, &flush);
+}
+EXPORT_SYMBOL(set_memory_uc_noflush);
+
+void set_memory_flush_all(void)
+{
+        cpa_flush_all(1);
+}
+EXPORT_SYMBOL(set_memory_flush_all);
+
 int _set_memory_wc(unsigned long addr, int numpages)
 {
         return change_page_attr_set(addr, numpages,
@@ -926,6 +960,14 @@ int set_pages_uc(struct page *page, int numpages)
 }
 EXPORT_SYMBOL(set_pages_uc);
 
+int set_pages_uc_noflush(struct page *page, int numpages)
+{
+        unsigned long addr = (unsigned long)page_address(page);
+
+        return set_memory_uc_noflush(addr, numpages);
+}
+EXPORT_SYMBOL(set_pages_uc_noflush);
+
 int set_pages_wb(struct page *page, int numpages)
 {
         unsigned long addr = (unsigned long)page_address(page);