x86: fix clflush_page_range logic

only present ptes must be flushed.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 24 insertions, 7 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index bbfc8e2466ab..97ec9e7d29d9 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -26,7 +26,6 @@ within(unsigned long addr, unsigned long start, unsigned long end)
  * Flushing functions
  */
 
-
 /**
  * clflush_cache_range - flush a cache range with clflush
  * @addr:       virtual start address
@@ -35,13 +34,19 @@ within(unsigned long addr, unsigned long start, unsigned long end)
  * clflush is an unordered instruction which needs fencing with mfence
  * to avoid ordering issues.
  */
-void clflush_cache_range(void *addr, int size)
+void clflush_cache_range(void *vaddr, unsigned int size)
 {
-        int i;
+        void *vend = vaddr + size - 1;
 
         mb();
-        for (i = 0; i < size; i += boot_cpu_data.x86_clflush_size)
-                clflush(addr+i);
+
+        for (; vaddr < vend; vaddr += boot_cpu_data.x86_clflush_size)
+                clflush(vaddr);
+        /*
+         * Flush any possible final partial cacheline:
+         */
+        clflush(vend);
+
         mb();
 }
 
@@ -74,9 +79,13 @@ static void __cpa_flush_range(void *arg)
         __flush_tlb_all();
 }
 
-static void cpa_flush_range(unsigned long addr, int numpages)
+static void cpa_flush_range(unsigned long start, int numpages)
 {
+        unsigned int i, level;
+        unsigned long addr;
+
         BUG_ON(irqs_disabled());
+        WARN_ON(PAGE_ALIGN(start) != start);
 
         on_each_cpu(__cpa_flush_range, NULL, 1, 1);
 
@@ -86,7 +95,15 @@ static void cpa_flush_range(unsigned long addr, int numpages)
          * will cause all other CPUs to flush the same
          * cachelines:
          */
-        clflush_cache_range((void *) addr, numpages * PAGE_SIZE);
+        for (i = 0, addr = start; i < numpages; i++, addr += PAGE_SIZE) {
+                pte_t *pte = lookup_address(addr, &level);
+
+                /*
+                 * Only flush present addresses:
+                 */
+                if (pte && pte_present(*pte))
+                        clflush_cache_range((void *) addr, PAGE_SIZE);
+        }
 }
 
 /*