1 files changed, 55 insertions, 95 deletions

diff --git a/include/asm-s390/tlbflush.h b/include/asm-s390/tlbflush.h
index 6de2632a3e4..3a9985fbc8a 100644
--- a/include/asm-s390/tlbflush.h
+++ b/include/asm-s390/tlbflush.h
@@ -6,68 +6,19 @@
 #include <asm/pgalloc.h>
 
 /*
- * TLB flushing:
- *
- *  - flush_tlb() flushes the current mm struct TLBs
- *  - flush_tlb_all() flushes all processes TLBs 
- *  - flush_tlb_mm(mm) flushes the specified mm context TLB's
- *  - flush_tlb_page(vma, vmaddr) flushes one page
- *  - flush_tlb_range(vma, start, end) flushes a range of pages
- *  - flush_tlb_kernel_range(start, end) flushes a range of kernel pages
- */
-
-/*
- * S/390 has three ways of flushing TLBs
- * 'ptlb' does a flush of the local processor
- * 'csp' flushes the TLBs on all PUs of a SMP
- * 'ipte' invalidates a pte in a page table and flushes that out of
- * the TLBs of all PUs of a SMP
- */
-
-#define local_flush_tlb() \
-do {  asm volatile("ptlb": : :"memory"); } while (0)
-
-#ifndef CONFIG_SMP
-
-/*
- * We always need to flush, since s390 does not flush tlb
- * on each context switch
+ * Flush all tlb entries on the local cpu.
  */
-
-static inline void flush_tlb(void)
+static inline void __tlb_flush_local(void)
 {
-        local_flush_tlb();
+        asm volatile("ptlb" : : : "memory");
 }
-static inline void flush_tlb_all(void)
-{
-        local_flush_tlb();
-}
-static inline void flush_tlb_mm(struct mm_struct *mm) 
-{
-        local_flush_tlb();
-}
-static inline void flush_tlb_page(struct vm_area_struct *vma,
-                                  unsigned long addr)
-{
-        local_flush_tlb();
-}
-static inline void flush_tlb_range(struct vm_area_struct *vma,
-                                   unsigned long start, unsigned long end)
-{
-        local_flush_tlb();
-}
-
-#define flush_tlb_kernel_range(start, end) \
-        local_flush_tlb();
-
-#else
 
-#include <asm/smp.h>
-
-extern void smp_ptlb_all(void);
-
-static inline void global_flush_tlb(void)
+/*
+ * Flush all tlb entries on all cpus.
+ */
+static inline void __tlb_flush_global(void)
 {
+        extern void smp_ptlb_all(void);
         register unsigned long reg2 asm("2");
         register unsigned long reg3 asm("3");
         register unsigned long reg4 asm("4");
@@ -89,66 +40,75 @@ static inline void global_flush_tlb(void)
 }
 
 /*
- * We only have to do global flush of tlb if process run since last
- * flush on any other pu than current. 
- * If we have threads (mm->count > 1) we always do a global flush, 
- * since the process runs on more than one processor at the same time.
+ * Flush all tlb entries of a page table on all cpus.
  */
+static inline void __tlb_flush_idte(pgd_t *pgd)
+{
+        asm volatile(
+                "       .insn   rrf,0xb98e0000,0,%0,%1,0"
+                : : "a" (2048), "a" (__pa(pgd) & PAGE_MASK) : "cc" );
+}
 
-static inline void __flush_tlb_mm(struct mm_struct * mm)
+static inline void __tlb_flush_mm(struct mm_struct * mm)
 {
         cpumask_t local_cpumask;
 
         if (unlikely(cpus_empty(mm->cpu_vm_mask)))
                 return;
+        /*
+         * If the machine has IDTE we prefer to do a per mm flush
+         * on all cpus instead of doing a local flush if the mm
+         * only ran on the local cpu.
+         */
         if (MACHINE_HAS_IDTE) {
                 pgd_t *shadow_pgd = get_shadow_pgd(mm->pgd);
 
-                if (shadow_pgd) {
-                        asm volatile(
-                                "       .insn   rrf,0xb98e0000,0,%0,%1,0"
-                                : : "a" (2048),
-                                "a" (__pa(shadow_pgd) & PAGE_MASK) : "cc" );
-                }
-                asm volatile(
-                        "       .insn   rrf,0xb98e0000,0,%0,%1,0"
-                        : : "a" (2048), "a" (__pa(mm->pgd)&PAGE_MASK) : "cc");
+                if (shadow_pgd)
+                        __tlb_flush_idte(shadow_pgd);
+                __tlb_flush_idte(mm->pgd);
                 return;
         }
         preempt_disable();
+        /*
+         * If the process only ran on the local cpu, do a local flush.
+         */
         local_cpumask = cpumask_of_cpu(smp_processor_id());
         if (cpus_equal(mm->cpu_vm_mask, local_cpumask))
-                local_flush_tlb();
+                __tlb_flush_local();
         else
-                global_flush_tlb();
+                __tlb_flush_global();
         preempt_enable();
 }
 
-static inline void flush_tlb(void)
-{
-        __flush_tlb_mm(current->mm);
-}
-static inline void flush_tlb_all(void)
-{
-        global_flush_tlb();
-}
-static inline void flush_tlb_mm(struct mm_struct *mm) 
-{
-        __flush_tlb_mm(mm); 
-}
-static inline void flush_tlb_page(struct vm_area_struct *vma,
-                                  unsigned long addr)
-{
-        __flush_tlb_mm(vma->vm_mm);
-}
-static inline void flush_tlb_range(struct vm_area_struct *vma,
-                                   unsigned long start, unsigned long end)
+static inline void __tlb_flush_mm_cond(struct mm_struct * mm)
 {
-        __flush_tlb_mm(vma->vm_mm); 
+        if (atomic_read(&mm->mm_users) <= 1 && mm == current->active_mm)
+                __tlb_flush_mm(mm);
 }
 
-#define flush_tlb_kernel_range(start, end) global_flush_tlb()
+/*
+ * TLB flushing:
+ *  flush_tlb() - flushes the current mm struct TLBs
+ *  flush_tlb_all() - flushes all processes TLBs
+ *  flush_tlb_mm(mm) - flushes the specified mm context TLB's
+ *  flush_tlb_page(vma, vmaddr) - flushes one page
+ *  flush_tlb_range(vma, start, end) - flushes a range of pages
+ *  flush_tlb_kernel_range(start, end) - flushes a range of kernel pages
+ */
 
-#endif
+/*
+ * flush_tlb_mm goes together with ptep_set_wrprotect for the
+ * copy_page_range operation and flush_tlb_range is related to
+ * ptep_get_and_clear for change_protection. ptep_set_wrprotect and
+ * ptep_get_and_clear do not flush the TLBs directly if the mm has
+ * only one user. At the end of the update the flush_tlb_mm and
+ * flush_tlb_range functions need to do the flush.
+ */
+#define flush_tlb()                             do { } while (0)
+#define flush_tlb_all()                         do { } while (0)
+#define flush_tlb_mm(mm)                        __tlb_flush_mm_cond(mm)
+#define flush_tlb_page(vma, addr)               do { } while (0)
+#define flush_tlb_range(vma, start, end)        __tlb_flush_mm_cond(mm)
+#define flush_tlb_kernel_range(start, end)      __tlb_flush_mm(&init_mm)
 
 #endif /* _S390_TLBFLUSH_H */