[MIPS] Do not use drop_mmu_context to flusing other task's VIPT I-cache.

c-r4k.c and c-sb1.c use drop_mmu_context() to flush virtually tagged
I-caches, but this does not work for flushing other task's icache.  This
is for example triggered by copy_to_user_page() called from ptrace(2).
Use indexed flush for such cases.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 33 insertions, 27 deletions

diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 4e1498246343..2d729f6f6348 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -475,7 +475,7 @@ static inline void local_r4k_flush_cache_page(void *args)
                 }
         }
         if (exec) {
-                if (cpu_has_vtag_icache) {
+                if (cpu_has_vtag_icache && mm == current->active_mm) {
                         int cpu = smp_processor_id();
 
                         if (cpu_context(cpu, mm) != 0)
@@ -599,7 +599,7 @@ static inline void local_r4k_flush_icache_page(void *args)
          * We're not sure of the virtual address(es) involved here, so
          * we have to flush the entire I-cache.
          */
-        if (cpu_has_vtag_icache) {
+        if (cpu_has_vtag_icache && vma->vm_mm == current->active_mm) {
                 int cpu = smp_processor_id();
 
                 if (cpu_context(cpu, vma->vm_mm) != 0)
diff --git a/arch/mips/mm/c-sb1.c b/arch/mips/mm/c-sb1.c
index 4bd9ad8a5e07..16bad7c0a63f 100644
--- a/arch/mips/mm/c-sb1.c
+++ b/arch/mips/mm/c-sb1.c
@@ -155,6 +155,26 @@ static inline void __sb1_flush_icache_all(void)
 }
 
 /*
+ * Invalidate a range of the icache.  The addresses are virtual, and
+ * the cache is virtually indexed and tagged.  However, we don't
+ * necessarily have the right ASID context, so use index ops instead
+ * of hit ops.
+ */
+static inline void __sb1_flush_icache_range(unsigned long start,
+        unsigned long end)
+{
+        start &= ~(icache_line_size - 1);
+        end = (end + icache_line_size - 1) & ~(icache_line_size - 1);
+
+        while (start != end) {
+                cache_set_op(Index_Invalidate_I, start & icache_index_mask);
+                start += icache_line_size;
+        }
+        mispredict();
+        sync();
+}
+
+/*
  * Flush the icache for a given physical page.  Need to writeback the
  * dcache first, then invalidate the icache.  If the page isn't
  * executable, nothing is required.
@@ -173,8 +193,11 @@ static void local_sb1_flush_cache_page(struct vm_area_struct *vma, unsigned long
         /*
          * Bumping the ASID is probably cheaper than the flush ...
          */
-        if (cpu_context(cpu, vma->vm_mm) != 0)
-                drop_mmu_context(vma->vm_mm, cpu);
+        if (vma->vm_mm == current->active_mm) {
+                if (cpu_context(cpu, vma->vm_mm) != 0)
+                        drop_mmu_context(vma->vm_mm, cpu);
+        } else
+                __sb1_flush_icache_range(addr, addr + PAGE_SIZE);
 }
 
 #ifdef CONFIG_SMP
@@ -210,26 +233,6 @@ void sb1_flush_cache_page(struct vm_area_struct *vma, unsigned long addr, unsign
         __attribute__((alias("local_sb1_flush_cache_page")));
 #endif
 
-/*
- * Invalidate a range of the icache.  The addresses are virtual, and
- * the cache is virtually indexed and tagged.  However, we don't
- * necessarily have the right ASID context, so use index ops instead
- * of hit ops.
- */
-static inline void __sb1_flush_icache_range(unsigned long start,
-        unsigned long end)
-{
-        start &= ~(icache_line_size - 1);
-        end = (end + icache_line_size - 1) & ~(icache_line_size - 1);
-
-        while (start != end) {
-                cache_set_op(Index_Invalidate_I, start & icache_index_mask);
-                start += icache_line_size;
-        }
-        mispredict();
-        sync();
-}
-
 
 /*
  * Invalidate all caches on this CPU
@@ -326,9 +329,12 @@ static void local_sb1_flush_icache_page(struct vm_area_struct *vma,
          * If there's a context, bump the ASID (cheaper than a flush,
          * since we don't know VAs!)
          */
-        if (cpu_context(cpu, vma->vm_mm) != 0) {
-                drop_mmu_context(vma->vm_mm, cpu);
-        }
+        if (vma->vm_mm == current->active_mm) {
+                if (cpu_context(cpu, vma->vm_mm) != 0)
+                        drop_mmu_context(vma->vm_mm, cpu);
+        } else
+                __sb1_flush_icache_range(start, start + PAGE_SIZE);
+
 }
 
 #ifdef CONFIG_SMP