1 files changed, 145 insertions, 6 deletions

diff --git a/arch/sparc64/mm/tsb.c b/arch/sparc64/mm/tsb.c
index dfe7144fcdf6..707af4b84a0e 100644
--- a/arch/sparc64/mm/tsb.c
+++ b/arch/sparc64/mm/tsb.c
@@ -10,6 +10,7 @@
 #include <asm/tlb.h>
 #include <asm/mmu_context.h>
 #include <asm/pgtable.h>
+#include <asm/tsb.h>
 
 /* We use an 8K TSB for the whole kernel, this allows to
  * handle about 4MB of modules and vmalloc mappings without
@@ -146,6 +147,9 @@ static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_bytes)
                 tte |= _PAGE_SZ4MB;
                 page_sz = 4 * 1024 * 1024;
                 break;
+
+        default:
+                BUG();
         };
 
         tsb_reg |= base;
@@ -157,23 +161,158 @@ static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_bytes)
         mm->context.tsb_map_pte = tte;
 }
 
+/* The page tables are locked against modifications while this
+ * runs.
+ *
+ * XXX do some prefetching...
+ */
+static void copy_tsb(struct tsb *old_tsb, unsigned long old_size,
+                     struct tsb *new_tsb, unsigned long new_size)
+{
+        unsigned long old_nentries = old_size / sizeof(struct tsb);
+        unsigned long new_nentries = new_size / sizeof(struct tsb);
+        unsigned long i;
+
+        for (i = 0; i < old_nentries; i++) {
+                register unsigned long tag asm("o4");
+                register unsigned long pte asm("o5");
+                unsigned long v;
+                unsigned int hash;
+
+                __asm__ __volatile__(
+                        "ldda [%2] %3, %0"
+                        : "=r" (tag), "=r" (pte)
+                        : "r" (&old_tsb[i]), "i" (ASI_NUCLEUS_QUAD_LDD));
+
+                if (!tag || (tag & TSB_TAG_LOCK))
+                        continue;
+
+                /* We only put base page size PTEs into the TSB,
+                 * but that might change in the future.  This code
+                 * would need to be changed if we start putting larger
+                 * page size PTEs into there.
+                 */
+                WARN_ON((pte & _PAGE_ALL_SZ_BITS) != _PAGE_SZBITS);
+
+                /* The tag holds bits 22 to 63 of the virtual address
+                 * and the context.  Clear out the context, and shift
+                 * up to make a virtual address.
+                 */
+                v = (tag & ((1UL << 42UL) - 1UL)) << 22UL;
+
+                /* The implied bits of the tag (bits 13 to 21) are
+                 * determined by the TSB entry index, so fill that in.
+                 */
+                v |= (i & (512UL - 1UL)) << 13UL;
+
+                hash = tsb_hash(v, new_nentries);
+                new_tsb[hash].tag = tag;
+                new_tsb[hash].pte = pte;
+        }
+}
+
+/* When the RSS of an address space exceeds mm->context.tsb_rss_limit,
+ * update_mmu_cache() invokes this routine to try and grow the TSB.
+ * When we reach the maximum TSB size supported, we stick ~0UL into
+ * mm->context.tsb_rss_limit so the grow checks in update_mmu_cache()
+ * will not trigger any longer.
+ *
+ * The TSB can be anywhere from 8K to 1MB in size, in increasing powers
+ * of two.  The TSB must be aligned to it's size, so f.e. a 512K TSB
+ * must be 512K aligned.
+ *
+ * The idea here is to grow the TSB when the RSS of the process approaches
+ * the number of entries that the current TSB can hold at once.  Currently,
+ * we trigger when the RSS hits 3/4 of the TSB capacity.
+ */
+void tsb_grow(struct mm_struct *mm, unsigned long rss, gfp_t gfp_flags)
+{
+        unsigned long max_tsb_size = 1 * 1024 * 1024;
+        unsigned long size, old_size;
+        struct page *page;
+        struct tsb *old_tsb;
+
+        if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
+                max_tsb_size = (PAGE_SIZE << MAX_ORDER);
+
+        for (size = PAGE_SIZE; size < max_tsb_size; size <<= 1UL) {
+                unsigned long n_entries = size / sizeof(struct tsb);
+
+                n_entries = (n_entries * 3) / 4;
+                if (n_entries > rss)
+                        break;
+        }
+
+        page = alloc_pages(gfp_flags | __GFP_ZERO, get_order(size));
+        if (unlikely(!page))
+                return;
+
+        if (size == max_tsb_size)
+                mm->context.tsb_rss_limit = ~0UL;
+        else
+                mm->context.tsb_rss_limit =
+                        ((size / sizeof(struct tsb)) * 3) / 4;
+
+        old_tsb = mm->context.tsb;
+        old_size = mm->context.tsb_nentries * sizeof(struct tsb);
+
+        if (old_tsb)
+                copy_tsb(old_tsb, old_size, page_address(page), size);
+
+        mm->context.tsb = page_address(page);
+        setup_tsb_params(mm, size);
+
+        /* If old_tsb is NULL, we're being invoked for the first time
+         * from init_new_context().
+         */
+        if (old_tsb) {
+                /* Now force all other processors to reload the new
+                 * TSB state.
+                 */
+                smp_tsb_sync(mm);
+
+                /* Finally reload it on the local cpu.  No further
+                 * references will remain to the old TSB and we can
+                 * thus free it up.
+                 */
+                tsb_context_switch(mm);
+
+                free_pages((unsigned long) old_tsb, get_order(old_size));
+        }
+}
+
 int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 {
-        unsigned long page = get_zeroed_page(GFP_KERNEL);
+        unsigned long initial_rss;
 
         mm->context.sparc64_ctx_val = 0UL;
-        if (unlikely(!page))
-                return -ENOMEM;
 
-        mm->context.tsb = (struct tsb *) page;
-        setup_tsb_params(mm, PAGE_SIZE);
+        /* copy_mm() copies over the parent's mm_struct before calling
+         * us, so we need to zero out the TSB pointer or else tsb_grow()
+         * will be confused and think there is an older TSB to free up.
+         */
+        mm->context.tsb = NULL;
+
+        /* If this is fork, inherit the parent's TSB size.  We would
+         * grow it to that size on the first page fault anyways.
+         */
+        initial_rss = mm->context.tsb_nentries;
+        if (initial_rss)
+                initial_rss -= 1;
+
+        tsb_grow(mm, initial_rss, GFP_KERNEL);
+
+        if (unlikely(!mm->context.tsb))
+                return -ENOMEM;
 
         return 0;
 }
 
 void destroy_context(struct mm_struct *mm)
 {
-        free_page((unsigned long) mm->context.tsb);
+        unsigned long size = mm->context.tsb_nentries * sizeof(struct tsb);
+
+        free_pages((unsigned long) mm->context.tsb, get_order(size));
 
         /* We can remove these later, but for now it's useful
          * to catch any bogus post-destroy_context() references