[POWERPC] cell: handle SPE kernel mappings that cross segment boundaries

[linux-2.6-omap-h63xx.git] / arch / powerpc / platforms / cell / spu_base.c

diff --git a/arch/powerpc/platforms/cell/spu_base.c b/arch/powerpc/platforms/cell/spu_base.c
index 95001cdfaa260dfa48377aa9ec3062811834b8fe..ee37e0e39b6b366767b87b6a82a8d451ef58d059 100644 (file)
--- a/arch/powerpc/platforms/cell/spu_base.c
+++ b/arch/powerpc/platforms/cell/spu_base.c
@@ -274,20 +274,56 @@ static void __spu_kernel_slb(void *addr, struct spu_slb *slb)
        slb->esid = (ea & ESID_MASK) | SLB_ESID_V;
 }
 
+/**
+ * Given an array of @nr_slbs SLB entries, @slbs, return non-zero if the
+ * address @new_addr is present.
+ */
+static inline int __slb_present(struct spu_slb *slbs, int nr_slbs,
+               void *new_addr)
+{
+       unsigned long ea = (unsigned long)new_addr;
+       int i;
+
+       for (i = 0; i < nr_slbs; i++)
+               if (!((slbs[i].esid ^ ea) & ESID_MASK))
+                       return 1;
+
+       return 0;
+}
+
 /**
  * Setup the SPU kernel SLBs, in preparation for a context save/restore. We
  * need to map both the context save area, and the save/restore code.
+ *
+ * Because the lscsa and code may cross segment boundaires, we check to see
+ * if mappings are required for the start and end of each range. We currently
+ * assume that the mappings are smaller that one segment - if not, something
+ * is seriously wrong.
  */
-void spu_setup_kernel_slbs(struct spu *spu, struct spu_lscsa *lscsa, void *code)
+void spu_setup_kernel_slbs(struct spu *spu, struct spu_lscsa *lscsa,
+               void *code, int code_size)
 {
-       struct spu_slb code_slb, lscsa_slb;
+       struct spu_slb slbs[4];
+       int i, nr_slbs = 0;
+       /* start and end addresses of both mappings */
+       void *addrs[] = {
+               lscsa, (void *)lscsa + sizeof(*lscsa) - 1,
+               code, code + code_size - 1
+       };
+
+       /* check the set of addresses, and create a new entry in the slbs array
+        * if there isn't already a SLB for that address */
+       for (i = 0; i < ARRAY_SIZE(addrs); i++) {
+               if (__slb_present(slbs, nr_slbs, addrs[i]))
+                       continue;
 
-       __spu_kernel_slb(lscsa, &lscsa_slb);
-       __spu_kernel_slb(code, &code_slb);
+               __spu_kernel_slb(addrs[i], &slbs[nr_slbs]);
+               nr_slbs++;
+       }
 
-       spu_load_slb(spu, 0, &lscsa_slb);
-       if (lscsa_slb.esid != code_slb.esid)
-               spu_load_slb(spu, 1, &code_slb);
+       /* Add the set of SLBs */
+       for (i = 0; i < nr_slbs; i++)
+               spu_load_slb(spu, i, &slbs[i]);
 }
 EXPORT_SYMBOL_GPL(spu_setup_kernel_slbs);