4 files changed, 28 insertions, 13 deletions

diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index a5302d319229..0ad771f7a7e1 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -212,6 +212,9 @@ config HIGHMEM
 
           If unsure, say "true".
 
+config ZONE_DMA
+        def_bool y
+
 # We do not currently support disabling NUMA.
 config NUMA
         bool # "NUMA Memory Allocation and Scheduler Support"
diff --git a/arch/tile/kernel/pci-dma.c b/arch/tile/kernel/pci-dma.c
index 9814d7082f24..edd856a000c5 100644
--- a/arch/tile/kernel/pci-dma.c
+++ b/arch/tile/kernel/pci-dma.c
@@ -45,14 +45,17 @@ void *dma_alloc_coherent(struct device *dev,
         gfp |= __GFP_ZERO;
 
         /*
-         * By forcing NUMA node 0 for 32-bit masks we ensure that the
-         * high 32 bits of the resulting PA will be zero.  If the mask
-         * size is, e.g., 24, we may still not be able to guarantee a
-         * suitable memory address, in which case we will return NULL.
-         * But such devices are uncommon.
+         * If the mask specifies that the memory be in the first 4 GB, then
+         * we force the allocation to come from the DMA zone.  We also
+         * force the node to 0 since that's the only node where the DMA
+         * zone isn't empty.  If the mask size is smaller than 32 bits, we
+         * may still not be able to guarantee a suitable memory address, in
+         * which case we will return NULL.  But such devices are uncommon.
          */
-        if (dma_mask <= DMA_BIT_MASK(32))
+        if (dma_mask <= DMA_BIT_MASK(32)) {
+                gfp |= GFP_DMA;
                 node = 0;
+        }
 
         pg = homecache_alloc_pages_node(node, gfp, order, PAGE_HOME_DMA);
         if (pg == NULL)
diff --git a/arch/tile/kernel/setup.c b/arch/tile/kernel/setup.c
index 6d179dfcc15e..fdde3b6986e5 100644
--- a/arch/tile/kernel/setup.c
+++ b/arch/tile/kernel/setup.c
@@ -658,6 +658,8 @@ static void __init zone_sizes_init(void)
         unsigned long zones_size[MAX_NR_ZONES] = { 0 };
         int size = percpu_size();
         int num_cpus = smp_height * smp_width;
+        const unsigned long dma_end = (1UL << (32 - PAGE_SHIFT));
+
         int i;
 
         for (i = 0; i < num_cpus; ++i)
@@ -729,6 +731,14 @@ static void __init zone_sizes_init(void)
                 zones_size[ZONE_NORMAL] = end - start;
 #endif
 
+                if (start < dma_end) {
+                        zones_size[ZONE_DMA] = min(zones_size[ZONE_NORMAL],
+                                                   dma_end - start);
+                        zones_size[ZONE_NORMAL] -= zones_size[ZONE_DMA];
+                } else {
+                        zones_size[ZONE_DMA] = 0;
+                }
+
                 /* Take zone metadata from controller 0 if we're isolnode. */
                 if (node_isset(i, isolnodes))
                         NODE_DATA(i)->bdata = &bootmem_node_data[0];
@@ -738,7 +748,7 @@ static void __init zone_sizes_init(void)
                        PFN_UP(node_percpu[i]));
 
                 /* Track the type of memory on each node */
-                if (zones_size[ZONE_NORMAL])
+                if (zones_size[ZONE_NORMAL] || zones_size[ZONE_DMA])
                         node_set_state(i, N_NORMAL_MEMORY);
 #ifdef CONFIG_HIGHMEM
                 if (end != start)
diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
index a2417a0a8222..ef29d6c5e10e 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c
@@ -733,16 +733,15 @@ static void __init set_non_bootmem_pages_init(void)
         for_each_zone(z) {
                 unsigned long start, end;
                 int nid = z->zone_pgdat->node_id;
+#ifdef CONFIG_HIGHMEM
                 int idx = zone_idx(z);
+#endif
 
                 start = z->zone_start_pfn;
-                if (start == 0)
-                        continue;  /* bootmem */
                 end = start + z->spanned_pages;
-                if (idx == ZONE_NORMAL) {
-                        BUG_ON(start != node_start_pfn[nid]);
-                        start = node_free_pfn[nid];
-                }
+                start = max(start, node_free_pfn[nid]);
+                start = max(start, max_low_pfn);
+
 #ifdef CONFIG_HIGHMEM
                 if (idx == ZONE_HIGHMEM)
                         totalhigh_pages += z->spanned_pages;