ARC: support HIGHMEM even without PAE40

[deliverable/linux.git] / arch / arc / mm / init.c

diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
index 5487d0b974005621a8cfaf119bdbf1f687d9ff7b..8be930394750a7cf7039a9dcc85cf6ee1994f4e6 100644 (file)
--- a/arch/arc/mm/init.c
+++ b/arch/arc/mm/init.c
@@ -30,11 +30,16 @@ static const unsigned long low_mem_start = CONFIG_LINUX_LINK_BASE;
 static unsigned long low_mem_sz;
 
 #ifdef CONFIG_HIGHMEM
-static unsigned long min_high_pfn;
+static unsigned long min_high_pfn, max_high_pfn;
 static u64 high_mem_start;
 static u64 high_mem_sz;
 #endif
 
+#ifdef CONFIG_DISCONTIGMEM
+struct pglist_data node_data[MAX_NUMNODES] __read_mostly;
+EXPORT_SYMBOL(node_data);
+#endif
+
 /* User can over-ride above with "mem=nnn[KkMm]" in cmdline */
 static int __init setup_mem_sz(char *str)
 {
@@ -109,13 +114,11 @@ void __init setup_arch_memory(void)
        /* Last usable page of low mem */
        max_low_pfn = max_pfn = PFN_DOWN(low_mem_start + low_mem_sz);
 
-#ifdef CONFIG_HIGHMEM
-       min_high_pfn = PFN_DOWN(high_mem_start);
-       max_pfn = PFN_DOWN(high_mem_start + high_mem_sz);
+#ifdef CONFIG_FLATMEM
+       /* pfn_valid() uses this */
+       max_mapnr = max_low_pfn - min_low_pfn;
 #endif
 
-       max_mapnr = max_pfn - min_low_pfn;
-
        /*------------- bootmem allocator setup -----------------------*/
 
        /*
@@ -129,7 +132,7 @@ void __init setup_arch_memory(void)
         * the crash
         */
 
-       memblock_add(low_mem_start, low_mem_sz);
+       memblock_add_node(low_mem_start, low_mem_sz, 0);
        memblock_reserve(low_mem_start, __pa(_end) - low_mem_start);
 
 #ifdef CONFIG_BLK_DEV_INITRD
@@ -149,13 +152,6 @@ void __init setup_arch_memory(void)
        zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
        zones_holes[ZONE_NORMAL] = 0;
 
-#ifdef CONFIG_HIGHMEM
-       zones_size[ZONE_HIGHMEM] = max_pfn - max_low_pfn;
-
-       /* This handles the peripheral address space hole */
-       zones_holes[ZONE_HIGHMEM] = min_high_pfn - max_low_pfn;
-#endif
-
        /*
         * We can't use the helper free_area_init(zones[]) because it uses
         * PAGE_OFFSET to compute the @min_low_pfn which would be wrong
@@ -168,6 +164,34 @@ void __init setup_arch_memory(void)
                            zones_holes);       /* holes */
 
 #ifdef CONFIG_HIGHMEM
+       /*
+        * Populate a new node with highmem
+        *
+        * On ARC (w/o PAE) HIGHMEM addresses are actually smaller (0 based)
+        * than addresses in normal ala low memory (0x8000_0000 based).
+        * Even with PAE, the huge peripheral space hole would waste a lot of
+        * mem with single mem_map[]. This warrants a mem_map per region design.
+        * Thus HIGHMEM on ARC is imlemented with DISCONTIGMEM.
+        *
+        * DISCONTIGMEM in turns requires multiple nodes. node 0 above is
+        * populated with normal memory zone while node 1 only has highmem
+        */
+       node_set_online(1);
+
+       min_high_pfn = PFN_DOWN(high_mem_start);
+       max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz);
+
+       zones_size[ZONE_NORMAL] = 0;
+       zones_holes[ZONE_NORMAL] = 0;
+
+       zones_size[ZONE_HIGHMEM] = max_high_pfn - min_high_pfn;
+       zones_holes[ZONE_HIGHMEM] = 0;
+
+       free_area_init_node(1,                  /* node-id */
+                           zones_size,         /* num pages per zone */
+                           min_high_pfn,       /* first pfn of node */
+                           zones_holes);       /* holes */
+
        high_memory = (void *)(min_high_pfn << PAGE_SHIFT);
        kmap_init();
 #endif
@@ -185,7 +209,7 @@ void __init mem_init(void)
        unsigned long tmp;
 
        reset_all_zones_managed_pages();
-       for (tmp = min_high_pfn; tmp < max_pfn; tmp++)
+       for (tmp = min_high_pfn; tmp < max_high_pfn; tmp++)
                free_highmem_page(pfn_to_page(tmp));
 #endif