[MIPS] Setup min_low_pfn/max_low_pfn correctly

This patch makes a better usage of these two globals.
'min_low_pfn' is now correctly setup for all configs, which
allow us to rely on it in boot memory code init.

Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 27 insertions, 9 deletions

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 89440a0d8528..f352cd9c834b 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -271,8 +271,7 @@ static void __init bootmem_init(void)
 static void __init bootmem_init(void)
 {
         unsigned long reserved_end;
-        unsigned long highest = 0;
-        unsigned long mapstart = -1UL;
+        unsigned long mapstart = ~0UL;
         unsigned long bootmap_size;
         int i;
 
@@ -284,6 +283,13 @@ static void __init bootmem_init(void)
         reserved_end = max(init_initrd(), PFN_UP(__pa_symbol(&_end)));
 
         /*
+         * max_low_pfn is not a number of pages. The number of pages
+         * of the system is given by 'max_low_pfn - min_low_pfn'.
+         */
+        min_low_pfn = ~0UL;
+        max_low_pfn = 0;
+
+        /*
          * Find the highest page frame number we have available.
          */
         for (i = 0; i < boot_mem_map.nr_map; i++) {
@@ -296,8 +302,10 @@ static void __init bootmem_init(void)
                 end = PFN_DOWN(boot_mem_map.map[i].addr
                                 + boot_mem_map.map[i].size);
 
-                if (end > highest)
-                        highest = end;
+                if (end > max_low_pfn)
+                        max_low_pfn = end;
+                if (start < min_low_pfn)
+                        min_low_pfn = start;
                 if (end <= reserved_end)
                         continue;
                 if (start >= mapstart)
@@ -305,22 +313,32 @@ static void __init bootmem_init(void)
                 mapstart = max(reserved_end, start);
         }
 
+        if (min_low_pfn >= max_low_pfn)
+                panic("Incorrect memory mapping !!!");
+        if (min_low_pfn > 0) {
+                printk(KERN_INFO
+                       "Wasting %lu bytes for tracking %lu unused pages\n",
+                       min_low_pfn * sizeof(struct page),
+                       min_low_pfn);
+                min_low_pfn = 0;
+        }
+
         /*
          * Determine low and high memory ranges
          */
-        if (highest > PFN_DOWN(HIGHMEM_START)) {
+        if (max_low_pfn > PFN_DOWN(HIGHMEM_START)) {
 #ifdef CONFIG_HIGHMEM
                 highstart_pfn = PFN_DOWN(HIGHMEM_START);
-                highend_pfn = highest;
+                highend_pfn = max_low_pfn;
 #endif
-                highest = PFN_DOWN(HIGHMEM_START);
+                max_low_pfn = PFN_DOWN(HIGHMEM_START);
         }
 
         /*
          * Initialize the boot-time allocator with low memory only.
          */
-        bootmap_size = init_bootmem(mapstart, highest);
-
+        bootmap_size = init_bootmem_node(NODE_DATA(0), mapstart,
+                                         min_low_pfn, max_low_pfn);
         /*
          * Register fully available low RAM pages with the bootmem allocator.
          */