+static int __init parse_highmem(char *arg)
+{
+ if (!arg)
+ return -EINVAL;
+
+ highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
+ return 0;
+}
+early_param("highmem", parse_highmem);
+
+/*
+ * Determine low and high memory ranges:
+ */
+void __init find_low_pfn_range(void)
+{
+ /* it could update max_pfn */
+
+ /* max_low_pfn is 0, we already have early_res support */
+
+ max_low_pfn = max_pfn;
+ if (max_low_pfn > MAXMEM_PFN) {
+ if (highmem_pages == -1)
+ highmem_pages = max_pfn - MAXMEM_PFN;
+ if (highmem_pages + MAXMEM_PFN < max_pfn)
+ max_pfn = MAXMEM_PFN + highmem_pages;
+ if (highmem_pages + MAXMEM_PFN > max_pfn) {
+ printk(KERN_WARNING "only %luMB highmem pages "
+ "available, ignoring highmem size of %uMB.\n",
+ pages_to_mb(max_pfn - MAXMEM_PFN),
+ pages_to_mb(highmem_pages));
+ highmem_pages = 0;
+ }
+ max_low_pfn = MAXMEM_PFN;
+#ifndef CONFIG_HIGHMEM
+ /* Maximum memory usable is what is directly addressable */
+ printk(KERN_WARNING "Warning only %ldMB will be used.\n",
+ MAXMEM>>20);
+ if (max_pfn > MAX_NONPAE_PFN)
+ printk(KERN_WARNING
+ "Use a HIGHMEM64G enabled kernel.\n");
+ else
+ printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
+ max_pfn = MAXMEM_PFN;
+#else /* !CONFIG_HIGHMEM */
+#ifndef CONFIG_HIGHMEM64G
+ if (max_pfn > MAX_NONPAE_PFN) {
+ max_pfn = MAX_NONPAE_PFN;
+ printk(KERN_WARNING "Warning only 4GB will be used."
+ "Use a HIGHMEM64G enabled kernel.\n");
+ }
+#endif /* !CONFIG_HIGHMEM64G */
+#endif /* !CONFIG_HIGHMEM */
+ } else {
+ if (highmem_pages == -1)
+ highmem_pages = 0;
+#ifdef CONFIG_HIGHMEM
+ if (highmem_pages >= max_pfn) {
+ printk(KERN_ERR "highmem size specified (%uMB) is "
+ "bigger than pages available (%luMB)!.\n",
+ pages_to_mb(highmem_pages),
+ pages_to_mb(max_pfn));
+ highmem_pages = 0;
+ }
+ if (highmem_pages) {
+ if (max_low_pfn - highmem_pages <
+ 64*1024*1024/PAGE_SIZE){
+ printk(KERN_ERR "highmem size %uMB results in "
+ "smaller than 64MB lowmem, ignoring it.\n"
+ , pages_to_mb(highmem_pages));
+ highmem_pages = 0;
+ }
+ max_low_pfn -= highmem_pages;
+ }
+#else
+ if (highmem_pages)
+ printk(KERN_ERR "ignoring highmem size on non-highmem"
+ " kernel!\n");
+#endif
+ }
+}
+
+#ifndef CONFIG_NEED_MULTIPLE_NODES
+void __init initmem_init(unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+#ifdef CONFIG_HIGHMEM
+ highstart_pfn = highend_pfn = max_pfn;
+ if (max_pfn > max_low_pfn)
+ highstart_pfn = max_low_pfn;
+ memory_present(0, 0, highend_pfn);
+ e820_register_active_regions(0, 0, highend_pfn);
+ printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
+ pages_to_mb(highend_pfn - highstart_pfn));
+ num_physpages = highend_pfn;
+ high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
+#else
+ memory_present(0, 0, max_low_pfn);
+ e820_register_active_regions(0, 0, max_low_pfn);
+ num_physpages = max_low_pfn;
+ high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
+#endif
+#ifdef CONFIG_FLATMEM
+ max_mapnr = num_physpages;
+#endif
+ printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
+ pages_to_mb(max_low_pfn));
+
+ setup_bootmem_allocator();
+}
+#endif /* !CONFIG_NEED_MULTIPLE_NODES */
+
+static void __init zone_sizes_init(void)
+{
+ unsigned long max_zone_pfns[MAX_NR_ZONES];
+ memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+ max_zone_pfns[ZONE_DMA] =
+ virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
+ max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
+#ifdef CONFIG_HIGHMEM
+ max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
+#endif
+
+ free_area_init_nodes(max_zone_pfns);
+}
+
+void __init setup_bootmem_allocator(void)
+{
+ int i;
+ unsigned long bootmap_size, bootmap;
+ /*
+ * Initialize the boot-time allocator (with low memory only):
+ */
+ bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
+ bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
+ max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
+ PAGE_SIZE);
+ if (bootmap == -1L)
+ panic("Cannot find bootmem map of size %ld\n", bootmap_size);
+ reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
+
+ /* don't touch min_low_pfn */
+ bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap >> PAGE_SHIFT,
+ min_low_pfn, max_low_pfn);
+ printk(KERN_INFO " mapped low ram: 0 - %08lx\n",
+ max_pfn_mapped<<PAGE_SHIFT);
+ printk(KERN_INFO " low ram: %08lx - %08lx\n",
+ min_low_pfn<<PAGE_SHIFT, max_low_pfn<<PAGE_SHIFT);
+ printk(KERN_INFO " bootmap %08lx - %08lx\n",
+ bootmap, bootmap + bootmap_size);
+ for_each_online_node(i)
+ free_bootmem_with_active_regions(i, max_low_pfn);
+ early_res_to_bootmem(0, max_low_pfn<<PAGE_SHIFT);
+
+ after_init_bootmem = 1;
+}
+
+static void __init find_early_table_space(unsigned long end)