x86: clean up using max_low_pfn on 32-bit

so that max_low_pfn is not changed after it is set.
so we can move that early and out of initmem_init.

could call find_low_pfn_range just after max_pfn is set.

also could move reserve_initrd out of setup_bootmem_allocator

so 32bit is more like 64bit.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 26 insertions, 37 deletions

diff --git a/arch/x86/kernel/setup_32.c b/arch/x86/kernel/setup_32.c
index 9a08490a3889..b42f570a5a56 100644
--- a/arch/x86/kernel/setup_32.c
+++ b/arch/x86/kernel/setup_32.c
@@ -188,13 +188,14 @@ static inline void copy_edd(void)
 
 static bool do_relocate_initrd = false;
 
-void __init reserve_initrd(void)
+static void __init reserve_initrd(void)
 {
         u64 ramdisk_image = boot_params.hdr.ramdisk_image;
         u64 ramdisk_size  = boot_params.hdr.ramdisk_size;
         u64 ramdisk_end   = ramdisk_image + ramdisk_size;
         u64 end_of_lowmem = max_low_pfn << PAGE_SHIFT;
         u64 ramdisk_here;
+        u64 ramdisk_target;
 
         if (!boot_params.hdr.type_of_loader ||
             !ramdisk_image || !ramdisk_size)
@@ -202,7 +203,7 @@ void __init reserve_initrd(void)
 
         initrd_start = 0;
 
-        if (ramdisk_size >= end_of_lowmem/2) {
+        if (ramdisk_size >= (end_of_lowmem>>1)) {
                 free_early(ramdisk_image, ramdisk_end);
                 printk(KERN_ERR "initrd too large to handle, "
                        "disabling initrd\n");
@@ -225,7 +226,8 @@ void __init reserve_initrd(void)
         }
 
         /* We need to move the initrd down into lowmem */
-        ramdisk_here = find_e820_area(min_low_pfn<<PAGE_SHIFT,
+        ramdisk_target = max_pfn_mapped<<PAGE_SHIFT;
+        ramdisk_here = find_e820_area(min(ramdisk_target, end_of_lowmem>>1),
                                  end_of_lowmem, ramdisk_size,
                                  PAGE_SIZE);
 
@@ -346,8 +348,6 @@ static void set_mca_bus(int x) { }
  */
 void __init setup_arch(char **cmdline_p)
 {
-        unsigned long max_low_pfn;
-
         memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
         pre_setup_arch_hook();
         early_cpu_init();
@@ -450,6 +450,10 @@ void __init setup_arch(char **cmdline_p)
                 max_pfn = e820_end_of_ram();
         }
 
+        find_low_pfn_range();
+
+        reserve_initrd();
+
         dmi_scan_machine();
 
         io_delay_init();
@@ -466,7 +470,7 @@ void __init setup_arch(char **cmdline_p)
         acpi_numa_init();
 #endif
 
-        max_low_pfn = initmem_init(0, max_pfn);
+        initmem_init(0, max_pfn);
 
 #ifdef CONFIG_ACPI_SLEEP
         /*
diff --git a/arch/x86/mm/discontig_32.c b/arch/x86/mm/discontig_32.c
index 3e75be46c4f2..1dfff700264c 100644
--- a/arch/x86/mm/discontig_32.c
+++ b/arch/x86/mm/discontig_32.c
@@ -309,11 +309,10 @@ static void init_remap_allocator(int nid)
                 (ulong) node_remap_end_vaddr[nid]);
 }
 
-unsigned long __init initmem_init(unsigned long start_pfn,
+void __init initmem_init(unsigned long start_pfn,
                                   unsigned long end_pfn)
 {
         int nid;
-        unsigned long system_start_pfn, system_max_low_pfn;
         long kva_target_pfn;
 
         /*
@@ -324,17 +323,11 @@ unsigned long __init initmem_init(unsigned long start_pfn,
          * and ZONE_HIGHMEM.
          */
 
-        /* call find_max_low_pfn at first, it could update max_pfn */
-        system_max_low_pfn = max_low_pfn = find_max_low_pfn();
-
         remove_all_active_ranges();
         get_memcfg_numa();
 
         kva_pages = round_up(calculate_numa_remap_pages(), PTRS_PER_PTE);
 
-        /* partially used pages are not usable - thus round upwards */
-        system_start_pfn = min_low_pfn = PFN_UP(init_pg_tables_end);
-
         kva_target_pfn = round_down(max_low_pfn - kva_pages, PTRS_PER_PTE);
         do {
                 kva_start_pfn = find_e820_area(kva_target_pfn<<PAGE_SHIFT,
@@ -357,19 +350,19 @@ unsigned long __init initmem_init(unsigned long start_pfn,
                      "KVA PG");
 #ifdef CONFIG_HIGHMEM
         highstart_pfn = highend_pfn = max_pfn;
-        if (max_pfn > system_max_low_pfn)
-                highstart_pfn = system_max_low_pfn;
+        if (max_pfn > max_low_pfn)
+                highstart_pfn = max_low_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
-        num_physpages = system_max_low_pfn;
-        high_memory = (void *) __va(system_max_low_pfn * PAGE_SIZE - 1) + 1;
+        num_physpages = max_low_pfn;
+        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
 #endif
         printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
-                        pages_to_mb(system_max_low_pfn));
-        printk("min_low_pfn = %ld, max_low_pfn = %ld, highstart_pfn = %ld\n", 
+                        pages_to_mb(max_low_pfn));
+        printk("min_low_pfn = %ld, max_low_pfn = %ld, highstart_pfn = %ld\n",
                         min_low_pfn, max_low_pfn, highstart_pfn);
 
         printk("Low memory ends at vaddr %08lx\n",
@@ -387,7 +380,6 @@ unsigned long __init initmem_init(unsigned long start_pfn,
         memset(NODE_DATA(0), 0, sizeof(struct pglist_data));
         NODE_DATA(0)->bdata = &node0_bdata;
         setup_bootmem_allocator();
-        return max_low_pfn;
 }
 
 void __init zone_sizes_init(void)
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index d1017336f1b5..27b829312944 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -561,9 +561,15 @@ early_param("highmem", parse_highmem);
 /*
  * Determine low and high memory ranges:
  */
-unsigned long __init find_max_low_pfn(void)
+void __init find_low_pfn_range(void)
 {
-        unsigned long max_low_pfn;
+        /* it could update max_pfn */
+
+        /*
+         * partially used pages are not usable - thus
+         * we are rounding upwards:
+         */
+        min_low_pfn = PFN_UP(init_pg_tables_end);
 
         max_low_pfn = max_pfn;
         if (max_low_pfn > MAXMEM_PFN) {
@@ -625,21 +631,12 @@ unsigned long __init find_max_low_pfn(void)
                                         " kernel!\n");
 #endif
         }
-        return max_low_pfn;
 }
 
 #ifndef CONFIG_NEED_MULTIPLE_NODES
-unsigned long __init initmem_init(unsigned long start_pfn,
+void __init initmem_init(unsigned long start_pfn,
                                   unsigned long end_pfn)
 {
-        /*
-         * partially used pages are not usable - thus
-         * we are rounding upwards:
-         */
-        min_low_pfn = PFN_UP(init_pg_tables_end);
-
-        max_low_pfn = find_max_low_pfn();
-
 #ifdef CONFIG_HIGHMEM
         highstart_pfn = highend_pfn = max_pfn;
         if (max_pfn > max_low_pfn)
@@ -661,8 +658,6 @@ unsigned long __init initmem_init(unsigned long start_pfn,
                         pages_to_mb(max_low_pfn));
 
         setup_bootmem_allocator();
-
-        return max_low_pfn;
 }
 
 void __init zone_sizes_init(void)
@@ -699,8 +694,6 @@ void __init setup_bootmem_allocator(void)
                 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
         reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
 
-        reserve_initrd();
-
         bootmap_size = init_bootmem(bootmap >> PAGE_SHIFT, max_low_pfn);
         printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
                  max_pfn_mapped<<PAGE_SHIFT);