x86: clean up max_pfn_mapped usage - 32-bit

on 32-bit in head_32.S after initial page table is done, we get initial
max_pfn_mapped, and then kernel_physical_mapping_init will give us
a final one.

We need to use that to make sure find_e820_area will get valid addresses
for boot_map and for NODE_DATA(0) on numa32.

XEN PV and lguest may need to assign max_pfn_mapped too.

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

3 files changed, 9 insertions, 2 deletions

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index bef4618feadb..ac7002fdd637 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -220,6 +220,8 @@ default_entry:
         jb 10b
 1:
         movl %edi,pa(init_pg_tables_end)
+        shrl $12, %eax
+        movl %eax, pa(max_pfn_mapped)
 
         /* Do early initialization of the fixmap area */
         movl $pa(swapper_pg_fixmap)+PDE_ATTR,%eax
@@ -251,6 +253,8 @@ page_pde_offset = (__PAGE_OFFSET >> 20);
         cmpl %ebp,%eax
         jb 10b
         movl %edi,pa(init_pg_tables_end)
+        shrl $12, %eax
+        movl %eax, pa(max_pfn_mapped)
 
         /* Do early initialization of the fixmap area */
         movl $pa(swapper_pg_fixmap)+PDE_ATTR,%eax
diff --git a/arch/x86/kernel/setup_32.c b/arch/x86/kernel/setup_32.c
index 29010420458d..c985a8c305e0 100644
--- a/arch/x86/kernel/setup_32.c
+++ b/arch/x86/kernel/setup_32.c
@@ -586,7 +586,7 @@ void __init setup_bootmem_allocator(void)
          */
         bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
         bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
-                                 max_low_pfn<<PAGE_SHIFT, bootmap_size,
+                                 max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
                                  PAGE_SIZE);
         if (bootmap == -1L)
                 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
@@ -595,6 +595,8 @@ void __init setup_bootmem_allocator(void)
         reserve_initrd();
 #endif
         bootmap_size = init_bootmem(bootmap >> PAGE_SHIFT, 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",
diff --git a/arch/x86/mm/discontig_32.c b/arch/x86/mm/discontig_32.c
index 73a983489c60..914a81ee7855 100644
--- a/arch/x86/mm/discontig_32.c
+++ b/arch/x86/mm/discontig_32.c
@@ -163,7 +163,8 @@ static void __init allocate_pgdat(int nid)
         else {
                 unsigned long pgdat_phys;
                 pgdat_phys = find_e820_area(min_low_pfn<<PAGE_SHIFT,
-                                 max_low_pfn<<PAGE_SHIFT, sizeof(pg_data_t),
+                                 (nid ? max_low_pfn:max_pfn_mapped)<<PAGE_SHIFT,
+                                 sizeof(pg_data_t),
                                  PAGE_SIZE);
                 NODE_DATA(nid) = (pg_data_t *)(pfn_to_kaddr(pgdat_phys>>PAGE_SHIFT));
                 reserve_early(pgdat_phys, pgdat_phys + sizeof(pg_data_t),