x86: not overmap more than the end of RAM in init_memory_mapping - 64bit

handle head and tail that are not aligned to big pages (2MB/1GB boundary).

with this patch, on system that support gbpages, change:

  last_map_addr: 1080000000 end: 1078000000

to:

  last_map_addr: 1078000000 end: 1078000000

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

1 files changed, 65 insertions, 12 deletions

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index f7d80313ede5..51f69b39b752 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -462,18 +462,25 @@ phys_pud_update(pgd_t *pgd, unsigned long addr, unsigned long end,
 
 static void __init find_early_table_space(unsigned long end)
 {
-        unsigned long puds, tables, start;
+        unsigned long puds, pmds, ptes, tables, start;
 
         puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
         tables = round_up(puds * sizeof(pud_t), PAGE_SIZE);
-        if (!direct_gbpages) {
-                unsigned long pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
-                tables += round_up(pmds * sizeof(pmd_t), PAGE_SIZE);
-        }
-        if (!cpu_has_pse) {
-                unsigned long ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
-                tables += round_up(ptes * sizeof(pte_t), PAGE_SIZE);
-        }
+        if (direct_gbpages) {
+                unsigned long extra;
+                extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
+                pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
+        } else
+                pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
+        tables += round_up(pmds * sizeof(pmd_t), PAGE_SIZE);
+
+        if (cpu_has_pse) {
+                unsigned long extra;
+                extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
+                ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
+        } else
+                ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
+        tables += round_up(ptes * sizeof(pte_t), PAGE_SIZE);
 
         /*
          * RED-PEN putting page tables only on node 0 could
@@ -660,8 +667,9 @@ static unsigned long __init kernel_physical_mapping_init(unsigned long start,
 unsigned long __init_refok init_memory_mapping(unsigned long start,
                                                unsigned long end)
 {
-        unsigned long last_map_addr;
+        unsigned long last_map_addr = end;
         unsigned long page_size_mask = 0;
+        unsigned long start_pfn, end_pfn;
 
         printk(KERN_INFO "init_memory_mapping\n");
 
@@ -682,8 +690,53 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
         if (cpu_has_pse)
                 page_size_mask |= 1 << PG_LEVEL_2M;
 
-        last_map_addr = kernel_physical_mapping_init(start, end,
-                                                         page_size_mask);
+        /* head if not big page aligment ?*/
+        start_pfn = start >> PAGE_SHIFT;
+        end_pfn = ((start + (PMD_SIZE - 1)) >> PMD_SHIFT)
+                        << (PMD_SHIFT - PAGE_SHIFT);
+        if (start_pfn < end_pfn)
+                last_map_addr = kernel_physical_mapping_init(
+                                        start_pfn<<PAGE_SHIFT,
+                                        end_pfn<<PAGE_SHIFT, 0);
+
+        /* big page (2M) range*/
+        start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
+                         << (PMD_SHIFT - PAGE_SHIFT);
+        end_pfn = ((start + (PUD_SIZE - 1))>>PUD_SHIFT)
+                         << (PUD_SHIFT - PAGE_SHIFT);
+        if (end_pfn > ((end>>PUD_SHIFT)<<(PUD_SHIFT - PAGE_SHIFT)))
+                end_pfn = ((end>>PUD_SHIFT)<<(PUD_SHIFT - PAGE_SHIFT));
+        if (start_pfn < end_pfn)
+                last_map_addr = kernel_physical_mapping_init(
+                                             start_pfn<<PAGE_SHIFT,
+                                             end_pfn<<PAGE_SHIFT,
+                                             page_size_mask & (1<<PG_LEVEL_2M));
+
+        /* big page (1G) range */
+        start_pfn = end_pfn;
+        end_pfn = (end>>PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
+        if (start_pfn < end_pfn)
+                last_map_addr = kernel_physical_mapping_init(
+                                             start_pfn<<PAGE_SHIFT,
+                                             end_pfn<<PAGE_SHIFT,
+                                             page_size_mask & ((1<<PG_LEVEL_2M)
+                                                         | (1<<PG_LEVEL_1G)));
+
+        /* tail is not big page (1G) alignment */
+        start_pfn = end_pfn;
+        end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
+        if (start_pfn < end_pfn)
+                last_map_addr = kernel_physical_mapping_init(
+                                             start_pfn<<PAGE_SHIFT,
+                                             end_pfn<<PAGE_SHIFT,
+                                             page_size_mask & (1<<PG_LEVEL_2M));
+        /* tail is not big page (2M) alignment */
+        start_pfn = end_pfn;
+        end_pfn = end>>PAGE_SHIFT;
+        if (start_pfn < end_pfn)
+                last_map_addr = kernel_physical_mapping_init(
+                                             start_pfn<<PAGE_SHIFT,
+                                             end_pfn<<PAGE_SHIFT, 0);
 
         if (!after_bootmem)
                 mmu_cr4_features = read_cr4();