x86: fix 1:1 mapping init on 64-bit (memory hotplug case)

While I don't have a hotplug capable system at hand, I think two issues need
fixing:

- pud_phys (in kernel_physical_ampping_init()) would remain uninitialized in
  the after_bootmem case

- the locking done just around phys_pmd_{init,update}() would leave out pgd
  updates, and it was needlessly covering code portions that do allocations
  (perhaps using a more friendly gfp value in alloc_low_page() would then be
  possible)

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 18 insertions, 14 deletions

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index a87ea0e4b3dc..8f487705c3e6 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -336,9 +336,12 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
                 }
 
                 if (pmd_val(*pmd)) {
-                        if (!pmd_large(*pmd))
+                        if (!pmd_large(*pmd)) {
+                                spin_lock(&init_mm.page_table_lock);
                                 last_map_addr = phys_pte_update(pmd, address,
-                                                                 end);
+                                                                end);
+                                spin_unlock(&init_mm.page_table_lock);
+                        }
                         /* Count entries we're using from level2_ident_pgt */
                         if (start == 0)
                                 pages++;
@@ -347,8 +350,10 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
 
                 if (page_size_mask & (1<<PG_LEVEL_2M)) {
                         pages++;
+                        spin_lock(&init_mm.page_table_lock);
                         set_pte((pte_t *)pmd,
                                 pfn_pte(address >> PAGE_SHIFT, PAGE_KERNEL_LARGE));
+                        spin_unlock(&init_mm.page_table_lock);
                         last_map_addr = (address & PMD_MASK) + PMD_SIZE;
                         continue;
                 }
@@ -357,7 +362,9 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
                 last_map_addr = phys_pte_init(pte, address, end);
                 unmap_low_page(pte);
 
+                spin_lock(&init_mm.page_table_lock);
                 pmd_populate_kernel(&init_mm, pmd, __va(pte_phys));
+                spin_unlock(&init_mm.page_table_lock);
         }
         update_page_count(PG_LEVEL_2M, pages);
         return last_map_addr;
@@ -370,9 +377,7 @@ phys_pmd_update(pud_t *pud, unsigned long address, unsigned long end,
         pmd_t *pmd = pmd_offset(pud, 0);
         unsigned long last_map_addr;
 
-        spin_lock(&init_mm.page_table_lock);
         last_map_addr = phys_pmd_init(pmd, address, end, page_size_mask);
-        spin_unlock(&init_mm.page_table_lock);
         __flush_tlb_all();
         return last_map_addr;
 }
@@ -408,20 +413,21 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end,
 
                 if (page_size_mask & (1<<PG_LEVEL_1G)) {
                         pages++;
+                        spin_lock(&init_mm.page_table_lock);
                         set_pte((pte_t *)pud,
                                 pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL_LARGE));
+                        spin_unlock(&init_mm.page_table_lock);
                         last_map_addr = (addr & PUD_MASK) + PUD_SIZE;
                         continue;
                 }
 
                 pmd = alloc_low_page(&pmd_phys);
-
-                spin_lock(&init_mm.page_table_lock);
                 last_map_addr = phys_pmd_init(pmd, addr, end, page_size_mask);
                 unmap_low_page(pmd);
+
+                spin_lock(&init_mm.page_table_lock);
                 pud_populate(&init_mm, pud, __va(pmd_phys));
                 spin_unlock(&init_mm.page_table_lock);
-
         }
         __flush_tlb_all();
         update_page_count(PG_LEVEL_1G, pages);
@@ -513,16 +519,14 @@ static unsigned long __init kernel_physical_mapping_init(unsigned long start,
                         continue;
                 }
 
-                if (after_bootmem)
-                        pud = pud_offset(pgd, start & PGDIR_MASK);
-                else
-                        pud = alloc_low_page(&pud_phys);
-
+                pud = alloc_low_page(&pud_phys);
                 last_map_addr = phys_pud_init(pud, __pa(start), __pa(next),
                                                  page_size_mask);
                 unmap_low_page(pud);
-                pgd_populate(&init_mm, pgd_offset_k(start),
-                             __va(pud_phys));
+
+                spin_lock(&init_mm.page_table_lock);
+                pgd_populate(&init_mm, pgd, __va(pud_phys));
+                spin_unlock(&init_mm.page_table_lock);
         }
 
         return last_map_addr;