[LINUX][X86_64] Destroy initial page-table mappings to avoid overlap with modules.

The temporary mappings needed to set up the 1:1 mappings must be torn
down after use; otherwise they may trigger the
WARN_ON() in vmap_pte_range() (namely if the chunk allocated to hold
kernel and initial page tables gets close to or
exceeds 128Mb, or if a sufficiently high mem= argument causes the
static allocations to grow beyond 128Mb, which in
either case means these mappings extend into the modules area).

Signed-off-by: Jan Beulich <jbeulich@novell.com>

diff --git a/linux-2.6-xen-sparse/arch/x86_64/mm/init-xen.c b/linux-2.6-xen-sparse/arch/x86_64/mm/init-xen.c
index 1de014d05b33e210c2d94ddca912c77cf9baf1fb..9646f60598f0a6e09181a26170ef27c11b5f4dc6 100644 (file)
--- a/linux-2.6-xen-sparse/arch/x86_64/mm/init-xen.c
+++ b/linux-2.6-xen-sparse/arch/x86_64/mm/init-xen.c
@@ -666,7 +666,18 @@ void __meminit init_memory_mapping(unsigned long start, unsigned long end)
                        set_pgd(pgd_offset_k(start), mk_kernel_pgd(pud_phys));
        }
 
-       BUG_ON(!after_bootmem && start_pfn != table_end);
+       if (!after_bootmem) {
+               BUG_ON(start_pfn != table_end);
+               /*
+                * Destroy the temporary mappings created above. Prevents
+                * overlap with modules area (if init mapping is very big).
+                */
+               start = __START_KERNEL_map + (table_start << PAGE_SHIFT);
+               end   = __START_KERNEL_map + (table_end   << PAGE_SHIFT);
+               for (; start < end; start += PAGE_SIZE)
+                       WARN_ON(HYPERVISOR_update_va_mapping(
+                               start, __pte_ma(0), 0));
+       }
 
        __flush_tlb_all();
 }