[IA64] Fill holes in FIXADDR_USER space with zero pages.

This fixes an oops reported by Jason Baron.

Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 17 insertions, 2 deletions

diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 547785e3cba2..4eb2f52b87a1 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -305,8 +305,9 @@ setup_gate (void)
         struct page *page;
 
         /*
-         * Map the gate page twice: once read-only to export the ELF headers etc. and once
-         * execute-only page to enable privilege-promotion via "epc":
+         * Map the gate page twice: once read-only to export the ELF
+         * headers etc. and once execute-only page to enable
+         * privilege-promotion via "epc":
          */
         page = virt_to_page(ia64_imva(__start_gate_section));
         put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
@@ -315,6 +316,20 @@ setup_gate (void)
         put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
 #else
         put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
+        /* Fill in the holes (if any) with read-only zero pages: */
+        {
+                unsigned long addr;
+
+                for (addr = GATE_ADDR + PAGE_SIZE;
+                     addr < GATE_ADDR + PERCPU_PAGE_SIZE;
+                     addr += PAGE_SIZE)
+                {
+                        put_kernel_page(ZERO_PAGE(0), addr,
+                                        PAGE_READONLY);
+                        put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
+                                        PAGE_READONLY);
+                }
+        }
 #endif
         ia64_patch_gate();
 }