linux/i386: enhance dump_fault_path() in the highpte case

As long as the pte page isn't really located in highmem, there is no
reason to not access it, in order to print the complete page table
hierarchy. A functionally similar patch will go to lkml for native
Linux.

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

diff --git a/linux-2.6-xen-sparse/arch/i386/mm/fault-xen.c b/linux-2.6-xen-sparse/arch/i386/mm/fault-xen.c
index cd40fabc0858b3758c82fbf20b9a4cf2081b4e5d..7e52b47b04fc14cda1fcf00b580fe3d156368c59 100644 (file)
--- a/linux-2.6-xen-sparse/arch/i386/mm/fault-xen.c
+++ b/linux-2.6-xen-sparse/arch/i386/mm/fault-xen.c
@@ -232,9 +232,12 @@ static void dump_fault_path(unsigned long address)
                p += (address >> 21) * 2;
                printk(KERN_ALERT "%08lx -> *pme = %08lx:%08lx\n", 
                       page, p[1], p[0]);
-#ifndef CONFIG_HIGHPTE
+               mfn  = (p[0] >> PAGE_SHIFT) | (p[1] << 20);
+#ifdef CONFIG_HIGHPTE
+               if (mfn_to_pfn(mfn) >= highstart_pfn)
+                       return;
+#endif
                if (p[0] & 1) {
-                       mfn  = (p[0] >> PAGE_SHIFT) | (p[1] << 20);
                        page = mfn_to_pfn(mfn) << PAGE_SHIFT; 
                        p  = (unsigned long *) __va(page);
                        address &= 0x001fffff;
@@ -242,7 +245,6 @@ static void dump_fault_path(unsigned long address)
                        printk(KERN_ALERT "%08lx -> *pte = %08lx:%08lx\n",
                               page, p[1], p[0]);
                }
-#endif
        }
 }
 #else
@@ -254,13 +256,16 @@ static void dump_fault_path(unsigned long address)
        page = ((unsigned long *) __va(page))[address >> 22];
        printk(KERN_ALERT "*pde = ma %08lx pa %08lx\n", page,
               machine_to_phys(page));
+#ifdef CONFIG_HIGHPTE
        /*
         * We must not directly access the pte in the highpte
-        * case, the page table might be allocated in highmem.
+        * case if the page table is located in highmem.
         * And lets rather not kmap-atomic the pte, just in case
         * it's allocated already.
         */
-#ifndef CONFIG_HIGHPTE
+       if ((page >> PAGE_SHIFT) >= highstart_pfn)
+               return;
+#endif
        if (page & 1) {
                page &= PAGE_MASK;
                address &= 0x003ff000;
@@ -269,7 +274,6 @@ static void dump_fault_path(unsigned long address)
                printk(KERN_ALERT "*pte = ma %08lx pa %08lx\n", page,
                       machine_to_phys(page));
        }
-#endif
 }
 #endif