From: kfraser@localhost.localdomain <kfraser@localhost.localdomain>
Date: Wed, 17 Jan 2007 14:45:00 +0000 (+0000)
Subject: linux/i386: enhance dump_fault_path() in the highpte case
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~15396^2~8
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=f8871496b97e9cd485de048d4ce1d987425081c5;p=xen.git

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 cd40fabc08..7e52b47b04 100644
--- 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