From: Andi Kleen <ak@suse.de>
Date: Wed, 11 Jan 2006 21:44:00 +0000 (+0100)
Subject: [PATCH] x86_64: Remove unnecessary case from the page fault handler
X-Git-Tag: v2.6.16-rc1~348
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f95190b28daa1bebf78ab5ec4129d01a223982c5;p=linux-2.6

[PATCH] x86_64: Remove unnecessary case from the page fault handler

Don't need to do the vmalloc check for the module range because its
PML4 is shared with the kernel text.

Also removed an unnecessary TLB flush.

Pointed out by Jan Beulich

Cc: jbeulich@novell.com

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c
index fd07b86c06..2a9c836133 100644
--- a/arch/x86_64/mm/fault.c
+++ b/arch/x86_64/mm/fault.c
@@ -237,7 +237,7 @@ static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
 }
 
 /*
- * Handle a fault on the vmalloc or module mapping area
+ * Handle a fault on the vmalloc area
  *
  * This assumes no large pages in there.
  */
@@ -283,7 +283,6 @@ static int vmalloc_fault(unsigned long address)
 	   that. */
 	if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref))
 		BUG();
-	__flush_tlb_all();
 	return 0;
 }
 
@@ -346,9 +345,13 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	 * protection error (error_code & 9) == 0.
 	 */
 	if (unlikely(address >= TASK_SIZE64)) {
+		/*
+		 * Don't check for the module range here: its PML4
+		 * is always initialized because it's shared with the main
+		 * kernel text. Only vmalloc may need PML4 syncups.
+		 */
 		if (!(error_code & 0xd) &&
-		      ((address >= VMALLOC_START && address < VMALLOC_END) ||
-		       (address >= MODULES_VADDR && address < MODULES_END))) {
+		      ((address >= VMALLOC_START && address < VMALLOC_END))) {
 			if (vmalloc_fault(address) < 0)
 				goto bad_area_nosemaphore;
 			return;