Re: serious performance regression due to NX patch

[David Mosberger <davidm@napali.hpl.hp.com>]

>>>>> On Sun, 11 Jul 2004 05:39:23 -0400 (EDT), Ingo Molnar <mingo@redhat.com> said:

  Ingo> On Sun, 11 Jul 2004, Ingo Molnar wrote:

  >> ok, agreed. I'll check that it still does the right thing on x86.

  Ingo> it doesnt seem to do the right thing for !PT_GNU_STACK applications on 
  Ingo> x86:

How about the patch below (on top of Linus' current bk tree)?  Only
platforms which had VM_DATA_DEFAULT_FLAGS changed (as a result of the
NX patch) will need to define LEGACY_VM_DATA_DEFAULT_FLAGS to the old
value.  AFAIK, that's x86 only, so the impact is very minimal and
should retain the existing behavior on all other platforms.

	--david

===== fs/binfmt_elf.c 1.80 vs edited =====
--- 1.80/fs/binfmt_elf.c	2004-07-16 16:46:22 -07:00
+++ edited/fs/binfmt_elf.c	2004-07-16 17:25:26 -07:00
@@ -662,9 +662,9 @@
 		SET_PERSONALITY(elf_ex, ibcs2_interpreter);
 	}
 
-	/* Now that personality is set, we can use VM_DATA_DEFAULT_FLAGS.  */
+	/* Now that personality is set, we can use LEGACY_VM_DATA_DEFAULT_FLAGS.  */
 	if (no_gnu_stack)
-		def_flags |= VM_DATA_DEFAULT_FLAGS & (VM_EXEC | VM_MAYEXEC);
+		def_flags |= LEGACY_VM_DATA_DEFAULT_FLAGS & (VM_EXEC | VM_MAYEXEC);
 
 	/* OK, we are done with that, now set up the arg stuff,
 	   and then start this sucker up */
===== include/asm-i386/page.h 1.26 vs edited =====
--- 1.26/include/asm-i386/page.h	2004-07-01 17:00:00 -07:00
+++ edited/include/asm-i386/page.h	2004-07-16 17:24:26 -07:00
@@ -142,6 +142,7 @@
 
 #define VM_DATA_DEFAULT_FLAGS	(VM_READ | VM_WRITE | \
 				 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+#define LEGACY_VM_DATA_DEFAULT_FLAGS	(VM_DATA_DEFAULT_FLAGS | VM_EXEC)
 
 #endif /* __KERNEL__ */
 
===== include/linux/mm.h 1.138 vs edited =====
--- 1.138/include/linux/mm.h	2004-07-06 22:19:25 -07:00
+++ edited/include/linux/mm.h	2004-07-16 17:23:41 -07:00
@@ -136,6 +136,10 @@
 #define VM_HUGETLB	0x00400000	/* Huge TLB Page VM */
 #define VM_NONLINEAR	0x00800000	/* Is non-linear (remap_file_pages) */
 
+#ifndef LEGACY_VM_DATA_DEFAULT_FLAGS
+#define LEGACY_VM_DATA_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
+#endif
+
 #ifndef VM_STACK_DEFAULT_FLAGS		/* arch can override this */
 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
 #endif