Ensure that executable pages are properly guarded.

Ensure that executable pages are properly guarded.

Split executable memory chunks into two pieces: header with all metadata (protection: RW) and body (protection: RWX). Separate header from metadata with a guard page and add a guard page after the page body.

R=erik.corry@gmail.com
BUG=http://crbug.com/115151

Committed: https://code.google.com/p/v8/source/detail?r=10809

[Vyacheslav Egorov (Chromium), 2012-02-23 01:40:52]

fyi: Cris.

[Erik Corry, 2012-02-23 12:00:39]

LGTM

http://codereview.chromium.org/9452002/diff/1/src/mark-compact.cc
File src/mark-compact.cc (right):

http://codereview.chromium.org/9452002/diff/1/src/mark-compact.cc#newcode3077
src/mark-compact.cc:3077: int cell_index =
I think it is clearer to move this down to immediately before the for loop. 
Especially in this case, but also in the other cases in this file.

http://codereview.chromium.org/9452002/diff/1/src/platform-cygwin.cc
File src/platform-cygwin.cc (right):

http://codereview.chromium.org/9452002/diff/1/src/platform-cygwin.cc#newcode362
src/platform-cygwin.cc:362: PAGE_READONLY | PAGE_GUARD)) {
Can we not map it with no permissions at all, instead of read only?

http://codereview.chromium.org/9452002/diff/1/src/platform-freebsd.cc
File src/platform-freebsd.cc (right):

http://codereview.chromium.org/9452002/diff/1/src/platform-freebsd.cc#newcode416
src/platform-freebsd.cc:416: return true;
You could have put this in the posix file.

[Cris Neckar, 2012-02-23 19:04:25]

LGTM Thanks Slava!

On 2012/02/23 12:00:39, Erik Corry wrote:
> LGTM
> 
> http://codereview.chromium.org/9452002/diff/1/src/mark-compact.cc
> File src/mark-compact.cc (right):
> 
> http://codereview.chromium.org/9452002/diff/1/src/mark-compact.cc#newcode3077
> src/mark-compact.cc:3077: int cell_index =
> I think it is clearer to move this down to immediately before the for loop. 
> Especially in this case, but also in the other cases in this file.
> 
> http://codereview.chromium.org/9452002/diff/1/src/platform-cygwin.cc
> File src/platform-cygwin.cc (right):
> 
>
http://codereview.chromium.org/9452002/diff/1/src/platform-cygwin.cc#newcode362
> src/platform-cygwin.cc:362: PAGE_READONLY | PAGE_GUARD)) {
> Can we not map it with no permissions at all, instead of read only?
> 
> http://codereview.chromium.org/9452002/diff/1/src/platform-freebsd.cc
> File src/platform-freebsd.cc (right):
> 
>
http://codereview.chromium.org/9452002/diff/1/src/platform-freebsd.cc#newcode416
> src/platform-freebsd.cc:416: return true;
> You could have put this in the posix file.