From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jakub Jelinek Date: Sun, 11 Jul 2004 12:38:04 +0000 Subject: Re: serious performance regression due to NX patch Message-Id: <20040711123803.GD21264@devserv.devel.redhat.com> List-Id: References: <200407100528.i6A5SF8h020094@napali.hpl.hp.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Ingo Molnar Cc: davidm@hpl.hp.com, suresh.b.siddha@intel.com, jun.nakajima@intel.com, Andrew Morton , Linus Torvalds , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org On Sun, Jul 11, 2004 at 05:52:59AM -0400, Ingo Molnar wrote: > > On Sun, 11 Jul 2004, Ingo Molnar wrote: > > > > ok, agreed. I'll check that it still does the right thing on x86. > > > > it doesnt seem to do the right thing for !PT_GNU_STACK applications on > > x86: > > how about the patch below? This way we recognize the fact that x86 didnt > have any executability check previously at the point where we discover > that it's a 'legacy' binary. > > Ingo > > --- linux/fs/binfmt_elf.c.orig3 > +++ linux/fs/binfmt_elf.c > @@ -627,8 +627,14 @@ static int load_elf_binary(struct linux_ > executable_stack = EXSTACK_DISABLE_X; > break; > } > +#ifdef __i386_ > + /* > + * Legacy x86 binaries have an expectation of executability for > + * virtually all their address-space - turn executability on: > + */ > if (i = elf_ex.e_phnum) > def_flags |= VM_EXEC | VM_MAYEXEC; > +#endif This looks incorrect. There are many arches where legacy binaries expect the executability for virtually all their address-space (my guess is all but x86-64 and ia64), and even on those two legacy binaries expected at least stack executable. And on x86-64 and ia64 ia32 binaries (i.e. when binfmt_elf.c is included in their binfmt_elf32.c or how is it called) should have VM_EXEC and VM_MAYEXEC in def_flags. Jakub