From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Date: Mon, 12 Jul 2004 18:08:11 +0000 Subject: Re: serious performance regression due to NX patch Message-Id: List-Id: References: <200407100528.i6A5SF8h020094@napali.hpl.hp.com> <20040711123803.GD21264@devserv.devel.redhat.com> In-Reply-To: <20040711123803.GD21264@devserv.devel.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Jakub Jelinek 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, 11 Jul 2004, Jakub Jelinek wrote: > > --- 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. so ... this should be #ifndef ia64? to all the purists: this cannot be done via VM_DATA_DEFAULT_FLAGS, because some architectures enforce the X bit, some dont. In fact only ia64 seems to enforce it reliably for all binaries. the #ifdef could be made an arch inline or define. But it's really academic as only ia64 seems to have this problem. So i'd suggest the patch below. Ingo --- linux/fs/binfmt_elf.c.orig +++ linux/fs/binfmt_elf.c @@ -627,8 +627,14 @@ static int load_elf_binary(struct linux_ executable_stack = EXSTACK_DISABLE_X; break; } +#ifndef __ia64__ + /* + * Legacy binaries (except ia64) 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 /* Some simple consistency checks for the interpreter */ if (elf_interpreter) {