From 4d3e13ce3849bc1c5e9ce3b4ab6f40f0b37f2bfe Mon Sep 17 00:00:00 2001 From: Miroslav Rezanina Date: Wed, 5 Feb 2014 15:02:19 +0100 Subject: configure: add option to disable -fstack-protect RH-Author: Miroslav Rezanina Message-id: Patchwork-id: 57118 O-Subject: [RHEL7 qemu-kvm PATCH 1/2] configure: add option to disable -fstack-protect Bugzilla: 1044182 RH-Acked-by: Paolo Bonzini RH-Acked-by: Marcel Apfelbaum RH-Acked-by: Markus Armbruster From: Miroslav Rezanina upstream: submitted (Do not wait for apply to get to RHEL 7.0 before Snapshot 8) The -fstack-protector flag family is useful for ensuring safety and for debugging, but has a performance impact. Here are some boot time comparisons of the various versions of -fstack-protector using qemu-system-arm on an x86_64 host: # -fstack-protector-all Startup finished in 1.810s (kernel) + 12.331s (initrd) + 49.016s (userspace) = 1min 3.159s Startup finished in 1.801s (kernel) + 12.287s (initrd) + 47.925s (userspace) = 1min 2.013s Startup finished in 1.812s (kernel) + 12.302s (initrd) + 47.995s (userspace) = 1min 2.111s # -fstack-protector-strong Startup finished in 1.744s (kernel) + 11.223s (initrd) + 44.688s (userspace) = 57.657s Startup finished in 1.721s (kernel) + 11.222s (initrd) + 44.194s (userspace) = 57.138s Startup finished in 1.693s (kernel) + 11.250s (initrd) + 44.426s (userspace) = 57.370s # -fstack-protector Startup finished in 1.705s (kernel) + 11.409s (initrd) + 43.563s (userspace) = 56.677s Startup finished in 1.877s (kernel) + 11.137s (initrd) + 43.719s (userspace) = 56.734s Startup finished in 1.708s (kernel) + 11.141s (initrd) + 43.628s (userspace) = 56.478s # no stack protector Startup finished in 1.743s (kernel) + 11.190s (initrd) + 43.709s (userspace) = 56.643s Startup finished in 1.763s (kernel) + 11.216s (initrd) + 43.767s (userspace) = 56.747s Startup finished in 1.711s (kernel) + 11.283s (initrd) + 43.878s (userspace) = 56.873s This patch introduces a configure option to disable the stack protector entirely, and conditional stack protector flag selection (in order, based on availability): -fstack-protector-strong, -fstack-protector, no stack protector. Signed-off-by: Steven Noonan Cc: Anthony Liguori Reviewed-by: Stefan Weil Signed-off-by: Miroslav Rezanina diff --git a/configure b/configure index 3cb1298..bebae4c 100755 --- a/configure +++ b/configure @@ -1281,6 +1281,7 @@ Advanced options (experts only): --disable-strip disable stripping binaries --disable-werror disable compilation abort on warning --disable-stack-protector disable compiler-provided stack protection + --enable-stack-protector enable compiler-provided stack protection --disable-sdl disable SDL --enable-sdl enable SDL --with-sdlabi select preferred SDL ABI 1.2 or 2.0