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Re: [Qemu-devel] [PATCH] configure: add option to disable -fstack-protec
From: |
Noonan, Steven |
Subject: |
Re: [Qemu-devel] [PATCH] configure: add option to disable -fstack-protector flags |
Date: |
Mon, 13 Jan 2014 12:38:24 -0800 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Jan 13, 2014 at 09:27:42PM +0100, Stefan Weil wrote:
> Hi,
>
> please see comments below.
>
> Am 13.01.2014 21:00, schrieb Steven Noonan:
> > 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 <address@hidden>
> > ---
> > configure | 18 +++++++++++++++---
> > 1 file changed, 15 insertions(+), 3 deletions(-)
> >
> > diff --git a/configure b/configure
> > index 07b6be3..c9c0b2c 100755
> > --- a/configure
> > +++ b/configure
> > @@ -147,6 +147,7 @@ audio_win_int=""
> > cc_i386=i386-pc-linux-gnu-gcc
> > libs_qga=""
> > debug_info="yes"
> > +stack_protector=""
> >
> > # Don't accept a target_list environment variable.
> > unset target_list
> > @@ -879,6 +880,10 @@ for opt do
> > ;;
> > --disable-werror) werror="no"
> > ;;
> > + --enable-stack-protector) stack_protector="yes"
> > + ;;
> > + --disable-stack-protector) stack_protector="no"
> > + ;;
> > --disable-curses) curses="no"
> > ;;
> > --enable-curses) curses="yes"
> > @@ -1117,6 +1122,7 @@ echo " --enable-sparse enable sparse
> > checker"
> > echo " --disable-sparse disable sparse checker (default)"
> > echo " --disable-strip disable stripping binaries"
> > echo " --disable-werror disable compilation abort on warning"
> > +echo " --disable-stack-protector disable GCC-provided stack protection"
>
>
> Clang also supports stack protection AFAIK, so "GCC-provided" can be
> removed here (or replaced by "compiler").
>
Fixed in v3 of the patch.
>
> > echo " --disable-sdl disable SDL"
> > echo " --enable-sdl enable SDL"
> > echo " --disable-gtk disable gtk UI"
> > @@ -1298,9 +1304,15 @@ for flag in $gcc_flags; do
> > fi
> > done
> >
> > -if compile_prog "-Werror -fstack-protector-all" "" ; then
> > - QEMU_CFLAGS="$QEMU_CFLAGS -fstack-protector-all"
> > - LIBTOOLFLAGS="$LIBTOOLFLAGS -Wc,-fstack-protector-all"
> > +if test "$stack_protector" != "no" ; then
> > + gcc_flags="-fstack-protector-strong -fstack-protector"
> > + for flag in $gcc_flags; do
> > + if compile_prog "-Werror $flag" "" ; then
> > + QEMU_CFLAGS="$QEMU_CFLAGS $flag"
> > + LIBTOOLFLAGS="$LIBTOOLFLAGS -Wc,$flag"
> > + break
> > + fi
> > + done
> > fi
> >
> > # Workaround for http://gcc.gnu.org/PR55489. Happens with -fPIE/-fPIC and
> >
>
>
> Reviewed-by: Stefan Weil <address@hidden>
>
> I think this patch can be used as a base for further improvements (MinGW
> specific settings, error handling when user's choice does not work).
>
> Maybe you will have to resend the patch as a top level patch (don't use
> the reply function of your mailer). As Paolo said, Anthony might
> overwise be unable to pick it up with his scripts.
Thanks, I've done that now.
- Steven
- Re: [Qemu-devel] [PATCH 3/3] Makefile: add bios-256k.bin to BLOBS, (continued)
- Re: [Qemu-devel] [PATCH 1/3] configure: add option to disable -fstack-protector flags, Peter Maydell, 2014/01/09
- Re: [Qemu-devel] [PATCH 1/3] configure: add option to disable -fstack-protector flags, Paolo Bonzini, 2014/01/09
- Re: [Qemu-devel] [PATCH 1/3] configure: add option to disable -fstack-protector flags, Brad Smith, 2014/01/09
- Re: [Qemu-devel] [PATCH 1/3] configure: add option to disable -fstack-protector flags, Noonan, Steven, 2014/01/10
- Re: [Qemu-devel] [PATCH 1/3] configure: add option to disable -fstack-protector flags, Noonan, Steven, 2014/01/10
- Re: [Qemu-devel] [PATCH 1/3] configure: add option to disable -fstack-protector flags, Stefan Weil, 2014/01/11
- Re: [Qemu-devel] [PATCH 1/3] configure: add option to disable -fstack-protector flags, Paolo Bonzini, 2014/01/13
- [Qemu-devel] [PATCH] configure: add option to disable -fstack-protector flags, Steven Noonan, 2014/01/13
- Re: [Qemu-devel] [PATCH] configure: add option to disable -fstack-protector flags, Stefan Weil, 2014/01/13
- Re: [Qemu-devel] [PATCH] configure: add option to disable -fstack-protector flags,
Noonan, Steven <=