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authorSteven Noonan2014-03-28 17:19:02 +0100
committerPeter Maydell2014-03-31 21:16:02 +0200
commit63678e17cf399ff81b93417fe7bee8d6ef6b6b1b (patch)
tree85c035792e228efd51594b60d7c6f345adf1b9a8 /configure
parentpci: Fix clearing IRQs on reset (diff)
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configure: add option to disable -fstack-protector flags
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-all, no stack protector. Signed-off-by: Steven Noonan <snoonan@amazon.com> Cc: Anthony Liguori <aliguori@amazon.com> Reviewed-by: Stefan Weil <sw@weilnetz.de> [Prefer -fstack-protector-all to -fstack-protector, suggested by Laurent Desnogues. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'configure')
-rwxr-xr-xconfigure18
1 files changed, 15 insertions, 3 deletions
diff --git a/configure b/configure
index fb3bd0588f..eb0e7bbce0 100755
--- a/configure
+++ b/configure
@@ -198,6 +198,7 @@ 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
@@ -950,6 +951,10 @@ 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"
@@ -1219,6 +1224,7 @@ Advanced options (experts only):
--disable-sparse disable sparse checker (default)
--disable-strip disable stripping binaries
--disable-werror disable compilation abort on warning
+ --disable-stack-protector disable compiler-provided stack protection
--disable-sdl disable SDL
--enable-sdl enable SDL
--with-sdlabi select preferred SDL ABI 1.2 or 2.0
@@ -1439,9 +1445,15 @@ 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-all"
+ 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