From: Andrew Donnellan <hidden> Date: 2016-05-18 08:54:11
On 13/05/16 09:57, Emese Revfy wrote:
This patch allows to build the whole kernel with GCC plugins. It was ported from
grsecurity/PaX. The infrastructure supports building out-of-tree modules and
building in a separate directory. Cross-compilation is supported too.
Currently the x86, arm, arm64 and uml architectures enable plugins.
The directory of the gcc plugins is scripts/gcc-plugins. You can use a file or a directory
there. The plugins compile with these options:
* -fno-rtti: gcc is compiled with this option so the plugins must use it too
* -fno-exceptions: this is inherited from gcc too
* -fasynchronous-unwind-tables: this is inherited from gcc too
* -ggdb: it is useful for debugging a plugin (better backtrace on internal
errors)
* -Wno-narrowing: to suppress warnings from gcc headers (ipa-utils.h)
* -Wno-unused-variable: to suppress warnings from gcc headers (gcc_version
variable, plugin-version.h)
The infrastructure introduces a new Makefile target called gcc-plugins. It
supports all gcc versions from 4.5 to 6.0. The scripts/gcc-plugin.sh script
chooses the proper host compiler (gcc-4.7 can be built by either gcc or g++).
This script also checks the availability of the included headers in
scripts/gcc-plugins/gcc-common.h.
The gcc-common.h header contains frequently included headers for GCC plugins
and it has a compatibility layer for the supported gcc versions.
The gcc-generate-*-pass.h headers automatically generate the registration
structures for GIMPLE, SIMPLE_IPA, IPA and RTL passes.
Note that 'make clean' keeps the *.so files (only the distclean or mrproper
targets clean all) because they are needed for out-of-tree modules.
The arm and arm64 architectures were tested by David Brown [off-list ref].
Signed-off-by: Emese Revfy <redacted>
I've done some basic sanity testing on powerpc with the cyclomatic
complexity plugin (with LE native + cross-compilers) and it seems to
work with the patch below.
Signed-off-by: Andrew Donnellan <redacted>
I've done some basic sanity testing on powerpc with the cyclomatic
complexity plugin (with LE native + cross-compilers) and it seems to
work with the patch below.
Signed-off-by: Andrew Donnellan <redacted>
From: Andrew Donnellan <hidden> Date: 2016-05-18 21:16:06
On 18/05/16 20:33, Emese Revfy wrote:
Did you test the plugins with all gcc versions (4.5-6)?
No, I tested with 4.8 and 5.2 as those are the toolchains I have on hand
- I'll try to test with the rest of 4.5 - 6.1.
--
Andrew Donnellan OzLabs, ADL Canberra
andrew.donnellan@au1.ibm.com IBM Australia Limited
From: Michael Ellerman <mpe@ellerman.id.au> Date: 2016-05-19 06:22:18
On Wed, 2016-05-18 at 12:33 +0200, Emese Revfy wrote:
quoted
I've done some basic sanity testing on powerpc with the cyclomatic
complexity plugin (with LE native + cross-compilers) and it seems to
work with the patch below.
Signed-off-by: Andrew Donnellan <redacted>
Hi,
Did you test the plugins with all gcc versions (4.5-6)?
What's the concern about gcc versions? Just not breaking the build on old
compilers?
I'm pretty sure powerpc big endian still builds with gcc 4.4.
However if Andrew's only tested on little endian, then that select should be
guarded with an "if CPU_LITTLE_ENDIAN". And to build LE you need gcc >= 4.9.
cheers
From: Andrew Donnellan <hidden> Date: 2016-05-19 06:41:27
On 19/05/16 16:22, Michael Ellerman wrote:
quoted
Did you test the plugins with all gcc versions (4.5-6)?
What's the concern about gcc versions? Just not breaking the build on old
compilers?
I'm pretty sure powerpc big endian still builds with gcc 4.4.
gcc's plugin support only landed in 4.5, so we don't care about <=4.4.
However if Andrew's only tested on little endian, then that select should be
guarded with an "if CPU_LITTLE_ENDIAN". And to build LE you need gcc >= 4.9.
I'm going to give BE a test too just to be sure.
--
Andrew Donnellan OzLabs, ADL Canberra
andrew.donnellan@au1.ibm.com IBM Australia Limited
On Wed, 2016-05-18 at 12:33 +0200, Emese Revfy wrote:
quoted
Did you test the plugins with all gcc versions (4.5-6)?
What's the concern about gcc versions? Just not breaking the build on old
compilers?
the earlier plugin capable gcc versions used to install gcc headers in a somewhat
ad-hoc manner resulting in compile time breakage for plugins and since some of
those potentially missing headers are target specific, each target arch should
be verified before enabling plugin support on them. things have much improved with
gcc 5 (see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61176) though there's still
an occasional missing header but with wider use of plugins they will hopefully be
discovered earlier now. perhaps linux-arch should be cc'ed on the plugin infrastructure
so that arch maintainers are aware of this?
I'm pretty sure powerpc big endian still builds with gcc 4.4.
However if Andrew's only tested on little endian, then that select should be
guarded with an "if CPU_LITTLE_ENDIAN". And to build LE you need gcc >= 4.9.
i guess that's part of the target tuple so in general arch maintainers should test
the target tuples used on their arch with all the supported gcc versions (speaking
of CC, not HOSTCC/HOSTCXX).
cheers,
PaX Team
From: Andrew Donnellan <hidden> Date: 2016-05-20 06:23:16
On 19/05/16 18:24, PaX Team wrote:
the earlier plugin capable gcc versions used to install gcc headers in a somewhat
ad-hoc manner resulting in compile time breakage for plugins and since some of
those potentially missing headers are target specific, each target arch should
be verified before enabling plugin support on them. things have much improved with
gcc 5 (see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61176) though there's still
an occasional missing header but with wider use of plugins they will hopefully be
discovered earlier now. perhaps linux-arch should be cc'ed on the plugin infrastructure
so that arch maintainers are aware of this?
Upon further testing it does seem we've got header issues as well as
hitting a segfault on 4.7.0. Looking into it further...
--
Andrew Donnellan OzLabs, ADL Canberra
andrew.donnellan@au1.ibm.com IBM Australia Limited
From: Michael Ellerman <mpe@ellerman.id.au> Date: 2016-05-20 10:10:38
On Thu, 2016-05-19 at 10:24 +0200, PaX Team wrote:
On 19 May 2016 at 16:22, Michael Ellerman wrote:
quoted
On Wed, 2016-05-18 at 12:33 +0200, Emese Revfy wrote:
quoted
Did you test the plugins with all gcc versions (4.5-6)?
What's the concern about gcc versions? Just not breaking the build on old
compilers?
the earlier plugin capable gcc versions used to install gcc headers in a somewhat
ad-hoc manner resulting in compile time breakage for plugins and since some of
those potentially missing headers are target specific, each target arch should
be verified before enabling plugin support on them. things have much improved with
gcc 5 (see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61176) though there's still
an occasional missing header but with wider use of plugins they will hopefully be
discovered earlier now.
OK thanks.
perhaps linux-arch should be cc'ed on the plugin infrastructure
so that arch maintainers are aware of this?
linux-arch is still fairly high traffic, so it's no guarantee arch maintainers
will see it, but it's probably worth a try.
quoted
I'm pretty sure powerpc big endian still builds with gcc 4.4.
However if Andrew's only tested on little endian, then that select should be
guarded with an "if CPU_LITTLE_ENDIAN". And to build LE you need gcc >= 4.9.
i guess that's part of the target tuple so in general arch maintainers should test
the target tuples used on their arch with all the supported gcc versions (speaking
of CC, not HOSTCC/HOSTCXX).
Yeah. I think we'll probably enable it gradually as folks get time to test it.
ie. ppc64le first, then ppc64 (BE), and then 32-bit if someone is interested.
cheers