From: Anthony PERARD <anthony.perard@citrix.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
"Roger Pau Monné" <roger.pau@citrix.com>, "Wei Liu" <wl@xen.org>,
Xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH 05/16] x86/shstk: Introduce Supervisor Shadow Stack support
Date: Fri, 15 May 2020 17:21:08 +0100 [thread overview]
Message-ID: <20200515162108.GM2116@perard.uk.xensource.com> (raw)
In-Reply-To: <d0347fec-3ccb-daa7-5c4d-f0e74b5fb247@suse.com>
On Mon, May 04, 2020 at 03:52:58PM +0200, Jan Beulich wrote:
> On 02.05.2020 00:58, Andrew Cooper wrote:
> > --- a/xen/scripts/Kconfig.include
> > +++ b/xen/scripts/Kconfig.include
> > @@ -31,6 +31,10 @@ cc-option = $(success,$(CC) -Werror $(CLANG_FLAGS) $(1) -E -x c /dev/null -o /de
> > # Return y if the linker supports <flag>, n otherwise
> > ld-option = $(success,$(LD) -v $(1))
> >
> > +# $(as-instr,<instr>)
> > +# Return y if the assembler supports <instr>, n otherwise
> > +as-instr = $(success,printf "%b\n" "$(1)" | $(CC) $(CLANG_FLAGS) -c -x assembler -o /dev/null -)
>
> CLANG_FLAGS caught my eye here, then noticing that cc-option
> also uses it. Anthony - what's the deal with this? It doesn't
> look to get defined anywhere, and I also don't see what clang-
> specific about these constructs.
It's because these constructs are gcc-specific :-). Indeed CLANG_FLAGS
probably needs to be defined as I don't think providing the full
AFLAGS/CFLAGS is going to be a good idea and may change the result of
the commands.
Linux has a few clang specific flags in CLANG_FLAGS, I have found those:
The ones for cross compilation: --prefix, --target, --gcc-toolchain
-no-integrated-as
-Werror=unknown-warning-option
And that's it.
So, I think we could keep using CLANG_FLAGS in Kconfig.include and
define it in Makefile with a comment saying that it's only used by
Kconfig. It would always have -Werror=unknown-warning-option and have
-no-integrated-as when needed, the -Wunknown-warning-option is present
in clang 3.0.0, according Linux's commit 589834b3a009 ("kbuild: Add
-Werror=unknown-warning-option to CLANG_FLAGS").
The options -Werror=unknown-warning-option is to make sure that the
warning is enabled, even though it is by default but could be disabled
in a particular build of clang, see e8de12fb7cde ("kbuild: Check for
unknown options with cc-option usage in Kconfig and clang")
I'll write a patch with this new CLANG_FLAGS.
--
Anthony PERARD
next prev parent reply other threads:[~2020-05-15 16:21 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-01 22:58 [PATCH 00/16] x86: Support for CET Supervisor Shadow Stacks Andrew Cooper
2020-05-01 22:58 ` [PATCH 01/16] x86/traps: Drop last_extable_addr Andrew Cooper
2020-05-04 12:44 ` Jan Beulich
2020-05-11 14:53 ` Andrew Cooper
2020-05-11 15:00 ` Jan Beulich
2020-05-01 22:58 ` [PATCH 02/16] x86/traps: Clean up printing in do_reserved_trap()/fatal_trap() Andrew Cooper
2020-05-04 13:08 ` Jan Beulich
2020-05-11 15:01 ` Andrew Cooper
2020-05-11 15:09 ` Jan Beulich
2020-05-18 16:54 ` Andrew Cooper
2020-05-19 8:50 ` Jan Beulich
2020-05-26 15:38 ` Andrew Cooper
2020-05-27 6:54 ` Jan Beulich
2020-05-01 22:58 ` [PATCH 03/16] x86/traps: Factor out exception_fixup() and make printing consistent Andrew Cooper
2020-05-04 13:20 ` Jan Beulich
2020-05-11 15:14 ` Andrew Cooper
2020-05-12 13:05 ` Jan Beulich
2020-05-26 18:06 ` Andrew Cooper
2020-05-27 7:01 ` Jan Beulich
2020-05-01 22:58 ` [PATCH 04/16] x86/smpboot: Write the top-of-stack block in cpu_smpboot_alloc() Andrew Cooper
2020-05-04 13:22 ` Jan Beulich
2020-05-01 22:58 ` [PATCH 05/16] x86/shstk: Introduce Supervisor Shadow Stack support Andrew Cooper
2020-05-04 13:52 ` Jan Beulich
2020-05-11 15:46 ` Andrew Cooper
2020-05-12 13:54 ` Jan Beulich
2020-05-15 16:21 ` Anthony PERARD [this message]
2020-05-01 22:58 ` [PATCH 06/16] x86/traps: Implement #CP handler and extend #PF for shadow stacks Andrew Cooper
2020-05-04 14:10 ` Jan Beulich
2020-05-11 17:20 ` Andrew Cooper
2020-05-12 13:58 ` Jan Beulich
2020-05-01 22:58 ` [PATCH 07/16] x86/shstk: Re-layout the stack block " Andrew Cooper
2020-05-04 14:24 ` Jan Beulich
2020-05-11 17:48 ` Andrew Cooper
2020-05-12 14:07 ` Jan Beulich
2020-05-01 22:58 ` [PATCH 08/16] x86/shstk: Create " Andrew Cooper
2020-05-04 14:55 ` Jan Beulich
2020-05-04 15:08 ` Andrew Cooper
2020-05-01 22:58 ` [PATCH 09/16] x86/cpu: Adjust enable_nmis() to be shadow stack compatible Andrew Cooper
2020-05-05 14:48 ` Jan Beulich
2020-05-11 18:48 ` Andrew Cooper
2020-05-01 22:58 ` [PATCH 10/16] x86/cpu: Adjust reset_stack_and_jump() " Andrew Cooper
2020-05-07 13:17 ` Jan Beulich
2020-05-11 20:07 ` Andrew Cooper
2020-05-01 22:58 ` [PATCH 11/16] x86/spec-ctrl: Adjust DO_OVERWRITE_RSB " Andrew Cooper
2020-05-07 13:22 ` Jan Beulich
2020-05-07 13:25 ` Andrew Cooper
2020-05-07 13:38 ` Jan Beulich
2020-05-01 22:58 ` [PATCH 12/16] x86/extable: Adjust extable handling " Andrew Cooper
2020-05-07 13:35 ` Jan Beulich
2020-05-11 21:09 ` Andrew Cooper
2020-05-12 14:31 ` Jan Beulich
2020-05-12 16:14 ` Andrew Cooper
2020-05-13 9:22 ` Jan Beulich
2020-05-01 22:58 ` [PATCH 13/16] x86/ioemul: Rewrite stub generation " Andrew Cooper
2020-05-07 13:46 ` Jan Beulich
2020-05-01 22:58 ` [PATCH 14/16] x86/alt: Adjust _alternative_instructions() to not create shadow stacks Andrew Cooper
2020-05-07 13:49 ` Jan Beulich
2020-05-01 22:58 ` [PATCH 15/16] x86/entry: Adjust guest paths to be shadow stack compatible Andrew Cooper
2020-05-07 14:12 ` Jan Beulich
2020-05-07 15:50 ` Andrew Cooper
2020-05-07 16:15 ` Jan Beulich
2020-05-11 21:45 ` Andrew Cooper
2020-05-12 14:56 ` Jan Beulich
2020-05-01 22:58 ` [PATCH 16/16] x86/shstk: Activate Supervisor Shadow Stacks Andrew Cooper
2020-05-07 14:54 ` Jan Beulich
2020-05-11 23:46 ` Andrew Cooper
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