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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 v2 03/14] x86/shstk: Introduce Supervisor Shadow Stack support
Date: Fri, 29 May 2020 16:51:18 +0100	[thread overview]
Message-ID: <20200529155118.GL2105@perard.uk.xensource.com> (raw)
In-Reply-To: <c3c3aea0-806f-4058-c1aa-cdc0f75007e2@suse.com>

On Fri, May 29, 2020 at 01:59:55PM +0200, Jan Beulich wrote:
> On 28.05.2020 20:10, Andrew Cooper wrote:
> > On 28/05/2020 11:25, Jan Beulich wrote:
> >> On 27.05.2020 21:18, 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 -)
> >> Is this actually checking the right thing in the clang case?
> > 
> > Appears to work correctly for me.  (Again, its either fine, or need
> > bugfixing anyway for 4.14, and raising with Linux as this is unmodified
> > upstream code like the rest of Kconfig.include).
> 
> This answer made me try it out: On a system with clang 5 and
> binutils 2.32 "incsspd	%eax" translates fine with
> -no-integrated-as but doesn't without. The previously mentioned
> odd use of CLANG_FLAGS, perhaps together with the disconnect
> from where we establish whether to use -no-integrated-as in the
> first place (arch.mk; I have no idea whether the CFLAGS
> determined would be usable by the kconfig invocation, nor how
> to solve the chicken-and-egg problem there if this is meant to
> work that way), may be the reason for this. Cc-ing Anthony once
> again ...

I've just prepare/sent a patch which should fix this CLANG_FLAGS issue
and allows to tests the assembler in Kconfig.

See: [XEN PATCH] xen/build: introduce CLANG_FLAGS for testing other CFLAGS

-- 
Anthony PERARD


  reply	other threads:[~2020-05-29 15:51 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-27 19:18 [PATCH v2 00/14] x86: Support for CET Supervisor Shadow Stacks Andrew Cooper
2020-05-27 19:18 ` [PATCH v2 01/14] x86/traps: Clean up printing in {do_reserved, fatal}_trap() Andrew Cooper
2020-05-28  9:45   ` [PATCH v2 01/14] x86/traps: Clean up printing in {do_reserved,fatal}_trap() Jan Beulich
2020-05-27 19:18 ` [PATCH v2 02/14] x86/traps: Factor out extable_fixup() and make printing consistent Andrew Cooper
2020-05-28  9:50   ` Jan Beulich
2020-05-28 17:26     ` Andrew Cooper
2020-05-27 19:18 ` [PATCH v2 03/14] x86/shstk: Introduce Supervisor Shadow Stack support Andrew Cooper
2020-05-28 10:25   ` Jan Beulich
2020-05-28 18:10     ` Andrew Cooper
2020-05-29 11:59       ` Jan Beulich
2020-05-29 15:51         ` Anthony PERARD [this message]
2020-05-29 18:39           ` Andrew Cooper
2020-06-02 12:09             ` Jan Beulich
2020-05-29 18:36         ` Andrew Cooper
2020-06-02 12:06           ` Jan Beulich
2020-06-02 12:26             ` Anthony PERARD
2020-06-02 12:41               ` Jan Beulich
2020-06-02 13:50                 ` Anthony PERARD
2020-06-02 14:13                   ` Jan Beulich
2020-05-27 19:18 ` [PATCH v2 04/14] x86/traps: Implement #CP handler and extend #PF for shadow stacks Andrew Cooper
2020-05-28 12:03   ` Jan Beulich
2020-05-28 13:22     ` Andrew Cooper
2020-05-28 13:31       ` Jan Beulich
2020-05-29 18:50         ` Andrew Cooper
2020-05-27 19:18 ` [PATCH v2 05/14] x86/shstk: Re-layout the stack block " Andrew Cooper
2020-05-28 12:33   ` Jan Beulich
2020-05-29 19:21     ` Andrew Cooper
2020-05-27 19:18 ` [PATCH v2 06/14] x86/shstk: Create " Andrew Cooper
2020-05-28 12:50   ` Jan Beulich
2020-05-29 19:35     ` Andrew Cooper
2020-05-29 21:45       ` Andrew Cooper
2020-06-02 12:32         ` Jan Beulich
2020-06-02 12:35       ` Jan Beulich
2020-05-27 19:18 ` [PATCH v2 07/14] x86/cpu: Adjust enable_nmis() to be shadow stack compatible Andrew Cooper
2020-05-27 19:18 ` [PATCH v2 08/14] x86/cpu: Adjust reset_stack_and_jump() " Andrew Cooper
2020-05-28 14:41   ` Jan Beulich
2020-05-27 19:18 ` [PATCH v2 09/14] x86/spec-ctrl: Adjust DO_OVERWRITE_RSB " Andrew Cooper
2020-05-27 19:18 ` [PATCH v2 10/14] x86/extable: Adjust extable handling " Andrew Cooper
2020-05-28 16:15   ` Jan Beulich
2020-05-29 19:43     ` Andrew Cooper
2020-05-29 21:17       ` Andrew Cooper
2020-06-02 13:11         ` Jan Beulich
2020-06-02 12:57       ` Jan Beulich
2020-05-27 19:18 ` [PATCH v2 11/14] x86/alt: Adjust _alternative_instructions() to not create shadow stacks Andrew Cooper
2020-05-29 12:23   ` Jan Beulich
2020-05-29 19:46     ` Andrew Cooper
2020-05-27 19:18 ` [PATCH v2 12/14] x86/entry: Adjust guest paths to be shadow stack compatible Andrew Cooper
2020-05-29 12:40   ` Jan Beulich
2020-05-29 19:58     ` Andrew Cooper
2020-05-27 19:18 ` [PATCH v2 13/14] x86/S3: Save and restore Shadow Stack configuration Andrew Cooper
2020-05-29 12:52   ` Jan Beulich
2020-05-29 20:00     ` Andrew Cooper
2020-05-27 19:18 ` [PATCH v2 14/14] x86/shstk: Activate Supervisor Shadow Stacks Andrew Cooper
2020-05-29 13:09   ` Jan Beulich
2020-05-29 20:28     ` Andrew Cooper
2020-05-29 22:28 ` [PATCH v2 00/14] x86: Support for CET " Andrew Cooper

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