From: Peter Zijlstra <peterz@infradead.org>
To: "Woodhouse, David" <dwmw@amazon.co.uk>
Cc: "Thomas.Lendacky@amd.com" <Thomas.Lendacky@amd.com>,
"bp@alien8.de" <bp@alien8.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"tim.c.chen@linux.intel.com" <tim.c.chen@linux.intel.com>,
"Ghitulete, Razvan-alin" <rga@amazon.com>,
"torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"ak@linux.intel.com" <ak@linux.intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"riel@redhat.com" <riel@redhat.com>,
"keescook@google.com" <keescook@google.com>,
"gnomes@lxorguk.ukuu.org.uk" <gnomes@lxorguk.ukuu.org.uk>,
"pjt@google.com" <pjt@google.com>,
"dave.hansen@intel.com" <dave.hansen@intel.com>,
"luto@amacapital.net" <luto@amacapital.net>,
"jikos@kernel.org" <jikos@kernel.org>,
"gregkh@linux-foundation.org" <gregkh@linux-foundation.org>
Subject: Re: [PATCH] x86/retpoline: Fill return stack buffer on vmexit
Date: Thu, 11 Jan 2018 10:32:31 +0100 [thread overview]
Message-ID: <20180111093231.GX6176@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1515661628.22302.294.camel@amazon.co.uk>
On Thu, Jan 11, 2018 at 09:07:09AM +0000, Woodhouse, David wrote:
> On Thu, 2018-01-11 at 09:49 +0100, Boris Petkov wrote:
> > On January 11, 2018 9:42:38 AM GMT+01:00, Peter Zijlstra wrote:
> > >Or we teach the alternative thing to patch in a jmp to end instead of
> > >NOP padding the entire thing as soon as the jmp (3 bytes) fits ?
> >
> > Or, even better: use alternative_call() to call functions instead of patching gazillion bytes.
>
> For this one I kind of wanted to keep it as a macro so we can select
> which register it uses.
can't you do lovely things like:
volatile asm ("call __fill_rsb_thunk_%1" : : "r" (dummy))
which would still let gcc select the register ?
next prev parent reply other threads:[~2018-01-11 9:32 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-10 22:51 [PATCH] x86/retpoline: Fill return stack buffer on vmexit David Woodhouse
2018-01-10 23:22 ` David Lang
2018-01-10 23:32 ` Woodhouse, David
2018-01-10 23:47 ` Tim Chen
2018-01-11 0:04 ` Woodhouse, David
2018-01-11 8:42 ` Peter Zijlstra
2018-01-11 8:49 ` Boris Petkov
2018-01-11 9:07 ` Woodhouse, David
2018-01-11 9:32 ` Peter Zijlstra [this message]
2018-01-11 9:47 ` Borislav Petkov
2018-01-11 9:58 ` Peter Zijlstra
2018-01-11 9:58 ` Woodhouse, David
2018-01-10 23:47 ` David Woodhouse
2018-01-11 0:14 ` Tom Lendacky
2018-01-11 1:04 ` David Woodhouse
2018-01-11 1:12 ` David Woodhouse
2018-01-12 0:34 ` Tom Lendacky
2018-01-11 8:49 ` Peter Zijlstra
2018-01-11 12:10 ` Woodhouse, David
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