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From: Thomas Gleixner <tglx@linutronix.de>
To: Borislav Petkov <bp@alien8.de>
Cc: dwmw@amazon.co.uk, tim.c.chen@linux.intel.com, pjt@google.com,
	jikos@kernel.org, gregkh@linux-foundation.org,
	dave.hansen@intel.com, mingo@kernel.org, riel@redhat.com,
	luto@amacapital.net, torvalds@linux-foundation.org,
	ak@linux.intel.com, keescook@google.com, jpoimboe@redhat.com,
	peterz@infradead.org, hpa@zytor.com,
	linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/pti] x86/retpoline: Fill return stack buffer on vmexit
Date: Sun, 14 Jan 2018 16:28:47 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1801141628170.2371@nanos> (raw)
In-Reply-To: <20180114145009.2irs22q7xsj325iz@pd.tnic>

On Sun, 14 Jan 2018, Borislav Petkov wrote:

> On Fri, Jan 12, 2018 at 03:37:49AM -0800, tip-bot for David Woodhouse wrote:
> > Commit-ID:  117cc7a908c83697b0b737d15ae1eb5943afe35b
> > Gitweb:     https://git.kernel.org/tip/117cc7a908c83697b0b737d15ae1eb5943afe35b
> > Author:     David Woodhouse <dwmw@amazon.co.uk>
> > AuthorDate: Fri, 12 Jan 2018 11:11:27 +0000
> > Committer:  Thomas Gleixner <tglx@linutronix.de>
> > CommitDate: Fri, 12 Jan 2018 12:33:37 +0100
> > 
> > x86/retpoline: Fill return stack buffer on vmexit
> 
> ...
> 
> > + /*
> > +  * A simpler FILL_RETURN_BUFFER macro. Don't make people use the CPP
> > +  * monstrosity above, manually.
> > +  */
> > +.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req
> > +#ifdef CONFIG_RETPOLINE
> > +	ANNOTATE_NOSPEC_ALTERNATIVE
> > +	ALTERNATIVE "jmp .Lskip_rsb_\@",				\
> > +		__stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP))	\
> > +		\ftr
> > +.Lskip_rsb_\@:
> > +#endif
> > +.endm
> 
> Looks unused to me. Was it ever gound to be used? If not:

It's for the outstanding RSB fill after context switch.

Thanks,

	tglx

  reply	other threads:[~2018-01-14 15:29 UTC|newest]

Thread overview: 85+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-11 21:46 [PATCH v8 00/12] Retpoline: Avoid speculative indirect calls in kernel David Woodhouse
2018-01-11 21:46 ` [PATCH v8 01/12] objtool: Detect jumps to retpoline thunks David Woodhouse
2018-01-11 23:22   ` [tip:x86/pti] " tip-bot for Josh Poimboeuf
2018-01-11 21:46 ` [PATCH v8 02/12] objtool: Allow alternatives to be ignored David Woodhouse
2018-01-11 23:22   ` [tip:x86/pti] " tip-bot for Josh Poimboeuf
2018-01-18 19:09   ` [v8,02/12] " Guenter Roeck
2018-01-18 19:33     ` Josh Poimboeuf
2018-01-18 19:41       ` Guenter Roeck
2018-01-22 19:34         ` David Woodhouse
2018-01-22 20:25           ` Guenter Roeck
2018-01-22 20:27             ` David Woodhouse
2018-01-28 21:06             ` Josh Poimboeuf
2018-01-29  1:26               ` Guenter Roeck
2018-01-29 17:15               ` Guenter Roeck
2018-01-29 17:30                 ` Josh Poimboeuf
2018-01-22 19:27       ` Guenter Roeck
2018-01-11 21:46 ` [PATCH v8 03/12] x86/retpoline: Add initial retpoline support David Woodhouse
2018-01-11 23:23   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 23:58   ` [PATCH v8 03/12] " Tom Lendacky
2018-01-12 10:28     ` David Woodhouse
2018-01-12 14:02       ` Tom Lendacky
2018-01-14 15:02   ` Borislav Petkov
2018-01-14 15:53     ` Josh Poimboeuf
2018-01-14 15:59       ` Borislav Petkov
2018-01-11 21:46 ` [PATCH v8 04/12] x86/spectre: Add boot time option to select Spectre v2 mitigation David Woodhouse
2018-01-11 23:23   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-23 22:40   ` [PATCH v8 04/12] " Borislav Petkov
2018-01-23 22:53     ` David Woodhouse
2018-01-23 23:05       ` Andi Kleen
2018-01-23 22:55     ` Jiri Kosina
2018-01-23 23:05       ` Borislav Petkov
2018-01-24  0:32         ` Kees Cook
2018-01-24  9:58           ` Borislav Petkov
2018-01-23 23:06       ` Jiri Kosina
2018-01-23 23:21       ` Andi Kleen
2018-01-23 23:24         ` Jiri Kosina
2018-01-23 23:45           ` Andi Kleen
2018-01-23 23:49             ` Jiri Kosina
2018-01-24  4:26               ` Greg Kroah-Hartman
2018-01-24  9:56                 ` Jiri Kosina
2018-01-24 13:58                   ` Greg Kroah-Hartman
2018-01-24 14:03                     ` Jiri Kosina
2018-01-24 14:22                       ` Greg Kroah-Hartman
2018-01-11 21:46 ` [PATCH v8 05/12] x86/retpoline/crypto: Convert crypto assembler indirect jumps David Woodhouse
2018-01-11 23:24   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 21:46 ` [PATCH v8 06/12] x86/retpoline/entry: Convert entry " David Woodhouse
2018-01-11 23:24   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 21:46 ` [PATCH v8 07/12] x86/retpoline/ftrace: Convert ftrace " David Woodhouse
2018-01-11 23:25   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 21:46 ` [PATCH v8 08/12] x86/retpoline/hyperv: Convert " David Woodhouse
2018-01-11 23:25   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 21:46 ` [PATCH v8 09/12] x86/retpoline/xen: Convert Xen hypercall " David Woodhouse
2018-01-11 23:25   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 21:46 ` [PATCH v8 10/12] x86/retpoline/checksum32: Convert assembler " David Woodhouse
2018-01-11 23:26   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 21:46 ` [PATCH v8 11/12] x86/retpoline/irq32: " David Woodhouse
2018-01-11 23:26   ` [tip:x86/pti] " tip-bot for Andi Kleen
2018-01-11 21:46 ` [PATCH v8 12/12] x86/retpoline: Fill return stack buffer on vmexit David Woodhouse
2018-01-11 23:27   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 23:51   ` [PATCH v8 12/12] " Andi Kleen
2018-01-12 11:11     ` [PATCH v8.1 " David Woodhouse
2018-01-12 11:15       ` Thomas Gleixner
2018-01-12 11:21         ` Woodhouse, David
2018-01-12 11:37       ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-14 14:50         ` Borislav Petkov
2018-01-14 15:28           ` Thomas Gleixner [this message]
2018-01-14 15:35         ` Borislav Petkov
2018-01-25 12:07         ` Borislav Petkov
2018-01-25 12:20           ` David Woodhouse
2018-01-25 12:45             ` Borislav Petkov
2018-01-25 15:10               ` Josh Poimboeuf
2018-01-25 15:51                 ` Borislav Petkov
2018-01-25 16:03                   ` David Woodhouse
2018-01-25 16:56                     ` Josh Poimboeuf
2018-01-25 17:00                       ` David Woodhouse
2018-01-25 17:05                         ` Andy Lutomirski
2018-01-25 17:44                           ` Josh Poimboeuf
2018-01-25 18:41                           ` Jiri Kosina
2018-01-25 17:10                         ` Thomas Gleixner
2018-01-25 17:32                         ` Josh Poimboeuf
2018-01-25 17:53                         ` Borislav Petkov
2018-01-25 18:04                           ` David Woodhouse
2018-01-25 18:32                             ` Josh Poimboeuf
2018-01-25 19:07                             ` Borislav Petkov
2018-01-25 19:10                               ` Borislav Petkov

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