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From: Borislav Petkov <bp@alien8.de>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Brian Gerst <brgerst@gmail.com>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	Ingo Molnar <mingo@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Alexei Starovoitov <ast@plumgrid.com>,
	Will Drewry <wad@chromium.org>, Kees Cook <keescook@chromium.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86/asm/entry/32: Restore %ss before SYSRETL if necessary
Date: Thu, 23 Apr 2015 23:46:16 +0200	[thread overview]
Message-ID: <20150423214616.GU28327@pd.tnic> (raw)
In-Reply-To: <55396617.4020303@zytor.com>

On Thu, Apr 23, 2015 at 02:37:27PM -0700, H. Peter Anvin wrote:
> Yes, the NULL SS is a special thing in 64-bit mode. I agree that
> context-switching it is probably the way to go; it should be cheap
> enough. We might even be able to conditionalize it on an X86_BUG_
> flag.

Oh sure, I was thinking of an AMD-specific

	"call amd_fixup_ss"

which gets NOPped out on Intel.

We do those for breakfast :-)

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

  reply	other threads:[~2015-04-23 21:46 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-23 12:34 [PATCH] x86/asm/entry/32: Restore %ss before SYSRETL if necessary Denys Vlasenko
2015-04-23 15:22 ` Linus Torvalds
2015-04-23 15:50   ` Andy Lutomirski
2015-04-23 16:05     ` Linus Torvalds
2015-04-23 16:11       ` Borislav Petkov
2015-04-23 16:06   ` Brian Gerst
2015-04-23 16:13     ` Linus Torvalds
2015-04-23 16:27       ` Andy Lutomirski
2015-04-23 20:01         ` Denys Vlasenko
2015-04-23 21:10           ` Borislav Petkov
2015-04-23 21:37             ` H. Peter Anvin
2015-04-23 21:46               ` Borislav Petkov [this message]
2015-04-23 22:29               ` Andy Lutomirski
2015-04-23 22:31                 ` H. Peter Anvin
2015-04-23 22:38                   ` Andy Lutomirski
2015-04-23 22:52                     ` H. Peter Anvin
2015-04-23 22:55                       ` Andy Lutomirski
2015-04-23 23:04                         ` Linus Torvalds
2015-04-23 23:22                           ` Denys Vlasenko
2015-04-24  0:59                         ` H. Peter Anvin

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