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From: Ingo Molnar <mingo@kernel.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Brian Gerst <brgerst@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andi Kleen <ak@linux.intel.com>,
	the arch/x86 maintainers <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 1/3] x86/entry: Clear extra registers beyond syscall arguments for 64bit kernels
Date: Mon, 5 Feb 2018 19:29:57 +0100	[thread overview]
Message-ID: <20180205182957.xbeufjgyhd7pgdvq@gmail.com> (raw)
In-Reply-To: <CALCETrU4S3owtVF5_zVMxH_dXox6HXBbb-Q3+GzTQ-RU_xqgcw@mail.gmail.com>


* Andy Lutomirski <luto@kernel.org> wrote:

> [...] Clearing R10 is mostly useless in the syscall path because we'll just 
> unconditionally reload it in do_syscall_64().

AFAICS do_syscall_64() doesn't touch R10 at all. So how does it reload R10?

In fact do_syscall_64() as a C function does not touch R10, R11, R12, R13, R14, 
R15 - it passes their values through.

What am I missing?

Thanks,

	Ingo

  reply	other threads:[~2018-02-05 18:33 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-03 23:21 [PATCH 0/3] x86/entry: clear registers to sanitize speculative usages Dan Williams
2018-02-03 23:21 ` [PATCH 1/3] x86/entry: Clear extra registers beyond syscall arguments for 64bit kernels Dan Williams
2018-02-04  0:14   ` Andy Lutomirski
2018-02-04  1:25     ` Dan Williams
2018-02-04  1:29       ` Andy Lutomirski
2018-02-04 13:01   ` Brian Gerst
2018-02-04 17:42     ` Dan Williams
2018-02-04 18:40       ` Linus Torvalds
2018-02-05 16:26         ` Ingo Molnar
2018-02-05 16:38           ` Andy Lutomirski
2018-02-05 18:29             ` Ingo Molnar [this message]
2018-02-05 18:47               ` Brian Gerst
2018-02-05 19:48                 ` Ingo Molnar
2018-02-05 20:25                   ` Andy Lutomirski
2018-02-05 20:05           ` Ingo Molnar
2018-02-06  8:48             ` Ingo Molnar
2018-02-03 23:21 ` [PATCH 2/3] x86/entry: Clear registers for 64bit exceptions/interrupts Dan Williams
2018-02-03 23:21 ` [PATCH 3/3] x86/entry: Clear registers for compat syscalls Dan Williams

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