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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Andi Kleen <ak@linux.intel.com>
Cc: mhiramat@kernel.org, Ingo Molnar <mingo@kernel.org>,
	David Woodhouse <dwmw@amazon.co.uk>,
	linux-kernel@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linux-foundation.org>,
	Arjan van de Ven <arjan@linux.intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H . Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v1 tip/master 0/3] kprobes/x86: retpoline: Fix kprobes for retpoline
Date: Fri, 19 Jan 2018 00:36:52 +0900	[thread overview]
Message-ID: <20180119003652.9842ce209b3b4aa72eb0c79e@kernel.org> (raw)
In-Reply-To: <20180118130157.GE7844@tassilo.jf.intel.com>

On Thu, 18 Jan 2018 05:01:57 -0800
Andi Kleen <ak@linux.intel.com> wrote:

> > Side effect: [1/3] will move __x86_indirect_thunk_* functions
> > in kernel text area. Of course those functions were in the
> > .text area, but placed in right after _etext. This just moves
> > it right before the _etext.
> 
> I assume you tested that with page table isolation on?
> 
> The thunks need to be accessible from the trampoline.

Yes, I've tested the kernel with CONFIG_PAGE_TABLE_ISOLATION=y.
As David pointed, maybe all those points are using JMP/CALL_NOSPEC macro directly?

Thanks,

> 
> -Andi


-- 
Masami Hiramatsu <mhiramat@kernel.org>

      parent reply	other threads:[~2018-01-18 15:36 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-18 12:00 [PATCH v1 tip/master 0/3] kprobes/x86: retpoline: Fix kprobes for retpoline Masami Hiramatsu
2018-01-18 12:01 ` [PATCH v1 tip/master 1/3] retpoline: Introduce start/end markers of indirect thunk Masami Hiramatsu
2018-01-18 12:06   ` Woodhouse, David
2018-01-18 15:34     ` Masami Hiramatsu
2018-01-18 12:01 ` [PATCH v1 tip/master 2/3] kprobes/x86: Blacklist indirect thunk functions for kprobes Masami Hiramatsu
2018-01-18 12:02 ` [PATCH v1 tip/master 3/3] kprobes/x86: Disable optimizing on the function jumps to indirect thunk Masami Hiramatsu
2018-01-18 13:01 ` [PATCH v1 tip/master 0/3] kprobes/x86: retpoline: Fix kprobes for retpoline Andi Kleen
2018-01-18 13:03   ` David Woodhouse
2018-01-18 18:50     ` Andi Kleen
2018-01-18 15:36   ` Masami Hiramatsu [this message]

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