From: Peter Zijlstra <peterz@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, Borislav Petkov <bp@alien8.de>,
David Woodhouse <dwmw@amazon.co.uk>
Subject: Re: [PATCH] x86/mce: Make machine check speculation protected
Date: Thu, 18 Jan 2018 16:46:07 +0100 [thread overview]
Message-ID: <20180118154607.GN2228@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.DEB.2.20.1801181626290.1847@nanos>
On Thu, Jan 18, 2018 at 04:28:26PM +0100, Thomas Gleixner wrote:
> The machine check idtentry uses an indirect branch directly from the low
> level code. This evades the speculation protection.
>
> Replace it by a direct call into C code and issue the indirect call there
> so the compiler can apply the proper speculation protection.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> arch/x86/entry/entry_64.S | 2 +-
> arch/x86/include/asm/traps.h | 1 +
> arch/x86/kernel/cpu/mcheck/mce.c | 5 +++++
> 3 files changed, 7 insertions(+), 1 deletion(-)
>
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -1264,7 +1264,7 @@ idtentry async_page_fault do_async_page_
> #endif
>
> #ifdef CONFIG_X86_MCE
> -idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vector(%rip)
> +idtentry machine_check do_mce has_error_code=0 paranoid=1
Nice, Thanks!
next prev parent reply other threads:[~2018-01-18 16:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-18 15:28 Thomas Gleixner
2018-01-18 15:46 ` Peter Zijlstra [this message]
2018-01-18 15:53 ` Borislav Petkov
2018-01-18 15:55 ` David Woodhouse
2018-01-19 8:46 ` Woodhouse, David
2018-01-19 15:46 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
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