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From: David Woodhouse <dwmw2@infradead.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org, "Ghitulete,
	Razvan-alin" <rga@amazon.com>
Cc: stable@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
	Nadav Amit <nadav.amit@gmail.com>, Borislav Petkov <bp@suse.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Arjan van de Ven <arjan@linux.intel.com>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@intel.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Mel Gorman <mgorman@suse.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Rik van Riel <riel@redhat.com>,
	linux-mm@kvack.org, Ingo Molnar <mingo@kernel.org>,
	Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH 4.4 29/63] x86/mm: Disable PCID on 32-bit kernels
Date: Tue, 09 Jan 2018 16:05:40 +0000	[thread overview]
Message-ID: <1515513940.22302.54.camel@infradead.org> (raw)
In-Reply-To: <20180101140047.443511959@linuxfoundation.org>

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On Mon, 2018-01-01 at 15:24 +0100, Greg Kroah-Hartman wrote:
> 
> --- a/arch/x86/kernel/cpu/bugs.c
> +++ b/arch/x86/kernel/cpu/bugs.c
> @@ -19,6 +19,14 @@
>  
>  void __init check_bugs(void)
>  {
> +#ifdef CONFIG_X86_32
> +       /*
> +        * Regardless of whether PCID is enumerated, the SDM says
> +        * that it can't be enabled in 32-bit mode.
> +        */
> +       setup_clear_cpu_cap(X86_FEATURE_PCID);
> +#endif
> +
>         identify_boot_cpu();
>  #ifndef CONFIG_SMP
>         pr_info("CPU: ");
> 


Razvan points out that the #ifdef there is redundant; in older kernels,
bugs.c is only built on 32-bit anyway.

We're working on backporting the other CPU_BUG_* and sysfs
vulnerabilities bits to 4.9 (first), and will probably end up
cherry-picking 62a67e123e ("x86/cpu: Merge bugs.c and bugs_64.c").

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  reply	other threads:[~2018-01-09 16:06 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20180101140042.456380281@linuxfoundation.org>
2018-01-01 14:24 ` [PATCH 4.4 27/63] x86/mm: Reimplement flush_tlb_page() using flush_tlb_mm_range() Greg Kroah-Hartman
2018-01-01 14:24 ` [PATCH 4.4 28/63] x86/mm: Remove the UP asm/tlbflush.h code, always use the (formerly) SMP code Greg Kroah-Hartman
2018-01-01 14:24 ` [PATCH 4.4 29/63] x86/mm: Disable PCID on 32-bit kernels Greg Kroah-Hartman
2018-01-09 16:05   ` David Woodhouse [this message]
2018-01-09 18:18     ` David Woodhouse
2018-01-01 14:24 ` [PATCH 4.4 30/63] x86/mm: Add the nopcid boot option to turn off PCID Greg Kroah-Hartman
2018-01-01 14:24 ` [PATCH 4.4 31/63] x86/mm: Enable CR4.PCIDE on supported systems Greg Kroah-Hartman

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