From: Nadav Amit <nadav.amit@gmail.com>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
luto@kernel.org, torvalds@linux-foundation.org,
keescook@google.com, hughd@google.com, jgross@suse.com,
x86@kernel.org
Subject: Re: [PATCH 2/3] x86/mm: introduce __PAGE_KERNEL_GLOBAL
Date: Fri, 16 Feb 2018 09:47:49 -0800 [thread overview]
Message-ID: <E0AB2852-C4E0-43D3-ABA7-34117A5516C1@gmail.com> (raw)
In-Reply-To: <20180215132055.F341C31E@viggo.jf.intel.com>
Dave Hansen <dave.hansen@linux.intel.com> wrote:
>
> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> Kernel mappings are historically _PAGE_GLOBAL. But, with PTI, we do not
> want them to be _PAGE_GLOBAL. We currently accomplish this by simply
> clearing _PAGE_GLOBAL from the suppotred mask which ensures it is
> cleansed from many of our PTE construction sites:
>
> if (!static_cpu_has(X86_FEATURE_PTI))
> __supported_pte_mask |= _PAGE_GLOBAL;
>
> But, this also means that we now get *no* opportunity to use global
> pages with PTI, even for data which is shared such as the cpu_entry_area
> and entry/exit text.
Doesn’t this patch change the kernel behavior when the “nopti” parameter is used?
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next prev parent reply other threads:[~2018-02-16 17:48 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-15 13:20 [PATCH 0/3] Use global pages with PTI Dave Hansen
2018-02-15 13:20 ` [PATCH 1/3] x86/mm: factor out conditional pageattr PTE bit setting code Dave Hansen
2018-02-15 13:20 ` [PATCH 2/3] x86/mm: introduce __PAGE_KERNEL_GLOBAL Dave Hansen
2018-02-16 17:47 ` Nadav Amit [this message]
2018-02-16 18:03 ` Dave Hansen
2018-02-16 18:25 ` Nadav Amit
2018-02-16 19:06 ` Dave Hansen
2018-02-16 19:54 ` Nadav Amit
2018-02-16 20:00 ` Dave Hansen
2018-02-16 23:19 ` Dave Hansen
2018-02-15 13:20 ` [PATCH 3/3] x86/pti: enable global pages for shared areas Dave Hansen
2018-02-15 17:47 ` [PATCH 0/3] Use global pages with PTI Linus Torvalds
2018-02-15 18:13 ` Dave Hansen
2018-02-15 23:55 ` Dave Hansen
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