From: Dave Hansen <dave.hansen@linux.intel.com>
To: Kees Cook <keescook@google.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Hugh Dickins <hughd@google.com>, Juergen Gross <jgross@suse.com>,
X86 ML <x86@kernel.org>,
namit@vmware.com
Subject: Re: [PATCH 11/11] x86/pti: leave kernel text global for !PCID
Date: Thu, 19 Apr 2018 09:02:31 -0700 [thread overview]
Message-ID: <db2f91ab-9565-7bda-b3c3-a1cdb61d1587@linux.intel.com> (raw)
In-Reply-To: <CAGXu5jJS-PYS7ONy_neDQCqVGRwrtjg=VdktXALQnzRe1+RNuA@mail.gmail.com>
On 04/18/2018 05:11 PM, Kees Cook wrote:
> On Fri, Apr 6, 2018 at 1:55 PM, Dave Hansen <dave.hansen@linux.intel.com> wrote:
>> +/*
>> + * For some configurations, map all of kernel text into the user page
>> + * tables. This reduces TLB misses, especially on non-PCID systems.
>> + */
>> +void pti_clone_kernel_text(void)
>> +{
>> + unsigned long start = PFN_ALIGN(_text);
>> + unsigned long end = ALIGN((unsigned long)_end, PMD_PAGE_SIZE);
> I think this is too much set global: _end is after data, bss, and brk,
> and all kinds of other stuff that could hold secrets. I think this
> should match what mark_rodata_ro() is doing and use
> __end_rodata_hpage_align. (And on i386, this should be maybe _etext.)
Sounds reasonable to me. This does assume that there are no secrets
built into the kernel image, right?
next prev parent reply other threads:[~2018-04-19 16:02 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-06 20:55 [PATCH 00/11] [v5] Use global pages with PTI Dave Hansen
2018-04-06 20:55 ` [PATCH 01/11] x86/mm: factor out pageattr _PAGE_GLOBAL setting Dave Hansen
2018-04-06 20:55 ` [PATCH 02/11] x86/mm: undo double _PAGE_PSE clearing Dave Hansen
2018-04-06 20:55 ` [PATCH 03/11] x86/mm: introduce "default" kernel PTE mask Dave Hansen
2018-04-06 20:55 ` [PATCH 04/11] x86/espfix: document use of _PAGE_GLOBAL Dave Hansen
2018-04-06 20:55 ` [PATCH 05/11] x86/mm: do not auto-massage page protections Dave Hansen
2018-04-06 20:55 ` [PATCH 06/11] x86/mm: remove extra filtering in pageattr code Dave Hansen
2018-04-06 20:55 ` [PATCH 07/11] x86/mm: comment _PAGE_GLOBAL mystery Dave Hansen
2018-04-06 20:55 ` [PATCH 08/11] x86/mm: do not forbid _PAGE_RW before init for __ro_after_init Dave Hansen
2018-04-06 20:55 ` [PATCH 09/11] x86/pti: enable global pages for shared areas Dave Hansen
2018-04-06 20:55 ` [PATCH 10/11] x86/pti: never implicitly clear _PAGE_GLOBAL for kernel image Dave Hansen
2018-04-06 20:55 ` [PATCH 11/11] x86/pti: leave kernel text global for !PCID Dave Hansen
2018-04-19 0:11 ` Kees Cook
2018-04-19 16:02 ` Dave Hansen [this message]
2018-04-19 16:55 ` Kees Cook
2018-04-09 18:04 ` [PATCH 00/11] [v5] Use global pages with PTI Tom Lendacky
2018-04-09 18:17 ` Dave Hansen
2018-04-09 18:59 ` Tom Lendacky
2018-04-09 19:50 ` Dave Hansen
2018-04-09 20:48 ` Tom Lendacky
-- strict thread matches above, loose matches on Subject: below --
2018-04-04 1:09 [PATCH 00/11] [v4] " Dave Hansen
2018-04-04 1:10 ` [PATCH 11/11] x86/pti: leave kernel text global for !PCID Dave Hansen
2018-04-04 7:42 ` kbuild test robot
2018-04-02 17:27 [PATCH 00/11] [v3] Use global pages with PTI Dave Hansen
2018-04-02 17:27 ` [PATCH 11/11] x86/pti: leave kernel text global for !PCID Dave Hansen
2018-03-23 17:44 [PATCH 00/11] Use global pages with PTI Dave Hansen
2018-03-23 17:45 ` [PATCH 11/11] x86/pti: leave kernel text global for !PCID Dave Hansen
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