From: Andy Lutomirski <luto@amacapital.net>
To: Dave Hansen <dave.hansen@intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
X86 ML <x86@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
"H. Peter Anvin" <hpa@zytor.com>, Andi Kleen <ak@linux.intel.com>,
linux-arch <linux-arch@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Linux API <linux-api@vger.kernel.org>
Subject: Re: [PATCHv3 33/33] mm, x86: introduce PR_SET_MAX_VADDR and PR_GET_MAX_VADDR
Date: Fri, 17 Feb 2017 09:21:47 -0800 [thread overview]
Message-ID: <CALCETrU957t7RQOAUJKWdjcA8t2ScWGkrnou2+cHksetC9aN=A@mail.gmail.com> (raw)
In-Reply-To: <ae15457f-731d-bb1b-c60d-14d641c265f0@intel.com>
On Fri, Feb 17, 2017 at 9:19 AM, Dave Hansen <dave.hansen@intel.com> wrote:
> On 02/17/2017 06:13 AM, Kirill A. Shutemov wrote:
>> +/*
>> + * Default maximum virtual address. This is required for
>> + * compatibility with applications that assumes 47-bit VA.
>> + * The limit can be changed with prctl(PR_SET_MAX_VADDR).
>> + */
>> +#define MAX_VADDR_DEFAULT ((1UL << 47) - PAGE_SIZE)
>
> This is a bit goofy. It's not the largest virtual adddress that can be
> accessed, but the beginning of the last page.
No, it really is the limit. We don't allow user code to map the last
page because ti would be a root hole due to SYSRET. Thanks, Intel.
See the comment near TASK_SIZE_MAX IIRC.
--Andy
next prev parent reply other threads:[~2017-02-17 17:21 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20170217141328.164563-1-kirill.shutemov@linux.intel.com>
2017-02-17 14:13 ` [PATCHv3 33/33] mm, x86: introduce PR_SET_MAX_VADDR and PR_GET_MAX_VADDR Kirill A. Shutemov
[not found] ` <20170217141328.164563-34-kirill.shutemov-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2017-02-17 16:50 ` Andy Lutomirski
2017-02-21 11:54 ` Dmitry Safonov
2017-02-21 12:42 ` Kirill A. Shutemov
2017-03-06 14:00 ` Dmitry Safonov
2017-03-06 14:17 ` Kirill A. Shutemov
2017-03-06 14:15 ` Dmitry Safonov
2017-02-17 17:19 ` Dave Hansen
2017-02-17 17:21 ` Andy Lutomirski [this message]
2017-02-17 20:02 ` Linus Torvalds
2017-02-17 20:12 ` Andy Lutomirski
2017-02-17 21:01 ` Linus Torvalds
2017-02-17 23:02 ` Andy Lutomirski
2017-02-17 23:11 ` hpa
2017-02-17 23:21 ` Linus Torvalds
2017-02-21 10:34 ` Catalin Marinas
2017-02-21 10:47 ` Kirill A. Shutemov
2017-02-21 10:54 ` Catalin Marinas
[not found] ` <CA+oaBQ+s5oXqu5TqddKs9LmUbaNNPGM7=gu5On4GYrkSDu0_XA@mail.gmail.com>
2017-02-21 6:00 ` Michael Pratt
2017-02-21 6:10 ` Michael Pratt
2017-02-17 21:04 ` Dave Hansen
2017-02-17 21:10 ` Linus Torvalds
2017-02-17 21:50 ` hpa
2017-02-18 9:21 ` Kirill A. Shutemov
[not found] ` <20170218092133.GA17471-sVvlyX1904swdBt8bTSxpkEMvNT87kid@public.gmane.org>
2017-02-20 13:15 ` Kirill A. Shutemov
2017-02-21 20:46 ` Dave Hansen
[not found] ` <0d05ac45-a139-6f8e-f98b-71876fbb509d-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-02-22 13:04 ` Kirill A. Shutemov
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