From: "H. Peter Anvin" <hpa@zytor.com>
To: Andrew Lutomirski <luto@mit.edu>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
mingo@kernel.org, tglx@linutronix.de,
torvalds@linux-foundation.org, akpm@linux-foundation.org,
hjl.tools@gmail.com
Subject: Re: [PATCH 30/30] x32: Add x32 VDSO support
Date: Tue, 21 Feb 2012 11:49:33 -0800 [thread overview]
Message-ID: <4F43F54D.50201@zytor.com> (raw)
In-Reply-To: <CAObL_7H=M7-wxobKkj+K2fcrpEv0Nfp8=6gV2yvdb2hqxCTAGg@mail.gmail.com>
On 02/21/2012 11:40 AM, Andrew Lutomirski wrote:
>>
>> I was having delusions that we could have a task-owned PDT in negative
>> space, but that would require unsharing the third level, too, which is
>> just way too messy.
>
> I'd like to do that, too, and I'd also like to have a per-cpu
> kernel-only page in there, but that's even worse. If we had a
> separate cr3-like register for negative addresses, life would be good
> :)
>
No, that wouldn't help. The situation is actually quite similar to the
current situation where we have an unshared fourth level, but since the
fourth entries are 512G per entry, we would have to push unsharing of
the kernel address space at least one more level (1G), possibly two
(2M). Painful.
The main advantage of a separate cr3 would be that we wouldn't need the
unshared top level for the kernel side.
-hpa
next prev parent reply other threads:[~2012-02-21 19:49 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-20 0:07 [PATCH 00/30] RFC: x32 support H. Peter Anvin
2012-02-20 0:07 ` [PATCH 01/30] x86: Factor out TIF_IA32 from 32-bit address space H. Peter Anvin
2012-02-20 0:07 ` [PATCH 02/30] x86-64: Use explicit sizes in sigcontext.h, prepare for x32 H. Peter Anvin
2012-02-20 0:51 ` Linus Torvalds
2012-02-20 0:56 ` H. Peter Anvin
2012-02-22 12:22 ` Arnd Bergmann
2012-02-22 12:22 ` Arnd Bergmann
2012-02-22 18:14 ` H. Peter Anvin
2012-02-22 21:23 ` Arnd Bergmann
2012-02-22 21:55 ` H. Peter Anvin
2012-02-22 21:55 ` H. Peter Anvin
2012-02-24 2:33 ` H. Peter Anvin
2012-03-06 5:25 ` H. Peter Anvin
2012-02-20 0:07 ` [PATCH 03/30] sysinfo: Move struct sysinfo to a separate header file H. Peter Anvin
2012-02-20 0:07 ` H. Peter Anvin
2012-02-20 0:07 ` [PATCH 04/30] posix_types: Introduce __kernel_[u]long_t H. Peter Anvin
2012-02-20 0:07 ` [PATCH 05/30] x32: Create posix_types_x32.h H. Peter Anvin
2012-02-20 0:07 ` [PATCH 06/30] sysinfo: Use explicit types in <linux/sysinfo.h> H. Peter Anvin
2012-02-20 12:12 ` Geert Uytterhoeven
2012-02-20 17:29 ` H. Peter Anvin
2012-02-20 20:01 ` Geert Uytterhoeven
2012-02-20 20:44 ` H. Peter Anvin
2012-02-20 0:07 ` [PATCH 07/30] compat: Introduce COMPAT_USE_64BIT_TIME H. Peter Anvin
2012-02-20 0:07 ` H. Peter Anvin
2012-02-20 0:07 ` [PATCH 08/30] compat: Use COMPAT_USE_64BIT_TIME in the lp driver H. Peter Anvin
2012-02-20 0:56 ` Linus Torvalds
2012-02-20 0:59 ` H. Peter Anvin
2012-02-20 2:22 ` [PATCH 0/7] COMPAT_USE_64BIT_TIME v2 H. Peter Anvin
2012-02-20 2:22 ` [PATCH 1/7] compat: Introduce COMPAT_USE_64BIT_TIME H. Peter Anvin
2012-02-20 2:22 ` H. Peter Anvin
2012-02-20 2:22 ` [PATCH 2/7] compat: Add helper functions to read/write struct timeval, timespec H. Peter Anvin
2012-02-20 2:22 ` [PATCH 3/7] compat: Handle COMPAT_USE_64BIT_TIME in the lp driver H. Peter Anvin
2012-02-20 2:22 ` [PATCH 4/7] compat: Use COMPAT_USE_64BIT_TIME in the input subsystem H. Peter Anvin
2012-02-20 2:22 ` [PATCH 5/7] compat: Use COMPAT_USE_64BIT_TIME in the Bluetooth subsystem H. Peter Anvin
2012-02-20 2:22 ` [PATCH 6/7] compat: Use COMPAT_USE_64BIT_TIME in net/compat.c H. Peter Anvin
2012-02-20 2:22 ` [PATCH 7/7] compat: Handle COMPAT_USE_64BIT_TIME in net/socket.c H. Peter Anvin
2012-02-20 2:42 ` [PATCH 0/7] COMPAT_USE_64BIT_TIME v2 H. Peter Anvin
2012-02-20 6:22 ` H. Peter Anvin
2012-02-20 0:07 ` [PATCH 09/30] compat: Use COMPAT_USE_64BIT_TIME in the input subsystem H. Peter Anvin
2012-02-20 0:07 ` [PATCH 10/30] compat: Use COMPAT_USE_64BIT_TIME in the Bluetooth subsystem H. Peter Anvin
2012-02-21 19:05 ` Gustavo Padovan
2012-02-21 19:15 ` H. Peter Anvin
2012-02-21 19:15 ` H. Peter Anvin
2012-02-22 13:47 ` Jiri Kosina
2012-02-22 13:47 ` Jiri Kosina
2012-02-22 14:45 ` Gustavo Padovan
2012-02-20 0:07 ` [PATCH 11/30] aio: Use __kernel_ulong_t to define aio_context_t H. Peter Anvin
2012-02-20 0:07 ` [PATCH 12/30] compat: Create compat_sys_p{read,write}v64 H. Peter Anvin
2012-02-20 0:07 ` [PATCH 13/30] elf: Allow core dump-related fields to be overridden H. Peter Anvin
2012-02-20 0:07 ` [PATCH 14/30] x86-64: Add prototype for old_rsp to a header file H. Peter Anvin
2012-02-20 0:07 ` [PATCH 15/30] x32: Add a thread flag for x32 processes H. Peter Anvin
2012-02-20 0:07 ` [PATCH 16/30] x86-64, ia32: Drop sys32_rt_sigprocmask H. Peter Anvin
2012-02-20 0:07 ` [PATCH 17/30] x32: Add x32 system calls to syscall/syscall_64.tbl H. Peter Anvin
2012-02-20 0:07 ` [PATCH 18/30] x32: Generate <asm/unistd_x32.h> H. Peter Anvin
2012-02-20 0:07 ` [PATCH 19/30] x32: Generate <asm/unistd_64_x32.h> H. Peter Anvin
2012-02-20 0:07 ` [PATCH 20/30] x86: Move some signal-handling definitions to a common header H. Peter Anvin
2012-02-20 0:07 ` [PATCH 21/30] x32: Export setup/restore_sigcontext from signal.c H. Peter Anvin
2012-02-20 0:08 ` [PATCH 22/30] x32: Add struct ucontext_x32 H. Peter Anvin
2012-02-20 0:08 ` [PATCH 23/30] x32: Add rt_sigframe_x32 H. Peter Anvin
2012-02-20 0:08 ` [PATCH 24/30] x32: Handle the x32 system call flag H. Peter Anvin
2012-02-20 0:08 ` [PATCH 25/30] x86: Add #ifdef CONFIG_COMPAT to <asm/sys_ia32.h> H. Peter Anvin
2012-02-20 0:08 ` [PATCH 26/30] x32: Signal-related system calls H. Peter Anvin
2012-02-20 0:08 ` [PATCH 27/30] x32: Handle process creation H. Peter Anvin
2012-02-20 0:08 ` [PATCH 28/30] x32: If configured, add x32 system calls to system call tables H. Peter Anvin
2012-02-20 0:08 ` [PATCH 29/30] x32: Allow x32 to be configured H. Peter Anvin
2012-02-20 0:08 ` [PATCH 30/30] x32: Add x32 VDSO support H. Peter Anvin
2012-02-21 0:12 ` Andy Lutomirski
2012-02-21 0:12 ` Andy Lutomirski
2012-02-21 3:58 ` H. Peter Anvin
2012-02-21 16:52 ` Andrew Lutomirski
2012-02-21 17:51 ` H. Peter Anvin
2012-02-21 18:54 ` Andrew Lutomirski
2012-02-21 19:03 ` H. Peter Anvin
2012-02-21 19:29 ` Andrew Lutomirski
2012-02-21 19:37 ` H. Peter Anvin
2012-02-21 19:40 ` Andrew Lutomirski
2012-02-21 19:40 ` Andrew Lutomirski
2012-02-21 19:49 ` H. Peter Anvin [this message]
2012-02-21 19:51 ` Andrew Lutomirski
2012-02-21 19:51 ` Andrew Lutomirski
2012-02-21 19:56 ` H. Peter Anvin
2012-02-21 19:56 ` H. Peter Anvin
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