From: Peter Zijlstra <peterz@infradead.org>
To: Fenghua Yu <fenghua.yu@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@linux.intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Rafael Wysocki <rafael.j.wysocki@intel.com>,
Tony Luck <tony.luck@intel.com>, Alan Cox <alan@linux.intel.com>,
Ravi V Shankar <ravi.v.shankar@intel.com>,
Arjan van de Ven <arjan@infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [RFC PATCH 04/16] x86/split_lock: Use non locked bit set instruction in set_cpu_cap
Date: Thu, 21 Jun 2018 21:55:40 +0200 [thread overview]
Message-ID: <20180621195540.GC13636@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <1527435965-202085-5-git-send-email-fenghua.yu@intel.com>
On Sun, May 27, 2018 at 08:45:53AM -0700, Fenghua Yu wrote:
> set_bit() called by set_cpu_cap() is a locked bit set instruction for
> atomic operation.
>
> Since the c->x86_capability can span two cache lines depending on kernel
> configuration and building evnironment, the locked bit set instruction may
> cause #AC exception when #AC exception for split lock is enabled.
That doesn't make sense. Sure the bitmap may be longer, but depending on
if the argument is an immediate or not we either use a byte instruction
(which can never cross a cacheline boundary) or a 'word' aligned BTS.
And the bitmap really _should_ be 'unsigned long' aligned.
If it is not aligned, fix that too.
/me looks at cpuinfo_x86 and finds x86_capability is in fact a __u32
array.. see that's broken and needs fixing first.
next prev parent reply other threads:[~2018-06-21 19:55 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-27 15:45 [RFC PATCH 00/16] x86/split_lock: Enable #AC exception for split locked accesses Fenghua Yu
2018-05-27 15:45 ` [RFC PATCH 01/16] x86/split_lock: Add CONFIG and enumerate #AC exception for split locked access feature Fenghua Yu
2018-05-27 15:45 ` [RFC PATCH 02/16] x86/split_lock: Handle #AC exception for split lock in kernel mode Fenghua Yu
2018-06-21 19:46 ` Peter Zijlstra
2018-06-22 10:49 ` Thomas Gleixner
2018-06-22 11:59 ` Thomas Gleixner
2018-06-22 22:41 ` Fenghua Yu
2018-06-22 22:57 ` Thomas Gleixner
2018-06-22 23:03 ` Thomas Gleixner
2018-06-22 23:18 ` Fenghua Yu
2018-06-23 9:08 ` Thomas Gleixner
2018-06-23 4:20 ` Fenghua Yu
2018-06-23 9:17 ` Thomas Gleixner
2018-06-23 15:05 ` Fenghua Yu
2018-06-24 0:55 ` Thomas Gleixner
2018-06-24 1:17 ` Fenghua Yu
2018-06-24 6:43 ` Thomas Gleixner
2018-05-27 15:45 ` [RFC PATCH 03/16] x86/split_lock: Set up #AC exception for split locked accesses on all CPUs Fenghua Yu
2018-05-27 15:45 ` [RFC PATCH 04/16] x86/split_lock: Use non locked bit set instruction in set_cpu_cap Fenghua Yu
2018-06-21 19:55 ` Peter Zijlstra [this message]
2018-06-21 20:37 ` Thomas Gleixner
2018-06-27 23:35 ` Fenghua Yu
2018-06-28 7:53 ` Thomas Gleixner
2018-06-28 14:23 ` Fenghua Yu
2018-06-28 14:54 ` Fenghua Yu
2018-05-27 15:45 ` [RFC PATCH 05/16] x86/split_lock: Use non atomic set and clear bit instructions in clear_cpufeature() Fenghua Yu
2018-05-27 15:45 ` [RFC PATCH 06/16] x86/split_lock: Save #AC setting for split lock in firmware in boot time and restore the setting in reboot Fenghua Yu
2018-06-21 19:58 ` Peter Zijlstra
2018-06-22 15:11 ` Alan Cox
2018-06-26 9:05 ` Peter Zijlstra
2018-06-26 9:40 ` Thomas Gleixner
2018-06-26 11:02 ` Alan Cox
2018-06-26 11:31 ` Peter Zijlstra
2018-05-27 15:45 ` [RFC PATCH 07/16] x86/split_lock: Handle suspend/hibernate and resume Fenghua Yu
2018-05-27 15:45 ` [RFC PATCH 08/16] x86/split_lock: Set split lock during EFI runtime service Fenghua Yu
2018-05-27 15:45 ` [RFC PATCH 09/16] x86/split_lock: Add CONFIG to control #AC for split lock at boot time Fenghua Yu
2018-05-27 15:45 ` [RFC PATCH 10/16] x86/split_lock: Add a debugfs interface to allow user to enable or disable #AC for split lock during run time Fenghua Yu
2018-05-29 18:43 ` Greg KH
2018-05-27 15:46 ` [RFC PATCH 11/16] x86/split_lock: Add CONFIG to control #AC for split lock from kernel at boot time Fenghua Yu
2018-05-27 15:46 ` [RFC PATCH 12/16] x86/split_lock: Add a debugfs interface to allow user to change how to handle split lock in kernel mode during run time Fenghua Yu
2018-05-27 15:46 ` [RFC PATCH 13/16] x86/split_lock: Add debugfs interface to control user mode behavior Fenghua Yu
2018-05-27 15:46 ` [RFC PATCH 14/16] x86/split_lock: Add debugfs interface to show and control firmware setting for split lock Fenghua Yu
2018-05-27 15:46 ` [RFC PATCH 15/16] x86/split_lock: Add CONFIG and debugfs interface for testing #AC for split lock in kernel mode Fenghua Yu
2018-05-27 15:46 ` [RFC PATCH 16/16] x86/split_lock: Add user space split lock test in selftest Fenghua Yu
2018-05-29 16:39 ` [RFC PATCH 00/16] x86/split_lock: Enable #AC exception for split locked accesses Dave Hansen
2018-05-29 17:25 ` Fenghua Yu
2018-05-29 17:28 ` Dave Hansen
2018-05-29 17:40 ` Fenghua Yu
2018-05-29 16:40 ` Dave Hansen
2018-05-29 17:38 ` Fenghua Yu
2018-06-21 20:06 ` Peter Zijlstra
2018-06-21 19:37 ` Peter Zijlstra
2018-06-21 20:18 ` Fenghua Yu
2018-06-21 20:32 ` Thomas Gleixner
2018-06-21 22:00 ` Fenghua Yu
2018-06-21 22:07 ` Peter Zijlstra
2018-06-21 22:08 ` Peter Zijlstra
2018-06-21 22:18 ` Dave Hansen
2018-06-21 22:42 ` Fenghua Yu
2018-06-22 8:11 ` Peter Zijlstra
2018-06-22 9:30 ` Thomas Gleixner
2018-06-21 22:10 ` Peter Zijlstra
2018-06-21 23:05 ` Fenghua Yu
2018-06-22 8:19 ` Peter Zijlstra
2018-06-21 22:11 ` Peter Zijlstra
2018-06-21 22:43 ` Fenghua Yu
2018-06-21 22:13 ` Peter Zijlstra
2018-06-23 18:47 ` Fenghua Yu
2018-06-22 9:18 ` Thomas Gleixner
2018-06-22 9:22 ` Thomas Gleixner
2018-06-22 9:25 ` Thomas Gleixner
2018-06-22 9:28 ` Thomas Gleixner
2018-06-21 20:36 ` Peter Zijlstra
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