From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 5 Apr 2013 13:50:25 +1100 From: Paul Mackerras To: Li Zhong Subject: Re: [RFC PATCH v2 2/6] powerpc: Exception hooks for context tracking subsystem Message-ID: <20130405025025.GB22465@drongo> References: <1364551221-23177-1-git-send-email-zhong@linux.vnet.ibm.com> <1364551221-23177-3-git-send-email-zhong@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1364551221-23177-3-git-send-email-zhong@linux.vnet.ibm.com> Cc: fweisbec@gmail.com, paulmck@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, Mar 29, 2013 at 06:00:17PM +0800, Li Zhong wrote: > This is the exception hooks for context tracking subsystem, including > data access, program check, single step, instruction breakpoint, machine check, > alignment, fp unavailable, altivec assist, unknown exception, whose handlers > might use RCU. > > This patch corresponds to > [PATCH] x86: Exception hooks for userspace RCU extended QS > commit 6ba3c97a38803883c2eee489505796cb0a727122 > > Signed-off-by: Li Zhong Is there a reason why you didn't put the exception_exit() call in ret_from_except_lite in entry_64.S, and the exception_entry() call in EXCEPTION_PROLOG_COMMON? That would seem to catch all these cases in a more centralized place. Also, I notice that with the exception_exit calls where they are, we can still deliver signals (thus possibly taking a page fault) or call schedule() for preemption after the exception_exit() call. Is that OK, or is it a potential problem? Paul.