From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760028Ab3B0DJw (ORCPT ); Tue, 26 Feb 2013 22:09:52 -0500 Received: from mail.windriver.com ([147.11.1.11]:44511 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760010Ab3B0DJs (ORCPT ); Tue, 26 Feb 2013 22:09:48 -0500 From: Tiejun Chen To: , CC: , , Subject: [v3][PATCH 6/6] powerpc/kgdb: remove copying the thread_info Date: Wed, 27 Feb 2013 11:09:28 +0800 Message-ID: <1361934568-31989-7-git-send-email-tiejun.chen@windriver.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1361934568-31989-1-git-send-email-tiejun.chen@windriver.com> References: <1361934568-31989-1-git-send-email-tiejun.chen@windriver.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently BookE and Book3E always copy the thread_info from the kernel stack when we enter the debug exception, so we can remove these action here to avoid copying again. Signed-off-by: Tiejun Chen --- arch/powerpc/kernel/kgdb.c | 28 ---------------------------- 1 file changed, 28 deletions(-) diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c index 1a57307..e954888 100644 --- a/arch/powerpc/kernel/kgdb.c +++ b/arch/powerpc/kernel/kgdb.c @@ -153,39 +153,11 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs) static int kgdb_singlestep(struct pt_regs *regs) { - struct thread_info *thread_info, *exception_thread_info; - struct thread_info *backup_current_thread_info; - if (user_mode(regs)) return 0; - backup_current_thread_info = (struct thread_info *)kmalloc(sizeof(struct thread_info), GFP_KERNEL); - /* - * On Book E and perhaps other processors, singlestep is handled on - * the critical exception stack. This causes current_thread_info() - * to fail, since it it locates the thread_info by masking off - * the low bits of the current stack pointer. We work around - * this issue by copying the thread_info from the kernel stack - * before calling kgdb_handle_exception, and copying it back - * afterwards. On most processors the copy is avoided since - * exception_thread_info == thread_info. - */ - thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1)); - exception_thread_info = current_thread_info(); - - if (thread_info != exception_thread_info) { - /* Save the original current_thread_info. */ - memcpy(backup_current_thread_info, exception_thread_info, sizeof *thread_info); - memcpy(exception_thread_info, thread_info, sizeof *thread_info); - } - kgdb_handle_exception(0, SIGTRAP, 0, regs); - if (thread_info != exception_thread_info) - /* Restore current_thread_info lastly. */ - memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info); - - kfree(backup_current_thread_info); return 1; } -- 1.7.9.5