From patchwork Wed Feb 27 03:09:28 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tiejun Chen X-Patchwork-Id: 223486 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id E53142C0827 for ; Wed, 27 Feb 2013 14:14:28 +1100 (EST) Received: from mail.windriver.com (mail.windriver.com [147.11.1.11]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mail.windriver.com", Issuer "Intel External Basic Issuing CA 3A" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 5F94B2C0ACE for ; Wed, 27 Feb 2013 14:09:47 +1100 (EST) Received: from ALA-HCA.corp.ad.wrs.com (ala-hca.corp.ad.wrs.com [147.11.189.40]) by mail.windriver.com (8.14.5/8.14.3) with ESMTP id r1R39iNP014693 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL); Tue, 26 Feb 2013 19:09:44 -0800 (PST) Received: from Linux.corp.ad.wrs.com (128.224.162.178) by ALA-HCA.corp.ad.wrs.com (147.11.189.50) with Microsoft SMTP Server id 14.2.328.9; Tue, 26 Feb 2013 19:09:44 -0800 From: Tiejun Chen To: , 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 Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, jason.wessel@windriver.com X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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; }