From patchwork Fri Jul 9 06:16:44 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Herrenschmidt X-Patchwork-Id: 58342 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from bilbo.ozlabs.org (localhost [127.0.0.1]) by ozlabs.org (Postfix) with ESMTP id 2327B100922 for ; Fri, 9 Jul 2010 16:17:13 +1000 (EST) Received: by ozlabs.org (Postfix) id 52376B6F06; Fri, 9 Jul 2010 16:17:00 +1000 (EST) Delivered-To: linuxppc-dev@ozlabs.org Received: from e23smtp08.au.ibm.com (e23smtp08.au.ibm.com [202.81.31.141]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp08.au.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 35528B6F04 for ; Fri, 9 Jul 2010 16:17:00 +1000 (EST) Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [202.81.31.245]) by e23smtp08.au.ibm.com (8.14.4/8.13.1) with ESMTP id o696GvnB027056 for ; Fri, 9 Jul 2010 16:16:57 +1000 Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o696GxhK1667324 for ; Fri, 9 Jul 2010 16:16:59 +1000 Received: from d23av04.au.ibm.com (loopback [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id o696GxdS003365 for ; Fri, 9 Jul 2010 16:16:59 +1000 Received: from ozlabs.au.ibm.com (ozlabs.au.ibm.com [9.190.163.12]) by d23av04.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id o696GwuY003358; Fri, 9 Jul 2010 16:16:58 +1000 Received: from localhost.localdomain (haven.au.ibm.com [9.190.164.82]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.au.ibm.com (Postfix) with ESMTP id 5808C73962; Fri, 9 Jul 2010 16:16:58 +1000 (EST) From: Benjamin Herrenschmidt To: linuxppc-dev@ozlabs.org Subject: [PATCH 02/13] powerpc/book3e: Hack to get gdb moving along on Book3E 64-bit Date: Fri, 9 Jul 2010 16:16:44 +1000 Message-Id: <1278656215-24705-2-git-send-email-benh@kernel.crashing.org> X-Mailer: git-send-email 1.6.3.3 In-Reply-To: <1278656215-24705-1-git-send-email-benh@kernel.crashing.org> References: <1278656215-24705-1-git-send-email-benh@kernel.crashing.org> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Our handling of debug interrupts on Book3E 64-bit is not quite the way it should be just yet. This is a workaround to let gdb work at least for now. We ensure that when context switching, we set the appropriate DBCR0 value for the new task. We also make sure that we turn off MSR[DE] within the kernel, and set it as part of the bits that get set when going back to userspace. In the long run, we will probably set the userspace DBCR0 on the exception exit code path and ensure we have some proper kernel value to set on the way into the kernel, a bit like ppc32 does, but that will take more work. Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/reg_booke.h | 4 ++-- arch/powerpc/kernel/process.c | 22 ++++++++++++++++++++++ 2 files changed, 24 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/reg_booke.h b/arch/powerpc/include/asm/reg_booke.h index 2360317..66dc6f0 100644 --- a/arch/powerpc/include/asm/reg_booke.h +++ b/arch/powerpc/include/asm/reg_booke.h @@ -29,8 +29,8 @@ #if defined(CONFIG_PPC_BOOK3E_64) #define MSR_ MSR_ME | MSR_CE #define MSR_KERNEL MSR_ | MSR_CM -#define MSR_USER32 MSR_ | MSR_PR | MSR_EE -#define MSR_USER64 MSR_USER32 | MSR_CM +#define MSR_USER32 MSR_ | MSR_PR | MSR_EE | MSR_DE +#define MSR_USER64 MSR_USER32 | MSR_CM | MSR_DE #elif defined (CONFIG_40x) #define MSR_KERNEL (MSR_ME|MSR_RI|MSR_IR|MSR_DR|MSR_CE) #define MSR_USER (MSR_KERNEL|MSR_PR|MSR_EE) diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 1e78453..551f671 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -477,6 +477,28 @@ struct task_struct *__switch_to(struct task_struct *prev, new_thread = &new->thread; old_thread = ¤t->thread; +#if defined(CONFIG_PPC_BOOK3E_64) + /* XXX Current Book3E code doesn't deal with kernel side DBCR0, + * we always hold the user values, so we set it now. + * + * However, we ensure the kernel MSR:DE is appropriately cleared too + * to avoid spurrious single step exceptions in the kernel. + * + * This will have to change to merge with the ppc32 code at some point, + * but I don't like much what ppc32 is doing today so there's some + * thinking needed there + */ + if ((new_thread->dbcr0 | old_thread->dbcr0) & DBCR0_IDM) { + u32 dbcr0; + + mtmsr(mfmsr() & ~MSR_DE); + isync(); + dbcr0 = mfspr(SPRN_DBCR0); + dbcr0 = (dbcr0 & DBCR0_EDM) | new_thread->dbcr0; + mtspr(SPRN_DBCR0, dbcr0); + } +#endif /* CONFIG_PPC64_BOOK3E */ + #ifdef CONFIG_PPC64 /* * Collect processor utilization data per process