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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 14 Jun 2019 16:44:30 +0100 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5EFiScT23789888 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 14 Jun 2019 15:44:28 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9C1FF11C050; Fri, 14 Jun 2019 15:44:28 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 22CE411C04A; Fri, 14 Jun 2019 15:44:27 +0000 (GMT) Received: from naverao1-tp.ibmuc.com (unknown [9.85.70.176]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 14 Jun 2019 15:44:26 +0000 (GMT) From: "Naveen N. Rao" To: Michael Ellerman Subject: [PATCH v2 4/9] powerpc/pseries: Introduce helpers to gatekeep DTLB usage Date: Fri, 14 Jun 2019 21:14:02 +0530 X-Mailer: git-send-email 2.21.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19061415-0016-0000-0000-00000289216E X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19061415-0017-0000-0000-000032E66337 Message-Id: <90930132f6c008d8bec58d5d258e49a696a7c8e0.1560526066.git.naveen.n.rao@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-06-14_07:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906140130 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nathan Lynch , "Aneesh Kumar K.V" , Mingming Cao , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Since we would be introducing a new user of the DTL buffer in a subsequent patch, add helpers to gatekeep use of the DTL buffer. The current usage of the DTL buffer from debugfs is at a per-cpu level (corresponding to the cpu debugfs file that is opened). Subsequently, we will have users enabling/accessing DTLB for all online cpus. These helpers allow any number of per-cpu users, or a single global user exclusively. Signed-off-by: Naveen N. Rao --- arch/powerpc/include/asm/plpar_wrappers.h | 2 ++ arch/powerpc/platforms/pseries/dtl.c | 10 +++++- arch/powerpc/platforms/pseries/lpar.c | 38 +++++++++++++++++++++++ 3 files changed, 49 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/plpar_wrappers.h b/arch/powerpc/include/asm/plpar_wrappers.h index d08feb1bc2bd..ab7dd454b6eb 100644 --- a/arch/powerpc/include/asm/plpar_wrappers.h +++ b/arch/powerpc/include/asm/plpar_wrappers.h @@ -88,6 +88,8 @@ static inline long register_dtl(unsigned long cpu, unsigned long vpa) return vpa_call(H_VPA_REG_DTL, cpu, vpa); } +extern bool register_dtl_buffer_access(bool global); +extern void unregister_dtl_buffer_access(bool global); extern void register_dtl_buffer(int cpu); extern void alloc_dtl_buffers(void); extern void vpa_init(int cpu); diff --git a/arch/powerpc/platforms/pseries/dtl.c b/arch/powerpc/platforms/pseries/dtl.c index a88176afba32..de531311cd9a 100644 --- a/arch/powerpc/platforms/pseries/dtl.c +++ b/arch/powerpc/platforms/pseries/dtl.c @@ -180,11 +180,15 @@ static int dtl_enable(struct dtl *dtl) if (dtl->buf) return -EBUSY; + if (register_dtl_buffer_access(false)) + return -EBUSY; + n_entries = dtl_buf_entries; buf = kmem_cache_alloc_node(dtl_cache, GFP_KERNEL, cpu_to_node(dtl->cpu)); if (!buf) { printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n", __func__, dtl->cpu); + unregister_dtl_buffer_access(false); return -ENOMEM; } @@ -201,8 +205,11 @@ static int dtl_enable(struct dtl *dtl) } spin_unlock(&dtl->lock); - if (rc) + if (rc) { + unregister_dtl_buffer_access(false); kmem_cache_free(dtl_cache, buf); + } + return rc; } @@ -214,6 +221,7 @@ static void dtl_disable(struct dtl *dtl) dtl->buf = NULL; dtl->buf_entries = 0; spin_unlock(&dtl->lock); + unregister_dtl_buffer_access(false); } /* file interface */ diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c index 8c5377fe9985..53e005c84078 100644 --- a/arch/powerpc/platforms/pseries/lpar.c +++ b/arch/powerpc/platforms/pseries/lpar.c @@ -99,6 +99,44 @@ void register_dtl_buffer(int cpu) } } +#ifdef CONFIG_PPC_SPLPAR +static DEFINE_SPINLOCK(dtl_buffer_refctr_lock); +static unsigned int dtl_buffer_global_refctr, dtl_buffer_percpu_refctr; + +bool register_dtl_buffer_access(bool global) +{ + int rc = 0; + + spin_lock(&dtl_buffer_refctr_lock); + + if ((global && (dtl_buffer_global_refctr || dtl_buffer_percpu_refctr)) + || (!global && dtl_buffer_global_refctr)) { + rc = -1; + } else { + if (global) + dtl_buffer_global_refctr++; + else + dtl_buffer_percpu_refctr++; + } + + spin_unlock(&dtl_buffer_refctr_lock); + + return rc; +} + +void unregister_dtl_buffer_access(bool global) +{ + spin_lock(&dtl_buffer_refctr_lock); + + if (global) + dtl_buffer_global_refctr--; + else + dtl_buffer_percpu_refctr--; + + spin_unlock(&dtl_buffer_refctr_lock); +} +#endif /* CONFIG_PPC_SPLPAR */ + void vpa_init(int cpu) { int hwcpu = get_hard_smp_processor_id(cpu); -- 2.21.0