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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 3 Mar 2020 18:04:56 -0000 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 023I3uiT39518482 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 3 Mar 2020 18:03:56 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8070442042; Tue, 3 Mar 2020 18:04:54 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5262D42041; Tue, 3 Mar 2020 18:04:53 +0000 (GMT) Received: from bali.tlslab.ibm.com (unknown [9.101.4.17]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 3 Mar 2020 18:04:53 +0000 (GMT) Subject: Re: [PATCH v3 18/27] powerpc/powernv/pmem: Add controller dump IOCTLs To: "Alastair D'Silva" , alastair@d-silva.org Cc: "Aneesh Kumar K . V" , "Oliver O'Halloran" , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Andrew Donnellan , Arnd Bergmann , Greg Kroah-Hartman , Dan Williams , Vishal Verma , Dave Jiang , Ira Weiny , Andrew Morton , Mauro Carvalho Chehab , "David S. Miller" , Rob Herring , Anton Blanchard , Krzysztof Kozlowski , Mahesh Salgaonkar , Madhavan Srinivasan , =?UTF-8?Q?C=c3=a9dric_Le_Goater?= , Anju T Sudhakar , Hari Bathini , Thomas Gleixner , Greg Kurz , Nicholas Piggin , Masahiro Yamada , Alexey Kardashevskiy , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-nvdimm@lists.01.org, linux-mm@kvack.org References: <20200221032720.33893-1-alastair@au1.ibm.com> <20200221032720.33893-19-alastair@au1.ibm.com> From: Frederic Barrat Date: Tue, 3 Mar 2020 19:04:53 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200221032720.33893-19-alastair@au1.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 20030318-0020-0000-0000-000003B02A77 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20030318-0021-0000-0000-000022085B20 Message-Id: <6d1f28bc-334c-e85b-9974-71cf88a1ad20@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-03-03_06:2020-03-03,2020-03-03 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=47 clxscore=1015 mlxscore=47 adultscore=0 spamscore=47 bulkscore=0 priorityscore=1501 suspectscore=2 mlxlogscore=5 phishscore=0 malwarescore=0 impostorscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2003030122 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Le 21/02/2020 =C3=A0 04:27, Alastair D'Silva a =C3=A9crit=C2=A0: > From: Alastair D'Silva >=20 > This patch adds IOCTLs to allow userspace to request & fetch dumps > of the internal controller state. >=20 > This is useful during debugging or when a fatal error on the controller > has occurred. >=20 > Signed-off-by: Alastair D'Silva > --- > arch/powerpc/platforms/powernv/pmem/ocxl.c | 132 ++++++++++++++++++++= + > include/uapi/nvdimm/ocxl-pmem.h | 15 +++ > 2 files changed, 147 insertions(+) >=20 > diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl.c b/arch/powerpc/= platforms/powernv/pmem/ocxl.c > index 2b64504f9129..2cabafe1fc58 100644 > --- a/arch/powerpc/platforms/powernv/pmem/ocxl.c > +++ b/arch/powerpc/platforms/powernv/pmem/ocxl.c > @@ -640,6 +640,124 @@ static int ioctl_error_log(struct ocxlpmem *ocxlp= mem, > return 0; > } > =20 > +static int ioctl_controller_dump_data(struct ocxlpmem *ocxlpmem, > + struct ioctl_ocxl_pmem_controller_dump_data __user *uarg) > +{ > + struct ioctl_ocxl_pmem_controller_dump_data args; > + u16 i; > + u64 val; > + int rc; > + > + if (copy_from_user(&args, uarg, sizeof(args))) > + return -EFAULT; > + > + if (args.buf_size % 8) > + return -EINVAL; > + > + if (args.buf_size > ocxlpmem->admin_command.data_size) > + return -EINVAL; > + > + mutex_lock(&ocxlpmem->admin_command.lock); > + > + rc =3D admin_command_request(ocxlpmem, ADMIN_COMMAND_CONTROLLER_DUMP)= ; > + if (rc) > + goto out; > + > + val =3D ((u64)args.offset) << 32; > + val |=3D args.buf_size; > + rc =3D ocxl_global_mmio_write64(ocxlpmem->ocxl_afu, > + ocxlpmem->admin_command.request_offset + 0x08, > + OCXL_LITTLE_ENDIAN, val); > + if (rc) > + goto out; > + > + rc =3D admin_command_execute(ocxlpmem); > + if (rc) > + goto out; > + > + rc =3D admin_command_complete_timeout(ocxlpmem, > + ADMIN_COMMAND_CONTROLLER_DUMP); > + if (rc < 0) { > + dev_warn(&ocxlpmem->dev, "Controller dump timed out\n"); > + goto out; > + } > + > + rc =3D admin_response(ocxlpmem); > + if (rc < 0) > + goto out; > + if (rc !=3D STATUS_SUCCESS) { > + warn_status(ocxlpmem, > + "Unexpected status from retrieve error log", > + rc); > + goto out; > + } It would help if there was a comment indicating how the 3 ioctls are=20 used. My understanding is that the userland is: - requesting the controller to prepare a state dump - then one or more ioctls to fetch the data. The number of calls=20 required to get the full state really depends on the size of the buffer=20 passed by user - a last ioctl to tell the controller that we're done, presumably to let=20 it free some resources. > + > + for (i =3D 0; i < args.buf_size; i +=3D 8) { > + u64 val; > + > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > + ocxlpmem->admin_command.data_offset + i, > + OCXL_HOST_ENDIAN, &val); > + if (rc) > + goto out; > + > + if (copy_to_user(&args.buf[i], &val, sizeof(u64))) { > + rc =3D -EFAULT; > + goto out; > + } > + } > + > + if (copy_to_user(uarg, &args, sizeof(args))) { > + rc =3D -EFAULT; > + goto out; > + } > + > + rc =3D admin_response_handled(ocxlpmem); > + if (rc) > + goto out; > + > +out: > + mutex_unlock(&ocxlpmem->admin_command.lock); > + return rc; > +} > + > +int request_controller_dump(struct ocxlpmem *ocxlpmem) > +{ > + int rc; > + u64 busy =3D 1; > + > + rc =3D ocxl_global_mmio_set64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_CHIC, > + OCXL_LITTLE_ENDIAN, > + GLOBAL_MMIO_CHI_CDA); > + rc is not checked here. > + > + rc =3D ocxl_global_mmio_set64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_HCI, > + OCXL_LITTLE_ENDIAN, > + GLOBAL_MMIO_HCI_CONTROLLER_DUMP); > + if (rc) > + return rc; > + > + while (busy) { > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > + GLOBAL_MMIO_HCI, > + OCXL_LITTLE_ENDIAN, &busy); > + if (rc) > + return rc; > + > + busy &=3D GLOBAL_MMIO_HCI_CONTROLLER_DUMP; Setting 'busy' doesn't hurt, but it's not really useful, is it? We should add some kind of timeout so that if the controller hits an=20 issue, we don't spin in kernel space endlessly. > + cond_resched(); > + } > + > + return 0; > +} > + > +static int ioctl_controller_dump_complete(struct ocxlpmem *ocxlpmem) > +{ > + return ocxl_global_mmio_set64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_HCI, > + OCXL_LITTLE_ENDIAN, > + GLOBAL_MMIO_HCI_CONTROLLER_DUMP_COLLECTED); > +} > + > static long file_ioctl(struct file *file, unsigned int cmd, unsigned = long args) > { > struct ocxlpmem *ocxlpmem =3D file->private_data; > @@ -650,7 +768,21 @@ static long file_ioctl(struct file *file, unsigned= int cmd, unsigned long args) > rc =3D ioctl_error_log(ocxlpmem, > (struct ioctl_ocxl_pmem_error_log __user *)args); > break; > + > + case IOCTL_OCXL_PMEM_CONTROLLER_DUMP: > + rc =3D request_controller_dump(ocxlpmem); > + break; > + > + case IOCTL_OCXL_PMEM_CONTROLLER_DUMP_DATA: > + rc =3D ioctl_controller_dump_data(ocxlpmem, > + (struct ioctl_ocxl_pmem_controller_dump_data __user *)args); > + break; > + > + case IOCTL_OCXL_PMEM_CONTROLLER_DUMP_COMPLETE: > + rc =3D ioctl_controller_dump_complete(ocxlpmem); > + break; > } > + > return rc; > } > =20 > diff --git a/include/uapi/nvdimm/ocxl-pmem.h b/include/uapi/nvdimm/ocxl= -pmem.h > index b10f8ac0c20f..d4d8512d03f7 100644 > --- a/include/uapi/nvdimm/ocxl-pmem.h > +++ b/include/uapi/nvdimm/ocxl-pmem.h > @@ -38,9 +38,24 @@ struct ioctl_ocxl_pmem_error_log { > __u8 *buf; /* pointer to output buffer */ > }; > =20 > +struct ioctl_ocxl_pmem_controller_dump_data { > + __u8 *buf; /* pointer to output buffer */ We only support 64-bit user app on powerpc, but using a pointer type in=20 a kernel ABI is unusual. We should use a know size like __u64. (also applies to buf pointer in struct ioctl_ocxl_pmem_error_log from=20 previous patch too) The rest of the structure will also be padded by the compiler, which we=20 should avoid. Fred > + __u16 buf_size; /* in/out, buffer size provided/required. > + * If required is greater than provided, the buffer > + * will be truncated to the amount provided. If its > + * less, then only the required bytes will be populated. > + * If it is 0, then there is no more dump data available. > + */ > + __u32 offset; /* in, Offset within the dump */ > + __u64 reserved[8]; > +}; > + > /* ioctl numbers */ > #define OCXL_PMEM_MAGIC 0x5C > /* SCM devices */ > #define IOCTL_OCXL_PMEM_ERROR_LOG _IOWR(OCXL_PMEM_MAGIC, 0x01, stru= ct ioctl_ocxl_pmem_error_log) > +#define IOCTL_OCXL_PMEM_CONTROLLER_DUMP _IO(OCXL_PMEM_MAGIC, 0x02) > +#define IOCTL_OCXL_PMEM_CONTROLLER_DUMP_DATA _IOWR(OCXL_PMEM_MAGIC, 0= x03, struct ioctl_ocxl_pmem_controller_dump_data) > +#define IOCTL_OCXL_PMEM_CONTROLLER_DUMP_COMPLETE _IO(OCXL_PMEM_MAGIC, = 0x04) > =20 > #endif /* _UAPI_OCXL_SCM_H */ >=20