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Subject: Re: [PATCH v3 24/27] powerpc/powernv/pmem: Expose SMART data via
 ndctl
To:     "Alastair D'Silva" <alastair@au1.ibm.com>, alastair@d-silva.org
Cc:     "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
        "Oliver O'Halloran" <oohall@gmail.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Frederic Barrat <fbarrat@linux.ibm.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Vishal Verma <vishal.l.verma@intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Rob Herring <robh@kernel.org>,
        Anton Blanchard <anton@ozlabs.org>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>,
        Madhavan Srinivasan <maddy@linux.vnet.ibm.com>,
        =?UTF-8?Q?C=c3=a9dric_Le_Goater?= <clg@kaod.org>,
        Anju T Sudhakar <anju@linux.vnet.ibm.com>,
        Hari Bathini <hbathini@linux.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Greg Kurz <groug@kaod.org>,
        Nicholas Piggin <npiggin@gmail.com>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Alexey Kardashevskiy <aik@ozlabs.ru>,
        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>
 <20200221032720.33893-25-alastair@au1.ibm.com>
From:   Andrew Donnellan <ajd@linux.ibm.com>
Date:   Thu, 5 Mar 2020 14:36:13 +1100
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On 21/2/20 2:27 pm, Alastair D'Silva wrote:
> +static int ndctl_smart(struct ocxlpmem *ocxlpmem, struct nd_cmd_pkg *pkg)
> +{
> +	u32 length, i;
> +	struct nd_ocxl_smart *out;
> +	int rc;
> +
> +	mutex_lock(&ocxlpmem->admin_command.lock);
> +
> +	rc = admin_command_request(ocxlpmem, ADMIN_COMMAND_SMART);
> +	if (rc)
> +		goto out;
> +
> +	rc = admin_command_execute(ocxlpmem);
> +	if (rc)
> +		goto out;
> +
> +	rc = admin_command_complete_timeout(ocxlpmem, ADMIN_COMMAND_SMART);
> +	if (rc < 0) {
> +		dev_err(&ocxlpmem->dev, "SMART timeout\n");
> +		goto out;
> +	}
> +
> +	rc = admin_response(ocxlpmem);
> +	if (rc < 0)
> +		goto out;
> +	if (rc != STATUS_SUCCESS) {
> +		warn_status(ocxlpmem, "Unexpected status from SMART", rc);
> +		goto out;
> +	}
> +
> +	rc = smart_header_parse(ocxlpmem, &length);
> +	if (rc)
> +		goto out;
> +
> +	pkg->nd_fw_size = length;
> +
> +	length = min(length, pkg->nd_size_out); // bytes
> +	out = (struct nd_ocxl_smart *)pkg->nd_payload;
> +	// Each SMART attribute is 2 * 64 bits
> +	out->count = length / (2 * sizeof(u64)); // attributes

 From what I can tell - 8 bytes of nd_ocxl_smart are taken up for the 
count + reserved bytes, so this is going to potentially overrun the user 
buffer.

> +
> +	for (i = 0; i < length; i += sizeof(u64)) {

It might be neater to make i count up by 1 and then multiply by 
sizeof(u64) later.

> +		rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
> +					     ocxlpmem->admin_command.data_offset + sizeof(u64) + i,

+ 0x08 rather than + sizeof(u64) for consistency.

> +					     OCXL_LITTLE_ENDIAN,
> +					     &out->attribs[i/sizeof(u64)]);
> +		if (rc)
> +			goto out;
> +	}
> +
> +	rc = admin_response_handled(ocxlpmem);
> +	if (rc)
> +		goto out;
> +
> +	rc = 0;
> +	goto out;
> +
> +out:
> +	mutex_unlock(&ocxlpmem->admin_command.lock);
> +	return rc;
> +}
> +
> +static int ndctl_call(struct ocxlpmem *ocxlpmem, void *buf, unsigned int buf_len)
> +{
> +	struct nd_cmd_pkg *pkg = buf;
> +
> +	if (buf_len < sizeof(struct nd_cmd_pkg)) {
> +		dev_err(&ocxlpmem->dev, "Invalid ND_CALL size=%u\n", buf_len);
> +		return -EINVAL;
> +	}
> +
> +	if (pkg->nd_family != NVDIMM_FAMILY_OCXL) {
> +		dev_err(&ocxlpmem->dev, "Invalid ND_CALL family=0x%llx\n", pkg->nd_family);
> +		return -EINVAL;
> +	}
> +
> +	switch (pkg->nd_command) {
> +	case ND_CMD_OCXL_SMART:
> +		ndctl_smart(ocxlpmem, pkg);

Did you intend to dispose of the return code here?

> +		break;
> +
> +	default:
> +		dev_err(&ocxlpmem->dev, "Invalid ND_CALL command=0x%llx\n", pkg->nd_command);
> +		return -EINVAL;
> +	}
> +
> +
> +	return 0;
> +}
> +
>   static int ndctl(struct nvdimm_bus_descriptor *nd_desc,
>   		 struct nvdimm *nvdimm,
>   		 unsigned int cmd, void *buf, unsigned int buf_len, int *cmd_rc)
> @@ -88,6 +211,10 @@ static int ndctl(struct nvdimm_bus_descriptor *nd_desc,
>   	struct ocxlpmem *ocxlpmem = container_of(nd_desc, struct ocxlpmem, bus_desc);
>   
>   	switch (cmd) {
> +	case ND_CMD_CALL:
> +		*cmd_rc = ndctl_call(ocxlpmem, buf, buf_len);
> +		return 0;
> +
>   	case ND_CMD_GET_CONFIG_SIZE:
>   		*cmd_rc = ndctl_config_size(buf);
>   		return 0;
> @@ -171,6 +298,7 @@ static int register_lpc_mem(struct ocxlpmem *ocxlpmem)
>   	set_bit(ND_CMD_GET_CONFIG_SIZE, &nvdimm_cmd_mask);
>   	set_bit(ND_CMD_GET_CONFIG_DATA, &nvdimm_cmd_mask);
>   	set_bit(ND_CMD_SET_CONFIG_DATA, &nvdimm_cmd_mask);
> +	set_bit(ND_CMD_CALL, &nvdimm_cmd_mask);
>   
>   	set_bit(NDD_ALIASING, &nvdimm_flags);
>   
> diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
> index 927690f4888f..0eb7a35d24ae 100644
> --- a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
> +++ b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
> @@ -7,6 +7,7 @@
>   #include <linux/libnvdimm.h>
>   #include <uapi/nvdimm/ocxl-pmem.h>
>   #include <linux/mm.h>
> +#include <linux/ndctl.h>
>   
>   #define LABEL_AREA_SIZE	(1UL << PA_SECTION_SHIFT)
>   #define DEFAULT_TIMEOUT 100
> @@ -98,6 +99,23 @@ struct ocxlpmem_function0 {
>   	struct ocxl_fn *ocxl_fn;
>   };
>   
> +struct nd_ocxl_smart {
> +	__u8 count;
> +	__u8 reserved[7];
> +	__u64 attribs[0];
> +} __packed;
> +
> +struct nd_pkg_ocxl {
> +	struct nd_cmd_pkg gen;
> +	union {
> +		struct nd_ocxl_smart smart;
> +	};
> +};
> +
> +enum nd_cmd_ocxl {
> +	ND_CMD_OCXL_SMART = 1,
> +};
> +
>   struct ocxlpmem {
>   	struct device dev;
>   	struct pci_dev *pdev;
> diff --git a/include/uapi/linux/ndctl.h b/include/uapi/linux/ndctl.h
> index de5d90212409..2885052e7f40 100644
> --- a/include/uapi/linux/ndctl.h
> +++ b/include/uapi/linux/ndctl.h
> @@ -244,6 +244,7 @@ struct nd_cmd_pkg {
>   #define NVDIMM_FAMILY_HPE2 2
>   #define NVDIMM_FAMILY_MSFT 3
>   #define NVDIMM_FAMILY_HYPERV 4
> +#define NVDIMM_FAMILY_OCXL 6
>   
>   #define ND_IOCTL_CALL			_IOWR(ND_IOCTL, ND_CMD_CALL,\
>   					struct nd_cmd_pkg)
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd@linux.ibm.com             IBM Australia Limited