Date:	Tue, 5 Apr 2016 12:36:40 +0200
From:	Gabriel Laskar <gabriel@....epita.fr>
To:	Alexandre Bounine <alexandre.bounine@....com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Matt Porter <mporter@...nel.crashing.org>,
	Aurelien Jacquiot <a-jacquiot@...com>,
	Andre van Herk <andre.van.herk@...drive-technologies.com>,
	Barry Wood <barry.wood@....com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 30/30] rapidio: add mport char device driver

Hi,

The userland api for this seems a bit dangerous, here are my first
comments

On Fri, Feb 05, 2016 at 06:19:46PM -0500, Alexandre Bounine wrote:
> Add mport character device driver to provide user space interface
> to basic RapidIO subsystem operations.
> See included Documentation/rapidio/mport_cdev.txt for more details.
> 
> Signed-off-by: Alexandre Bounine <alexandre.bounine@....com>
> Tested-by: Barry Wood <barry.wood@....com>
> Cc: Matt Porter <mporter@...nel.crashing.org>
> Cc: Aurelien Jacquiot <a-jacquiot@...com>
> Cc: Andre van Herk <andre.van.herk@...drive-technologies.com>
> Cc: Barry Wood <barry.wood@....com>
> Cc: linux-kernel@...r.kernel.org
> ---
>  Documentation/rapidio/mport_cdev.txt     |  104 ++
>  drivers/rapidio/Kconfig                  |    8 +
>  drivers/rapidio/devices/Makefile         |    1 +
>  drivers/rapidio/devices/rio_mport_cdev.c | 2711 ++++++++++++++++++++++++++++++
>  include/linux/rio_mport_cdev.h           |  271 +++
>  include/uapi/linux/Kbuild                |    1 +
>  6 files changed, 3096 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/rapidio/mport_cdev.txt
>  create mode 100644 drivers/rapidio/devices/rio_mport_cdev.c
>  create mode 100644 include/linux/rio_mport_cdev.h 

[...]

> diff --git a/include/linux/rio_mport_cdev.h b/include/linux/rio_mport_cdev.h
> new file mode 100644
> index 0000000..b65d19d
> --- /dev/null
> +++ b/include/linux/rio_mport_cdev.h
> @@ -0,0 +1,271 @@
> +/*
> + * Copyright (c) 2015-2016, Integrated Device Technology Inc.
> + * Copyright (c) 2015, Prodrive Technologies
> + * Copyright (c) 2015, Texas Instruments Incorporated
> + * Copyright (c) 2015, RapidIO Trade Association
> + * All rights reserved.
> + *
> + * This software is available to you under a choice of one of two licenses.
> + * You may choose to be licensed under the terms of the GNU General Public
> + * License(GPL) Version 2, or the BSD-3 Clause license below:
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions are met:
> + *
> + * 1. Redistributions of source code must retain the above copyright notice,
> + * this list of conditions and the following disclaimer.
> + *
> + * 2. Redistributions in binary form must reproduce the above copyright notice,
> + * this list of conditions and the following disclaimer in the documentation
> + * and/or other materials provided with the distribution.
> + *
> + * 3. Neither the name of the copyright holder nor the names of its contributors
> + * may be used to endorse or promote products derived from this software without
> + * specific prior written permission.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
> + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
> + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
> + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
> + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
> + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
> + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
> + * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
> + * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
> + * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
> + * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> + */
> +
> +#ifndef _RIO_MPORT_CDEV_H_
> +#define _RIO_MPORT_CDEV_H_


> +
> +#ifndef __user
> +#define __user
> +#endif

this will be stripped by headers_install

> +
> +struct rio_mport_maint_io {
> +	uint32_t rioid;		/* destID of remote device */
> +	uint32_t hopcount;	/* hopcount to remote device */
> +	uint32_t offset;	/* offset in register space */

there is a 4 bytes hole here (x86_64)

> +	size_t length;		/* length in bytes */
> +	void __user *buffer;	/* data buffer */
> +};

stdint types should not be used in kernel headers, it should use __u32
instead (and appropriate ones for the others)

size_t should not be used either, prefer __kernel_size_t. Also, this
will probably be broken on 32bit compat mode on 64bit kernels (size_t
would be 4 bytes in userland and 8 in kernel), this will need
compat_ioctl. Maybe use the right size should be better.

> +
> +/*
> + * Definitions for RapidIO data transfers:
> + * - memory mapped (MAPPED)
> + * - packet generation from memory (TRANSFER)
> + */
> +#define RIO_TRANSFER_MODE_MAPPED	(1 << 0)
> +#define RIO_TRANSFER_MODE_TRANSFER	(1 << 1)
> +#define RIO_CAP_DBL_SEND		(1 << 2)
> +#define RIO_CAP_DBL_RECV		(1 << 3)
> +#define RIO_CAP_PW_SEND			(1 << 4)
> +#define RIO_CAP_PW_RECV			(1 << 5)
> +#define RIO_CAP_MAP_OUTB		(1 << 6)
> +#define RIO_CAP_MAP_INB			(1 << 7)
> +
> +struct rio_mport_properties {
> +	uint16_t hdid;
> +	uint8_t id;			/* Physical port ID */
> +	uint8_t  index;
> +	uint32_t flags;
> +	uint32_t sys_size;		/* Default addressing size */
> +	uint8_t  port_ok;
> +	uint8_t  link_speed;
> +	uint8_t  link_width;

There is a 1 byte hole on x86_64 here (checked with pahole).

> +	uint32_t dma_max_sge;
> +	uint32_t dma_max_size;
> +	uint32_t dma_align;
> +	uint32_t transfer_mode;		/* Default transfer mode */
> +	uint32_t cap_sys_size;		/* Capable system sizes */
> +	uint32_t cap_addr_size;		/* Capable addressing sizes */
> +	uint32_t cap_transfer_mode;	/* Capable transfer modes */
> +	uint32_t cap_mport;		/* Mport capabilities */
> +};
> +
> +/*
> + * Definitions for RapidIO events;
> + * - incoming port-writes
> + * - incoming doorbells
> + */
> +#define RIO_DOORBELL	(1 << 0)
> +#define RIO_PORTWRITE	(1 << 1)
> +
> +struct rio_doorbell {
> +	uint32_t rioid;
> +	uint16_t payload;
> +};
> +
> +struct rio_doorbell_filter {
> +	uint32_t rioid;			/* 0xffffffff to match all ids */
> +	uint16_t low;
> +	uint16_t high;
> +};
> +
> +
> +struct rio_portwrite {
> +	uint32_t payload[16];
> +};
> +
> +struct rio_pw_filter {
> +	uint32_t mask;
> +	uint32_t low;
> +	uint32_t high;
> +};
> +
> +/* RapidIO base address for inbound requests set to value defined below
> + * indicates that no specific RIO-to-local address translation is requested
> + * and driver should use direct (one-to-one) address mapping.
> +*/
> +#define RIO_MAP_ANY_ADDR	(uint64_t)(~((uint64_t) 0))
> +
> +struct rio_mmap {
> +	uint32_t rioid;

And there is hole here too.

Maybe there is more, I have just checked the entry points of the ioctl
requests.

> +	uint64_t rio_addr;
> +	uint64_t length;
> +	uint64_t handle;
> +	void *address;
> +};
> +
> +struct rio_dma_mem {
> +	uint64_t length;		/* length of DMA memory */
> +	uint64_t dma_handle;		/* handle associated with this memory */
> +	void *buffer;			/* pointer to this memory */
> +};
> +
> +
> +struct rio_event {
> +	unsigned int header;	/* event type RIO_DOORBELL or RIO_PORTWRITE */
> +	union {
> +		struct rio_doorbell doorbell;	/* header for RIO_DOORBELL */
> +		struct rio_portwrite portwrite; /* header for RIO_PORTWRITE */
> +	} u;
> +};
> +
> +enum rio_transfer_sync {
> +	RIO_TRANSFER_SYNC,	/* synchronous transfer */
> +	RIO_TRANSFER_ASYNC,	/* asynchronous transfer */
> +	RIO_TRANSFER_FAF,	/* fire-and-forget transfer */
> +};
> +
> +enum rio_transfer_dir {
> +	RIO_TRANSFER_DIR_READ,	/* Read operation */
> +	RIO_TRANSFER_DIR_WRITE,	/* Write operation */
> +};
> +
> +/*
> + * RapidIO data exchange transactions are lists of individual transfers. Each
> + * transfer exchanges data between two RapidIO devices by remote direct memory
> + * access and has its own completion code.
> + *
> + * The RapidIO specification defines four types of data exchange requests:
> + * NREAD, NWRITE, SWRITE and NWRITE_R. The RapidIO DMA channel interface allows
> + * to specify the required type of write operation or combination of them when
> + * only the last data packet requires response.
> + *
> + * NREAD:    read up to 256 bytes from remote device memory into local memory
> + * NWRITE:   write up to 256 bytes from local memory to remote device memory
> + *           without confirmation
> + * SWRITE:   as NWRITE, but all addresses and payloads must be 64-bit aligned
> + * NWRITE_R: as NWRITE, but expect acknowledgment from remote device.
> + *
> + * The default exchange is chosen from NREAD and any of the WRITE modes as the
> + * driver sees fit. For write requests the user can explicitly choose between
> + * any of the write modes for each transaction.
> + */
> +enum rio_exchange {
> +	RIO_EXCHANGE_DEFAULT,	/* Default method */
> +	RIO_EXCHANGE_NWRITE,	/* All packets using NWRITE */
> +	RIO_EXCHANGE_SWRITE,	/* All packets using SWRITE */
> +	RIO_EXCHANGE_NWRITE_R,	/* Last packet NWRITE_R, others NWRITE */
> +	RIO_EXCHANGE_SWRITE_R,	/* Last packet NWRITE_R, others SWRITE */
> +	RIO_EXCHANGE_NWRITE_R_ALL, /* All packets using NWRITE_R */
> +};
> +
> +struct rio_transfer_io {
> +	uint32_t rioid;			/* Target destID */
> +	uint64_t rio_addr;		/* Address in target's RIO mem space */
> +	enum rio_exchange method;	/* Data exchange method */
> +	void __user *loc_addr;
> +	uint64_t handle;
> +	uint64_t offset;		/* Offset in buffer */
> +	uint64_t length;		/* Length in bytes */
> +	uint32_t completion_code;	/* Completion code for this transfer */
> +};
> +
> +struct rio_transaction {
> +	uint32_t transfer_mode;		/* Data transfer mode */
> +	enum rio_transfer_sync sync;	/* Synchronization method */
> +	enum rio_transfer_dir dir;	/* Transfer direction */
> +	size_t count;			/* Number of transfers */
> +	struct rio_transfer_io __user *block;	/* Array of <count> transfers */
> +};
> +
> +struct rio_async_tx_wait {
> +	uint32_t token;		/* DMA transaction ID token */
> +	uint32_t timeout;	/* Wait timeout in msec, if 0 use default TO */
> +};
> +
> +#define RIO_MAX_DEVNAME_SZ	20
> +
> +struct rio_rdev_info {
> +	uint32_t destid;
> +	uint8_t hopcount;
> +	uint32_t comptag;
> +	char name[RIO_MAX_DEVNAME_SZ + 1];
> +};
> +
> +/* Driver IOCTL codes */
> +#define RIO_MPORT_DRV_MAGIC           'm'
> +
> +#define RIO_MPORT_MAINT_HDID_SET	\
> +	_IOW(RIO_MPORT_DRV_MAGIC, 1, uint16_t)
> +#define RIO_MPORT_MAINT_COMPTAG_SET	\
> +	_IOW(RIO_MPORT_DRV_MAGIC, 2, uint32_t)
> +#define RIO_MPORT_MAINT_PORT_IDX_GET	\
> +	_IOR(RIO_MPORT_DRV_MAGIC, 3, uint32_t)
> +#define RIO_MPORT_GET_PROPERTIES \
> +	_IOR(RIO_MPORT_DRV_MAGIC, 4, struct rio_mport_properties)
> +#define RIO_MPORT_MAINT_READ_LOCAL \
> +	_IOR(RIO_MPORT_DRV_MAGIC, 5, struct rio_mport_maint_io)
> +#define RIO_MPORT_MAINT_WRITE_LOCAL \
> +	_IOW(RIO_MPORT_DRV_MAGIC, 6, struct rio_mport_maint_io)
> +#define RIO_MPORT_MAINT_READ_REMOTE \
> +	_IOR(RIO_MPORT_DRV_MAGIC, 7, struct rio_mport_maint_io)
> +#define RIO_MPORT_MAINT_WRITE_REMOTE \
> +	_IOW(RIO_MPORT_DRV_MAGIC, 8, struct rio_mport_maint_io)
> +#define RIO_ENABLE_DOORBELL_RANGE	\
> +	_IOW(RIO_MPORT_DRV_MAGIC, 9, struct rio_doorbell_filter)
> +#define RIO_DISABLE_DOORBELL_RANGE	\
> +	_IOW(RIO_MPORT_DRV_MAGIC, 10, struct rio_doorbell_filter)
> +#define RIO_ENABLE_PORTWRITE_RANGE	\
> +	_IOW(RIO_MPORT_DRV_MAGIC, 11, struct rio_pw_filter)
> +#define RIO_DISABLE_PORTWRITE_RANGE	\
> +	_IOW(RIO_MPORT_DRV_MAGIC, 12, struct rio_pw_filter)
> +#define RIO_SET_EVENT_MASK		\
> +	_IOW(RIO_MPORT_DRV_MAGIC, 13, unsigned int)
> +#define RIO_GET_EVENT_MASK		\
> +	_IOR(RIO_MPORT_DRV_MAGIC, 14, unsigned int)
> +#define RIO_MAP_OUTBOUND \
> +	_IOWR(RIO_MPORT_DRV_MAGIC, 15, struct rio_mmap)
> +#define RIO_UNMAP_OUTBOUND \
> +	_IOW(RIO_MPORT_DRV_MAGIC, 16, struct rio_mmap)
> +#define RIO_MAP_INBOUND \
> +	_IOWR(RIO_MPORT_DRV_MAGIC, 17, struct rio_mmap)
> +#define RIO_UNMAP_INBOUND \
> +	_IOW(RIO_MPORT_DRV_MAGIC, 18, uint64_t)
> +#define RIO_ALLOC_DMA \
> +	_IOWR(RIO_MPORT_DRV_MAGIC, 19, struct rio_dma_mem)
> +#define RIO_FREE_DMA \
> +	_IOW(RIO_MPORT_DRV_MAGIC, 20, uint64_t)
> +#define RIO_TRANSFER \
> +	_IOWR(RIO_MPORT_DRV_MAGIC, 21, struct rio_transaction)
> +#define RIO_WAIT_FOR_ASYNC \
> +	_IOW(RIO_MPORT_DRV_MAGIC, 22, struct rio_async_tx_wait)
> +#define RIO_DEV_ADD \
> +	_IOW(RIO_MPORT_DRV_MAGIC, 23, struct rio_rdev_info)
> +#define RIO_DEV_DEL \
> +	_IOW(RIO_MPORT_DRV_MAGIC, 24, struct rio_rdev_info)
> +
> +#endif /* _RIO_MPORT_CDEV_H_ */
> diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
> index ebd10e6..d3dc8ca 100644
> --- a/include/uapi/linux/Kbuild
> +++ b/include/uapi/linux/Kbuild
> @@ -352,6 +352,7 @@ header-y += reiserfs_fs.h
>  header-y += reiserfs_xattr.h
>  header-y += resource.h
>  header-y += rfkill.h
> +header-y += rio_mport_cdev.h
>  header-y += romfs_fs.h
>  header-y += rose.h
>  header-y += route.h

If this is a public header, it should belong in include/uapi/linux
instead of include/linux

-- 
Gabriel Laskar

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