Commit 6dd0e5cc authored by Alison Schofield's avatar Alison Schofield Committed by Dan Williams
Browse files

cxl/mbox: Move cxl_mem_command construction to helper funcs 



Sanitizing and constructing a cxl_mem_command from a userspace
command is part of the validation process prior to submitting
the command to a CXL device. Move this work to helper functions:
cxl_to_mem_cmd(), cxl_to_mem_cmd_raw().

This declutters cxl_validate_cmd_from_user() in preparation for
adding new validation steps.

Signed-off-by: default avatarAlison Schofield <alison.schofield@intel.com>
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/7d9b826f29262e3a484cb4bb7b63872134d60bd7.1648687552.git.alison.schofield@intel.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent ce522ba9

drivers/cxl/core/mbox.c

+76 −71
Original line number Diff line number Diff line
@@ -207,58 +207,10 @@ static bool cxl_mem_raw_command_allowed(u16 opcode) 
	return true;

}



/**

 * cxl_validate_cmd_from_user() - Check fields for CXL_MEM_SEND_COMMAND.

 * @cxlds: The device data for the operation

 * @send_cmd: &struct cxl_send_command copied in from userspace.

 * @out_cmd: Sanitized and populated &struct cxl_mem_command.

 *

 * Return:

 *  * %0	- @out_cmd is ready to send.

 *  * %-ENOTTY	- Invalid command specified.

 *  * %-EINVAL	- Reserved fields or invalid values were used.

 *  * %-ENOMEM	- Input or output buffer wasn't sized properly.

 *  * %-EPERM	- Attempted to use a protected command.

 *  * %-EBUSY	- Kernel has claimed exclusive access to this opcode

 *

 * The result of this command is a fully validated command in @out_cmd that is

 * safe to send to the hardware.

 *

 * See handle_mailbox_cmd_from_user()

 */

static int cxl_validate_cmd_from_user(struct cxl_dev_state *cxlds,

static int cxl_to_mem_cmd_raw(struct cxl_mem_command *mem_cmd,

			      const struct cxl_send_command *send_cmd,

				      struct cxl_mem_command *out_cmd)

			      struct cxl_dev_state *cxlds)

{

	const struct cxl_command_info *info;

	struct cxl_mem_command *c;



	if (send_cmd->id == 0 || send_cmd->id >= CXL_MEM_COMMAND_ID_MAX)

		return -ENOTTY;



	/*

	 * The user can never specify an input payload larger than what hardware

	 * supports, but output can be arbitrarily large (simply write out as

	 * much data as the hardware provides).

	 */

	if (send_cmd->in.size > cxlds->payload_size)

		return -EINVAL;



	/*

	 * Checks are bypassed for raw commands but a WARN/taint will occur

	 * later in the callchain

	 */

	if (send_cmd->id == CXL_MEM_COMMAND_ID_RAW) {

		const struct cxl_mem_command temp = {

			.info = {

				.id = CXL_MEM_COMMAND_ID_RAW,

				.flags = 0,

				.size_in = send_cmd->in.size,

				.size_out = send_cmd->out.size,

			},

			.opcode = send_cmd->raw.opcode

		};



	if (send_cmd->raw.rsvd)

		return -EINVAL;
@@ -273,11 +225,25 @@ static int cxl_validate_cmd_from_user(struct cxl_dev_state *cxlds, 
	if (!cxl_mem_raw_command_allowed(send_cmd->raw.opcode))

		return -EPERM;



		memcpy(out_cmd, &temp, sizeof(temp));

	*mem_cmd = (struct cxl_mem_command) {

		.info = {

			.id = CXL_MEM_COMMAND_ID_RAW,

			.size_in = send_cmd->in.size,

			.size_out = send_cmd->out.size,

		},

		.opcode = send_cmd->raw.opcode

	};



	return 0;

}



static int cxl_to_mem_cmd(struct cxl_mem_command *mem_cmd,

			  const struct cxl_send_command *send_cmd,

			  struct cxl_dev_state *cxlds)

{

	struct cxl_mem_command *c = &cxl_mem_commands[send_cmd->id];

	const struct cxl_command_info *info = &c->info;



	if (send_cmd->flags & ~CXL_MEM_COMMAND_FLAG_MASK)

		return -EINVAL;
@@ -287,10 +253,6 @@ static int cxl_validate_cmd_from_user(struct cxl_dev_state *cxlds, 
	if (send_cmd->in.rsvd || send_cmd->out.rsvd)

		return -EINVAL;



	/* Convert user's command into the internal representation */

	c = &cxl_mem_commands[send_cmd->id];

	info = &c->info;



	/* Check that the command is enabled for hardware */

	if (!test_bit(info->id, cxlds->enabled_cmds))

		return -ENOTTY;
@@ -307,15 +269,58 @@ static int cxl_validate_cmd_from_user(struct cxl_dev_state *cxlds, 
	if (info->size_out >= 0 && send_cmd->out.size < info->size_out)

		return -ENOMEM;



	memcpy(out_cmd, c, sizeof(*c));

	out_cmd->info.size_in = send_cmd->in.size;

	*mem_cmd = (struct cxl_mem_command) {

		.info = {

			.id = info->id,

			.flags = info->flags,

			.size_in = send_cmd->in.size,

			.size_out = send_cmd->out.size,

		},

		.opcode = c->opcode

	};



	return 0;

}



/**

 * cxl_validate_cmd_from_user() - Check fields for CXL_MEM_SEND_COMMAND.

 * @cxlds: The device data for the operation

 * @send_cmd: &struct cxl_send_command copied in from userspace.

 * @out_cmd: Sanitized and populated &struct cxl_mem_command.

 *

 * Return:

 *  * %0	- @out_cmd is ready to send.

 *  * %-ENOTTY	- Invalid command specified.

 *  * %-EINVAL	- Reserved fields or invalid values were used.

 *  * %-ENOMEM	- Input or output buffer wasn't sized properly.

 *  * %-EPERM	- Attempted to use a protected command.

 *  * %-EBUSY	- Kernel has claimed exclusive access to this opcode

 *

 * The result of this command is a fully validated command in @out_cmd that is

 * safe to send to the hardware.

 *

 * See handle_mailbox_cmd_from_user()

 */

static int cxl_validate_cmd_from_user(struct cxl_dev_state *cxlds,

				      const struct cxl_send_command *send_cmd,

				      struct cxl_mem_command *out_cmd)

{

	if (send_cmd->id == 0 || send_cmd->id >= CXL_MEM_COMMAND_ID_MAX)

		return -ENOTTY;



	/*

	 * XXX: out_cmd->info.size_out will be controlled by the driver, and the

	 * specified number of bytes @send_cmd->out.size will be copied back out

	 * to userspace.

	 * The user can never specify an input payload larger than what hardware

	 * supports, but output can be arbitrarily large (simply write out as

	 * much data as the hardware provides).

	 */

	if (send_cmd->in.size > cxlds->payload_size)

		return -EINVAL;



	return 0;

	/* Sanitize and construct a cxl_mem_command */

	if (send_cmd->id == CXL_MEM_COMMAND_ID_RAW)

		return cxl_to_mem_cmd_raw(out_cmd, send_cmd, cxlds);

	else

		return cxl_to_mem_cmd(out_cmd, send_cmd, cxlds);

}



int cxl_query_cmd(struct cxl_memdev *cxlmd,