cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

cq_desc.h (2516B)

      1/*
      2 * Copyright 2008-2010 Cisco Systems, Inc.  All rights reserved.
      3 * Copyright 2007 Nuova Systems, Inc.  All rights reserved.
      4 *
      5 * This program is free software; you may redistribute it and/or modify
      6 * it under the terms of the GNU General Public License as published by
      7 * the Free Software Foundation; version 2 of the License.
      8 *
      9 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     10 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     11 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     12 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
     13 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
     14 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     15 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     16 * SOFTWARE.
     17 *
     18 */
     19
     20#ifndef _CQ_DESC_H_
     21#define _CQ_DESC_H_
     22
     23/*
     24 * Completion queue descriptor types
     25 */
     26enum cq_desc_types {
     27	CQ_DESC_TYPE_WQ_ENET = 0,
     28	CQ_DESC_TYPE_DESC_COPY = 1,
     29	CQ_DESC_TYPE_WQ_EXCH = 2,
     30	CQ_DESC_TYPE_RQ_ENET = 3,
     31	CQ_DESC_TYPE_RQ_FCP = 4,
     32};
     33
     34/* Completion queue descriptor: 16B
     35 *
     36 * All completion queues have this basic layout.  The
     37 * type_specfic area is unique for each completion
     38 * queue type.
     39 */
     40struct cq_desc {
     41	__le16 completed_index;
     42	__le16 q_number;
     43	u8 type_specfic[11];
     44	u8 type_color;
     45};
     46
     47#define CQ_DESC_TYPE_BITS        4
     48#define CQ_DESC_TYPE_MASK        ((1 << CQ_DESC_TYPE_BITS) - 1)
     49#define CQ_DESC_COLOR_MASK       1
     50#define CQ_DESC_COLOR_SHIFT      7
     51#define CQ_DESC_Q_NUM_BITS       10
     52#define CQ_DESC_Q_NUM_MASK       ((1 << CQ_DESC_Q_NUM_BITS) - 1)
     53#define CQ_DESC_COMP_NDX_BITS    12
     54#define CQ_DESC_COMP_NDX_MASK    ((1 << CQ_DESC_COMP_NDX_BITS) - 1)
     55
     56static inline void cq_desc_dec(const struct cq_desc *desc_arg,
     57	u8 *type, u8 *color, u16 *q_number, u16 *completed_index)
     58{
     59	const struct cq_desc *desc = desc_arg;
     60	const u8 type_color = desc->type_color;
     61
     62	*color = (type_color >> CQ_DESC_COLOR_SHIFT) & CQ_DESC_COLOR_MASK;
     63
     64	/*
     65	 * Make sure color bit is read from desc *before* other fields
     66	 * are read from desc.  Hardware guarantees color bit is last
     67	 * bit (byte) written.  Adding the rmb() prevents the compiler
     68	 * and/or CPU from reordering the reads which would potentially
     69	 * result in reading stale values.
     70	 */
     71
     72	rmb();
     73
     74	*type = type_color & CQ_DESC_TYPE_MASK;
     75	*q_number = le16_to_cpu(desc->q_number) & CQ_DESC_Q_NUM_MASK;
     76	*completed_index = le16_to_cpu(desc->completed_index) &
     77		CQ_DESC_COMP_NDX_MASK;
     78}
     79
     80#endif /* _CQ_DESC_H_ */