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From: Andy Green <andy@warmcat.com>
To: dev@dpdk.org
Subject: [dpdk-dev] [PATCH v4 04/18] bus/dpaa: solve inconsistent struct alignment
Date: Fri, 11 May 2018 09:45:35 +0800	[thread overview]
Message-ID: <152600313586.53146.7523419645550338762.stgit@localhost.localdomain> (raw)
In-Reply-To: <152600304856.53146.9681482138854493833.stgit@localhost.localdomain>

The actual descriptor for qm_mr_entry is 64-byte aligned.

But the original code plays a trick, and puts a u8 common
to the three descriptor subtypes in the union afterwards
outside their structure definitions.

Unfortunately since they compose a struct qm_fd with
alignment 8, this trick destroys the ability of the compiler
to understand what has happened, resulting in this kind of
problem:

/home/agreen/projects/dpdk/drivers/bus/dpaa/include/
fsl_qman.h:354:3: error: alignment 1 of ‘struct <anonymous>’
is less than 8 [-Werror=packed-not-aligned]
   } __packed dcern;

on gcc 8 / Fedora 28 out of the box.

This patch moves the u8 verb into the structure definitions
composed into the union, so the alignment of the parent struct
containing the alignment 8 object can also be seen to be
alignment 8 by the compiler.  Uses of .verb are fixed up to use
.ern.verb (the same offset of +0 inside all the structs in
the union).

The final struct layout should be unchanged.

Signed-off-by: Andy Green <andy@warmcat.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Tested-by: Hemant Agrawal <hemant.agrawal@nxp.com>
---
 drivers/bus/dpaa/base/qbman/qman.c  |   14 +++++++-------
 drivers/bus/dpaa/include/fsl_qman.h |   24 +++++++++++++-----------
 2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/drivers/bus/dpaa/base/qbman/qman.c b/drivers/bus/dpaa/base/qbman/qman.c
index 2810fdd26..27d98cc10 100644
--- a/drivers/bus/dpaa/base/qbman/qman.c
+++ b/drivers/bus/dpaa/base/qbman/qman.c
@@ -314,9 +314,9 @@ static int drain_mr_fqrni(struct qm_portal *p)
 		if (!msg)
 			return 0;
 	}
-	if ((msg->verb & QM_MR_VERB_TYPE_MASK) != QM_MR_VERB_FQRNI) {
+	if ((msg->ern.verb & QM_MR_VERB_TYPE_MASK) != QM_MR_VERB_FQRNI) {
 		/* We aren't draining anything but FQRNIs */
-		pr_err("Found verb 0x%x in MR\n", msg->verb);
+		pr_err("Found verb 0x%x in MR\n", msg->ern.verb);
 		return -1;
 	}
 	qm_mr_next(p);
@@ -483,7 +483,7 @@ static inline void qm_mr_pvb_update(struct qm_portal *portal)
 	/* when accessing 'verb', use __raw_readb() to ensure that compiler
 	 * inlining doesn't try to optimise out "excess reads".
 	 */
-	if ((__raw_readb(&res->verb) & QM_MR_VERB_VBIT) == mr->vbit) {
+	if ((__raw_readb(&res->ern.verb) & QM_MR_VERB_VBIT) == mr->vbit) {
 		mr->pi = (mr->pi + 1) & (QM_MR_SIZE - 1);
 		if (!mr->pi)
 			mr->vbit ^= QM_MR_VERB_VBIT;
@@ -832,7 +832,7 @@ static u32 __poll_portal_slow(struct qman_portal *p, u32 is)
 			goto mr_done;
 		swapped_msg = *msg;
 		hw_fd_to_cpu(&swapped_msg.ern.fd);
-		verb = msg->verb & QM_MR_VERB_TYPE_MASK;
+		verb = msg->ern.verb & QM_MR_VERB_TYPE_MASK;
 		/* The message is a software ERN iff the 0x20 bit is set */
 		if (verb & 0x20) {
 			switch (verb) {
@@ -1666,7 +1666,7 @@ int qman_retire_fq(struct qman_fq *fq, u32 *flags)
 			 */
 			struct qm_mr_entry msg;
 
-			msg.verb = QM_MR_VERB_FQRNI;
+			msg.ern.verb = QM_MR_VERB_FQRNI;
 			msg.fq.fqs = mcr->alterfq.fqs;
 			msg.fq.fqid = fq->fqid;
 #ifdef CONFIG_FSL_QMAN_FQ_LOOKUP
@@ -2643,7 +2643,7 @@ int qman_shutdown_fq(u32 fqid)
 				qm_mr_pvb_update(low_p);
 				msg = qm_mr_current(low_p);
 				while (msg) {
-					if ((msg->verb &
+					if ((msg->ern.verb &
 					     QM_MR_VERB_TYPE_MASK)
 					    == QM_MR_VERB_FQRN)
 						found_fqrn = 1;
@@ -2711,7 +2711,7 @@ int qman_shutdown_fq(u32 fqid)
 			qm_mr_pvb_update(low_p);
 			msg = qm_mr_current(low_p);
 			while (msg) {
-				if ((msg->verb & QM_MR_VERB_TYPE_MASK) ==
+				if ((msg->ern.verb & QM_MR_VERB_TYPE_MASK) ==
 				    QM_MR_VERB_FQRL)
 					orl_empty = 1;
 				qm_mr_next(low_p);
diff --git a/drivers/bus/dpaa/include/fsl_qman.h b/drivers/bus/dpaa/include/fsl_qman.h
index e9793f30d..e4ad7ae48 100644
--- a/drivers/bus/dpaa/include/fsl_qman.h
+++ b/drivers/bus/dpaa/include/fsl_qman.h
@@ -284,20 +284,20 @@ static inline dma_addr_t qm_sg_addr(const struct qm_sg_entry *sg)
 	} while (0)
 
 /* See 1.5.8.1: "Enqueue Command" */
-struct qm_eqcr_entry {
+struct __rte_aligned(8) qm_eqcr_entry {
 	u8 __dont_write_directly__verb;
 	u8 dca;
 	u16 seqnum;
 	u32 orp;	/* 24-bit */
 	u32 fqid;	/* 24-bit */
 	u32 tag;
-	struct qm_fd fd;
+	struct qm_fd fd; /* this has alignment 8 */
 	u8 __reserved3[32];
 } __packed;
 
 
 /* "Frame Dequeue Response" */
-struct qm_dqrr_entry {
+struct __rte_aligned(8) qm_dqrr_entry {
 	u8 verb;
 	u8 stat;
 	u16 seqnum;	/* 15-bit */
@@ -305,7 +305,7 @@ struct qm_dqrr_entry {
 	u8 __reserved2[3];
 	u32 fqid;	/* 24-bit */
 	u32 contextB;
-	struct qm_fd fd;
+	struct qm_fd fd; /* this has alignment 8 */
 	u8 __reserved4[32];
 };
 
@@ -323,18 +323,19 @@ struct qm_dqrr_entry {
 /* "ERN Message Response" */
 /* "FQ State Change Notification" */
 struct qm_mr_entry {
-	u8 verb;
 	union {
 		struct {
+			u8 verb;
 			u8 dca;
 			u16 seqnum;
 			u8 rc;		/* Rejection Code */
 			u32 orp:24;
 			u32 fqid;	/* 24-bit */
 			u32 tag;
-			struct qm_fd fd;
-		} __packed ern;
+			struct qm_fd fd; /* this has alignment 8 */
+		} __packed __rte_aligned(8) ern;
 		struct {
+			u8 verb;
 #if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
 			u8 colour:2;	/* See QM_MR_DCERN_COLOUR_* */
 			u8 __reserved1:4;
@@ -349,18 +350,19 @@ struct qm_mr_entry {
 			u32 __reserved3:24;
 			u32 fqid;	/* 24-bit */
 			u32 tag;
-			struct qm_fd fd;
-		} __packed dcern;
+			struct qm_fd fd; /* this has alignment 8 */
+		} __packed __rte_aligned(8) dcern;
 		struct {
+			u8 verb;
 			u8 fqs;		/* Frame Queue Status */
 			u8 __reserved1[6];
 			u32 fqid;	/* 24-bit */
 			u32 contextB;
 			u8 __reserved2[16];
-		} __packed fq;		/* FQRN/FQRNI/FQRL/FQPN */
+		} __packed __rte_aligned(8) fq;	/* FQRN/FQRNI/FQRL/FQPN */
 	};
 	u8 __reserved2[32];
-} __packed;
+} __packed __rte_aligned(8);
 #define QM_MR_VERB_VBIT			0x80
 /*
  * ERNs originating from direct-connect portals ("dcern") use 0x20 as a verb

  parent reply	other threads:[~2018-05-11  1:45 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-11  1:45 [dpdk-dev] [PATCH v4 00/18] Fix default build on gcc8.0.1 Andy Green
2018-05-11  1:45 ` [dpdk-dev] [PATCH v4 01/18] devtools/check-git: provide more generic grep pattern Andy Green
2018-05-11  8:11   ` De Lara Guarch, Pablo
2018-05-11  1:45 ` [dpdk-dev] [PATCH v4 02/18] net/nfp: solve buffer overflow Andy Green
2018-05-11  8:58   ` De Lara Guarch, Pablo
2018-05-11 10:13   ` De Lara Guarch, Pablo
2018-05-11  1:45 ` [dpdk-dev] [PATCH v4 03/18] bus/pci: replace strncpy dangerous code Andy Green
2018-05-11  8:17   ` De Lara Guarch, Pablo
2018-05-11  1:45 ` Andy Green [this message]
2018-05-11  8:26   ` [dpdk-dev] [PATCH v4 04/18] bus/dpaa: solve inconsistent struct alignment De Lara Guarch, Pablo
2018-05-11  1:45 ` [dpdk-dev] [PATCH v4 05/18] net/axgbe: solve broken eeprom string comp Andy Green
2018-05-11 10:09   ` De Lara Guarch, Pablo
2018-05-11  1:45 ` [dpdk-dev] [PATCH v4 06/18] net/nfp/nfpcore: solve strncpy misuse Andy Green
2018-05-11 10:26   ` De Lara Guarch, Pablo
2018-05-11  1:45 ` [dpdk-dev] [PATCH v4 07/18] net/nfp/nfpcore: off-by-one and no NUL on strncpy use Andy Green
2018-05-11 10:33   ` De Lara Guarch, Pablo
2018-05-12  1:17     ` Andy Green
2018-05-11  1:45 ` [dpdk-dev] [PATCH v4 08/18] net/nfp: don't memcpy out of source range Andy Green
2018-05-11 10:36   ` De Lara Guarch, Pablo
2018-05-11  1:46 ` [dpdk-dev] [PATCH v4 09/18] net/qede: strncpy length constant and NUL Andy Green
2018-05-11 10:43   ` De Lara Guarch, Pablo
2018-05-11 10:48     ` Andy Green
2018-05-11 12:48       ` De Lara Guarch, Pablo
2018-05-11 13:38         ` Andy Green
2018-05-11 15:14           ` De Lara Guarch, Pablo
2018-05-11 17:13         ` Shaikh, Shahed
2018-05-11  1:46 ` [dpdk-dev] [PATCH v4 10/18] net/qede: solve broken strncpy Andy Green
2018-05-11 10:47   ` De Lara Guarch, Pablo
2018-05-11  1:46 ` [dpdk-dev] [PATCH v4 11/18] net/sfc: correct strncpy length Andy Green
2018-05-11  8:11   ` Andrew Rybchenko
2018-05-11 10:51   ` De Lara Guarch, Pablo
2018-05-12  1:21     ` Andy Green
2018-05-11  1:46 ` [dpdk-dev] [PATCH v4 12/18] net/sfc: solve strncpy size and NUL Andy Green
2018-05-11  8:13   ` Andrew Rybchenko
2018-05-11 10:55   ` De Lara Guarch, Pablo
2018-05-12  1:24     ` Andy Green
2018-05-11  1:46 ` [dpdk-dev] [PATCH v4 13/18] net/vdev_netvsc: readlink inputs cannot be aliased Andy Green
2018-05-11 15:39   ` De Lara Guarch, Pablo
2018-05-11  1:46 ` [dpdk-dev] [PATCH v4 14/18] net/vdev_netvsc: 3 x strncpy misuse Andy Green
2018-05-11 10:58   ` De Lara Guarch, Pablo
2018-05-11  1:46 ` [dpdk-dev] [PATCH v4 15/18] app: can't find include Andy Green
2018-05-11 11:04   ` De Lara Guarch, Pablo
2018-05-11 11:12     ` Andy Green
2018-05-11 13:20       ` De Lara Guarch, Pablo
2018-05-12  0:52         ` Andy Green
2018-05-11  1:46 ` [dpdk-dev] [PATCH v4 16/18] app/proc-info: sprintf overrun bug Andy Green
2018-05-11 12:26   ` De Lara Guarch, Pablo
2018-05-12  1:33     ` Andy Green
2018-05-11  1:46 ` [dpdk-dev] [PATCH v4 17/18] app/test-bbdev: strcpy ok for allocated string Andy Green
2018-05-11 12:55   ` De Lara Guarch, Pablo
2018-05-11  1:46 ` [dpdk-dev] [PATCH v4 18/18] " Andy Green
2018-05-11 13:02   ` De Lara Guarch, Pablo
2018-05-12  1:39     ` Andy Green
2018-05-11 11:14 ` [dpdk-dev] [PATCH v4 00/18] Fix default build on gcc8.0.1 Neil Horman

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