bus/dpaa: fix inconsistent struct alignment

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:

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.

Fixes: c47ff048b99a ("bus/dpaa: add QMAN driver core routines")
Fixes: f6fadc3e6310 ("bus/dpaa: add QMAN interface driver")
Cc: stable@dpdk.org
Signed-off-by: Andy Green <andy@warmcat.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Tested-by: Hemant Agrawal <hemant.agrawal@nxp.com>

diff --git a/drivers/bus/dpaa/base/qbman/qman.c b/drivers/bus/dpaa/base/qbman/qman.c
index 2810fdd..27d98cc 100644 (file)
--- a/drivers/bus/dpaa/base/qbman/qman.c
+++ b/drivers/bus/dpaa/base/qbman/qman.c
@@ -314,9 +314,9 @@ loop:
                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 @@ mr_loop:
                        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 e9793f3..e4ad7ae 100644 (file)
--- 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