[intel] Avoid spurious compiler warning on GCC 10

GCC 10 produces a spurious warning about an out-of-bounds array access
for the unsized raw dword array in union intelvf_msg.

Avoid the warning by embedding the zero-length array within a struct.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/drivers/net/intelvf.c b/src/drivers/net/intelvf.c
index ac6fea745457863544edf66581380f369bf2adc2..0d48b4178cb5aa0542ba7c507d044ba5546780c0 100644 (file)
--- a/src/drivers/net/intelvf.c
+++ b/src/drivers/net/intelvf.c
@@ -52,14 +52,15 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  */
 static void intelvf_mbox_write ( struct intel_nic *intel,
                                 const union intelvf_msg *msg ) {
+       const struct intelvf_msg_raw *raw = &msg->raw;
        unsigned int i;
 
        /* Write message */
        DBGC2 ( intel, "INTEL %p sending message", intel );
-       for ( i = 0 ; i < ( sizeof ( *msg ) / sizeof ( msg->dword[0] ) ) ; i++){
-               DBGC2 ( intel, "%c%08x", ( i ? ':' : ' ' ), msg->dword[i] );
-               writel ( msg->dword[i], ( intel->regs + intel->mbox.mem +
-                                         ( i * sizeof ( msg->dword[0] ) ) ) );
+       for ( i = 0 ; i < ( sizeof ( *msg ) / sizeof ( raw->dword[0] ) ) ; i++){
+               DBGC2 ( intel, "%c%08x", ( i ? ':' : ' ' ), raw->dword[i] );
+               writel ( raw->dword[i], ( intel->regs + intel->mbox.mem +
+                                         ( i * sizeof ( raw->dword[0] ) ) ) );
        }
        DBGC2 ( intel, "\n" );
 }
@@ -72,14 +73,15 @@ static void intelvf_mbox_write ( struct intel_nic *intel,
  */
 static void intelvf_mbox_read ( struct intel_nic *intel,
                                union intelvf_msg *msg ) {
+       struct intelvf_msg_raw *raw = &msg->raw;
        unsigned int i;
 
        /* Read message */
        DBGC2 ( intel, "INTEL %p received message", intel );
-       for ( i = 0 ; i < ( sizeof ( *msg ) / sizeof ( msg->dword[0] ) ) ; i++){
-               msg->dword[i] = readl ( intel->regs + intel->mbox.mem +
-                                       ( i * sizeof ( msg->dword[0] ) ) );
-               DBGC2 ( intel, "%c%08x", ( i ? ':' : ' ' ), msg->dword[i] );
+       for ( i = 0 ; i < ( sizeof ( *msg ) / sizeof ( raw->dword[0] ) ) ; i++){
+               raw->dword[i] = readl ( intel->regs + intel->mbox.mem +
+                                       ( i * sizeof ( raw->dword[0] ) ) );
+               DBGC2 ( intel, "%c%08x", ( i ? ':' : ' ' ), raw->dword[i] );
        }
        DBGC2 ( intel, "\n" );
 }

diff --git a/src/drivers/net/intelvf.h b/src/drivers/net/intelvf.h
index ab404698fe6de9f48370931fdf5664c1a2569e2e..ffb18e04052f1b4a6fe406f5062c11148873da90 100644 (file)
--- a/src/drivers/net/intelvf.h
+++ b/src/drivers/net/intelvf.h
@@ -119,6 +119,12 @@ struct intelvf_msg_queues {
        uint32_t dflt;
 } __attribute__ (( packed ));
 
+/** Raw mailbox message */
+struct intelvf_msg_raw {
+       /** Raw dwords */
+       uint32_t dword[0];
+} __attribute__ (( packed ));
+
 /** Mailbox message */
 union intelvf_msg {
        /** Message header */
@@ -132,7 +138,7 @@ union intelvf_msg {
        /** Queue configuration message */
        struct intelvf_msg_queues queues;
        /** Raw dwords */
-       uint32_t dword[0];
+       struct intelvf_msg_raw raw;
 };
 
 /** Maximum time to wait for mailbox message