imx_fec: Move Tx frame buffer away from the stack

Make Tx frame assembly buffer to be a paort of IMXFECState structure
to avoid a concern about having large data buffer on the stack.

Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Philippe Mathieu-Daudé <f4bug@amsat.org>
Cc: qemu-devel@nongnu.org
Cc: qemu-arm@nongnu.org
Cc: yurovsky@gmail.com
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

hw/net/imx_fec.c

@@ -405,8 +405,7 @@ static void imx_eth_update(IMXFECState *s)
 static void imx_fec_do_tx(IMXFECState *s)
 {
     int frame_size = 0, descnt = 0;
-    uint8_t frame[ENET_MAX_FRAME_SIZE];
-    uint8_t *ptr = frame;
+    uint8_t *ptr = s->frame;
     uint32_t addr = s->tx_descriptor;
 
     while (descnt++ < IMX_MAX_DESC) {
@@ -431,8 +430,8 @@ static void imx_fec_do_tx(IMXFECState *s)
         frame_size += len;
         if (bd.flags & ENET_BD_L) {
             /* Last buffer in frame.  */
-            qemu_send_packet(qemu_get_queue(s->nic), frame, frame_size);
-            ptr = frame;
+            qemu_send_packet(qemu_get_queue(s->nic), s->frame, frame_size);
+            ptr = s->frame;
             frame_size = 0;
             s->regs[ENET_EIR] |= ENET_INT_TXF;
         }
@@ -456,8 +455,7 @@ static void imx_fec_do_tx(IMXFECState *s)
 static void imx_enet_do_tx(IMXFECState *s)
 {
     int frame_size = 0, descnt = 0;
-    uint8_t frame[ENET_MAX_FRAME_SIZE];
-    uint8_t *ptr = frame;
+    uint8_t *ptr = s->frame;
     uint32_t addr = s->tx_descriptor;
 
     while (descnt++ < IMX_MAX_DESC) {
@@ -482,13 +480,13 @@ static void imx_enet_do_tx(IMXFECState *s)
         frame_size += len;
         if (bd.flags & ENET_BD_L) {
             if (bd.option & ENET_BD_PINS) {
-                struct ip_header *ip_hd = PKT_GET_IP_HDR(frame);
+                struct ip_header *ip_hd = PKT_GET_IP_HDR(s->frame);
                 if (IP_HEADER_VERSION(ip_hd) == 4) {
-                    net_checksum_calculate(frame, frame_size);
+                    net_checksum_calculate(s->frame, frame_size);
                 }
             }
             if (bd.option & ENET_BD_IINS) {
-                struct ip_header *ip_hd = PKT_GET_IP_HDR(frame);
+                struct ip_header *ip_hd = PKT_GET_IP_HDR(s->frame);
                 /* We compute checksum only for IPv4 frames */
                 if (IP_HEADER_VERSION(ip_hd) == 4) {
                     uint16_t csum;
@@ -498,8 +496,10 @@ static void imx_enet_do_tx(IMXFECState *s)
                 }
             }
             /* Last buffer in frame.  */
-            qemu_send_packet(qemu_get_queue(s->nic), frame, len);
-            ptr = frame;
+
+            qemu_send_packet(qemu_get_queue(s->nic), s->frame, len);
+            ptr = s->frame;
+
             frame_size = 0;
             if (bd.option & ENET_BD_TX_INT) {
                 s->regs[ENET_EIR] |= ENET_INT_TXF;

include/hw/net/imx_fec.h

@@ -252,6 +252,9 @@ typedef struct IMXFECState {
     uint32_t phy_int_mask;
 
     bool is_fec;
+
+    /* Buffer used to assemble a Tx frame */
+    uint8_t frame[ENET_MAX_FRAME_SIZE];
 } IMXFECState;
 
 #endif