[Qemu-devel] [PATCH] hw/dma/omap_dma: Fix bugs with DMA requests above 32

[Qemu-devel] [PATCH] hw/dma/omap_dma: Fix bugs with DMA requests above 32

[Peter Maydell]

The drqbmp field of struct soc_dma_s is a uint64_t; however several
places in the code attempt to set bits in it using "(1 << drq)",
which will fail if drq is large enough that the 1 bit gets shifted
off the top of a 32 bit integer.  Change these to "(1ULL << drq)" so
that the promotion to 64 bit happens before the shift rather than
afterwards.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
Another bug spotted by clang (while running 'make check', in this case.)

 hw/dma/omap_dma.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/hw/dma/omap_dma.c b/hw/dma/omap_dma.c
index 184fcee..26ba988 100644
--- a/hw/dma/omap_dma.c
+++ b/hw/dma/omap_dma.c
@@ -248,7 +248,7 @@ static void omap_dma_deactivate_channel(struct omap_dma_s *s,
 
     /* Don't deactive the channel if it is synchronized and the DMA request is
        active */
-    if (ch->sync && ch->enable && (s->dma->drqbmp & (1 << ch->sync)))
+    if (ch->sync && ch->enable && (s->dma->drqbmp & (1ULL << ch->sync)))
         return;
 
     if (ch->active) {
@@ -268,8 +268,9 @@ static void omap_dma_enable_channel(struct omap_dma_s *s,
         /* TODO: theoretically if ch->sync && ch->prefetch &&
          * !s->dma->drqbmp[ch->sync], we should also activate and fetch
          * from source and then stall until signalled.  */
-        if ((!ch->sync) || (s->dma->drqbmp & (1 << ch->sync)))
+        if ((!ch->sync) || (s->dma->drqbmp & (1ULL << ch->sync))) {
             omap_dma_activate_channel(s, ch);
+        }
     }
 }
 
@@ -1551,12 +1552,12 @@ static void omap_dma_request(void *opaque, int drq, int req)
     struct omap_dma_s *s = (struct omap_dma_s *) opaque;
     /* The request pins are level triggered in QEMU.  */
     if (req) {
-        if (~s->dma->drqbmp & (1 << drq)) {
-            s->dma->drqbmp |= 1 << drq;
+        if (~s->dma->drqbmp & (1ULL << drq)) {
+            s->dma->drqbmp |= 1ULL << drq;
             omap_dma_process_request(s, drq);
         }
     } else
-        s->dma->drqbmp &= ~(1 << drq);
+        s->dma->drqbmp &= ~(1ULL << drq);
 }
 
 /* XXX: this won't be needed once soc_dma knows about clocks.  */
-- 
1.7.9.5