From: Peter Maydell <peter.maydell@linaro.org>
Date: Fri, 16 Oct 2015 16:19:35 +0000 (+0100)
Subject: hw/ide/ahci.c: Fix shift left into sign bit
X-Git-Tag: v2.5.0-rc0~69
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=40fe17bea478793fc9106a630fa3610dad51f939;p=thirdparty%2Fqemu.git

hw/ide/ahci.c: Fix shift left into sign bit

Avoid undefined behaviour from shifting left into the sign bit:

hw/ide/ahci.c:551:36: runtime error: left shift of 255 by 24 places cannot be represented in type 'int'

(Unfortunately C's promotion rules mean that in the expression
"some_uint8_t_variable << 24" the LHS gets promoted to signed
int before shifting.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: John Snow <jsnow@redhat.com>
---

diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index 796be156353..21f76ed86e4 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -548,7 +548,7 @@ static void ahci_init_d2h(AHCIDevice *ad)
         ad->init_d2h_sent = true;
         /* We're emulating receiving the first Reg H2D Fis from the device;
          * Update the SIG register, but otherwise proceed as normal. */
-        pr->sig = (ide_state->hcyl << 24) |
+        pr->sig = ((uint32_t)ide_state->hcyl << 24) |
             (ide_state->lcyl << 16) |
             (ide_state->sector << 8) |
             (ide_state->nsector & 0xFF);