Em Qua, 2018-09-12 às 09:31 -0500, Gustavo A. R. Silva escreveu: > Function intel_port_to_tc() returns PORT_TC_NONE on error, which is > a negative value -1. In case PORT_TC_NONE is returned, there is an > undefined behavior when shifting by a negative number of bits in > both DP_PHY_MODE_STATUS_NOT_SAFE and P_PHY_MODE_STATUS_COMPLETED > macros. > > Fix this by adding sanity checks on intel_port_to_tc return value, > before > using macros DP_PHY_MODE_STATUS_NOT_SAFE and > P_PHY_MODE_STATUS_COMPLETED. This was just discussed yesterday in a patch by Rodrigo: https://patchwork.freedesktop.org/patch/246903/ I would personally prefer his version because it avoids passing -1 to register macros that Coverity doesn't seem to care about, it's a single check and it prints WARN() instead of DRM_DEBUG_KMS(). Although I do prefer your commit message explanation :). Perhaps I should reconsider my vote to not merge it. Or we could actually go and test what happens when intel_port_to_tc() is broken, fixing all the issues instead of just the ones reported by Coverity. Anyway, Rodrigo's patch with an improved commit message could receive my R-B tag now. > > Addresses-Coverity-ID: 1473324 ("Bad bit shift operation") > Addresses-Coverity-ID: 1473325 ("Bad bit shift operation") > Fixes: 39d1e234e1e1 ("drm/i915/icl: implement the tc/legacy HPD > {dis,}connect flows") > Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_dp.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/gpu/drm/i915/intel_dp.c > b/drivers/gpu/drm/i915/intel_dp.c > index 436c22d..e34b7b1 100644 > --- a/drivers/gpu/drm/i915/intel_dp.c > +++ b/drivers/gpu/drm/i915/intel_dp.c > @@ -4811,6 +4811,11 @@ static bool icl_tc_phy_connect(struct > drm_i915_private *dev_priv, > dig_port->tc_type != TC_PORT_TYPEC) > return true; > > + if (tc_port < 0) { > + DRM_DEBUG_KMS("Bad TC port %d\n", tc_port); > + return false; > + } > + > val = I915_READ(PORT_TX_DFLEXDPPMS); > if (!(val & DP_PHY_MODE_STATUS_COMPLETED(tc_port))) { > DRM_DEBUG_KMS("DP PHY for TC port %d not ready\n", > tc_port); > @@ -4857,6 +4862,10 @@ static void icl_tc_phy_disconnect(struct > drm_i915_private *dev_priv, > dig_port->tc_type != TC_PORT_TYPEC) > return; > > + if (tc_port < 0) { > + DRM_DEBUG_KMS("Bad TC port %d\n", tc_port); > + return; > + } > /* > * This function may be called many times in a row without > an HPD event > * in between, so try to avoid the write when we can. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
