| Message ID | 20210929175134.15808-1-tim.gardner@canonical.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | drm/msm/dsi: prevent unintentional integer overflow in dsi_pll_28nm_clk_recalc_rate() | expand |
On 29/09/2021 20:51, Tim Gardner wrote: > Coverity warns of an unintentional integer overflow > > CID 120715 (#1 of 1): Unintentional integer overflow (OVERFLOW_BEFORE_WIDEN) > overflow_before_widen: Potentially overflowing expression ref_clk * sdm_byp_div > with type unsigned int (32 bits, unsigned) is evaluated using 32-bit arithmetic, > and then used in a context that expects an expression of type unsigned long > (64 bits, unsigned). > To avoid overflow, cast either ref_clk or sdm_byp_div to type unsigned long. > 263 vco_rate = ref_clk * sdm_byp_div; > > Fix this and another possible overflow by casting ref_clk to unsigned long. Changing ref_clk from u32 to unsigned long would be a more simple and elegant way of fixing this issue. Could you please update your patch? > > Cc: Rob Clark <robdclark@gmail.com> > Cc: Sean Paul <sean@poorly.run> > Cc: David Airlie <airlied@linux.ie> > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > Cc: Abhinav Kumar <abhinavk@codeaurora.org> > Cc: linux-arm-msm@vger.kernel.org > Cc: dri-devel@lists.freedesktop.org > Cc: freedreno@lists.freedesktop.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Tim Gardner <tim.gardner@canonical.com> > --- > drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c > index 2da673a2add6..cfe4b30eb96d 100644 > --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c > +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c > @@ -260,7 +260,7 @@ static unsigned long dsi_pll_28nm_clk_recalc_rate(struct clk_hw *hw, > sdm_byp_div = FIELD( > dsi_phy_read(base + REG_DSI_28nm_PHY_PLL_SDM_CFG0), > DSI_28nm_PHY_PLL_SDM_CFG0_BYP_DIV) + 1; > - vco_rate = ref_clk * sdm_byp_div; > + vco_rate = (unsigned long)ref_clk * sdm_byp_div; > } else { > /* sdm mode */ > sdm_dc_off = FIELD( > @@ -274,7 +274,7 @@ static unsigned long dsi_pll_28nm_clk_recalc_rate(struct clk_hw *hw, > sdm_freq_seed = (sdm3 << 8) | sdm2; > DBG("sdm_freq_seed = %d", sdm_freq_seed); > > - vco_rate = (ref_clk * (sdm_dc_off + 1)) + > + vco_rate = ((unsigned long)ref_clk * (sdm_dc_off + 1)) + > mult_frac(ref_clk, sdm_freq_seed, BIT(16)); > DBG("vco rate = %lu", vco_rate); > } >
diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c index 2da673a2add6..cfe4b30eb96d 100644 --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c @@ -260,7 +260,7 @@ static unsigned long dsi_pll_28nm_clk_recalc_rate(struct clk_hw *hw, sdm_byp_div = FIELD( dsi_phy_read(base + REG_DSI_28nm_PHY_PLL_SDM_CFG0), DSI_28nm_PHY_PLL_SDM_CFG0_BYP_DIV) + 1; - vco_rate = ref_clk * sdm_byp_div; + vco_rate = (unsigned long)ref_clk * sdm_byp_div; } else { /* sdm mode */ sdm_dc_off = FIELD( @@ -274,7 +274,7 @@ static unsigned long dsi_pll_28nm_clk_recalc_rate(struct clk_hw *hw, sdm_freq_seed = (sdm3 << 8) | sdm2; DBG("sdm_freq_seed = %d", sdm_freq_seed); - vco_rate = (ref_clk * (sdm_dc_off + 1)) + + vco_rate = ((unsigned long)ref_clk * (sdm_dc_off + 1)) + mult_frac(ref_clk, sdm_freq_seed, BIT(16)); DBG("vco rate = %lu", vco_rate); }
Coverity warns of an unintentional integer overflow CID 120715 (#1 of 1): Unintentional integer overflow (OVERFLOW_BEFORE_WIDEN) overflow_before_widen: Potentially overflowing expression ref_clk * sdm_byp_div with type unsigned int (32 bits, unsigned) is evaluated using 32-bit arithmetic, and then used in a context that expects an expression of type unsigned long (64 bits, unsigned). To avoid overflow, cast either ref_clk or sdm_byp_div to type unsigned long. 263 vco_rate = ref_clk * sdm_byp_div; Fix this and another possible overflow by casting ref_clk to unsigned long. Cc: Rob Clark <robdclark@gmail.com> Cc: Sean Paul <sean@poorly.run> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Cc: Abhinav Kumar <abhinavk@codeaurora.org> Cc: linux-arm-msm@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: freedreno@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Tim Gardner <tim.gardner@canonical.com> --- drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)