6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>
commit 5b511572660190db1dc8ba412efd0be0d3781ab6 upstream.
On the off chance that clock value ends up being too high (by means
of skl_ddi_calculate_wrpll() having been called with big enough
value of crtc_state->port_clock * 1000), one possible consequence
may be that the result will not be able to fit into signed int.
Fix this issue by moving conversion of clock parameter from kHz to Hz
into the body of skl_ddi_calculate_wrpll(), as well as casting the
same parameter to u64 type while calculating the value for AFE clock.
This both mitigates the overflow problem and avoids possible erroneous
integer promotion mishaps.
Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.
Fixes: 82d354370189 ("drm/i915/skl: Implementation of SKL DPLL programming")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20240729174035.25727-1-n.zhandarovich@xxxxxxxxxx
(cherry picked from commit 833cf12846aa19adf9b76bc79c40747726f3c0c1)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_dpll_mgr.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
+++ b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
@@ -1658,7 +1658,7 @@ static void skl_wrpll_params_populate(st
}
static int
-skl_ddi_calculate_wrpll(int clock /* in Hz */,
+skl_ddi_calculate_wrpll(int clock,
int ref_clock,
struct skl_wrpll_params *wrpll_params)
{
@@ -1683,7 +1683,7 @@ skl_ddi_calculate_wrpll(int clock /* in
};
unsigned int dco, d, i;
unsigned int p0, p1, p2;
- u64 afe_clock = clock * 5; /* AFE Clock is 5x Pixel clock */
+ u64 afe_clock = (u64)clock * 1000 * 5; /* AFE Clock is 5x Pixel clock, in Hz */
for (d = 0; d < ARRAY_SIZE(dividers); d++) {
for (dco = 0; dco < ARRAY_SIZE(dco_central_freq); dco++) {
@@ -1808,7 +1808,7 @@ static int skl_ddi_hdmi_pll_dividers(str
struct skl_wrpll_params wrpll_params = {};
int ret;
- ret = skl_ddi_calculate_wrpll(crtc_state->port_clock * 1000,
+ ret = skl_ddi_calculate_wrpll(crtc_state->port_clock,
i915->display.dpll.ref_clks.nssc, &wrpll_params);
if (ret)
return ret;
