6.6-stable review patch. If anyone has any objections, please let me know.
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From: Nikita Zhandarovich n.zhandarovich@fintech.ru
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@vger.kernel.org Signed-off-by: Nikita Zhandarovich n.zhandarovich@fintech.ru Reviewed-by: Jani Nikula jani.nikula@intel.com Signed-off-by: Jani Nikula jani.nikula@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20240729174035.25727-1-n.zhand... (cherry picked from commit 833cf12846aa19adf9b76bc79c40747726f3c0c1) Signed-off-by: Joonas Lahtinen joonas.lahtinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -1556,7 +1556,7 @@ 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) { @@ -1581,7 +1581,7 @@ 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++) { @@ -1713,7 +1713,7 @@ static int skl_ddi_hdmi_pll_dividers(str
ctrl1 |= DPLL_CTRL1_HDMI_MODE(0);
- 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;