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drm/i915: Fix potential overflows in ilk ips calculations

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A bunch of the ips calculations require 64bit math. In particular
'corr' and 'corr2' look like they can overflow on 32bit systems.
Switch to explicit u64 for those.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201021131443.25616-3-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
This commit is contained in:
Ville Syrjälä 2020-10-21 16:14:41 +03:00
parent e82351e74d
commit d08c4e2327
1 changed files with 5 additions and 5 deletions
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10
drivers/gpu/drm/i915/gt/intel_rps.c
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@ -1281,8 +1281,9 @@ static unsigned long __ips_gfx_val(struct intel_ips *ips)
{
struct intel_rps *rps = container_of(ips, typeof(*rps), ips);
struct intel_uncore *uncore = rps_to_uncore(rps);
unsigned long t, corr, state1, corr2, state2;
unsigned int t, state1, state2;
u32 pxvid, ext_v;
u64 corr, corr2;
lockdep_assert_held(&mchdev_lock);
@ -1303,11 +1304,10 @@ static unsigned long __ips_gfx_val(struct intel_ips *ips)
else /* < 50 */
corr = t * 301 + 1004;
corr = corr * 150142 * state1 / 10000 - 78642;
corr /= 100000;
corr2 = corr * ips->corr;
corr = div_u64(corr * 150142 * state1, 10000) - 78642;
corr2 = div_u64(corr, 100000) * ips->corr;
state2 = corr2 * state1 / 10000;
state2 = div_u64(corr2 * state1, 10000);
state2 /= 100; /* convert to mW */
__gen5_ips_update(ips);